014153   Biswal T K;Biswal B;Mitra S;Moulik M R (Department of Earth Sci, IIT, Mumbai-400 076) : Deformation pattern of the NW terrane boundary of the Eastern Ghats Mobile Belt, India : a tectonic model and correlation with Antarctica. Gondwana Res 2002, 5(1), 45-52.

Thrusts interspersed with lateral ramp and wrench structures mark the joint between Proterozoic Eastern Ghats Mobile Belt and Archaean cratons of the eastern India. The join, referred to as Terrane Boundary Shear Zone, exhibits an arcuate geometry at the NW margin of the Eastern Ghats where the mobile belt shows the presence of northwesterly verging nappes. Based on this, the area has been described to represent the salient part of a fold thrust belt. Juxtaposition of the granulites over the low grade craton is largely attributed to thrusting along the terrane boundary shear zone. As the folds are disoriented and the granulites are retrograded along the thrusts, the terrane boundary shear zone is interpreted to be a retrograde shear zone. The shear zone hosts a number of synkinematic alkali intrusive rocks that constrain the age of thrusting to 1.4 Ga. In the correlative framework of Gondwanaland the terrane boundary shear zone is very likely to be contiguous with the Ray-Napier boundary of Antarctica.

26 ref

014152   Bhattacharya S (Geol Studies Unit, , ISI, Calcutta-700 035) : Nature of crustal tri-junction between the Eastern Ghats Mobile Belt, Singhbhum craton and Bastar craton, around Paikmal, western Orissa structural evidence of oblique collision. Gondwana Res 2002, 5(1), 53-62.

From detailed structural studies in several sectors, the Eastern Ghats granulite belt could be described as a convergent orogen that evolved under a NW-SE directed sub horizontal compression. Rotation of tectonic trends in both the northern and western boundary regions and the occurrence of strike-slip shear-zones indicate oblique collisional juxtaposition of the Eastern Ghats granulite belt against both the cratons. The orientations of the palaeo-stress axes in the shear zone around Paikmal indicate a NW directed tectonic transport and is consistent with the NW-SE compression in the Eastern Ghats granulite belt. Thus, the Eastern Ghats Mobile Belt may be considered as a convergent orogon that collided against an `irregular' continental margin : roughly E-W margin of Singhbhum and roughtly N-S margin, strike-slip shear zones developed in both the boundary regions.

22 ref

014151   Bhattacharya A;Gupta S (Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur-721 302) : Reappraisal of polymetamorphism in the Eastern Ghats belt - a view from north of the Godavari rift. Proc Indian Acad Sci-Earth Planet Sci 2001, 110(4), 369-83.

It is suggested on the basis of the evidences that the late Proterozoic/Pan-African granulites in the Eastern Ghats belt north of the Godavari rift, are unlikely to be reworked equivalents of any older granulitic crust, such as the <126>1.6 Ga granulites south of the rift. Instead, the temporally disparate sectors may represent different crustal segments with unconnected pre-amalgamation tectoni history. However, if the <126>1.6 Ga granulites of the Western Charnockite Zone continue northwards across the rift, as suggested by recent isotype data, there are serious doubts as to the validity of a north-south division within the Eastern Ghats belt.

4 illus, 33 ref

014150   Basu S;Iyengar G R;Mitra A K (NO, , ) : Impact of a nonlocal closure scheme in a simulation of a monsoon system over India. Monthly Weather Rev 2002, 130(1), 161-70.

The performance of the nonlocal closure scheme for the boundary layer has been tested in the operational global model of the National Centre for Medium Range Weather Forecasting (NCMRWF) for its possible implementation and operational use. Keeping the parameterization schemes for all other physical processes the same, the performance of the nonlocal closure scheme is studied and compared with the performance of the operational local closure scheme of the boundary layer processes. Incorporation of the nonlocal closure shceme shows marginal impact in the prediction of the flow pattern. However, systematic improvement in the precipitation distribution over the Indian region is seen with the incorporation of a nonlocal closure scheme during the month of August 1999. Location of the precipitation maximum along the west coast of the southern peninsula is better predicted. The skill score for predicing areas of higher precipation is increased with the nonlocal closure scheme. The systematic errors of the model are also reduced with the inclusion of the nonlocal closure scheme. An efficient transport mechanism in the vertical associated with the nonlocal closure scheme could be one of the main reasons for the better performance.

32 ref

014149   Basu A R;Premo W R (Department of Earth & Environmental Sciences, University of Rochester, Rochester, New York 14627, USA) : U-Pb age of the Diana complex and Adirondack granulite petrogenesis. Proc Indian Acad Sci-Earth Planet Sci 2001, 110(4), 385-95.

The magmatic portions are characterized by typical dipyramidal prismatic zoning and numerous black inclusions that make them quite distinct from adjacent overgrowths or cores when observed in polarizing light microscopy and in back scattered electron micrographs. Careful handpicking and analysis of the "best" magmatic grains, devoid of visible overgrowth of core material, produced two nearly concordant points that along with two of the multi-grain analyses yielded an upper-intercept age of 1118±2.8 Ma and a lower-intercept age of 251±13 Ma. The older age is interpreted as the crystallization age of the syenite and the younger one is consistent with late stage uplift of the Appalachian region. The 1118 Ma synchronous with the main Adirondack anorthosite intrusion, implying a cogenetic relationship among the various meta-igneous rocks of the Adirondacks. The retention of a high-temperature contact metamorphic aureole around Diana convincingly places the timing of Adirondack regional metamorphism as early as 1118 Ma. This result also implies that the sources of anomalous high temperature during granulite metamorphism are the syn-metamorphic intrusions, such as the Diana Complex.

3 illus, 2 tables, 37 ref

014148   baksi A K (Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803, USA) : Rajahmundry traps, Andhra Pradesh : evaluation of their petrogenesis relative to the Deccan traps. Proc Indian Acad Sci-Earth Planet Sci 2001, 110(4), 397-407.

Geochemical and geochronological data for rocks from the Rajahmundry Traps, are evaluated for possible correlation with the main Deccan province. Lava flows are found on both banks of the Godavari Rive and contain an intertrappean sedimentary layer. Based on ⁴⁰Ar/³⁹Ar age data, rocks on the east bank are post K-T boundary, show normal magnetic polarity, and belong to chron 29N. Their chemistry is identical to lavas in the Mahabaleshwar Formation in the Western Ghats, <126>1000 km away. It was suggested earlier that the genetic link between these geographically widely separated rocks resulted from lava flowing down freshly incised river canyons at <126>64 Ma. For the west bank rocks, recent paleomagnetic work indicates lava flows below and above the intertrappean (sedimentary) layer show reversed and normal magnetic polarity, respectively. The chemical composition of the west bank flow above the intertrappean layer is identical to rocks on the east bank. The west bank lava lying below the sedimentary layer, shows chemistry similar to Ambenali Formation lava flows in the western Deccan. ⁴⁰/Ar³⁹Ar dating and complete chemical characterization of this flow is required to elucidate its petrogenesis with respect to the main Deccan Province.

9 illus, 3 tables, 50 ref

014147   Attri S D;Singh K K;Kaushsik A;Rathore L S; Mendiratta N;Lal B (India Meteological Department, , New Delhi) : Evaluation of dynamic simulation model for wheat genotypes under diverse environments in India. Mausam 2001, 52(3), 561-6.

Performance of dynamic crop growth simulation model (CERES - Wheat v3.5) has been evaluated for various wheat genotypes in wheat growing regions of India. The genetic coefficients were developed and sensitivity analysis was carried out for the genotypes under study. The simulated phenology and yield were found in agreement with observed ones suggesting that calibrated model may be operationally used with routinely observed soil, crop and weather parameters.

3 illus, 2 tables, 15 ref

014146   Akhilesh Kumar;Arora U;Jain R (Department of Soil & Water Conservation Engineering, College of Technology, Pantnagar-263 145) : Performance evaluation of hydraulic energy dissipaters. Indian J Soil Conserv 2001, 29(3), 206-12.

Hydraulic energy dissipaters, also known as stilling basins, like SAF, USBR-II, and USBR-III, are commonly used at the outlet of a drop structure in order to dissipate hydraulic energy of flow. Energy dissipation of super-critical inflow is required to establish safe outflow conditions to prevent detrimental effects on the downstream lands. The performance of these energy dissipaters varies with drop and discharge conditions. An attempt has been made to evaluate the performance of SAF, USBR-II and USBR-III energy dissipaters in terms of the amount of energy dissipation and the rate of down stream soil erosion. The experimentation was carried out on simulated models under laboratory condition for varying discharge rates.

4 illus, 3 tables, 6 ref

014145   Adhikari R N;Selvi V;Rao M S R;Rao P B (NO, Central Soil and Water Conservation Research and Training Institute,, Bellary-583 104) : Classification of agroclimatic zones in Bellary region. Indian J Soil Conserv 2001, 29(3), 266-7.

7 ref

013125   Thapliyal V;Desai D S;Krishnan V (Meteorological Office, , Pune) : Hot weather season (March - May 2000). Mausam 2001, 52(2), 437-52.

2 illus, 5 tables

013124   Thapliyal V;Desai D S;Krishnan V (NO, Meteorological Office, Pune) : Post-monsoon season (October to December 2000). Mausam 2001, 52(4), 749-64.

2 illus, 5 tables, 5 ref

013123   Suresh R;Raj Y E A (NO, Regional Meteorological Centre, Chennai-600 006) : Some aspects of Indian northeast monsoon as derived from TOVS data. Mausam 2001, 52(4), 727-32.

Tiros Operational Vertical Sounder (TOVS) is a popular satellite sounding system. Certain features of Indian northeast monsoon have been studied with the help of three years of TOVS data received through the satellite ground station located at the Regional Meteorological Centre, Chennai. The TOVS based latitudinal and longitudinal profiles of outgoing Longwave Radiation (OLR) and Precipitable Water Vapour (PWV) were derived for various phases of northeast monsoon activity, over coastal and interior Tamil Nadu and oceanic regions. These were consistent with the known spatial rainfall characteristics of northeast monsoon. The average vertical temperature profiles derived for the various phases of northeast monsoon for the different regions revealed that the lowest layer and upper troposphere are warmer and mid troposphere colder during active northeast monsoon compared to dry phase. The diurnal variation of OLR and PWV and the comparability of TOVS derived data with conventional upper air data and INSAT data have been briefly discussed.

3 illus, 5 tables, 13 ref

013122   Suresh Prasad Babu;Jaya Prasad B K;Rajeev V S (Geosciences Division, Centre for Earth Science Studies, Akkulam, Thiruvananthapuram-695031) : Terrain evaluation using remote sensing and GIS-case study of Neyyar wild life sanctuary, Kerala. J Indian Soc Remote Sens 1999, 27(4), 253-67.

A multi-thematic analysis based on different physical factors has been adopted to generate integrated maps on erosion proneness as well as on critical slope under a GIS platform for terrain evaluation. This spatial data on erosion proneness has demonstrated that 17.62 km² area, out of the 140 km² in the catchment zone, needs careful attention for ecorestoration. In the critical slope map four land stability classes have been demarcated. The area represented as Unstable and Moderately-stable is found to be important for slope stability problems. Temporal change in the drainage network over a period of four decades as well as the extent of loss in the perennial status of tributaries have been recorded to evaluate the landform changes. A catchment treatment plan has also been suggested.

7 illus, 2 tables, 11 ref

013121   Singh O P (NO, Meteorological Centre, Bhubaneswar) : Long term trends in the frequency of monsoonal cyclonic disturbances over the north Indian ocean. Mausam 2001, 52(4), 655-8.

Long term trends in the frequencies of cyclonic disturbances (i.e. depressions and cyclonic storms) and the cyclonic storms forming over the Bay of Bengal and the Arabian Sea during the southwest monsoon season (June-September) have been studied utilizing 110 years data from 1890-1999. There have been significant decreasing trends in both the frequencies but the frequency of cyclonic disturbances has diminished at a faster rate. The trend analysis shows that the frequency of cyclonic disturbances has decreased at the rate of about six to seven disturbances per hundred years in the monsoon season. The frequency of cyclonic storms of monsoon season has decreased at the rate of one to two cyclones per hundred years.

2 illus, 7 ref

013120   Shravan Kumar;Thakur Prasad;Sashidharan N V; Nair S K (NO, Regional Meteorological Centre, Colaba, Mumbai-400 005) : Heat island intensities over Brihan Mumbai on a cold winter and hot summer night. Mausam 2001, 52(4), 703-08.

Mobile temperature survey of Brihan Mumbai (Greater Bombay) was undertaken on 16 January 1997 which incidentally turned out to be the coldest winter night. Heat islands were found well inside the city, away from the coastal boundary, within a distinct tongue of warm air splitting in three branches roughly along the three sub-urban railway tracks. The finding of the study were in sharp contrast with similar studies conducted during the early seventies by Daniel and Krishnamurthy (1973) and later by Mukherjee and Daniel (1976). They found a remarkable influence of sea on the horizontal temperature distribution in comparison to other factors of urbanisation and noticed the heat island over Malabar Hill, Girgaum and Cuffe Parade area. The survey conducted after a span of twenty-two years, showed that the temperature distribution in the city and suburbs has been modified significantly and that the effect of urbanisation has overtaken the effect of maritime influence in the formation and maintenance of heat islands. Another mobile temperature survey was conducted during the early hours of 11 May 1997 on the same lines as survey conducted on 16 January 1997, to confirm the findings of earlier survey and to assess seasonal changes in the intensities of heat island. This later survey showed similar pattern of horizontal temperature distribution, though the intensity of heat island observed was only 5.5°C as compared to 11.8°C observed during winter.

2 illus, 3 ref

013119   Sharma D K;Bansal M K;Rai J;Israil M (Department of Physics, University of Roorkee, Roorkee-247 667) : Variation of aerosols in relation to some meteorological parameters. Mausam 2001, 52(4), 709-16.

Atmospheric aerosol concentration has been measured at Roorkee (29°52' N, 77°53'E and hmsl 275m) during November 1998 to August 1999 at a height of 9m above the ground level. The variation of aerosol concentration has been studied in view of some meteorological parameters like relative humidity, temperature, rainfall and wind speed during the period from April-July, 1999 at Roorkee. The measurements were done with the help of an optical particle counter. The counter monitors the number concentration of aerosols in the size range from 0.3 to 5.0 μm. This size range is mainly responsible for the optical effects and radiation budget in the atmosphere. The aerosol concentration for large size ranges (1.0-2.0 μm and 2.0-5.0μm) has a tendency to be higher in the month of June due to prevailing meteorolgical conditions and minimum during July. Further, aerosol concentration in the small size ranges (0.3-0.5 μm and 0.5-1.0 μm) decreases monotonically up to the end of July. The decrease of concentration of aerosols in the month of July has been attributed to the scavenging due to rain. The variation of aerosol concentration with relative humidity has been explained in terms of condensation taking place in the atmosphere. During this period the meteorological parameters play important role in characterizing the aerosol distribution.

6 illus, 1 table, 12 ref

013118   Sarkar J;Seetharam K;Shaha S K (India Meteorological Department, , Pune-411 005) : Climatology of dry and wet spell over Vidarbha region during monsoon months. Mausam 2001, 52(2), 365-70.

Ten day periodwise simple probability, 10-day periodwise probability of consecutive dry and wet spells of different lengths, and monthwise different parameters and properties of Markov Chain Model over Vidarbha region during south-west monsoon months have been studied. For this purpose, daily rainfall data (1 June - 30 September) of 11 stations covering all the districts of Vidarbha for the period 1960-90 have been utilized. The study reveals that over Vidarbha during monsoon season (June - September) probability of a day being and probability of consecutive wet spell of different lengths are by and large high during the last and first 10-day periods of July and August respectively when the monsoon is at its peak. During the first two 10-day periods in June and last two 10-day periods in September, the probabilities of a dry day and that of consecutive dry spell of different lengths are quite high. During July and August a maximum of 12-14 wet days are expected and wet spell, on an average, lasts for 2 days. Stationary probability of the occurrence of wet day (π2) is found to be maximum during July making it the most humid month in the monsoon season.

1 illus, 3 tables, 6 ref

013117   Sarangi R K;Chauhan P;Nayak S R (Marine and Water Resources Group, Remote Sensing Applications Area, Ahmedabad-380 015) : Phytoplankton bloom monitoring in the offshore water of northern Arabian sea using IRS-p4 OCM satellite data. Indian J Mar Sci 2001, 30(4), 214-21.

IRS-P4 Ocean Color Monitor (OCM) satellite data were analyzed to generate chlorophyll a images during the winter monsoon period to understand the high productivity and algal bloom patches as observed in the chlorophyll images. The winter bloom in the northern Arabian Sea is the most intense because of the nutrient build-up prior to its onset is so large and the mixed layer detrains earlier than in the other regions, which in turn triggers the surface productivity. A few bloom forming features are identified in the OCM derived chlorophyll images in nine days of overpasses (February, 15 to March 4, 2000) of the late winter monsoon period and their movement mechanism on temporal scale has been studied. Very high chlorophyll concentration in the range of 2.0 to 5.0 mg/m³ have been observed around the bloom forming waters in satellite images. The peak chlorophyll concentration observed in the center of patches reduces towards their peripheral water. The curly bloom forming features initiates with moderate chlorophyll concentration (0.6-1.0 mg/m³), grows to high concentration (1.0-2.0 mg/m³) and diminishes with low concentration (<60> mg/m³) ranges, lasting for about two-three weeks duration.

5 illus, 1 table, 23 ref

013116   Santhosh K;Sarasakumari R;Gangadharan V K; Sasidharan N V (NO, Meteorological Centre, Thiruvananthapuram) : Some climatological features of thunderstroms at Thiruvananthapuram, Kochi and Kozhikode airports. Mausam 2001, 52(2), 357-64.

Average monthly frequency of thunderstorms, its annual and monthly frequency of duration, time of commencement and frequency of thunderstorms, in relation to duration and time of commencement at three aerodrome stations of Thiruvananthapuram, Kochi and Kozhikode have been presented. It is found that thunderstrom activity is maximum in pre-monsoon months at Thiruvananthapuram and Kochi and in post monsoon months at Kozhikode. Majority of the thunderstorms are of duration less than three hours and have a preference to commence between 9 and 18 UTC in all stations whereas long duration thunderstorms generally commence between 9 and 15 UTC.

6 tables, 6 ref

013115   Saha K;Saha S (NO, , 27, B-Road, Maharani Bagh, New Delhi-110 065) : Australian monsoon. II. Depressions and cyclones. Mausam 2001, 52(2), 333-50.

Study of the NCEP/NCAR Reanalysis for the Australian region during the southern summer reveals that most of the depressions and cyclones over the region form and develop in a stationary wave that develops along the continent's northern coastline during this period due to land-sea thermal contrast. The structure and properties of the stationary wave are brought out in detail and internal and external forcings that lead to its development into depressions and cyclones are discussed. Environmental factors that appear to influence the movement and recurvature of cyclones over the region are discussed with two case studies.

14 illus, 38 ref

013114   Ravinder K;Rabindranathan S (Division of Environmental Sciences, Indian Agricultural Research Institute, New Delhi-110012) : Ground validation of an algorithm for estimating surface suspended sediment concentrations from multi-spectral reflectance data. J Indian Soc Remote Sens 1999, 27(4), 235-51.

Presents the results of a ground validation study on characterization and quantification of surface suspended sediment concentrations (SSC) in sediment laden water bodies through an n-waveband specific numerical index, total information content. A comparison of SSC-predictive potential of the proposed new index, derived from four broad Landsat MSS, five broad Landsat TM and eight narrow IRS-P4 OCM spectral bands, with that of the conventional indices, computed from the same spectral band data, is also presented. Revealed that is SSCs 250 mg/l, the proposed index (derived from either broad / narrow landsat MSS/TM or IRS-P4 OCM spectral data) could lead to SSC predictions (with mean errors within 20%) comparable with those obtained with the conventional indices (derived from the same spectral band data). It could further be observed that, in general, lower sediment concentrations (i.e. SSCs 150 mg/l) were associated with higher prediction inaccuracies. A comparison of the mean errors of predictions associated with the proposed and the conventional (NIR-Red and NIR+RED) indices computed from broad and narrow band data for SSCs 150 mg/l, revealed that an increase in number of wavebands and a decrease in the bandwidth of these wavebands led to a significant increase in the prediction accuracy of the proposed new index. Prediction accuracies were observed to be the highest with the proposed index calculated from narrow OCM P4 spectral data.

6 illus, 2 Tables, 23 Ref

013113   Rao N S;Reddy R P (Hydrogeology Laboratory, Department of Geology, Andhra University, Visakhapatnam-530 003) : Groundwater prospects in a developing satellite township of Andhra Pradesh, India, Using remote sensing techniques. J Indian Soc Remote Sens 1999, 27(4), 193-203.

Geomorphologic map prepared, using the remote sensing techniques and conventional methods, has been used to assess grouundwater prospects in a developing satellite township of Visakhapatnam Metropolitan Complex, Andhra Pradesh, India. The geomorphic units delineated are denudational, fluvial and coastal. Indicates that the fluvial and rolling plains are promising zones for groundwater occurrence. The denudational landforms are not considered as groundwater potential zones, whereas the groundwater occurring in the coastal plain is not suitable for any use, because of its brackish nature.

5 illus, 1table, 19 ref

013112   Rama Rao Y V;Prasad K;Sant Prasad (India Meteorological Department, , New Delhi) : Case study of the impact of INSAT derived humidity profiles on precipitation forecast by limited area model. Mausam 2001, 52(4), 647-54.

Impact of humidity profiles estimated from INSAT digital IR cloud imagery data on initial moisture analysis in the IMD's operational limited area forecast system has been investigated. Method for assimilation of humidity profiles data as pseudo observations in the analysis scheme has been developed and implemented in the regional analysis scheme. Verification of humidity analysis with this data has shown substantial improvements in the moisture analysis over the data sparse region of tropics. Impact of the improved humidity analysis on model predicted rainfall is examined. The experiments show improved rainfall prediction.

6 illus, 8 ref

013111   Raghavan B R;Vinod B T;Dimple K A;Venkatesh Prabhu H;Udayashankar H N;Sreedhara Murthy T R (Department of Marine Geology, Mangalore University, Mangalore-574 199) : Evaluation of the Nethravathi spit complex, west coast of India: integrated change detection study using topographic and remotely sensed data. Indian J Mar Sci 2001, 30(4), 268-70.

Nethravathi spit complex of Karnataka coast consists of Mangalore spit to the north and Ullal spit to the south of Nethravathi-Gurupur river mouth. The integration of topographic sheets and satellite imageries of this area has enabled the evaluation of the migration of spits over a period of 83 years. Morphologically, Mangalore spit has shrunk by 750 m in length and 749780 m² in area. On the other hand the Ullal spit exhibits an increase in length of 800 m and an area of 111620 m². The spits show no prominent lateral migration. Shrinkage of the Mangalore spit and the growth of the Ullal spit indicates net northward migration of the estuarine mouth.

^ssc1 illus, 1 table, 14 ref

013110   Patel I P;Krishna Kumar G (NO, Meteorological Office, Pune-411 005) : Cyclonic storms and depressions, affecting Orissa state. Mausam 2001, 52(2), 424-7.

^ssc5 illus, 2 tables, 8 ref

013109   Nayak S;Bahuguna A (Marine and Water Resources Group, Space Applications Centre, Ahmedabad-380 015) : Application of remote sensing data to monitor mangroves and other coastal vegetation of India. Indian J Mar Sci 2001, 30(4), 195-213.

Remote sensing data, because of its repetitive, synoptic and multi-spectral nature, has proved to be of an immense value in monitoring of coastal vegetation. Indian Remote Sensing Satellite (IRS) data have been extensively used to map mangroves and other coastal vegetation for the entire country's coastline. Large database on spatial extent of mangroves and their conditions has been created on 1:250,000, 1:50,000 and 1:25,000 scale using IRS data (the database provides information for the first time on the mangrove areas of the entire Indian coast). Based on this study, it was observed that the Kori creek, Gujarat, has large area under mangroves. The repetitie nature of the data has helped in monitoring vital and critical areas, periodically. In one such study, on the Marine Natioanl Park, in the Gulf of Kachchh, mangrove areas were monitored for the last 25 years. The degradation of mangroves continued up to 1985 and the condition significantly improved due to the adoption of conservation measures. This has helped in planning various mangement actions to conserve this vital ecosystem. IRS data have been used in identifying dominant plant communities in many mangrove areas such as Bhitarkanika, Coringa, Mandovi estuary in Goa and the Gulf of Kachchh, etc. This is a unique approach for providing spatial information at plant community level and can be seen as a first step towards bio-diversity assessment.

14 illus, 3 tables, 56 ref

013108   Naidu J V M;Visweswara Rao D;Prasada Rao V L; Rao S V (NO, Cyclone Warning Centre, Visakhapatnam) : Tornadoes associated with Bay of Bengal cyclone of 8-10 November 1995. Mausam 2001, 52(2), 427-31.

6 illus, 5 ref

013107   Muthuchami A;Ramakrishnan B;Subadra P A (NO, Regional Meteorological Centre, Chennai-600 006) : Salient features of maximum temperature distribution over Tamil Nadu. Mausam 2001, 52(2), 351-6.

Attempt is made to study the spatial variations of maximum temperature over Tamil Nadu. From the data of daily maximum temperature of eleven stations in Tamil Nadu for the first six months from 1981 to 1997, it is observed that there are two separate regions namely high maximum temperature region of interior stations and low maximum temperature region of coastal stations from January to May and the distinction disappears in June. Hill station Kodaikanal recorded less maximum temperature than Ootacamund from January to May and it reverses in June. During onset phase of southwest monsoon, maximum temperature decreases over Coimbatore, Pamban and Kanyakumari. In the presence of cyclonic storm over the Bay of Bengal the maximum temperatures are fallen during the period when the storm affects Tamil Nadu or Andhra coast in May and June whereas when the storms moves farther away from the coast maximum temperature over interior places decreases and increases over north coastal stations.

5 illus, 1 table, 2 ref

013106   Madan O P;Ravi N;Mohanaty U C (Centre for Atmospheric Sciences, Indian Institute of Technology, Hauz Khas, New Delhi-110 016) : Forecasting peak surface gust wind in association with thunderstorm activity during pre-monsoon season at Delhi. Mausam 2001, 52(2), 385-96.

Attempt is made to develop an objective method for forecasting the direction and speed of the gusty winds associated with thunderstorms at Delhi. For this purpose, surface and upper-air data for April, May and June (AMJ) for the years 1985-90 are utilized. Multiple regression equations are developed for forecasting the direction and speed for the gusty winds, using stepwise screening method, for which a total of 181 potential predictors are utilized. The developed dynamical-statistical models are tested with independent data sets of 1994 and 1995 for April, May and June. The dynamical-statistical models give satisfactory results with the developmental as well as the independent data sets. The root mean square error of the direction vary between 58° and 77° and the speed forecast vary between 9 and 12 knots. Possible reasons for large deviations of the forecast, noticed on a very few occasions, have also been examined.

8 illus, 3 tables, 9 ref

013105   Kulshrestha M;Shekh A M (Department of Agricultural Meteorology, B.A. College of Agriculture, Gujarat Agricultural University, Anand, Gujarat) : Estimation of soil temperature by harmonic analysis. Mausam 2001, 52(2), 379-84.

Soil temperatures recorded at 5, 10 and 20 cm depth at Anand station of Gujarat state for the period of 1982-93 were analyzed by harmonic analysis and tested it for the year 1998. The amplitude of the soil temperature wave for the various depths decreases from a maximum of 5.76°C in the first harmonic to 0.96°C in the third harmonic. First, second and third harmonic explained 55 to 76 percent, 18 to 37 percent and 2 to 4 percent of the total variance, respectively. Total percentage of total variance covered by the three harmonics at different depths are in the range of 95 to 97 percentage for the period of 1982-93 normalized data series which shows the applicability of harmonic analysis in describing soil temperatures. The weekly observed and computed soil temperatures by harmonic analysis were in agreement and their differences were non significant by Chi-Square test.

3 illus, 4 tables, 8 ref

013104   Kane R P;Casiccia C (Instituto Nacional de Pesquisas Espacias, Sao Jose dos Campos, , Sao Paulo) : Twisting turning and pulsating of the Antarctic ozone hole, as revealed by TOMS data. Mausam 2001, 52(2), 397-412.

Using data from TOMS/Nimbus 7 and Meteor 3, the evolution of Antarctic ozone holes during the southern springs of 1992, 1993, 1994 was studied. At the South Pole, the evolution was mostly smooth, a steady decrease up to about September end and a steady recovery up to about December end. At latitudes near 65° S, the ozone levels (″220 DU) at different latitudes and longitudes showed fluctuations compatible with passing of a noncircular (oval) vortex boundary (two ends of a major axis of an ellipse), with a rotation period of ″15 days (full rotation period ″30 days) in 1992 and ″17 days (full rotation period ″34 days) in 1994, different from the 2-3 weeks reported by earlier workers. However, the rotation was not with uniform speeds. During a full rotation, the speeds varied sometimes from almost zero (stalling) for a few days to ″20° per day during other intervals. Outside the oval boundary, often there were depletions with spacings of a few (5-8) days, extending to lower latitudes up to ″30°S, indicating corrugations in the oval boundary, probably due to the effects of synoptic disturbances on total ozone through tropopause pressure changes and/or ozone mini-holes caused by anticyclonic tropospheric forcing under the southern polar vortex.

7 illus, 70 ref

013103   Kane R P (NO, Instituto Nacional de Pesquisas Espaciais - INPE, C.P. 515, 12201-970 - Sao Jose dos Campos, SP, Brasil) : Trends, periodicities and ENSO relationships of the annual precipitation over the contiguous United State and Southern Canada. Mausam 2001, 52(4), 659-68.

Century-long (1891-1990) time series of Groisman and Easterling (1994a,b) representing estimates of annual precipitation amounts over five homogenous regions of the United States and Southern Canada (south of 55° N) were examined for trends, periodicities and ENSO relationship. The trends were not uniformly up or down during the 100-year interval, for any region. From 1891 to about 1930, the trends were downward or negligible. Thereafter, the trends were mostly upward, with cyclic variations superposed. A spectral analysis revealed significant periodicities in the QBO and QTO regions (2-3 years and 3-4 years) as also higher periodicities, some common to all regions and hence seen in the series for the entire region. To study the ENSO relationship, a finer classification of El Nino events was used. Each year was examined to check whether it has an El Nino (EN) and/or a Southern Oscillation Index SOI minimum (SO) and/or warm (W) or cold (C) equatorial eastern Pacific sea surface temperatures SST. Several years were ENSOW, which were further subdivided into two groups viz. Unambiguous ENSOW where El Nino existed and SOI minima and SST maxima were in the middle of the calendar year (May-Aug.), and, Ambiguous ENSOW where EL Nino existed but the SOI minima and SST maxima were in the early or late part of the calendar year, not in the middle. Other El Nino events were of the type ENSO, ENW, ENC, EN.

4 illus, 2 tables, 23 ref

013102   Jegede O O;Foken T;Balogun A A;Abimbola O J (Department of Physics, Obafemi Awolowo University, Ile-Ife, Nigeria) : Bowen ratio determination of sensible and latent heat fluxes in a humid tropical environment at Ile-Ife, Nigeria. Mausam 2001, 52(4), 669-78.

Bowen ratio energy balance (BREB) method is the most widely used for estimating the fluxes of sensible heat and latent heat near the surface largely because of its conceptual simplicity and the robustness of instrumentation required. It has been adopted the same technique to study partitioning of measured available energy (difference of net radiation and soil heat flux) over bare soil at a humid tropical location in Ile-Ife, Nigeria (7°33'N, 4° 34' E) between 7 and 10 March, 1999. Results obtained of the diurnal variations of the both fluxes in relation to the changing surface conditions (case studies) are quite satisfactory. For dry days, the sensible heat flux is comparatively of the same magnitude as the latent heat flux but it is less, about 10-60% for the wet surface conditions. It is clear from the study that for the tropical forest zone, evaporation is the next important factor after radiation in the energy balance due to the humid conditions that usually prevail. Except for the few instances when very weak gradients exist, particularly of moisture, during transition period (at sunrise or sunset), the technique has worked satisfactorily for day as well as night time periods regardless of prevailing weather conditions.

3 illus, 2 tables, 20 ref

013101   Ganesan G S;Muthuchami A;Ponnuswamy A S (NO, Regional Meteorological Centre, Chennai-600 006) : Various classes of rainfall in the coastal stations of Tamil Nadu. Mausam 2001, 52(2), 433-6.

1 illus, 2 tables, 2 ref

013100   Dutta S (NO, Meteorological Office, Pune-411 005) : Momentum flux, energy flux and pressure drag associated with mountain wave across Western Ghat. Mausam 2001, 52(2), 325-32.

Attempt has been made to parameterize the wave momentum flux wave energy flux and pressure drag associated with mountain wave across the Mumbai-Pune section of western ghat mountain in India. A two dimensional frictionless, adiabatic, hydrostatic, Boussinesq flow with constant basic flow (U) and constant Brunt Vaisala frequency (N) across a meso scale mountain with infinite extension in the Cross wind direction, has been considered. It has been shown that for a vertically propagating (or decaying) waves the wave momentum flux is downward (or upward) and the wave energy flux is upward (or downward). It has also been shown that both the fluxes are independent of the half width of the bell shaped part of the western ghat. The analytically derived formula have been used to compute the pressure drag and to find out the vertical profile of wave momentum flux and wave energy flux for different cases of mountain wave across western ghat, as reported by earlier workers.

2 illus, 18 ref

013099   De U S;Prakasa Rao G S;Jaswal A K (NO, Meteorological Office, Pune-411 005) : Visibility over Indian airports during winter season. Mausam 2001, 52(4), 717-26.

Visibility plays a key role at the time of landing and take off operations at airports. The daily visibility data from 1969 onwards for 25 stations in the country (at 2100,0000,0300 and 0600 UTC) are examined for the winter period. Side by side the dry bulb temperatures and the relative humidity recorded at the same time are also examined. Linear trend regressions have been fitted on the data sets for each of the cities. The significance is tested at 99% level of confidence. In recent years, degradation of air quality in the cities has often been suggested as the cause for the increase in the number of poor visibility days (<60> 2000 meters) particularly in the morning hours. Continuous persistence of this phenomenon for a number of days has also been reported. The results show that there are decreasing trends in visibility at most of the stations. At 0300 UTC the visibility is generally low and increased afterwards due to mixing and turbulence in the boundary layer.

3 illus, 4 tables, 9 ref

013098   Chaudhuri S;Chattopadhyay S (Centre for Atmospheric Science, University of Calcutta, Calcutta-700 009) : Measure of CINE - a relevant parameter for forecasting pre-monsoon thunderstorms over GWB. Mausam 2001, 52(4), 679-84.

Method of testing the significance of Z - Statistic is introduced to discern the role of Convective Available Potential Energy (CAPE) and Convective Inhibition Energy (CINE) in forecasting the occurrence of pre-monsoon thunderstorms over Gangetic West Bengal (GWB). The result reveals that a negative correlation exists between CAPE and CINE. It further indicates that a range for the lower values of CINE can be fixed where the frequency of occurrence of such storms will be maximum, but such range, either for lower or for higher values of CAPE, is not possible. Reveals the finding that a measure of CINE is the only relevant parameter whereas CAPE has no significant role in forecasting the occurrence of pre-monsoon thunderstorms over GWB, which is in contrast to the concept of severe thunderstorms of Great Plains of America.

4 illus, 1 table, 23 ref

013097   Chattopadhyay N;Samui R P;Ravindra P S (NO, Meteorological Office, Pune-411 005) : Abiotic control on the incidence of pod borer on red gram. Mausam 2001, 52(4), 691-6.

Attempt has been made to work out the role of meteorological parameters on the incidence of pod borer on red gram. Minimum temperature and relative humidity (both morning and afternoon) were found to be negatively correlated while bright hours of sunshine in the preceding weeks was positively correlated with the pod borer population. Decrease in minimum temperature (≤ 12°C), morning and afternoon relative humidity (≤ 80% and ≤ 45% respectively) under clear skies favoured the multiplication and growth of the pest. Weather based guidelines generated could be used for the operational crop protection of pod borer on red gram.

4 illus, 26 ref

013096   Begum D A (Department of Physics, University of Chittagong, Chittagong, Bangladesh) : Total ozone potential vorticity and tropopause pressure: a comparative analysis over south-east Asia. Mausam 2001, 52(2), 413-20.

On the basis of TOMS data, a comparative analysis of total ozone, potential vorticity and tropopause pressure has been done over the area 20° - 50° N, 90° - 160° E (south-east Asia) for a period October 1982 to September 1983. The study has been done for three different latitude bands 20°-30° N, 30°-40° N and 40°-50° N. High correlations have been found near the tropopause level at all seasons except in autumn.

6 illus, 15 ref

013095   Basu G C;Basu S K (NO, Regional Meteorological Centre, Alipore, Calcutta-700 027) : Probabilistic study of monsoon daily rainfall at Calcutta by Markovian model and trend of rainfall during monsoon season. Mausam 2001, 52(2), 371-8.

One-step transitional probability matrices are obtained by Markovian model from one transitional state to other for different rainfall characteristics (such as, non-rainy days, light rains, moderate rains, heavy rains and very heavy rains) at Calcutta (Alipore) for different monsoon months. The disorderness (uncertainty) of the transitional system of the monsoon rainfall characteristics are studied by Shannon's model. The favourable or unfavourable condition of different states are also studied by redundancy test during monsoon period at Calcutta. A long-run probability vectors of such rainfall characteristics are found out from probability matrices. A trend in rainfall amounts during monsoon period at Calcutta for each of the monsoon month, June to September, has also been studied.

5 illus, 3 tables, 7 ref

013094   Basu G C (Regional Meteorological Centre, , Calcutta-700 027) : Feature of monsoon rainfall and its variability with comparative study in meteorological sub-divisions of West Bengal. Mausam 2001, 52(4), 736-46.

6 illus, 2 tables, 7 ref

013093   Ballal A S;Das H P (NO, Meteorological Office, Pune-411 005) : Contribution of water and radiation to growth and yield of pearl millet in Deccan plateau - a case study. Mausam 2001, 52(4), 685-90.

Agrometeorological data for the period from 1991 to 1997 have been used to study evapotranspiration demand and crop characteristics of pearl millet at Solapur. Crop coefficients, water use efficiency and radiation use efficiency have been worked out and discussed. This has been done for two varieties of the crop viz., ICTP-8203 and Shraddha. Reveals that pearl millet crop consumed maximum amount of water during earhead emergence phase, followed by flowering phase. During earhead emergence and flowering phase together, ICTP-8203 variety used nearly 50% of total water used while shraddha consumed about 60%. The highest values of crop coefficient are seen during earhead emergence phase for both the varieties. Maximum photosynthetically active radiation is availed by the crop during its vegetative phase. Radiation use efficiency is more for ICTP-8203 variety than Shraddha variety.

3 illus, 2 tables, 19 ref

013092   Abraham Thambi Raja S;Renuka G;Retnakumari K (Department of Physics, University of Kerala, Kariavattom, Thiruvananthapuram-695 581) : Ramdas layer and thermal wave during winter period. Mausam 2001, 52(4), 697-702.

Earlier works on Ramdas Layer were about its certainty, its existence, energy balance on the layer and a matching mathematical model. It was first identified in Thiruvananthapuram, Kerala, for eight days during a fortnight study on soil heat flux. A lifted minimum in temperature could have implications in agriculture and horticulture and so with a view to finding out a range of height through which Ramdas layer occurs, Ramdas-max, Ramdas-min are identified. On 24 January 1994, Ramdas layer occurred at a maximum height of 0.8m from the surface and the day is labeled as Ramdas-max. On 1 February 1994, it occurred at a lower height of 0.4m from the surface and the day is labeled as Ramdas-min. The thermal wave the ground and at 0.05m depth, the range of thermal wave at, its relationship with Ramdas layer, the temperature profile, the rate of change of heat in that layer with that at the surface and the subsoil heat flux at the sub-soil surface stratum (surface-0.05m) during Ramdas-max and Ramdas-min are duly compared and discussed.

5 illus, 3 tables, 13 ref

011950   Sudheer K P;Rangan D M;Saheb S M;Ramasastri K S (Deltaic Regional Centre, National Institute of Hydrology, Siddarth Nagar, Kakinada-533 003) : Estimating hydrological processes for watershed management : a case study of the tambaraparni river basin, Tamil Nadu. J appl Hydrol 2001, 14(2-3), 1-8.

The Tambaraparni river in Tamil nadu has a drainage area of 5969 Sq. Km. Relatively few analysis have been conducted on this river basin. A study has been conducted to estimate the components of hydrologic cycle for one of the sub basins (Pachaiyar) of Tambaraparni. The study employed the process-generating module of the SWRRB model developed by USDA. Since the model required continuous wheather data, a time series of weather data has been generated using another model. The efficiency of this model has been checked for a meteorological station out side the basin, whose data were readily available. The analysis resulted that the basin experiences 18.47 water stress days annually, which is a very low figure, indicating there is sufficient water available in the basin for agricultural purposes.

8 illus, 2 tables, 14 ref

011949   Sreenivasa Rao A;Rao P R M (Department of Inorganic and Analytic Chemistry, School of Chemistry, Andhra University, Visakhapatnam-530 003) : Assessment of drinking water quality in Kolleru lake area with reference to pesticides. Indian J envir Prot 2000, 20(9), 668-73.

Use of pesticides for agriculture and aquaculture purposes is widespread in Kolleru Lake area. The major population centers in Kolleru Lake region are the 148 villages of which 50 island villa ges around the lake. Ground water and water samples from village drinking water ponds were collected and analyzed for pesticides and physico - chemical parameters to assess the quality of drinking water in lake area with reference to pesticides.

2 illus, 6 tables, 21 ref

011948   Singh S K;Seth S M (G.P.S. Regional Centre, National Institute of Hydrology, Sagar-470 001) : Development and extrapolation of rating equation. J appl Hydrol 2001, 14(2-3), 36-42.

In order to obtain continuous discharge data from continuously measured stage, a reliable relationship between monitored variable stage and the corresponding discharge is essential at a gauging site. The stage discharge relationship may be expressed by a mathematical equation, commonly known as rating equation. The range of stage discharge relationship derived from measurements is nearly always exceeded by flood flows. Apart from this, conditions in a natural river are often unstable especially during floods. Another problem is the assessment of discharge during high stages by extrapolating the rating curve. Method for development of rating equation is presented along with the method to extrapolate the rating equation. The application of the procedure has been demonstrated and discussed on field data (1980-87) at Patan gauging site on rive Hiran, a tributary of Narmada. The shifting in the rating equation for different years and different discharges are discussed and accounted.

3 illus, 4 tables, 2 ref

011947   Shiv Kumar;Chauhan H S (Irrigation and Drainage Engineering, College of Technology, G.B. Pant University of Agriculture and Technol, Pantnagar-263 145) : Subsurface drainage in horizontally heterogeneous soil. J appl Hydrol 2001, 14(2-3), 49-58.

In the solutions of problems of subsurface drainage or seepage, the soils are generally assumed isotropic. In nature however, soils with heterogeneity, vertical or horizontal do occur. The problem of subsurface drainage/seepage between two parallel ditches or two water bodies reaching up to impermeable layer in a two layered horizontally heterogeneous aquifer receiving a constant recharge was formulated. Analytical solutions for steady state water table profiles were obtained using Boussinesq equation. The analytical solutions thus obtained were validated with experimental results on a vertical Hele-Shaw model simulating three sets of horizontal heterogeneity. The solutions were found to predict water table heights reasonably comparable with the experimental observations. The theoretically determined seepage parameters such as location of water divide and height of water table at interface of the two regions were found to be fairly comparable with experimental observations.

1 illus, 3 tables, 18 ref

011946   Saadon M N;Camerlengo A (NO, Universiti College Terengganu (UPM), Mengabang Telipot 21030 Kuala Terengganu, Malaysia) : Variation of the principal physical properties of the east coast of peninsular Malaysia. Ultra Scient phys Sci 2001, 13(1), 1-10.

Temperature, salinity and density profiles along the east coast of Peninsular Malaysia, are analyzed and compared. The data has been obtained from both the MV SEAFDEC cruise (during the southwest (SW) monsoon season) and the KTD KEPAH) oceanographic cruise (during the north (NE) monsoon). Results show that there are slight variations of temperature, salinity and density profiles during both monsoon seasons. However, the temperature salinity and density values are higher during the SW monsoon season as compared to the NE monsoon season. The thermocline, the halocline and pycnocline are absent at all stations, during the NE monsoon season. However, during the SW monsoon season, these layers are present only in the southern part of the study area.

7 illus, 12 ref

011945   Roy A B (Department of Geology, Mohanlal Sukhadia University, Udaipur-313 002) : Precambrian crustal growth: from the earliest transient crust to the assembly and breakup of supercontinents. Proc Indian Natn Sci Acad-Pt A 2001, 67(4-5), 439-60.

15 illus, 1 table, 121 ref

011944   Ram Babu B L;Dhyani;Nirmal Kumar;Tandon R (NO, Central Soil & Water Conservation Research & Training Institute, Dehradun-248 195) : Rainfall intensity-duration-return period equations and nomographs for Tamil Nadu. Madras agric J 2001, 88(4-6), 203-10.

Rainfall intensity-duration-return period equations and nomographs for various stations are required for designing soil conservation and runoff disposal structures and also for planning flood control projects. Such relationships and nomographs for the state of Tamil Nadu were developed during 1978 for few stations namely Madras (Chennai), Tiruchirapalli and Kodaikanal. Presently, long period self recording rainfall data for 18 stations of Tamil Nadu State have been obtained from Indian Meteorological Department, Pune. Based on the data, the intensity-duration-return period equations and nomographs for all the 18 stations have been developed and discussed along with the general equation and nomograph for the State of Tamil Nadu.

6 illus, 2 tables, 12 ref