012319   Yadav J K S;Giri R K;Malik D K (India Meteorological Dep, , New Delhi-110 003, Email: jksmet@gmail.com) : Effect of broadcast and precise satellite orbits in the estimation of zenith tropospheric delay and integrated precipitable water vapour from GPS. Mausam 2010, 61(2), 197-202.

Global Positioning System (GPS) estimates the total delay in zenith direction by the propagation delay of the neutral atmosphere in presence of water vapour present in the troposphere. This total delay has been treated as a nuisance parameter for many years by the geodesists. The above delay have two parts dry delay and wet delay and known as Zenith Hydrostatic Delay (ZHD) and Zenith Wet Delay (ZWD) respectively. The Integrated Precipitable Water Vapour (IPWV) is estimated through ZWD overlying the receiver at ground-based station. The accuracy of the above said estimates depends on the quality of the predicted satellite orbits, which are not the same for each individual satellite. India Meteorological Department (IMD) is operationally estimating the IPWV on near real time basis at five places and matches fairly well (error <126>6.7 mm) with Radisonde (RS) data. This paper examine the effect of International GPS Service (IGS) predicted precise orbits and near real time predicted rapid or broadcast orbits supplied by the Scripps Orbit and Permanent Array Center (SOPAC) on Zenith Total Delay (ZTD) and IPWV estimates by calculating the mean Bias and Root Mean Square Error (RMSE) for ZTD and IPWV in mm for all the five stations. The observed bias for ZTD is almost of the order of less than 1 mm in most cases and RMSE is less than 6 mm. Similarly the bias observed in the case of derived IPWV is almost negligible and RMSE is less than 1 mm.

15 illus, 2 tables, 12 ref

012318   Vethamony P;Babu M T (NO, National Institute of Oceanography, Dona Paula, Goa-403 004) : Physical processes in the gulf of Kachchh: a review. Indian J Geomar Sci 2010, 39(4), 497-503.

A brief review of various physical processes acting in the Gulf of Kachchh (GoK), which have prominent roles in Gulf dynamics, is presented in this article. The eddies present in the GoK confirm that they are permanent features of the GoK circulation. Accurate estimation of residual currents and eddies in an active industrial coastal zone like the Gulf of Kachchh is important because of its potential applications with respect to discharge of pollutants. Though GoK is considered as a well-mixed system, recent studies revealed that only the central Gulf is well mixed. Stratification in temperature and salinity is noticed in the eastern Gulf, where a cold and high saline tongue is observed in the subsurface layers. Model results indicated the effect of seasonally changing winds the circulation. During southwest monsoon, the predominant westerly winds enhance the flood currents by about 20% and reduce the ebb currents significantly. In spite of semi-arid climate and lack of major rivers flowing into it, the Gulf is highly turbid with suspended sediment concentrations (SSC) during October-November 2002 ranging between 0.5 mg l^-1 and 674 mg l^-1.

5 illus, 1 table, 17 ref

012317   Unnikrishnan A S (National Institute of Oceanography, Dona Paula, Goa-403 004, Email: unni@nio.org) : Tidal propagation off the central west coast of India. Indian J Geomar Sci 2010, 39(4), 485-8.

The study reviews the characteristics of tidal propagation on the continental shelf off the central west coast of India. Available observations from tide gauges are used to describe the variations of tidal ranges along the west coast. Amplitudes and phases from a global tidal model in the open ocean and those at the coast are used to construct co-amplitude and co-phase lines of M₂ and K₁ which are the largest among the semi-diurnal and diurnal constituents respectively. One of the characteristic features off the central west coast of India, particularly north of Mumbai, is the amplification of semi-diurnal constituents caused primarily by large width of the continental shelf in the region.

4 illus, 15 ref

012316   Swain J;Umesh P A;Harikrishnan M (NO, Naval Physical & Oceanographic Laboratory, Kochi-682 021, Email: tsonpal@vsnl.com) : Role of oceanography in naval defence. Indian J Geomar Sci 2010, 39(4), 631-45.

The study of oceans is an essential aspect from strategic, economic and ocean engineering points of view. Recent advancements in SONAR (Sound Navigation and Ranging) technology for under water applications including naval defence demand a clear understanding of the sound propagation in the ocean which is vital for detection of a target. As compared to deep waters, the detection in coastal waters is relatively a challenging task. Detection becomes still complex in the littoral waters. To ensure success in these highly complex oceanic regions, high resolution descriptions/predictions of past, current and future conditions (hindcast, nowcast and forecast) as well the analysis of open ocean, coastal, and nearshore/littoral zones around the Indian continent is an essential pre-requisite. At any given situation, the detection and discrimination of an underwater target is highly dependant on the propagation characteristics of the medium, the surface and bottom boundaries, leaving apart the efficiency of the SONAR system and the type of the target. It can be either a SONAR performance model or an operational model for tactical warfare; one has to have the predicted sound speed for the 3-dimensional ocean environment concerned since it is not always feasible to depend only on measurements. There are on-going programs of collecting and analyzing ocean and atmospheric data and a wide range of research and development activities, some of which are reviewed/presented in this paper with typical examples. In addition to in-situ measurements, significant progress has been achieved in India by demonstrating the utility of satellite based remote sensing data for oceanographic research and applications. By utilizing the existing and on-going experimental data from the regions of interest, it has become feasible for implementation of an integrated "Naval Operational Ocean Prediction System" consisting of wave, tide, circulation and internal wave models. The ocean environmental information predicted by these ocean models shall provide necessary inputs to the SONAR range prediction models for routine operational use, tactical operations and simulating warfare scenarios.

15 illus, 45 ref

012315   Suresh M;Gurugnanam B;Vasudevan S;Ramesh D; Lingeswara Rao S V (Earth Sciences Dep, Geographic Information Technology Lab, Annamalai Univ, Tamil Nadu, Email: gurugis@yahoo.co.in) : GIScience in exploring groundwater studies at upper thirumanimuthar sub-basin, Cauvery river, Tamil Nadu, India. Ultra Scient phys Sci 2009, 21(1), 51-62.

GIS is a powerful tools in analysing the multiple thematic maps at a time. GIS analysis is carried out in the present study to locate favorable groundwater potential zones. To do this subsurface investigation and its interpretation were carried out through geophysical survey. Forty seven vertical electrical soundings (VES) survey were carried out in the study area. The field data were interpreted by curve matching techniques and RESIST software is used to determine the resistivity and thickness of the different layers. By using conventional GIS method, the spatial distribution maps for weathered zone resistivity and its thickness were prepared. Integration of the said themes was done it in GIS. The out put combinations are 4 of Excellent, Very good, Good and Medium groundwater potential zones were derived, and it is designated as output map-1 (groundwater potential zone map). This map was superposed over groundwater fluctuation map. The derived final result map designated as suitable sites for artificial recharge area. From the final out put area as Excellent, Very good, Good and Medium zones were recommended of this locations suitable sites for artificial recharge structures will be constructed. Other aquifer properties, coefficient of anisotropy varies from 1.02 to 2.40 and longitudinal conductance varies from 0.07 to 0.5 mhos. These values indicate the hardness and compaction of rocks. It is evidenced by low permeability and porosity of the study area.

4 illus, 5 tables, 12 ref

012314   Sundar V;Anand K V (Ocean Engineering Dep, Indian Institute of Technology Madras, Chennai, Email: vsundar@iitm.ac.in ) : Dynamic pressure and run-up on curved seawalls compared with vertical wall under cnoidal waves. Indian J Geomar Sci 2010, 39(4), 579-88.

Seawalls are the most widely adopted coastal protection measure. The design of an efficient seawall should be such that overtopping is minimized even during coastal flooding and extreme events by maintaining its crest elevation lower. This may possibly be achieved by reshaping the front shape of the structure in such a way that it offers maximum resistance to the flow or enhances the dissipation of incident wave energy. With this background, an experimental study on the measurement of run-up and dynamic pressures over three different types of curved front face seawall models along with a vertical seawall was carried out. The measured parameters for the three types of curved seawalls are compared with that for a vertical seawall. All the tests were carried out with the models rigidly fixed over a bed slope of 1 in 30 in a wave flume and subjected to the action of Cnoidal waves. The dynamic pressure distributions measured along the surface and the run-up over the models are reported in a dimensionless form as a function of relative water depth and ursell parameter. The details of the test facility, models, experimental program, results and analysis are presented and discussed.

9 illus, 9 ref

012313   Sukumaran P V (Marine and Coastal Surveys Div, Geological Survey of India, Mangalore, Email: ddgmarinemanglore@rediffmail.com) : Marine sand resources in the south-west continental shelf of India. Indian J Geomar Sci 2010, 39(4), 572-8.

Considering the impending shortage of construction material, the Marine and Coastal Surveys Division of the GSI, Mangalore has been in the look out for marine sand in the territorial waters and EEZ of the western offshore of India since the early nineteen nineties. Though sandy sediments were identified at many locations on the shelf and slope during several cruises, it was during two of the GSI's cruises on board R.V. Samudra Shaudhikama, (SD-153 and SD-160 off Kollam, 1998-2000) that a detailed assessment of the distribution of construction sand was made. So far the GSI has executed five cruises exclusively for exploring construction sand off the West Coast. Out of these, two cruises off Kollam have indicated probable sand reserves of 184 million tonnes over an area of 180 sq km to a depth of 1.5 m down from the seafloor and located 25-40 km away from the coast. The data of the other cruises identified the occurrence of sand deposits off Kannur (267 million tonnes over an area of 500 sq km) and Chavakkad (1336 million tonnes over an area of 543 sq km). Off Kochi-Kollam marine sediments containing <62>85% silica sand have been identified during cruises SD-207, 209 and 216. Besides in an area, 8 km west of Beypore-Ponnani coast, good quality quartz sand was identified in two large basins close to the coastline where the thickness of sand formation exceeds 3.5 metres.

4 illus, 1 table, 17 ref

012312   Singh P K;Singh U C (Civil Engineering Dep, Center for Remote Sensing and GIS, Maulana Azad National Institute of, Bhopal, Email: uc.singh@rediffmail.com) : Application of geophysical approach for selection of suitable structures for rainwater harvesting system in Jiwaji University compus, Gwalior M.P. India. Ind Res Commun 2010, 4(2), 118-20.

The present study an electrical resistivity survey involving Vertical Electrical Sounding (VES) was carried out in the Jiwaji University Campus to understand the nature and extent of shallow and deep aquifers and to findout the thickness of unsaturated zones for the construction of artificial recharge structures within the campus. Two sites were are selected for vertical electrical sounding (VES) using Schlumberger electrode configuration and four to five layers in sub-surface set-up in study area have been detected.

2 tabls, 9 ref

012311   Singh P K;Bhargava A K;Mitra V;Prasad A; Jayapalan M. (NO, India Meteorological Dep, New Delhi-110 003, Email: pksingh@ncmrwf.gov.in) : Water balance studies for the crop planning in Ranchi, Jharkhand. Mausam 2010, 61(2), 223-8.

The rainfall data of 35 years was analyzed to quantify the rainfall efficiency for increased production for Ranchi region. The actual evaporation in driest year due to prolonged dry spell gives rise to severe drought condition affecting the crop growth adversely. No surplus water was recorded during driest year. In respect of coefficient of variation, the month of July registered the lowest coefficient of variation of 35 per cent followed by August (38 per cent) indicating lesser variability during this month. The threshold level of coefficient of variation ranges of 50-100 per cent was associated with April to October and indicated the dependability of rainfall in these months as compared to other months. The maximum length of growing season of 28 week, while minimum 12 week was recorded. In normal conditions, the length of growing season were recorded 18 week. Therefore, short duration paddy variety Birsa Gora-101, maize, i.e., Devki, Ganga-11, Suran and kharif pulses are suitable for the region.

3 illus, 3 tables, 6 ref

012310   Singh K M;Prasad M C;Prasad G;Prasad R;Jha M K (NO, , Shanti Kunj, Mausam Colony, Patna-800 014, Email: krishnamurari@yahoo.com) : Semi-quantitative precipitation forecasts for Kosi/Mahananda catchment by synoptic analogue method. Mausam 2010, 61(2), 175-86.

An attempt has been made to issue semi-quantitative precipitation forecasts for Kosi/Mahananda catchment by synoptic analogue method. Based upon 22 years of data (1982 - 2003) the study reveals that it is possible to issue semi-quantitative forecasts with confidence. Local topography of the catchments and its steep gradient from Bhim nagar to Chatra / Brahkshetra in Kosi and hills in Darjeeling are favourable regions where moist air masses of the Bay of Bengal and the Arabian Sea during South West Monsoon in lower troposphere converge and trough at 500 hPa especially diffluent in rear creates divergence and moist air mass is pulled up resulting in heavy / very heavy rainfall in sub montane districts of Bihar and Nepal Himalaya in addition to orographic effects. This gives birth to severe floods and makes the life of densely populated districts of Pumea / Katihar / Saharsa / Kisanganj / Madhepura miserable and badly affects the economy of the region.

3 illus, 4 tables, 10 ref

012309   Shukla S B;Prizomwala S P;Ukey V;Bhatt N; Chamyal L S (Geology Dep, The M.S. Baroda Univ, Vdodara-390 002, Email: lschamyal@yahoo.com) : Coastal geomorphology and tsunami hazard scenario along the Kachchh coast, western India. Indian J Geomar Sci 2010, 39(4), 549-56.

Geomorphology and coastal configuration plays a vital role during tsunami events as different coastal geomorphic units respond differently to a tsunami hazard. The study of ability of different coastal landforms to respond tsunami surge is very much important for vulnerability mapping of coast. The Kachchh coast that runs for about more than 450 km has conspicuous presence of both, wave as well as tide influenced landforms. Following the classification suggested by Ramasamy et al., the geomorphic features for possible response of tsunami event can be classified as facilitators, conveyors, accommodators, absorbers and barriers. Depending upon its action as facilitator, conveyor or accommodator, the geomorphic units like estuary, creek, mudflats and backwater increase the possibility of tsunami run ups and inundation. The beach ridges and wide sandy beaches on the other hand absorb tsunami energy and act as barriers. In view of these six distinct segments have been identified along the Kachchh coast and are described for their possible response to tsunami event. Accordingly, the segment between Jakhau and Suthari has barrier kind of geomorphic set up with presence of backswamps that has higher preservation potential of tsunami deposits. The segment from Suthari to Kanthada has steep beaches and dune ridges that can reduce the intensity of tsunami hazard. The Kanthada - Rawal Pir segment has Rukmavati River mouth that can convey the effect of tsunami to a considerable landward area whereas, the Rawal Pir - Mundra and Mundra - Tuna segments have dominant accommodator type of geomorphic assemblage that also has a higher preservation potential for tsunami sediments. The segment between Tuna and Kandla has relatively much wider mudflats and mangrove swamps which accommodates as well as reduces tsunami energy. However, the configuration suggests much intensified tsunami surge that can devastate the large scale developments in this part. Response mechanism of the coastal geomorphic assemblages will not only help in the disaster risk reduction activities but will also be useful in better understanding of palaeo and historical tsunamis.

3 illus, 2 table, 21 ref

012308   Shenoi S S C (NO, Indian National Centre for Ocean Information Services, Hyderabad-500 055, Email: shenoi@incois.gov.in) : Intra-seasonal variability of the coastal currents around India: a review of the evidences from new observations. Indian J Geomar Sci 2010, 39(4), 489-96.

The seasonal cycle of the coastal currents along the Indian coast and their dynamics is well known. Till recently, it was believed that the seasonal signal dominates the coastal currents due the seasonal reversals of monsoonal winds. But the recent studies using satellite based altimeter and in situ measurements using moored instruments provided evidences on the importance of intra and interannual variabilities embedded in them. This article reviews the evidences available from these observations.

9 illus, 1 tables, 35 ref

012307   Shah J;Somusundaram S (NO, Gujarat Institute of Desert Ecology (GUIDE), Post Box No-83, Opp. Changleswer Temple, Mundra Road, Bhuj, Kachchh-370 001, Email: jhsphd@gmail.com) : Preliminary GIS and remote sensing analysis on banni grasslands, Kachchh. Prajna 2010, 18(1-4), 15-7.

The study was earned out in Banni grassland (23° 19" to 23° 52" N; 69° 8" to 70° 11" E) of Kachchh district which spreads 2,617 km². Land use - land cover map of Banni region was prepared using Are GIS and ERDAS Imagine. Sub-setting of the Satellite Imageries was done using Survey of India (Sol) maps 1: 50,000 scale. Five major land use classes were identified and the Prosopis juliflora L. distribution map was prepared and it estimated that about 45 % of the total area was under Prosopis cover.

3 illus, 1 table, 11 ref

012306   Seetharam K (NO, Regional Meteorological Centre, Alipore, Kolkata, Email: kovelasitaram99@rediffmail.com) : Rainfall models-a study over Gangtok. Mausam 2010, 61(2), 225-8.

In this paper, the Pearsonian system of curves were fitted to the monthly rainfalls from January to December, in addition to the seasonal as well as annual rainfalls totalling to 14 data sets of the period 1957-2005 with 49 years of duration for the station Gangtok to determine the probability distribution function of these data sets. The study indicated that the monthly rainfall of July and summer monsoon seasonal rainfall did not fit in to any of the Pearsonian system of curves, but the monthly rainfalls of other months and the annual rainfalls of Gangtok station indicated to fit into Pearsonian type-I distribution which in other words is an uniform distribution. Anderson-Darling test was applied to for null hypothesis. The test indicated the acceptance of null-hypothesis. The statistics of the data sets and their probability distributions are discussed in this paper.

2 tables, 3 ref

012305   Ravichandran K;Jayaprakash M (NO, Central Ground Water Board, Rajaji Bhavan, Besant Nagar, Chennai-600 090) : Assessment of groundwater quality in a Subruban area of Chennai city, India. Ultra Scient phys Sci 2009, 21(1), 157-66.

Hydrochemical investigations were carried out in and around Ambattur industrial area, Tamilnadu, India to assess the chemical composition of groundwater and its quality for drinking purpose. A total of 54 representative groundwater samples were collected from different wells to monitor the water chemistry of various ions. The type of water that predominated in the study area was assessed based on hydrochemical facies. Interpretation of analytical data shows that Na-Cl, Ca-Cl and mixed are the dominant hydrochemical facies in the study area. Alkali metals (Na⁺, K⁺) and strong acids (Cl^-, SO₄^2-) are dominating over alkaline earths (Ca²⁺, Mg²⁺) and weak acids (HCO₃^-, CO₃^2-). The mean concentration of the cations is in the order of Na⁺<62> Ca²⁺<62> Mg²⁺<62> K⁺, while that for anions is C!^-<62> HCC₃^-<62> SO₄^2- NO₃^-. Statistical analyses indicate the highest positive correlation between EC and Cl with correlation coefficient of 0.97. Progressive reduction in correlation coefficient for EC with Na, TH and Mg are observed as 0.87, 0.84 and 0.77 respectively. Groundwater in the study area is generally hard, fresh to brackish and low in alkaline nature. The unsuitability of groundwater for drinking was identified in few places due to high total hardness and TDS. Fluoride is within permissible limit for human consumption as per international standards.

5 illus, 2 tables, 7 ref

012304   Rao A D (Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi-110 016, Email: adrao@cas.iitd.ernet.in) : Variability of coastal ocean processes along the west coast of India. Indian J Geomar Sci 2010, 39(4), 475-84.

Three-dimensional Princeton Ocean Model (POM) is used to understand coastal ocean processes and its variability along the west coast of India. An attempt is first made to understand variability of the surface circulation and associated SST during July-August 2000 and 2002 as a response of daily wind stress forcing derived from the QSCAT winds. The coastal current reverses its direction to either off-shore or northward if the wind reduces its strength suddenly to less than 3 ms^-1 towards the coast. In this event, the coastal upwelling is inhibited by the reversal of near shore currents and results in an increase in the local SST. This feature is also noticed in the buoy data available for 2002. Another experiment is made to understand the dynamics in relation to the fact of observed low-salinity plume off Gulf of Khambhat during post-monsoon season. It is found that the freshwater discharge to the gulf from the adjoining rivers during monsoon season is trapped in the region as the currents are onshore. As the currents change its direction to offshore after withdrawal of the monsoon, the confined low-salinity waters are being released to the open ocean. Lastly, the study is made to understand the response of the ocean to tropical cyclones in the Arabian Sea (AS). The study focuses on surface cooling and temperature rise in the subsurface waters and explained its mechanism through upwelling and downwelling processes respectively. Local stratification of the vertical temperature plays an important role for the cooling of the surface waters and warming in the sub-surface depths. The analysis of the model simulations and observations suggest that the extent of sub-surface warming is directly related to the depth of the thermocline region.

14 illus, 1 table, 18 ref

012303   Ramesh Kumar M R;Sankar S (Physical Oceanography Div, National Institute of Oceanography, Dona, Paula, Goa, Email: rameshkumar.me@gmail.com) : Impact of global warming on cyclonic storms over north Indian Ocean. Indian J Geomar Sci 2010, 39(4), 516-20.

The impact of global warming on the cyclonic storms over the north Indian Ocean have been studied using a suite of multiple datasets that includes the NCEP/NCAR Reanalysis, the extended reconstruction sea surface temperature (ERSST) and tracks of storms over the north Indian Ocean for the period 1951 to 2007. Results suggest that the frequency of storms and severe storms do not show a dramatic rise in-spite of substantial increase in the sea surface temperature in the Bay of Bengal from 1951-2007 compared to the 1901-1951. This prompted us to conclude that, the frequency of storms is related to the changes in a couple of atmospheric parameters over the north Indian Ocean during the global warming period. It is identified that there is a large decrease in the mid-tropospheric humidity over the Bay of Bengal during the latter period (1951-2007). The relationship between the SST over the Bay of Bengal and the maximum wind speed of the cyclonic systems is complex and there is no preferred range for the formation of cyclonic or severe cyclonic storms over the north Indian Ocean. Examination of various aspects related to storms in the present study revealed that warm SST's alone are not sufficient for the initiation of convective systems over the Bay of Bengal. The present study thus suggests that atmospheric parameters, such as low-level vorticity, mid-tropospheric humidity and vertical wind shear, play an influential role on the genesis and intensification of storms over the north Indian Ocean. The present study assumes significance due to the large contribution of rainfall over India from storms that form over the north Indian Ocean during the summer and the winter monsoons.

2 illus, 3 tables, 9 ref

012302   Rajakumari S;Subramanian B R;Balasubramanian T (Integrated Coastal and Marine Area Management Project Directorate, Ministry of Earth Sciences, Chennai, Email: brs@icmam.gov.in) : GIS based spatial distribution of environmental parameters at selected locations along the coastline of the country. Indian J Geomar Sci 2010, 39(4), 541-8.

The study presents the spatial distribution of chemical elements, such as, dissolved oxygen and nitrate at Ennore and Puri using the data collected under the COMAPS programme to elucidate the extent of spatial variation of chemical elements seasonally. Transect based spatial data of these parameters collected at 0, 2 and 5 km distance in the sea was interpolated using the spatial analyst module of G1S and the interpolated area was ranged from 97-917 sq km. Data revealed the extent of spatial distribution of low oxygenated water in Ennore and Puri. From the spatial data collected at Chilika, it could be found that nitrate concentrations in the range of 0.01-2 μmol/l provided substantial Chlorophyll concentration of more than 4 mg/m³. Similar result was obtained for coastal waters of Ennore. Further, increase of nitrate levels did not lead to higher productivity. This implies that the nitrate uptake saturation levels could happen even at 2 μmol/l. From the results obtained, the spatial data has been found to be useful in determining zones of safe use of seawater and to understand the extent of relationship between the relatable parameters.

10 illus, 4 tables, 4 ref

012301   Raha G N;Kakaty S C (Statistics Dep, Dibrugarh Univ, Dibrugarh, Email: itsraha@gmail.com) : Stochastic modeling of the occurrence of rainfall over some districts of Assam during 1987-1992. Mausam 2010, 61(2), 221-4.

The Primary aim in this paper is to find an alternative approach that consists of modeling the pattern of dry and wet spell over some districts of Assam. The Markov Chain Model is used to predict the length of dry and wet spells during the Indian summer monsoon season (June to September). This information may help the agronomists and agricultural scientists in crop planning. Five districts viz., Dibrugarh, Kamrup, Sonitpur, Dhemaji and North Lakhimpur are considered here for this study. Markov Chain Model is fitted for each of the district and the results of the five districts are pooled. This pooled result reveals that during the period 1987-1992, the probability for the day being wet when the immediately preceding day is dry for different years varies from 0.44 to 0.54 while the probability of the day being wet when the immediately preceding day is wet for different years varies from 0.74 to 0.86. It is also found that in the Indian summer monsoon season after about every consecutive 4-7 wet days a dry day is expected to occur whereas alter about consecutive 2 dry days, a wet day is expected to occur. The number of days required for the process to reach the state of equilibrium varies from 4-7 days.

1 illus, 2 tables, 15 ref

012300   Puviarasan N;Giri R K;Panalkar M (NO, India Meteorological Dep, New Delhi-110 003, Email: puvi4@yahoo.com) : Precipitable water vapour monitoring using ground based GPS system. Mausam 2010, 61(2), 203-15.

The sensing of near real time Precipitable Water Vapour (PWV) using Global Positioning System (GPS) over Indian region were analyzed. GPS data collected from five stations at hourly interval were utilized to determine near real time PWV using GAMTT software. Sliding window technique was used to derive near real time PWV. The PWV determined from GPS observations of each site were compared with respective radiosonde measurements. The results shows that the derived GPS precipitable water well agree for some stations with the independent radiosonde measurements. We have also examined the variation of hourly GPS-PWV with hourly rainfall observation and found that PWV increases significantly before the event take place and decreases after the event.

5 illus, 1 table, 13 ref

012299   Prasada Rao C V K (Naval Physical & Oceanographic Laboratory, Thrikkakara, Kochi-682 021, Email: prasadarao_cvk@yahoo.co.in) : Modelling of coastal ocean environment for underwater surveillance. Indian J Geomar Sci 2010, 39(4), 616-22.

Significance of ocean environment for underwater surveillance, namely for sonar systems, has been discussed in this paper. The passive as well as active sonar equations and the various parameters which are important for assessing sonar performance from environment point of view are highlighted. Some important published results which are available in the literature on the modelling of mermohaline structure of our coastal waters have been reviewed in this paper. Among 1-D mixed layer ocean models the model by Niiler and Kraus shows lesser deviations on Mixed Layer Depth (MLD) and Mixed Layer Temperature (MLT) when compared to the observations. The model given by Price et al simulates the Sea Surface Temperature (SST) and the vertical profile of temperature. The comparison of simulated values with observations revealed that the diurnal variability of SST is well represented through this model but deviations are noticed in the thermocline zone. The 1-D ocean models are simple and easy to implement for operational purposes because they are computationally less intensive. However, it was found that these models accumulate more error for long-term simulation due to non-inclusion of advection processes which are important in coastal as well as open ocean conditions. The observed and predicted results of a 3-D model proposed by Blumberg and Mellor, also known as Princeton Ocean Model (POM), showed a reasonable good comparison and this model could simulate successfully the Arabian Sea mini warm pool which is an important phenomenon that occurs in the south-eastern Arabian Sea before the onset of summer monsoon.

2 illus, 27 ref

012298   Prasad K V S R;ArunKumar S V V;Ramu C V; Patnaik K V K R K (Meteorolgoy and Oceanography Dep, Andhra Univ, Visakhapatnam-530 003, Email: arunocean@gmail.com) : Wave refraction and energy patterns in the vicinity of Gangavaram, east coast of India. Indian J Geomar Sci 2010, 39(4), 509-15.

Wave energy distribution along Gangavaram, east coast of India has been carried out for the predominant waves representing southwest monsoon (June-September), northeast monsoon (October-February) and storm period (March-May and October) using a wave refraction model. Model computes refraction coefficient, shoaling coefficient, breaker heights and breaker energies along the coast. During all seasons, higher wave energy pattern is observed in the region to the south of the port but towards north, complex wave conditions exist due to rocky headlands and promontories and as a result wave breaking transpires at deeper depths. Low wave energy conditions are observed very near to north breakwater during all the seasons and even during storms. During storm conditions wave energies amplify along the coast. South breakwater of the port is under the region of convergence during southwest monsoon and for the storms approaching in south-south-east direction. Numerical wave refraction studies facilitate the coastal engineers and scientists to understand the coastal processes.

7 illus, 1 table, 11 ref

012297   Nag P (NO, National Atlas and Thematic Mapping Organisation Bidhan Nagar, Kolkata-700 064, Email: prithvishnag@hotmail.com) : Coastal geomorphic features around Indian Ocean. Indian J Geomar Sci 2010, 39(4), 557-61.

Coastal areas are important globally. These areas have also drawn attention of geomorphologists for in-depth studies. Several institutions have made contributions towards analysis, identifications of different geomorphic features and their mapping. Attempts have been made to map oceans and associated coastal geomorphic features. In this paper an effort has been made for the Indian Ocean. There are straits, channels, continental sub-marine margins and continental shelf which form different components of the coastal ocean. They are shaped by land erosion, sub aerial deposition, volcanic, diastrophic, marine erosion and deposition and organisms. The interactions of these features are so variable that the coastal features are almost infinitely complex. The coasts of Indian Ocean realm fall into more than one category. Therefore, a matrix reference can be used with definite colour band to depict each single or compound feature.

3 illus, 8 ref

012296   Metri S M;Singh K (NO, Meteorological Office, Panaji, Goa, Email: metrisunder@yahoo.com) : Study of rainfall features over state during southwest monsoon season. Mausam 2010, 61(2), 155-62.

In this paper the rainfall features at different raingauge stations of Goa state have been studied for the period of 30 years. The statistical parameters such as mean monthly rainfall, Standard Deviation and Coefficient of Variation have been computed for each raingauge station of Goa. Some heavy rainfall events during the period have also been studied. The study shows the significant rising trend of rainfall towards the eastern parts of Goa. Goa experiences an average rainfall of about 330 cm annually and around 90% of annual rainfall occurs during southwest monsoon season i.e. (June to September). Studies revealed that most of heavy rainfall events caused due to active off-shore trough and low pressure systems formed over southeast Arabian Sea. It has also come out from the study that the orography of Goa plays an important role in rainfall distribution. Valpoi receives maximum rainfall due to its orographic effect.

5 illus, 2 tables, 9 ref

012295   Menon H B;Sangekar N P (Marine Science Dep, Goa Univ, Goa-403 206, Email: harilalm@gmail.com) : Measurement of salinity of Mandovi and Zuari estuarine waters form OCM data. Indian J Geomar Sci 2010, 39(4), 504-8.

Present study deals with a method/algorithm to retrieve salinity through optical remote sensing. The basis is the relation between one of the optically active substances of coastal and estuarine waters viz; chromophoric dissolved organic matter (CDOM) and salinity. Two important conditions for the algorithm to work are 1) CDOM should be the main light absorbing component and 2) the main source of CDOM should be fresh water discharge. Relationship between waters with salinity 26 to 35 PSU and CDOM for the Mandovi and Zuari estuaries have been developed and applied to OCM data of the year 2005, Specific algorithm developed is utilized for the study. Validation of satellite retrieved salinity and in-situ resulted in a correlation of 0.86.

3 illus, 9 ref

012294   Kushwaha H S;Chaubey A K;Phool Chand;Manisha Rani;Shahi U P (Soil Science Dep, Agriculture College, G.B. Pant Agriculture and Technology Univ, Pantnagar-263 145) : Verification of NCMRWF forecast of four years at Pantnagar on the basis of per cent accuracy, H.K. score and ratio score. Pantnagar J Res 2009, 7(1), 60-3.

The influence of weather is in fact operative even before the crop is sown, as the moisture availability and the thermal regime of the seed zone determine the date of sowing and the appropriate crop genotype to be sown. In spite of cultivation of high yielding varieties, improved cultural practices and plant protection measures, favorable weather is must for good harvest. In India, the agromet advisory service in terms of adoption of NCMRWF weather forecast based farm operations by the farmers has become very successful in the country in general and G.B Pant University of Agriculture and Technology, Pantnagar in particular and is operative since 1991, The accuracy of weather forecast elements has increased manifold from 30% (1991-92) to 78% (2005-06) and farmers have been benefited by utilizing weather forecast based advisory in this area. In the present investigation, the economic use of location specific agro-meteorological medium range weather forecast (MRWF) of major weather elements viz. rainfall, cloud amount, wind speed & its direction, and maximum & minimum temperatures developed at National Centre for Medium Range Weather Forecast (NCMRWF), Noida on each Tuesday was carried out. The feed back collected indicated that farmers using the advisory based on MRWF on weather sensitive farm operations have been benefited significantly and required Agromet Advisory Service to continue in future for raising their economy. With a critical evaluation it could be concluded that the NCMRWF forecast accuracy for maximum and minimum temperature was found maximum and in all the four seasons it has been more than 80 per cent correct. As far as wind speed and wind direction forecast are concerned, it has been found to be 70 per cent accurate in almost all the four seasons. However, accuracy of cloud cover was maximum in south west monsoon season (66.5%) followed by hot summer season (57.9%), post monsoon season (53.6%) and winter season (44.5%). The rainfall which is the most important from agriculture point of view, the forecast value were found to be most accurate in post monsoon season (96.2%) followed by winter season (84.5%), hot summer season (82.3%) and lowest in the south west monsoon season (44.7%). The maximum value of ratio score for rainfall for Post monsoon season was 97.33% and that of H.K. Raio value for the same season was highest to be 0.621.

2 tables, 3 ref

012293   Kurian N P;Praveen S S (NO, Centre for Earth Science Studies, Thiruvananthapuram-695 031, Email: npkurian@gmail.com) : Tsunami wave propagation in the Arabian sea and its implicatins on run-up/inundation characteristics along the Kerala coast. Indian J Geomar Sci 2010, 39(4), 531-40.

December 2004 tsunami generated by the M9.3 Sumatra-Andaman earthquake devastated many parts of the Kerala coast of southwest India, though it was in the shadow zone of that tsunami. Post-tsunami field survey and sea level data provided a rare opportunity for the study of wave transformation characteristics along this coast. A review of the available studies on the effects of 2004 tsunami wave propagation like the observed focusing/defocusing, number and arrival times of waves along the Kerala coast is undertaken in this paper. The important processes identified to be responsible for the observed runup and inundation are refraction, diffraction, reflection, and total internal reflection. Water level variations from the third day onwards are attributed to energy trapping on the continental shelf and secondary undulations. In addition, the implications of the wave propagation characteristics on tsunami run-up and inundation along the Kerala coast for the two probable sources of tsunami viz. Sumatra and Makran are examined through numerical modeling. It is found that the central and northern sectors of the coast are more hazard prone to the Makran than Sumatra for the same rupture intensity.

8 illus, 1 table, 20 ref

012292   Kumar G R R;Sreejith C (NO, Centre for Earth Science Studies, Akkulam, Trivandrum-695 031, Email: grrkumar@gmail.com) : Relationship between heavy mineral placer deposits and hinterland rocks of southern Kerala: a new approach for source-to sink link from the chemistry of garnets. Indian J Geomar Sci 2010, 39(4), 562-71.

Beach sediments of the Kerala coast contain rich economically important heavy mineral deposits. Most previous studies have traced- the source of heavy minerals to the Precambrian crystalline formations in the hinterland based on comparative mineral occurrences. No previous study has attempted to utilize petrological and geochemical characteristics and mineral chemistry of source rocks to effectively compare and determine sediment provenance. A clear knowledge on the composition of minerals from source and sink is important in precise recognition of source rock. Present study consists the geological, geomorphologic setting and mineralogical characteristics of hinterland rocks to trace their connection to placer deposits. It is recognized that garnet as the abundant heavy mineral in the placer sediments and in source rocks of different ages and petrogenetic affinity. Garnet composition varies between different source rock types due to its strong dependency on the bulk rock composition. In order to decipher the provenance we have compared major element composition of garnet in the source rocks and placer deposits. Compelling similarities in mineralogical and mineral chemical characteristics of garnets (Alm_68>Prp₂₈Grs₃Sps₁) is noted between khondalites and placer sediments suggesting latter as major source rock for placer deposits of southern Kerala. The study demonstrates excellent potential of garnets in identifying placer mineral source.

4 illus, 2 tables, 38 ref

012291   Kumar B P (Ocean Engineering & Naval Architecture Dep, Indian Institute of Technology, Kharagpur-721 302, Email: pkbhaskaran@naval.iitkgp.ernet.in) : Reliability based design method for coastal structures in shallow seas. Indian J Geomar Sci 2010, 39(4), 605-15.

Reliability based approach is considered an important component in risk assessment of coastal related projects. Such an approach is mandatory during the initial planning stage of coastal projects thereby providing information on the failure of structures. The damage to a structure can result from various environmental forcing and moreover depends on where the structure is located. As a case study, an existing coastal jetty at Andaman Sea was chosen which was subjected to extreme waves during a cyclonic episode prevalent in the Bay of Bengal. Wave information encompassing this coastal jetty was investigated using a very high resolution state-of-art SWAN wave model run in non-stationary mode. Wave forces are estimated using Sainflou and Miche-Rundgren methods along structural length of this jetty. In addition, wave run-up and wave overtopping were estimated using SWAN model generated wave information. A Level-II reliability analysis was carried out for this coastal jetty, subjected to various levels of assumed uncertainty. Further, lifetime and encounter probability under various degrees of uncertainty in load and resistance for this coastal jetty has been investigated and analyzed. Based on analysis, it is believed the significance of this work can lead vital information for assessment studies in integrated coastal zone management.

7 illus, 4 tables, 16 ref

012290   Kudale M D (NO, Central Water and Power Reseach Station, Pune-411 024, Email: kudale_md@cwprs.gov.in) : Impact of port development on the coastline and the need for protection. Indian J Geomar Sci 2010, 39(4), 597-604.

Coastal areas are varied in physical features. The coastline shows constantly varying nature due to tidal effects and seasonal changes in wave and wind climate. Occasional cyclones in the region also have influence on the overall morphology. It is necessary to understand the coastal processes and predict likely effects before undertaking any coastal project. Developments of major/minor ports and fishery harbours consist of the construction of coastal structures like breakwaters, jetties, groynes and reclamation bunds. Developments of the ports also involve the dredging and disposal activities to maintain the required depths for navigation. These coastal structures and the dredging activities interfere in the coastal processes of the region. Modifications in the coastal processes have large impact on the coastline. Major morphological impact is felt in the coastal region having high rate of longshore littoral drift. Accumulation of sediments on the updrift side and erosion of the downdrift side is inevitable in these regions. Sand bypassing is one of the best solutions to mitigate this problem. Sand bypassing should form an integral part of any port development project at the planning stage.

6 illus, 5 ref

012289   Jha T N;Ram R D (India Meteorological Dep, , New Delhi-110 003) : Rainfall over catchments of Bihar plains. Mausam 2010, 61(2), 187-96.

Station wise daily rainfall data of sixty years is used to study rainfall departure and variability in Kosi, Kamala/Bagmati/Adhwara and Gandak/Burhi Gandak catchments during monsoon season. Station and catchment wise rainfall time series have been made to compute rainfall departure and Coefficient of Variation (CV). Southern Oscillation Index (SOI), Multivariate ENSO Index (MEI) and ENSO strength based on percentile analysis are used to ascertain their impact on rainfall distribution in the category as excess, normal, deficient and scanty. Results indicate that the variability is greater over Kosi as compared to the other catchments. Probability of normal rainfall is found 0.75 and there is no possibility of scanty rain over the catchments during El Nino and La Nina year. Similarly probabilities of normal, deficient, excess rainfall are found as 0.67, 0.18 and 0.15 respectively during mixed year. SOI has emerged as principal parameter which modifies the departure during El Nino and La Nina year. MEI along vith ENSO strength are more prominent during mixed year particularly to ascertain deficient and excess rain in weak and strong- moderate La Nina respectively.

9 illus, 2 tables, 19 ref

012288   Jaswal A K (India Meteorological Dep, , Pune-411 005, Email: akjaswal@imdpune.gov.in) : Recent winter warming over India-spatial and temporal characteristics of monthly maximum and minimum temperature trends for January to March. Mausam 2010, 61(2), 163-74.

In the backdrop of recent warmer winters over India, temperature series of 174 stations well distributed over the country were statistically analyzed to document the long term variations and trends in monthly mean maximum and minimum temperatures for lanuary to March. From the trend analysis, February month has emerged as the warmer winter month over North India where increase in both maximum (+0.29° C/decade) and minimum (+0.38° C / decade) temperatures is highest with noteworthy increase in maximum temperature at a rate 1.5 times that of the South India averaged increase. Spatially, North India minimum temperature trends for February and March and South India maximum temperature trends for all months are more coherent. Both day-time and night-time total cloud amounts are increasing significantly over Indo-Gangetic plains and south peninsula and decreasing significantly in central and east India. However increase in temperatures over extreme south peninsula in January and March is difficult to explain on the basis of increase in day-time total cloud amount indicating strong influence of other climatic factors. At the same time, sea surface temperatures of the Arabian Sea and the Bay of Bengal are rising and there is strong positive correlation between land surface temperatures and sea surface temperatures suggesting significant contribution of warmer sea waters which may have important climatic implications over neighbouring regions.

11 illus, 4 tables, 23 ref

012287   Hegde A V (Applied Mechanics and Hydraulics Dep, National Institute of Technology Karnataka, Surathkal, Mangalore-575 025, Email: arkalvittal@gmail.com) : Coastal erosion and mitigation methods - global state of art. Indian J Geomar Sci 2010, 39(4), 521-30.

Coastal erosion is assuming large proportions these days. Global climate change coupled with local attributes is eroding the coasts of the world in alarming proportions. Most of the conventional protection methods are hard, short lived, expensive and not eco-friendly. Trend in coastal erosion mitigation and protection has been shifting these days towards soft but novel, eco-friendly methods. Pro-active methods are being developed and used which are eco-friendly, construction-friendly, cheaper and which also reasonably address the root cause of the problem without much 'side effects'. Many non-traditional ways to armor, stabilize or restore beaches, including the use of patented precast concrete units, geotextile sand-filled bags, green belts, bio-engineering, sand fencing, beach-face dewatering systems, integrated costal protection methods are being used. Retreat from the coast is also thought about, in many circles. Present study consists the global coastal erosion scenario and also some of the state of the art soft and pro-active erosion mitigation methods.

15 illus, 19 ref

012286   Gurugnanam B;Suresh M;Monokaran K;Vasudevan S;Kumaravel S (Earth Sciences Dep, Annamalai Univ, Annamalai Nagar, Chidambaram, Tamil Nadu, Email: gurugis@yahoo.co.in) : IPI2 win software usage for the interpretation of sub-surface water in Sirukattur villege, Cuddalore district, Tamil Nadu (India). Ultra Scient phys Sci 2009, 21(1), 29-36.

The work is aimed to study the shallow fresh Water aquifer insedimentary area. 3 vertical electrical soundings (VES) were carried out in the study area using Schlumberger method. CRM 500 instrument was used in the present study. The field data were interpreted by IPI2WIN software. Using the interpreted sounding results the best location (VES 1) of the 3 test locations. The test data interpretation was validated in bore well drilled at the recommended site. The results obtained from IPI2Win software was found to be 100% correct in the field check. The top shallow aquifers are commonly fresh in nature in the study area. 18 m depth bore hole was drilled and samples were collected at 1 m interval. The observed subsurface details are 1-2 m (Clay mixed sand), 2-4 m (Medium to coarse sand), 5-8 m (Coarse sand), 8-9 m (Sandstone), 9-10 m (Coarse Sand), 10-17 (Medium Sand), 17-18 m (Sandstone). The study reveals that the top shallow aquifers are noticed fromS m to 17 m with good groundwater potential. It is thus established that the lPI2Win software interpretation is reliable in sedimentary area.

3 illus, 2 tables, 6 ref

012285   Dutta S K;Gupta M D;Prasad V S (NO, National Centre for Medium Range Weather Forecasting (NCMRWF), Noida-201 307, Email: surya@ncmrwf.gov.in) : Impact of AMDAR observations from lufthansa aircraft on global analysis - forecast system. Mausam 2010, 61(2), 213-220.

AMDAR observations from Lufthansa and Lufthansa cargo aircrafts in BUFR format (with header IUADOI EGGR and IUAHOI EGRR) were made available to India Meteorological Department (IMD) and in turn to National Centre for Medium Range Weather Forecasting (NCMRWF) under special arrangement for a period of two weeks w.e.f. 14^th May 2008. These data have been assimilated at NCMRWF (National Centre for Medium Range Weather Forecasting) model for the period 14^th - 31^st May. 2008 to assess its impact on NWP. Use of these observations gave some positive impact on NWP systems.

10 illus, 1 table, 8 ref

012284   Durai V R;Roy Bhowmik S K;Mukhopadhyay B (India Meteorologial Dep, , New Delhi-110 003) : Performance ealuation of precipitation prediction skill NCEP global forecasting system (GFS) over Indian region during summer monsoon 2008. Mausam 2010, 61(2), 139-54.

The study provides a concise and synthesized documentation of the current level of skill of the NCEP GFS day-1 to day-5 precipitation forecasts during Indian summer monsoon of 2008, making detailed inter-comparison with daily rainfall analysis from the use of rain gauge observations and satellite (KALPANA-1) derived Quantitative Precipitation Estimates (QPE) obtained from IMD. Model performance is evaluated for day-1 to day-5 forecasts of 24-hr accumulated precipitation in terms of several accuracy and skill measures. Forecast quality and potential value are found to depend strongly on the verification dataset, geographic region and precipitation threshold. Precipitation forecasts of the model, when accumulated over the whole season, reproduce the observed pattern. However, the model predicted rainfall is comparatively higher than the observed rainfall over most parts of the country during the season. The model showed considerable skill in predicting the daily and seasonal mean rainfall over all India and also over four broad homogeneous regions of India. The model bias for rainfall prediction changes from overestimation to underestimation at the threshold of 25 mm/day except for day-1 forecast. Model skill falls dramatically for occurrence rainfall thresholds greater than 10 mm/day. This implies that the model is much better at predicting the occurrence of rainfall than they are at predicting the magnitude and location of the peak values. Various skill score and categorical statistics for the NCEP GFS model rainfall forecast for monsoon 2008 are prepared and discussed.

11 illus, 1 table, 15 ref

012283   Deo M C (Civil Engineering Dep, Indian Institute of Technology Bombay, Powai, Mumbai-400 076, Email: mcdeo@civil.iitb.ac.in) : Artificial neural networks in coastal and ocean engineering. Indian J Geomar Sci 2010, 39(4), 589-96.

Artificial neural network (ANN)s have been applied to solve a variety of problems related to the coastal and ocean areas over a period of last one and a half decades. Most of these studies have involved estimation or forecasting of environmental parameters, structural loads and responses. The aim in such studies were to carry out a cause-effect modeling, temporal or spatial mapping, and property integration and resolution. ANN models have been generally found to outperform the traditional empirical, statistical or numerical models to a smaller or larger extent. There are however certain grey areas where the modeling and its usefulness needs to be improved. This paper takes a stock of all such past works and summarizes author's experience in working with ANNs for the benefit of future researchers.

2 illus, 122 ref

012282   Das P K;Barthakur P (Geological Sciences Dep, Gauhati Univ, Gauhati-781 014) : Petrography of lakadong limestones occurring in and around Mawsynram, East Khasi district, Meghalaya (India). Ultra Scient phys Sci 2009, 21(3), 619-38.

Petrographical study of the Lakadong Limestone member of Sheila Formation (Jaintia Group) was carried, out for identification of different constituents, mineralogical classifications and to decipher depositional environment. The limestone includes fossils, pellets, odites and intraclasts as allochem microcrystalline calcite and sparry calcite. The limestone is represented as sparry allochemical limestone and biogenic pellet limestone. This biogenic rock contains more than 3.1 pellet ratio. Hence it is also known as Biosparrude. In physical character, limestone is mostly packstone and boundstone types. Moreover, non-ferroan calcite is dominant in the limestone. The process of cementation consists of chemical deposition of sparry calcite. Both equigranular and inequigranular fabrics are present in the limestone. The major diagenetic processes worked on the limestone include solution, cementation, neomorphism and pressure solution. Strained calcite, vein, vug, stylolite are the notable microstructure present in the limestone. In the limestone, aggrading neomorphism is common. The petrographic studies indicate that deposition of carbonate sediments took place in a quiet water marine basin (lagoon type).

5 illus, 6 tables, 30 ref

012281   Chaure S K (Geology Dep, Govt. Holkar Science College Indore, Madhya Pradesh, Email: sk_chaure@rediffmail.com) : Google earth: excellent tool for learning geomorphology. Ind Res Commun 2010, 4(2), 121-4.

Google Earth is a virtual globe, map and geographic information program accessible through internet. It interactively displays high resolution images, 2-D and 3-D vector data. One of the most useful aspects of Google Earth from a geosciences education point of view is the availability of a variety of geosciences related datasets for free on the web. Commonly people use Google Earth for finding locations of places, addresses and other points of interests. But there is lot of data available on this site which can be used for teaching and learning geology. From this site one can see the geology of entire globe. It gives opportunity to teachers and students of geology to make a virtual trip to different geological terrains of the world. Author of this paper is using Google Earth for teaching basics of geomorphology and in this paper spectacular geological features present in the different parts of India are listed and described.

4 illus, 3 ref

012280   Chattopadhyay S (NO, Centre for Earth Science Studies, Thiruvananthapuram, Email: radresource@vsnl.com) : Geomorphology for integrated coastal zone management: a theoretical approach with examples form Kerala, India. Indian J Geomar Sci 2010, 39(4), 623-30.

Coastal zone, triple interface of land, ocean and air, is a geographic entity of intense human activities. This area experiences several problems due to competing and multiple usability of coastal resource, which is a matter of global concern. Concept of Integrated Coastal Zone Management (ICZM) is advanced as a tool to tackle these problems and to devise sustainable development plans. Drawing examples from Kerala at macro and micro scales this paper demonstrates that in depth study of geomorphic processes and geomorphic assets is necessary as part of ICZM plan. Identification of morpho-dynamic units following the scheme of landscape classification at the ground level helps devising appropriate management action plans. While dealing with the geomorphologic processes a larger approach/perspective should be maintained by identifying system boundaries and the degree of activity and the relationships among the processes involved. This also includes human induced processes that, in aggregation, trigger large scale environmental change.

4 illus, 5 tables, 10 ref

011241   Yellappa T;Chalapathi Rao N V;Chetty T R K (National Geophysical Research Institute, CSIR, Uppal Road, Hyderabad-500 007, Email: nvcr100@gmail.com) : Occurrence of lamproitic dykes at the northern margin of the Indravati basin, Bastar craton, central India. J Geol Soc India 2010, 75(4), 632-43.

Occurrence of two lamproitic dykes intruding the basement granite near Khadka village at the northern margin of the Indravati Basin, Bastar craton is reported. Combined field, microscopy, XRD, EPMA and whole-rock geochemical investigations reveal that these lamproites were subjected to high degree of hydrothermal alteration as well as possible metamorphism. However, relicts of their original textures are well-preserved thereby providing important clues as to the nature of the protolith. Quartz, carbonate, chlorite and phlogopite constitute the bulk mineralogy whereas spinel, apatite and iron oxides are the accessory phases. Chemical composition of the groundmass spinels are strikingly similar to those from the lamproites. The Khadka lamproite dykes display high abundances of compatible elements such as Ni (238-396 ppm), Cr (484-892 ppm), and V (160-200 ppm) as well as high-field strength elements such as Zr (71920S 7 ppm) and Nb (92-126 ppm) that resemble those in lamproites. Khadka lamproites also have high whole-rock REE abundances (∑ REE up to 1260 ppm) and display fractionated chondrite-normalized REE patterns (La/Yb= 113-237) which together with their average compatible and incompatible trace elemental ratios (e.g. Nb/Zr, Nb/La, Ba/Rb) are strikingly similar to those of the Mesoproterozoic Krishna lamproites of the Eastern Dharwar craton. Available field evidences suggest the Khadka lamproites to be of at least Palaeoproterzoic age (1.88 Ga) which makes them some of the oldest such rocks as yet documented from the Indian shield.

9 illus, 3 tables, 51 ref

011240   Yadav P K;Avadich P C (Geology Dep, MLS Univ, Udaipur-313 0016epyarekrishna@gmail.com) : Synthesis of geological and airborne geophysical data for prognosticating new area for the exploration of lead and zinc in Sindesar Khurd area, Rajpura-Dariba belt, Rajsamand district, Rajasthan. J Geol Soc India 2010, 75(5), 731-8.

In the Rajpura-Dariba belt zinc and lead mineralization was established on the basis of gossan and opinions were given that the deposits are stratiform and syngenetic. During last two decades metamorphism and volcanic processes have been attributed for the generation of exhalative and remobilized lead-zinc ore bodies. Subsequent exploration was based on the concept of successive borehole planning around positive intersections. Areas having surface indications of base metal mineralization and their extensions have been already explored. Recent deep drilling by Hindustan Zinc Limited (HZL) in this area has intersected rich ore lodes, thereby confirming depth ward continuity of ore zones at some places. It indicates possibility of searching hidden deposits by innovative techniques. Therefore, today, there is a challenge before geoscientists to discover new deposits in this area by an exploration technique which should have low risk, consume less time and it should be cost effective. In view of the above objective for Rajpura-Dariba belt, an integrated method of exploration has been discussed. The exploration strategy is based on synthesis of all the available data and its reinterpretation to prognosticate favourable sites of exploration and also to suggest new scheme of exploration. Based on previous data and present studies structural and lithological controls of base metal mineralization have been recorded and guides for searching new areas and exploration strategy has been suggested. Based on these data six new areas have been identified for future exploration. The data includes lithological configuration, structural setup and controls of lead-zinc mineralization collected from previous data and present studies. It is suggested that for further exploration in these six areas ground magnetic survey should be carried out to understand magnetic lows and highs to decipher structural discontinuity and faults which could be favourable sites of mineralization. Combination of SP, IP, EM and gravity shall help in distinguishing between base metals from graphite mica schist.

4 illus, 1 table, 13 ref

011239   Vijith H;Rejith P G;Madhu G (Centralized R S & GIS Facility, School of Environmental Sciences, Mahatma Gandhi Univ, Kottayam, Kerala-686 022, Email: vijithh@gmail.com) : Using info val method and Gis Techniques for the spatial modelling of landslide susceptibility in the upper catchment of river meenachil in Kerala. J Indian Soc Remote Sens 2009, 17(2), 241-50.

A GIS-based statistical methodology for landslide susceptibility zonation is described and its application to a study area in the Western Ghats of Kerala (India) is presented. The study area was approximately 218.44 km² and 129 landslides were identified in this area. The environmental attributes used for the landslide susceptibility analysis include geomorphology, slope, aspect, slope length, plan curvature, profile curvature, elevation, drainage density, distance from drainages, lineament density, distance from lineaments and land use. The quantitative relationship between landslides and factors affecting landslides are established by the data driven-Information Value (InfoVal) - method. By applying and integrating the InfoVal weights using ArcGIS software, a continuous scale of numerical indices (susceptibility index) is obtained with which the study area is divided into five classes of landslide susceptibility. In order to validate the results of the susceptibility analysis, a success rate curve was prepared. The map obtained shows that a great majority of the landslides (74.42%) identified in the field were located in susceptible and highly susceptible zones (27.29%). The area ratio calculated by the area under curve (AUC) method shows a prediction accuracy of 80.45%. The area having a high scale of susceptibility lies on side slope plateaus and denudational hills with high slopes where drainage density is relatively low and terrain modification is relatively intense.

4 illus, 2 tables, 35 ref

011238   Suresh G;Ananthanarayana R;Hanumanthau R C; Ghosh S;Anil Kumar A;Reddy K V S (NO, Training Institute, Bandlaguda, Hyderabad-500 068) : Geology of Pulikonda and Dancherla alkaline complxes, Andhra Pradesh. J Geol Soc India 2010, 75(4), 576-95.

Geological studies on saturated to oversaturated and subsolvus aegirine-riebeckite syenite bodies of the Pulikonda alkaline complex and Dancherla alkaline complex were carried out. The REE distribution of the Dancherla syenite shows a high fractionation between LREE and HREE. The absence of Eu anomaly suggests source from garnet peridotite. The Pulikonda syenite shows moderate fractionation between LREE and HREE as reflected by enrichment of HREE and moderate enrichment of LREE. The negative Eu anomaly indicates role of plagioclase fractionation. Three distinct co-eval primary magmas i.e. mafic syenite-, felsic syenite- and alkali basalt magmas - all derived from low-degrees of partial melting of mantle differentiates and enriched metasomatised lower crust played a major role in the genesis and emplacement of the syenites into overlying crust along deep seated regional scale trans-lithospheric strike-slip faults and shear zones following immediately after late-Archaean calc-alkaline arc magmatism at different time-space episodes i.e. initially at craton margin and later on into the thickened interior of the Eastern Dharwar craton. The ductile sheared and folded Pulikonda alkaline complex was evolved dominantly from the magmas derived from partial melting of lower crust and minor juvenile magmas from mantle. Differentiation and fractionation by liquid immiscibility of mafic magma and commingling-mixing of intermediate and felsic magmas followed by fractionational crystallisation under extensional tectonics during waning stages of calc-alkaline arc magmatism nearer to the craton margin were attributed as the main processes for the genesis of Pulikonda syenite complex. Commingling and limited mixing of independent mantle derived mafic and felsic syenitic magmas and accompanying fractionation resulting into soda rich and potash rich syenite variants was tentatively deduced mechanism for the origin of Dancherla, Danduvaripalle, Reddypalle syenites and other bodies belonging to Dancherla alkaline complex at the craton interior. The Peddavaduguru syenite was formed by differentiation of alkali mafic magma (gabbro to diorite) and it's simultaneous mingling with fractionated felsic syenitic magma under incipient rift. Vannedoddi and Yeguvapalli syenites were derived due to desilicification and accompanying alkali feldspar mestasomatism of younger potash rich granites along Guntakal-Gooty fault and along Singanamala shear zone respectively. Dancherla syenite body has yielded a six point Rb-Sr whole rock isochron age of 2211±110 Ma with low initial ⁸⁷Sr/⁸⁶ Sr ratio of 0.7004±0.00046; MSWD = 5.8 The low initial Sr(i) ratio suggests mantle derived juvenile additions to the crust. The Pulikonda syenite body yielded a six point whole rock isochron age of 1500 ±100 Ma with initial ⁸⁷Sr/⁸⁶Sr ratio of 0.7085±0.0047 and MSWD = 2%. The higher initial Sr(i) value for this body suggests metasomatised source. Resetting of Rb-Sr systematics has resulted younger age for Pulikonda syenite though it is supposed to be older as per the geological setting and this anomaly is interpreted interms of repeated deformation and reactivation of shear zone, emplacement of alkali granite into Pulikonda syenite and the role of Rudravaram shear zone (basement tectonics) in the formation of the Nallamali fold belt of the Cuddapah Basin. Alkaline magmatism was initially triggered along microplate margin tectonic setting and later confined to the intraplate tectonic setting.

10 illus, 3 tables, 40 ref

011237   Srivastava G;Mehrotra R C (NO, Birbal Sahani Institute of Palaeobotany, 53, University Road, Lucknow-226 007, Email: rcmehrotra@yahoo.com) : New legume fruits from the oligocene sediments of Assam. J Geol Soc India 2010, 75(6), 820-8.

For the first time a rich assemblage of legume fruits is described from the Late Oligocene sediments of the Makum as well as Dilli-Jeypore coalfields of Assam. A new genus Buteocarpon has been instituted for the fossil fruits resembling Butea Roxb. of the family Fabaceae. In addition, six new species of the genus Leguminocarpon Goeppert are also described. Their presence indicates a warm and humid climate in the region during the deposition of the sediments.

5 illus, 1 table, 29 ref

011236   Singh V;Singh U C (School of Studies in Earth Science, Jiwaji Univ, Gwalior-474 001, Email: vineesha2005@yahoo.co.in) : Satellite based identification of archaeological monuments sites of Gwalior, MP, India. Indian J Sci Technol 2011, 4(1), 27-8.

Gwalior cultural legacy consists of rich archaeological ruins (monuments) and we made efforts to identify the important sites using remote sensing techniques. The satellite images provide data for mapping of the cultural heritage site areas on high resolution. The improper mapping has caused a serious cultural crisis where such monuments are depicted with ordinary symbols and only few well known monuments are mapped.

3 illus, 4 ref

011235   Shekhawat M S;Prabhulingaiah G (Geology Dep, M.L. Sukhadia Univ, Udaipur-313 001, Email: shekhawatgeol@yahoo.com) : Mineralogical characteristics and mineral economics of Sanu and Gotan SMS grade limestone deposits of Rajasthan. J Geol Soc India 2010, 75(5), 739-48.

Two large, chemically similar, SMS grade limestone deposits occur in Sanu area of Jaisalmer and Gotan area of Nagaur, Rajasthan. The Sanu deposit belongs to Khuiala Formation of Tertiary sequence of lower Eocene age, while Gotan deposit belongs to Bilara Group of Marwar Supergroup of late Neoproterozoic to early Cambrian. These deposits are being developed and utilised as flux in the steel plants of India. The Sanu limestone of Jaisalmer is more suitable compared to Gotan and other limestone deposits of the country due to its superior and favourable physical properties. Mineralogically, it consists of fine-grained, sub-rounded to rounded grains of calcite mainly replacing tests of the larger foraminifera. While, the Gotan limestone is composed of fine to coarse-grained, angular to sub-rounded grains of calcite. In Sanu area, about 54% of the limestone produced is being generated as -30 mm grit during the process of sizing for SMS grade. This lower size of limestone is suitable for making cement but due to non-avaibility of rail transport facility from Sanu to Jaisalmer for a distance of about 60 km, it remains unutilised as mineral reject.

6 illus, 3 tables, 36 ref

011234   Santosh Kumar;Pathak M (Geology Dep, Kumaun Univ, Nainital-263 002, Email: skyyadavan@yahoo.com) : Mineralogy and geochemistry of biotites from proterozoic granitoids of western Arunachal Himalaya: evidence of bimodal granitogeny and tectonic affinity. J Geol Soc India 2010, 75(5), 715-30.

Felsic magmatic rocks in Kameng corridor of western Arunachal Himalaya are represented by extensively exposed Palaeoproterozoic porphyritic muscovite-biotite granite (GGn) of the Bomdila Group and small stock-like Mesoproterozoic hornblende-biotite granite (HBG) of the Salari Group. Mineralogy and chemical composition of biotites from GGn and HBG have been utilized to understand the nature and tectonic environment of their parental felsic melts. Biotites in GGn (FeO^t/MgO=3.1-4.6) are Fe-biotites and have shown affinity with primary biotites co-precipitating with muscovite in aperaluminous (S-type) felsic melt of syn-collisional tectonic environment. Biotites in HBG (FeOVMgO=1.3-2.2) are transitional between Fe and Mg biotites evolved from Fayalite-Magnetite-Quartz (FMQ) to Nickel-Nickel Oxide (NNO) buffers and are related to primary biotites co-existing with amphibole and other ferromagnesian minerals in a calc-alkaline metaluminous (I-type) felsic melt mostly formed in a subduction setting. Both GGn and HBG biotites exhibit Mg≠Fe substitution, which is more pronounced in HBG biotites. GGn biotites exhibit 2A1≠Fe²⁺ substitution as expected in peraluminous melt, whereas 3Mg≠2A1 substitution normally expected to operate in metaluminous melt is less pronounced in HBG biotites. GGn biotites are markedly enriched in siderophyllite, and depleted in phlogopite components as compared to HBG biotites, which point to diverse genetic conditions. HBG biotites indicate oxidizing environment of the felsic melt unlike the reducing nature of the porphyritic granite (GGn).

10 illus, 3 tables, 38 ref

011233   Roy P;Jain A K;Singh S (Earth Sciences Dep, Indian Institute of Technology Roorkee, Roorkee-247 667, Email: himalfes@gmail.com) : Microstructures of mylonites along the Karakoram shear zone, Tangste valley, Pangong mountains, Karakoram. J Geol Soc India 2010, 75(5), 679-94.

The Karakoram Shear Zone is a northwest-southeast trending dextral ductile shear zone, which has affected the granitic and granodioritic bodies of the southern Asian Plate margin in three distinct episodes. The ductile shearing of the granitic bodies at Tangste and Darbuk has resulted in the development of mylonites with mylonitic foliation and stretching lineation. More intense deformation is noted in the Tangste granite grading up to orthomylonite, as compared to the Darbuk granite. Kinematic indicators include S-C foliation, synthetic C and C" antithetic shear bands, Type A s-mantled porphyroclasts, oblique quartz foliation, micro-shears with bookshelf gliding, mineral fishes including Group 2 mica fishes, and Type 1 and 2a pull-apart microstructures, and exhibit strong dextral sense of ductile shearing towards southeast. The textural features of the minerals, especially that of quartz and feldspar, indicate temperature of mylonitisation ranging between 300 and 500°C in the upper greenschist facies, and appear to have been evolved during exhumation as a consequence of oblique strike-slip movements along the Karakoram shear zone.

7 illus, 54 ref

011232   Roy D K;Ray G K;Biswas A K (MBA Basin, ONGC, Kolkata-700 088) : Overview of overpressure in Bengal basin, India. J Geol Soc India 2010, 75(4), 644-60.

Abnormally high formation pressures are encountered worldwide, ranging in geological age from Cenozoic to Paleozoic, within a depth range of few hundred meters to as deep as six thousand meters while carrying out exploratory drilling by E and P companies. Several causes can increase formation fluid pressure i.e. rapid loading of sediments results compaction disequilibrium, thermal expansion of fluids, compression and/or upliftment of strata by tectonic forces, generation of oil and gas from organic matter and its volume expansion due to high thermal stress within the restricted pore volume in subsurface condition. Few global examples on overpressure occurrences have been compiled in the paper with special reference to Bengal Basin. Emphasis has been given on methodology and interpretation on abnormal pressure detection in Bengal Basin with a compiled data package on generated curves (Geologs), charts, tables in a systematic way to understand the depth/stratigraphic horizons proved/interpreted as proved or likely to be within transition and overpressure regime. The integrated analysis indicates that the wells drilled in the east of Eocene hinge zone in the onshore and offshore parts of Bengal Basin have penetrated overpressure formation within Miocene in the depth range of 2800 m to 5340 m and the mud weight used to control this overpressure zone was more than 2.0 sp gr mud. The generated Geologs can be used as reference to understand the regime of transition and overpressure, as a valuable document for exploration drilling planning and monitoring. The generated model curve (modified using available data after Hottman and Johnson,1956 curve) using sonic departure (i.e. At_ob(sh) - At_n(sh)) from drilled wells may be used as an additional tool to find out the expected formation pressure gradient and equivalent mud weight in all future wells. The correlation of wells based on the trend of dcs and o logs will be useful for predicting transition and overpressure top provided all the parameters required for calculating dcs and a log recorded smoothly during drilling phase. The study has brought out the detail procedure to generate the pressure profile in the future wells. The generation of pressure profile of a well prior to drilling has got immense importance in oil industry. The drilling of the well should be done by maintaining the optimum mud weight generated from the pressure profile. In case, during drilling, formation pressure is more than the mud pressure, resulted gas kicks or worse, blowouts of the well. Excessively high mud pressure can fracture the formation and cause lost circulation. The oil and gas companies, worldwide, attributed 15% losses due to various problems associated with drilling complications, mostly related to improper pressure prediction of a well. The losses include loss of material as well as drilling process continuity, called non-productive time (NPT). The generation of accurate pressure profile reduces drilling problems, cuts exploration and development costs and allows billions of dollars now spent on losses to be better spent-building and replacing reserves.

14 illus, 2 tables, 10 ref