007767   Garde R J (Central Water and Power Research Station, , P.O. Khadakwasla, Pune-411 024) : Hydraulic geometry and resistance of gravel-bed rivers. Proc Indian Natn Sci Acad-Pt A 2001, 67(6), 597-607.

Knowledge about the hydraulic geometric parameters viz. width, depth and area of the river at the bankful discharge are required for solving a variety of problems related to river training, location of bridges, and navigation. Further, the resistance offered to the flow by the boundary and air-water interface needs to be known in order to predict the average velocity of flow. Describes the results of the analysis of all the available gravel-bed river data, which has resulted in methods for the prediction of width, depth, area and the flow velocity or resistance coefficient.

9 illus, 2 tables, 26 ref

007766   Das D P;Sarkar K;Chakrabarti D K (Geological Survey of India, , Central Headquarters, Calcutta-700 016) : Statistical study of lineament fabric for targeting probable locales of kimberlite diatremes in the precambrians of central India. Indian Miner 2000, 54(3-4), 209-22.

Study covering about 6700 sq km area in the Precambrians of eastern M.P. and adjoining Orissa state was based on interpretation of Landsat TM-FCC and analysis of lineament fabric aimed at targeting probable locales of kimberlite diatremes in the host rocks. The magnitude and orientation aspects of lineament data have been studied through construction of frequency histograms and rose diagrams to describe the textural properties of the interpreted lineament fabric. The spatial pattern, shows a N-S0 trending zone of high lineament concentration parallel and close to the western margin of Khariar basin. The residuals computed from the trend surface recognise three distinct zones of high positive values occupying the southwest, west and northern parts of the terrain and show high positive correlation with the lineament intersection counts. Finally, a discriminant function analysis of the lineament attribute data, enabled identification of 20 sampled sites on weighted basis within the primary targeted zones as potential sites for kimberlite diatremes. However, it was noticed that the primary targeted zones as potential site for kimberlite diatremes. However, it was noticed that the reported kimberlite bodies in southwest part of the terrain are located in three of the 20 potential sampled sites having high score values.

4 illus, 5 tables, 6 ref

007765   Chauhan D S;Mathur K M;Narayan Ram (Department of Geology, Jai Narain Vyas University, Jodhpur-342 001) : Geological nature of the Pokaran boulder bed: palaeoenvironmental, palaeoclimatic and Stratigraphic implications. J Geol Soc India 2001, 58(5), 425-33.

Pokaran Boulder Bed forms the basal lithofacies of neoproterozoic-Cambrian Marwar Supergroup. The boulder bed denotes specific sedimentary milieus and palaeoclimatic settings during the terminal Proterozoic period and occurs in three distinct forms, viz., massive conglomerate, boulder spread and stratified conglomerate. These three forms of the boulder bed independently rest over the basement of Malani rhyolite and/or granite (<62>698 Ma) and mark an erosional unconformity at the base of the Neoproterozoic Marwar Supergroup (1000-540 Ma). It is suggested that the massive conglomerate is a product of weathering and disintegration of the basement rocks operating under semi-arid to arid conditions. The boulder spread is envisaged to be glaciogenic, whereas the stratified conglomerate is a product of glaciofluvial action. The stratigraphy of Marwar Supergroup is believed to be linked to the global Neoproterozoic glaciation. The base of Marwar Supergroup is interpreted to be late Neoproterozoic (<60>610 Ma). The occurrence in the same basin of climatically incompatible glaciogenic Pokaran Boulder Bed and Hanseran Evaporite vis-a-vis diamictite-evaporite fill is visualized to the effect of ice rings orbiting the earth. This has implications for stratigraphic correlation of such unique sequences.

7 illus, 2 tables, 28 ref

007764   Chadwick B;Hegde G V;Nutman A P;Vasudev V N (p12 Pennsylvania Close, Exeter EX4 6DJ, UK, , ) : Syenite emplacement during accretion of the late archaean Dharwar batholith, South India: SHRIMP U/Pb age and structure of the Koppal pluton, Karnataka. J Geol Soc India 2001, 58(5), 381-90.

Predominantly syenitic Koppal pluton was emplaced in the western flank of the Dharwar batholith which forms the eastern half of the Dharwar craton. Previous work has shown that the batholith accreted against an older continental foreland represented by the western half of the craton during Late Archaean oblique convergence. A sample of syenite has yielded a SHRIMP U/Pb zircon age of 2528±9 Ma which is interpreted as the time of emplacement at a late stage in the accretion of the batholith. Its age and composition make the Koppal pluton a unique feature of the Dharwar craton. Melt commingling of syenite with other intermediate to basic magmas is indicated by common mafic enclaves, disrupted mafic sheets and larger netveined bodies rich in hornblende and pyroxene. The arc setting of the Koppal pluton is consistent with syenitic plutons in other Late Archaean terrains. The pluton has an elliptical outcrop trending NE-SW with an upright, asymmetrical funnel shape indicated by its magmatic-state LS fabrics and diffuse compositional banding. Banding is a function of variations in microcline, hornblende and clinopyroxene abundances. The pluton was emplaced broadly parallel to diffuse magmatic banding in the host granites which lies oblique to trends of the steep NW-SE belts of plutonic rocks that characterise the Dharwar batholith as a whole.

8 illus, 2 tables, 31 ref

007763   Bhunya R K;Patwary B C;Nema R K (NO, National Institute of Hydrology, Roorkee-247 667) : Non-linear rainfall-runoff simulation for small basins using short term data: a case study for Myntdu-Leska basin (Meghalaya) and Krishnai basin (Assam). J Instn Engrs-Pt CI 2001, 82(Aug), 105-11.

Simple rainfall-runoff simulation model, based on a modified non-linear reservoir, is presented. The introduction of a time lag parameter in the dynamic non-linear equation S = ƒ (K, Q, n) changes its solution from implicit to explicit. The method uses forced runoff as a variable with accumulated storage lag to establish a non-linear relationship that can be used for approximate runoff prediction in the basin. The performance of the model was tested on short-term rainfall and discharge data of Myntdu-Leska basin (Meghalaya) and Krishnai basin (Assam) with catchment areas of 350 km² and 950 km², respectively. The analysis was carried on 13 selected events distributed over two years and the results showed degree of regression coefficient (R²) ranging from 62% to 91%. The goodness of fit is checked using integral standards error (ISE), error in peak estimates (PEAK) and chi square test. The ISE and PEAK gave low values indicating a good fit and chi square showed a better fit except for two events of Krishnai basin. In the dynamic equation parameters A is largely a scale parameters dependent on the units used and the other parameter B represents the degree of non-linearity in catchment response. Since only two basins are considered for the analysis, the relationship of parameter B with the catchment area could not be established.

4 illus, 2 tables, 10 ref

007762   Bhattacharya R S;Srirama B V (Geological Survey of India, , ER, 4, Chowringhee Lane, 8th Floor, D-Block, Calcutta-700 016) : Noise survey to establish broadband seismic station at Jabalpur, Madhya Pradesh. Indian Miner 2000, 54(3-4), 249-52.

^ssc3 illus, 3 ref

007761   Bansal O P;Gupta R (Department of Chemistry, D.S. College, Aligarh-202 001) : Groundwater quality of Aligarh District of Uttar Pradesh. Pesticide Res J 2000, 12(2), 188-94.

Groundwater samples from eight irrigation wells, five domestic wells (depth 4 to 36 m) and two canals (both rural and urban) used for irrigation and drinking purposes were analysed for nutrients, heavy metals and pesticides during the period 1996-97. The results indicate that pH, alkalinity, NO3^-, F^-, PO4^-1 and Cl^-, Zn, Al, Cu, Fe and Pb were within the tolerance limits, while Cr and Cd were at threshold level. The concentration of heavy metals was higher in domestic wells than in irrigation wells and concentration of heavy metals decreased with increase in the depth of well. Concentration of pesticides, viz., HCH, 2,4-D, malathion, parathion, aldrin/dieldrin were within the recommended limits, while DDT was beyond the limit.

3 illus, 3 tables, 10 ref

007760   Bandyopadhyay K P;Choudhury A (Marine Wing, Geological Survey of India, , Kolkata) : Early cretaceous megaflora from Belkher beds, Belkher, Amravati District, Maharashtra. Indian Miner 2000, 54(3-4), 151-68.

Fairly-rich megaflora collected from exposed section in the southern foothills of Satpura Range along Salbardi-Gawilgarh Fault Zone at Belkher (21°21'48"N: 77°31'42"E), Amravati District of Maharashtra has been systematically studied. This is the first report on the occurrence of Ptilophyllum assemblage in Gondwanas between Satpura Basin in north and Pranhita-Wardha Basin in the south. The Gondwana sediments comprising of fireclay-sandstone-siltstone sequence, exposed at Belkher is named here as `Belkher Beds'. A total of thirty-eight megaplant species are mentioned. Of these, eleven forms represented by insufficient specimens and, of fragmenting remains have been compared but not named. The Belkher floral assemblage constitutes a readily recognisable horizon in the Late Gondwana succession of India. This assemblage shows affinity with those of Early Cretaceous (119-144 Ma.) Bansa flora of Late Jabalpur assemblages of South Rewa Basin, Madhya Pradesh Nipania and Chunakhal flora of Rajmahal Basin, Bihar; Songad and Bhuj flora of Kathiawar and Kachchha Basins respectively of Gujarat and the flora of Early Cretaceous coastal indian Gondwana formations viz., Athgarh Formation of Orissa, Raghavapuram Shale and Gangapur Formation of Andhra Pradesh, Sivaganga Formation and Dalmiapuram Formation of Tamilnadu.

7 illus, 2 tables, 46 ref

007759   Alam M M;Ahmad A H M (Geology Section, Department of Civil Engineering, Zakir Hussain Engineering College, Aligarh Muslim University, Aligarh-202 002) : Lithofa cies and petrofacies analysis of alluvial fan deposits of the Bayana formation, Bharatpur district, Rajasthan. Indian Miner 2000, 54(3-4), 233-44.

Bayana sub-basin comprises thick sequence of basal metavolcanics and metasedimentary rocks belonging to the Delhi Supergroup. The Bayana Formation consists alternate conglomerate and sandstone lithofacies dedposited in fluvial-dominated tidal channels, tidal flats and subtidal environments. Aims to reconstruct depositional model and tectomic setting with the help of integrated litho- and petrofacies analysis. Three sedimentary lithofacies recognised are massive conglomerete, massie sandstone and crossbedded sandstone. Sedimentary attributes of these facies indicate that the sediments were deposited under alluvial fan complex buitl by braided streams. The detrital mineralogy of both conglomerate matrix and sandstones consists of several varieties of quartz, followed by mica, rock fragments, feldspar and heavies. The petrofacies plot in Qt=F-L, Qm-F-Lt and Qp-Lv-Ls ternary diagrams suggest craton interior, recycled orogen provenance and rifted continental-margin-type basin setting.

6 illus, 3 tables, 21 ref

007758   Agrawal R P;Saha D;Murugan S S (Central Groundwater Board, , Mid-Eastern Region, Lok Nayak Bhawan, 6th Floor, Dak Bungalow Chowk, Patna-800 001) : Hydrogeological investigation aided by resistivity survey in hard rock area - a case study in Palamu district, Jharkhand. Indian Miner 2000, 54(3-4), 201-08.

Study area is confined in west-central part of Palamu district of Jharkhand (erstwhile south Bihar) and is underlain by granitic gneiss of Precambrian age. As experienced in adjacent hard rock areas, the area experiences acute drinking water crisis in peak summer season i.e. in the months of May and June. The entire rural water supply is dependent on groundwater. Dug wells of 8 to 10 m depth range are most common groundwater structures. The water table ranges from 2.5 to 8 m below ground level in pre-monsoon period. The results of 11 VES study reveal the presence of potential fracture zone at depth between 20 to 50 m below ground level. The thickness of fracture zone generally ranges from 2 to 3 m bgl. Spatially, the groundwater-bearing zone are controlled by the alignment of fracture. These zones have good potential and can be developed through hand pumps and bore wells. A chemical factory producing caustic soda (Na OH) and hydrochloric acid (HCl) is located within the study area. One of the teething problems for groundwater development in the area is contamination groundwater in certain pockets due to leaching from salt stockpile and also from solid-waste dumping sites. The depth and distribution of fractures conforming polluted ground water have been demarcated and finally five sites have been selected for groundwater development through bore wells and dug-cum-bore wells.

4 illus, 3 tables, 6 ref

006830   Thapliyal V (India Meteorological Department, , Pune-411 005) : Long range forcast of summer monsoon rainfall over India: evolution and development of a new power transfer model. Proc Indian Natn Sci Acad-Pt A 2001, 67(3), 343-59.

Evolution of LRF of IMR over past hundred years is briefly reviewed. Currently used operational LRF models which helped IMD to issue, towards the end of May, reasonably accurate LRF during all the past 13 years (1988-2000) in succession, are described in detail. In addition, a few LRF models with greater forecast lead-time are also discussed. For developing a new LRF technique, the predictor-predictand relationship has been analysed in detail. Based on this analysis, an hypothesis has been proposed which states that the resultant association between a predictor and predictand can be expressed as a sum of the basic climate (long period) and perturbed climate (short period) associations, and both of these associations should be used by a model for accurate prediction. The hypothesis has been used for formulating a new Power Transfer (PT) model which used 9 predictors for LRF of IMR. These are land-ocean-atmosphere-related parameters which appear to have physical linkages with the monsoon. Performance of new PT (9) model with respect to operational PR (16) has been, in general, found better. During past 24 years (1977-2000), the new model has correctly predicted all the extreme events like the excess and deficient monsoons. The model has been abale to explain 88% of the variance. The root mean square error for past 23 years (1977-19990 has been found less than the half standard deviation (i.e. 5%) of IMR.

3 illus, 3 tables, 41 ref

006829   Thakur K S (Oilseeds Research Station (HPKV), , Kangra-176 001) : Trends of rainfall distribution in Kangra, H.P.. Himachal J agric Res 1998, 24(1-2), 1-10.

Daily rainfall data of 20 years (1977-1996) have been used to analyse for annual, seasonal and weekly distribution pattern and its variability in Kangra, H.P. Average annual rainfall of area is 1987 mm out which 80 per cent is received between June-September, rabi season (October to May) showed higher variability in rainfall as compared to Kharif season. The dates of onset and withdrawal of South-West monsoon fall with in 24th (June 11-17) and 37th (September 10-18) meteorological weeks, respectively. It reveals that period between mid June to mid-september can be considered as an assured period for crop growth. The chances of water stress increases in second fortnight of September for Kharif crops especially paddy. October, November and fist fortnight of December have 60-90 per cent chances of getting no rainfall. Keeping in view the rainfall pattern, and its distribution in the area, a few suggestions have been made with respect to crop planning to increase the productivity under rainfed conditions.

4 tables, 5 ref

006828   Solanki H U;Dwivedi R M;Nayak S R;Jadeja J V; Thakar D B;Dave H B;Patel M I (NO, Marine and Water Resources Group, Space Applications Centre (ISRO), Ahmedabad-380 015) : Application of ocean colour monitor chlorophyll and A VHRR SST for fisher forecast: preliminary validation results of Gujarat coast, northwest coast of India. Indian J Mar Sci 2001, 30(3), 132-8.

Ocean Chlorophyll - 2 (OC2) bio-optical algorithm was applied to corrected radiance to calculate chlorophyll concentration. Multi channel sea surface temperature (MCSST) approach was adopted for estimation of SST from split windo of NOAA AVHRR. Both data sets were geometrically corrected and registered with master image of north westcoast of India so as to generate geocoded chlorophyll and SST images. Sea surface temperature contours generated and overlaid on chlorophyll images to generate composite images. These composite images were interpreted for generating experimental fishery forecast along the Gujarat coast. Different types of the oceanic features like, coastal fronts, fringe fronts, rings mushrooms, meanders and features shaped as tongue and mushroom, jet etc. were selected for forecast. The information was disseminated to Porbandar for validation. Gillnetters were used for experimental fishing. Suggested areas were located using global positioning system (GPS). The feedback received from fishing sites were analysed. The catch per gill net operation was normalised and compared with month wise normal catch available around Porbandar. About 2-3 fold increase in the catch in potential fishing zones (PFZ) area was observed. The frontal positions in chlorophyll image coincide with temperature boundaries at some locations. This co-incidence indicates that physical and bio-chemical processes are closely coupled at these locations and can be used for identification of potential fishing zones (PFZs).

4 illus, 1 table, 13 ref

006827   Rajesh Kumar;Sarkar S K;Mali P (Radio and Atmospheric Sciences Division, National Physical Laboratory, , Dr. K. S. Krishnan Road, New Delhi-110 012) : Cloud characteristics and cloud attenuation over Kolkata. Indian J Phys-Pt B 2001, 75(5), 403-06.

Cloud occurs for higher percentage of time than rains so its effects in relation to the deterioration of signals in the radio systems can not be ignored. Cloud statistics over Kolkata for different months have been presented. The attenuation of radiowave due to clouds from 10 GHz to 100 GHz is more in winter season than the other seasons.

4 illus, 1 table, 13 ref

006826   Raikar M T;Raghukumar S;Vani V;David J J; Chandramohan D (Biological Oceanography Division, National Institute of Onceanography, Dona Paula, Goa-403 004) : Thraustochytrid protists degrade hydrocarbons. Indian J Mar Sci 2001, 30(3), 139-45.

Although thraustochytrid protists are known to be of widespread occurrence in the sea, their hydrocarbon-degrading abilities have never been investigated. Three isolates tested showed positive hydrophobicity of cell walls as judged by the Microbial Adhesion to Hydrocarbons (MATH) assay. Addition of Bombay High crude oil to nutrient broth slightly enhanced growth of the protists as compared to unenriched controls. Autoclaved crude oil added to sediments was degraded by 2 thraustochytrids to a much greater extent than non-autoclaved oil. Tarballs supported excellent growth of thraustochytrids when added to a peptone broth. Inoculation of thraustochytrids to tarball-enriched sediment resulted in a decrease of up to 71% of tarball contents after a month. Up to 30% of tarballs added to peptone broth was degraded by thraustochytrids in 7 days, as estimated by gravimetry and gas chromatography. Fractions above the retention time for 20°C aliphatics were degreded to a much greater degree than those below 20°C. Thraustochytrids appear to play a definite role in the ball degradation in sediments.

9 illus, 1 table, 27 ref

006825   Narasimha R;Kailas S V (Jawaharlal Nehru Centre for Advanced Scientific Research, , Jakkur, Bangalore-560 094) : Wavelet map of monsoon variability. Proc Indian Natn Sci Acad-Pt A 2001, 67(3), 327-41.

Rainfall over the homogeneous Indian monsoon area. for the period 1870-1990, has been analysed using wavelets. A methodology involving continuous wavelets and local scaling has been developed to reveal the possible existence of temporal structures in the original time series through maxima in locally normalized wavelet transform coefficients. The wavelet maps that are the outcome of this methodology reveal six modes, characterized by jittery oscillations or quasi-cycles with the approximate average periods of 3.0, 5.8, 11.6, 20.8, 37 and 80 years. There is some evidence for a mode with an even shorter period, but it is concluded that data would be required at shorter intervals than monthly to determine whether such a mode exists. It is concluded that data would be required at shorter intervals than monthly to determine whether such a mode exists. It is noted that the shortest period in the six modes mentioned above leans towards the higher end of the range usually quoted for the quasi-biennial oscillation, and the first two modes bracket the range of periods usually quoted for the quasi-biennial oscillation, and the first two modes bracket the range of periods usually quoted for ENSO. The other four modes with longer average periods suggest strongly an association with sun spot cycles with periods of successive modes going up approximately by a factor of two.

11 illus, 24 ref

006824   Mohan Kumar N;Harees Kumar P V;Rao R R (NO, Naval Physical and Oceanographic Laboratory, Thrikkakara (PO), Cochin-682 021) : Empirical model for estimating hourly solar radiation over the India seas during summer monsoon season. Indian J Mar Sci 2001, 30(3), 123-31.

This model was found to overestimate radiation for all sky conditions, in particular for 7 and 8 octa cloud cover by 300 W.m^-2. For overeast sky conditions, observed radiation was found to be independent of the altitude of the sun and dependent only on cloud thickness. The dominant cloud types observed during this period are thic cumulus and cumulonimbus with an everage base height of 300-1000 m. With a view to improve hourly estimation of radiation for all cloud categories, a new set of regression equations was developed based on transmission of radiation in the atmosphere and the altitude of sum. With the new model, estimation has considerably improved for all cloud amounts as indicated by the reduction in the standard error estimates, in particular for 7 and 8 octa cloud cover. Application of these two models to three independent data sets als sggests the suitability of the new model for the hourly estimation of radiation for monsoon cloud conditions the Indian Seas.

7 illus, 5 tables, 12 ref

006823   Mahadevan R;Latha G (NO, National Institute of Ocean Technology, Chennai-600 036) : Influence of coastal flooding on surge estimates along the east coast of India. Indian J Mar Sci 2001, 30(3), 115-22.

Influence of coastal flooding on surge estimates along the coast is examined using a procedure that is different from the conventional wet-dry grid point method. The mass and momentum fluxes across the coastal bondary due to surge flooding the coastal regions are modelled as sources/sinks along this boundary in the equations governing the flow field. The equations are solved using an explicit finite element scheme. The surges estimated with the source terms in the governing equations (i.e. allowing coastal flooding) and without them (i.e. applying the impermeable vertical wall assumption along the coast) show that the coastal flooding has insignificant influence on surge levels along the coast. Hence surges along the coast could be accurately estimated using the simple model, which assumes a fixed impermeable vertical wall along the coastal boundary.

7 illus, 3 tables, 22 ref

006822   Kumar V;Manivannan V (Department of Geology, National College, Tiruchirapalli-620 001) : Benthic foraminferal responses to bottom water characteristics in the Palk Bay, off Rameswaram, southeast coast of India. Indian J Mar Sci 2001, 30(3), 173-9.

Recent benthic foraminiferal assemblages from the shallow shelf sediments of the Palk Bay, off Rameswaram were studied qualitatively and quantitatively. The study revealed that the microfaunal assemblage consisting of 108 benthic foraminiferal species belonging to 50 genera of 27 families. Various bottom water parameters were determined and correlated with the foraminiferal population and seasonal distribution of living population was evaluated. The ecology and distribution of eight widespread and abundant foraminiferal species of the study area viz. Spiroloculina communis, Quinqueloculina seminulum, Triloculina insignis, T. trigonula, Ammonia beccorii, A. tepida, Pararotalia nipponica and Osangularia venusta were discussed in detail. Increase in temperature, salinity and dissolved oxygen content of the bottom water were observed as favourable factors promoting the abundance of living population in the study area.

4 illus, 1 table, 23 ref

006821   Kripalani R H;Kulkarni A;Sabade S S (Indian Institute of Tropical Meteorology, , Pashan, Pune-411 008) : El Nino Southern Oscillation, Eurasian snow cover and the Indian monsoon rainfall. Proc Indian Natn Sci Acad-Pt A 2001, 67(3), 361-8.

Investigates the E1 Nino Southern Oscillation (ENSO)-Monsoon and snow-monsoon teleconnections using long data series for more than one hundred years. Analysis of short-term climate variability over India reveals distinct epochs of above and below normal summer monsoon rainfall over India. The epochs tend to last for about 3 decades. It is seen that the impact of EI Nino (La Nina) is more severe during the below (above) normal epochs. Thus the impact of ENSO events on Indian monsoon rainfall (IMR) is modulated by the decadal variability of rainfall. The snow-monsoon relationship reveals that the winter-time snow depth over western (eastern) Eurasia is negatively (positively) related with the subsequent summer monsoon rainfall over India. The dipole correlation configuration is indicative of a mid-laitude long-wave pattern with an anomalous ridge (trough) over north Asia prior to strong (weak) Indian monsoon. The decadal scale IMR variations seem to be more associated with mid-latitude snow depth variations rather than the tropical ENSO variability.

5 illus, 29 ref

006820   Jayaraman A (Physical Research Laboratory, , Navrangpura, Ahmedabad-380 009) : Aerosol radiative forcing over teh tropical Indian ocean. Proc Indian Natn Sci Acad-Pt A 2001, 67(3), 385-94.

One of the important consequences of the increased aerosol loading in the atmosphere is the aerosol radiative forcing of the climate. The Indian Ocean Experiment (INDOEX) conducted over the Arabian Sea and the tropical Indian Ocean show a significant amount of continental aerosols get entrained with the surface air flow down to thousands of kilometers over the Indian ocean. The startling discovery is that these aerosols are highly absorbing (due to the prexence of soot) and contribute more to absorption (leading to a warm atmosphere) than scattering (resulting in a cooling of the Earth's surface) particularly near the coastal region and the polluted open ocean region. Ship cruise measurements of the columnar aerosol optical depth, surface reaching direct as well as the scattered sky radiation flux values are used to obtain the aerosol radiative forcing, which is defined as the reduction in the radiation energy due to the presence of aerosols compared to an aerosol free clean atmosphere. Over the coastal region, aerosols cause a reduction of about 27 Wm^-2 (about 15%) in the surface reaching solar visible radiation, of which about 20.1 Wm^-2 radiation energy is absorbed int he atmosphere. This atmospheric solar heating is more than a factor of 5 greater than due to all known Greenhouse grases. The amount of aerosol absorption however decreases with increasing distance from the coast.

6 illus, 17 ref

006819   Granat L;Rodhe H (Department of Meterology, Stockholm University, S-10691, Stockholm, Sweden) : Influence of air mass trajectories on the chemical composition of precipitation in India. Atmos Envir 2001, 35(25), 4223-35.

Chemical composition of precipitation was measured with wet-only samplers at a rural site at Bhubaneswar in eastern India during 1997-1998. All rain events were compared with trajectories and precipitation fields from the ECMWF. The pH and ionic concentrations were found to vary systematically, with the origin of air and the amount of rainfall along the trajectory. A seasonal cycle for pH was found with a monthly median pH below 5.0 during October December. The highest monthly median concentration of Ca2+ was found in May with 20 mu mol 1(-1) and for SO42- in January with 52 mu mol 1(-1). Samples with trajectories within 400 km from Bhubaneswar during the last 5 days were found to have a median pH slightly below 5.0 as an average. These samples also had the highest concentration for all measured ions, indicating large pollution sources within the region. Samples with continental origin showed a decrease of similar to 70% in concentration of there had been rein during <62>50% days compared to rain during <60> 50% of the last 5 days. High concentration of Na⁺ and Cl^- were also found in continental samples. Resuspension of previously deposited sea salt is believed to be the reason. The data were compared with data from three other sites in western India and higher concentrations of almost all ions (NH4+ being the exception) compared to Bhubaneswar were found at the west coast in monsoon samples.

26 ref

006818   Goswami B N;Ajaya Mohan R S (Center for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore-560 012) : Intra-seasonal oscillations and predictability of the Indian summer monsoon. Proc Indian Natn Sci Acad-Pt A 2001, 67(3), 369-83.

Modelling and observational evidence is presented to support a hypothesis that the vigorous monsoonal intra-seasonal oscillations (ISO's) sets a limit on predictability of the Indian summer monsoon by producing `internal' low frequency variability that is often comparable or even larger than those produced by the predictable slowly varying boundary forcings. Two long simulations of an atmospheric general circulation model one of which has no inter-annual forcing are used to estimate the ratio between `internal' and `external' variability. This ratio is found to be close to one over the Indian monsoon region indicating that the Indian summer monson may be only marginally predictable. Using a nonlinear dynamical system model it is shown that the large low frequency `internal' variability may arise from an interaction between the ISO's and the annual cycle. Daily observations of circulation for 33 years and outgoing long-wave radiation (OLR) data for 24 years are then used and a method is presented to estimate this ratio from observations. It is shown that the monsoonal ISO's primarily contribute to the `internal' low frequency variability and that the ratio between the `internal' and `external' variability is close to one over the Indian monsoon region. To derive further insight how the ISO's effect the seasonal mean monsoon, the structure of spatial and temporal variability of the ISO's are studied in relation to those of the seasonal mean monsoon.

9 illus, 1 table, 40 ref

006817   Godhantanterama N (Coastal Ecosystem Research Group, Marine Resources and Environment Res, National Institute of Advanced Industrial Science and Technology (AIS, 2-2-2, Hiro-Suehiro, Jure, Hiroshima, 7370197, Japan) : Seasonal variations in taxonomic composition, abundance and food web relationship of microzooplankton in esturaine and mangrove waters, Parangipettai region, southeast coast of India. Indian J Mar Sci 2001, 30(3), 151-60.

Seasonal abundance and the relationship of microzooplankton with higher trophic level were studied in the tropical estuarine and mangrove waters, from parangipettai (11° 29' N; 79° 46' E). Taxonomic composition and abundance of microzooplankton exhibited clear seasonal variations, being highest in summer and lowest in monsoon. The overall mean abundance in summer was 4.0 fold (estuary) and 2.5 fold (mangrove) higher than in monsoon. Over the study period, titinnid ciliates overwhelmingly dominated the microzooplankton community both in terms of species diversity (mean 62%) and abundance (mean 65%). The remaining raxa included notifers, copepod nauplii, naked ciliates, metazoan larval forms and veliger larvae. Their position in the food web was assumed from the gut content of the common secondary and tertiary consumers. The food web relationships closely followed the existing seasonal pattern of microzooplankton abundance, i.e. tintinnids, cirriped nauplii, veliger larvae, forminferans and naked ciliates constituted the basic food for the higher trophic level organisms during dry months (January to September), whereas in (rainy) monsoon season (October to December) the food items comprised of those from rotifers, coppod nauplii and some euryhaline tininnids.

8 illus, 2 tables, 35 ref

006816   Bhat G S (Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore-560 012) : The bay of Bengal monsoon experiment : bobmex. Proc Indian Natn Sci Acad-Pt A 2001, 67(3), 395-404.

Despite its economic and scientific importance, in situ observations providing accurate data for studying the properties of the atmosphere, ocean and their coupling has been lacking over the Bay of Bengal during the monsoon period. Detailed observations of the atmosphere and ocean were carried out in the Bay of Bengal during the peak monsoon months of July-August in 1999 under the Indian Climate Research Programme. Describes the motivation, objectives and field phase of this experiment along with some initial results. High resolution radiosondes, launched for the first time in the North Bay, provided the differences in the atmospheric characteristics between active and weak phases of monsoon. A strong diurnal dependence of convection is observed. Also, a major difference is noted in the near surface characteristics between the North Bay and other tropical oceans, the West pacific in particular. The sea air temperature and specific humidity differences are significantly smaller in the North Bay compared to that observed over the tropical West Pacific.

6 illus, 18 ref

005766   Tripathi R P (Department of Botany, J.N. Vyas University, Jodhpur-342 001) : Correlations of dispersed megaspores with the associated palaeozoic and mesozoic pteridophytes. Indian Fern J 1999, 16(1-2), 38-43.

Correlations are suggested of dispersed megaspores from Permian, Triassic and Lower Cretaceous rocks of India with the heterosporous pteridophytes and/or their fructifications having in situ megaspores from Palaeozoic and Mesozoic rocks of northern hemisphere. Probable parent plants or plant parts and their megaspores are listed. Occurrence of correlated megaspores during the Indian Gondwana is also given.

2 tables, 46 ref

005765   Srivastava M P;Pan S K;Prasad N;Mishra B K (Dept of Materials and Met Engineering, Indian Institute of Technology, Kanpur-208 016) : Characterization and processing of iron ore fines of Kiriburu deposit of India. Int J Miner Process 2001, 61(2), 93-107.

The beneficiation potential of the iron ore slimes produced from the washing plants and tailing ponds of Kiriburu mines assaying up to 60% Fe, 3.34% Si02, and 2.93% Al203 is analyzed. To start with, the ores lime was characterized in sufficient detail to reveal that it is extremely fine 80% below 110 mum and contains substantial amount of goethite (Fe203.H20). The liberation study indicates that the finer particles (-45 mum) are less liberated than the coarser particles. Taking into account all the physical and chemical attributes of the ore, a two-stage hydrocyclone-spiral circuit was envisaged for processing the ore. At first, the performance of this circuit was assessed through simulation using MODSIM - a modular simulator for ore dressing plant flow sheets. Simulation results showed that the ore could be upgraded up to 64% Fe that formed the basis for a pilot plant campaign. A 5-in. hydrocyclone followed by a five-step spiral (5-ft diameter) was set up to process the ore in close circuit. The experimental results show that it is possible to raise the iron content up to 64.17% at a solid recovery of 37.38 with simultaneous decrease in the alumina content down to 1.17%.

20 ref

005764   Singh D;Sharan S K;Singh K P (NO, Govt. P G Science College, Seepat Road, Bilaspur (CG)-495 006) : Response of microwave scattering from crop (wheat) and crop covered soil moisture for remote sensing. Indian J Radio Space Phys 2001, 30(4), 198-204.

Investigates the potential use of active microwave observations at 9.5 GHz frequency of X-band to monitor soil moisture and vegetation leaf area index (LAI) over a wheat cover for remote sensing. Using an X-band (9.5GHz) scatterometer, measurements have been made out for different growth stage of crop (wheat). The leaf area index (LAI) is an important parameter for understanding the crop characteristics. Attempt has been made to highlight the effect of crop (wheat) LAI and crop covered soil moisture (mg) on microwave scattering. Using simple scattering model, an empirical relation has been developed for observing the LAI and mg effect on scattering coefficient. The angular and polarization dependence of scattering coefficient on crop LAI and crop covered soil moisture has been investigated, which indicates that, when incidence angle is less than 30°, the crop (wheat) covered soil moisture is well observed, whereas when the incidence angle is greater than 30°, crop effect is more dominant at 9.5 GHz. The VV-polarization is more sensitive to sense the crop effect than HH-polarization. This type of study is helpful to make the algorithm for air- or space-born data to access the crop parameters and crop covered soil moisture. All these data can also be used as reference data for space-borne sensors.

6 illus, 4 tables, 28 ref

005763   Sarkar S K;Megha Raju K;Punyaseshundu D;Gupta M M;Rajesh Kumar;Prasad M V S N (Radio & Atmospheric Science Division, National Physical Laboratory, Dr. K S Krishnan Road, New Delhi-110 012) : Multipath effects on a line-of-sight microwave link. Indian J Radio Space Phys 2001, 30(4), 194-7.

Effect of multipath in relation to the deteriorated performance of a microwave communication link situated between Guntakal and Adoni over the Indian southern region have been invesigated. The received signal level under normal condition is usually found to be around-60 dBm. The performance of the link is satisfactory when the signal level is equal to and greater than -74 dBm, which is the satisfactory level of the signal. It has been seen that the link performance starts deteriorating when the signal level reduces to as low as around -75 dBm. The most problematic months during which the performance of the radio link is not up to the satisfactory level are found to be from November to May. The peaks of the disturbances are in the months of February through May. The performance of the link has been found to be disturbed during 2300-0800 hrs LT. On the basis of the low signal level (multipath fading), causes of deterioration in relation to meteorological conditions have been determined. In order to counter multipath fading, some techniques have been discussed.

4 illus, 1 table, 8 ref

005762   Sangode S J;Bloemendal J;Kumar R;Ghosh S K (NO, Wadia Institute of Himalayan Geology, P.B. 74, Dehradun-248 001) : Plio-pleistocene pedogenic changes in the Siwalik palaeosols: a rock magnetic approach. Curr Sci 2001, 81(4), 387-92.

Thirty-one pedogenic horizons of the Upper Siwalik (Plio-Pleistocene) sequence near Haripur, Himachal Pradesh (HP) in NW Himalaya are studied using rock magnetic properties to investigate their climatic and stratigraphic significance. The palaeosols are characterized by low initial susceptibility (χ_if- mean = 9 x 10^-8 m³/kg), high coercivity of remanence (B_ocr-mean = 447 mT), and low frequency-dependent susceptibility (X_fd-max = 6%) as a result of predominance of the canted-antiferromagnetic minerals of SD-PSD range. Stepwise acquisition of isothermal remanent magnetization (IRM) to a forward field of 7000 mT and backfield of 1000 mT indicates the presence of high coercivity minerals (goethite and haematite). Rock magnetic properties of pedogenic levels are inferred with reference to parental horizon of each palaeosol profile. Based on selective saturation levels of induced magnetic field, inorganic and organic carbon content and Rb/Sr ratios, new parameters are attempted to infer the relative variation in pedogenic changes of oxidation, hydroxylation and humification. These parameters record dynamic changes in the soil development processes of the Indo-Gangetic foreland basin, suitable for high-resolution stratigraphic correlations and reconstruction of climate change during the Plio-Pleistocene time.

4 illus, 1 table, 31 ref

005761   Roy A B;kroner A;Laul V (Department of Geology, ML Sukhadia University, Udaipur-313 002) : Detrital zircons constraining basement age in a late Archaean greenstone belt of south-eastern Rajasthan, India. Curr Sci 2001, 81(4), 407-10.

Reports a ²⁰⁷Pb/²⁰⁶Pb age of ca. 3230 Ma age for detrital zircon grains from the quartzite of the greenstone association in the Rakhiawal area, east of Udaipur, sourth-eastern Rajasthan. The age helps to constrain the maximum age of the greenstone belt of the region.

3 illus, table, 17 ref

005760   Rao K S;Pant R (NO, GB Pant Inst Himalayan Environm and Dev, Kosi Katarmal-263 643, Almora) : Land use dynamics and landscape change pattern in a typical micro watershed in the mid elevation zone of central Himalaya, India. Agric Ecosyst Envir 2001, 86(2), 113-23.

Analyses the process of human-induced landscape transformation in a micro watershed in mid elevation zone of central Himalaya of India in 1963, 1986 and 1996. The watershed (about 80 km (2) in size) comprises a small mountainous valley with steep slopes and deep cut ravines, typical of the landscape pattern in high population intensity mid elevation zone of central Himalaya. The spatial and temporal change patterns of land use were quantified by interpreting remote sensing (RS) data and use a geographical information system (GIS). Showed that although development interventions such as World Bank aided Integrated Watershed Development Programme, etc., showed promising results in regenerating the resources, the lack of follow-up required after programme withdrawal might cause the deterioration of resources accrued during such regeneration activities. Such local impacts need to be considerd in national policies and especially when time bound international aid based programmes are to be implemented.

50 ref

005759   Raman N;Murugesan A (Department of Chemistry, VHNSN College, Virudhunagar-626 001) : Evaluation of borewell water of various places located in and around Virudhunagar. Asian J Chem 2001, 13(3), 995-1000.

Suitability of water for drinking purpose is studied by collecting samples from the places located in and ground Virudhunagar. The physico-chemical parameters of the above samples indicate that the drinking water is not so much polluted. Some of the samples have TDS, hardness, sulphate, calcium and magnesium values exceeding the permissible limits for drinking purposes. It is observed that the main sources of pollution are due to waste water industries, municipal sewage, lack of sanitation, presence of inorganic constituents in waste water.

1 illus, 2 tables, 8 ref

005758   Ozcan O;Unal I (Department of Physics, Faculty of Art and Science, Firat University, 23119 Elazig-Turkey) : Comparison of total electron content predicted by IRI with that measured over Ankara. Indian J Radio Space Phys 2001, 30(4), (NULL).

TEC measurements obtained with Faraday technique at Ankara (geogr. lat. 40° N, geogr. long. 33° E, geomagn. lat. 36.9° N, dip angle 56.7°) are compared with the TEC obained by using the International Reference Ionosphere (IRI) model to check the performance of IRI for predicting TEC over this station. The measurements have been taken between October 1975 and June 1976 during low solar activity period. In general, the IRI model was found to give good predictions except for spring equinox and summer solstice time.

3 illus, 3 tables, 15 ref

005757   Negi G C S (Land and Water Resource Management Div, GB Pant Inst Himalyan Environm and Dev, Post Box 92, Srinagar-246 174, Garhwal) : Need for micro-scale and meso-scale hydrological research in the Himalayan mountains. Envir Conserv J 2001, 28(2), 95-8.

005756   Murthy B S;Parasnis S S (NO, Indian Institute of Tropical Meteorology, Pune-411 008) : Sodar observed winds in the convective boundary layer at Kharagpur, India, during monsoon 1990. Indian J Radio Space Phys 2001, 30(4), 181-93.

Sodar has been installed at Kharagpur (22.2°N, 87.3°E) as a part of the Monsoon Trough Boundary Layer Experiment (MONTBLEX-90) and data were collected during the monsoon period. The monthly-mean window field variation in the convective boundary layer (CBL) at Kharagpur during the S-W monsoon of 1990 has been studied. Monthly-mean horizontal winds were found to be westerly/north-westerly in the convective boundary layer above ″ 600 m in all the monsoon months. In August, mean winds near the surface have become easterly in response to the monsoon depressions formed in the north Bay of Bengal during 15-31 Aug. 1990. Two case studies of depression are studied in terms of winds and thermal structure in the convective boundary layer at Kharagpur. The variation of CBL height over Kharagpur during the onset, active and low/depression phases of the moonsoon 1990 is also presented.

12 illus, 2 tables, 15 ref

005755   Madhupratap M;Nair K N V;Gopalakrishnan T C; Haridas P;Nair K K C;Venugopal P;Gauns M (NO, National Institute of Oceanography, Dona Paula, Goa-403 004) : Arabian sea oceanography and fisheries of the west coast of India. Curr Sci 2001, 81(4), 355-61.

Physical and chemical forcing, which drives the Arabian Sea production is now fairly understood. The main attributes which contribute to the productivity are the boundary and open ocean processes, which manifest as upwelling during summer monsoon and cooling in the northern Aarabian Sea during winter. These bring in higher amount of nutrients into the upper ocean, which enhance primary productivity and examine how these might contribute to the fisheries along the west coast of India. The highest catches are between October and March. From an oceanographic point, this region can be divided into two areas: south of 15°N and north of this latitude. Although the fish catches from these two areas are fairly equal, there is considerable difference in the composition. In the south, planktonivorous fishes dominate, whereas in the north carnivores are more abundant. This appears to be a puzzle, and not reported hitherto. Based on the lower food-web, which appears to be similar in the two regions seem to be unable to explain this difference.

2 illus, 4 table, 37 ref

005754   Joshi P K;Sarnam Singh;Agarwal S;Roy P S (NO, Indian Institute of Remote Sensing, 4, Kalidas Road, Dehradun-248 001) : Land cover assessment in Jammu and Kashmir using phenology as discriminant - an approach of wide swath satellite (IRS-WiFS). Curr Sci 2001, 81(4), 392-9.

Climatic and seasonal variations guide the change in the internal features of vegetation and thus the vegetation mapping. A correlation between the vegetation units and the normalized difference vegetation index (NDVI) is established and the spatial distribution of phenology and seasonal distribution is deduced for mapping. High amount of spectral variability contributed by phenological phases made us generate a large number of clusters to distinguish features. The study has significance in the light of national development needs vis-a-vis advancement expected in the future indigenous and international remote sensing missions. The study suggests that multi-date data consider the variability and enables us to delineate the land use and land cover pattern of Jammu and Kashmir. The regional phyto-phenological classified map provides details on vegetation stratum. They can be an excellent source of data for understanding the land dynamic processes and human interventions in the region. The map derived can delineate finer, the biogeographical zones.

4 illus, 1 table, 25 ref

005753   Jana P K;Midya S K;De U K (Department of Chemistry, Howrah Zilla School, Howrah-712 201) : Short-term ozone trend in India. Indian J Radio Space Phys 2001, 30(4), 176-80.

Presents the variation of ozone concentrations at different stations in India and average variation of O3 concentraiton over India. The results are also compared with those of Halley Bay (76°S, 27°W), a British Antarctic Survey Station.

2 illus, 1 table, 32 ref

005752   Devi M;Barman M K;Barbara A K (Department of Physics, Gauhati University, Guwahati-781 014) : Ionospheric electron content near anomaly crest as precursor of earthquake. Indian J Radio Space Phys 2001, 30(4), 209-13.

Ionospheric electron content (IEC) values, derived from Faraday rotations of VHF radio beacons from satellites and recorded at an equatorial anomaly crest station, Guwahati (lat.26.2° N, long.91.75°E; and situated at a seismically active zone of east Himalayas), have been examined to see if these data could be used as precursor of earthquake. The earthquake events are so selected that the epicentres lie within 12°-30° N and 81°- 120°E. Analyses IEC variations during and prior to an earthquake event, in relation to epicentric position.

^ssc6 illus, 4 ref

005751   Banola S;Pathan B M;Rao D R K (NO, Indian Institute of Geomagnetism, Colaba, Mumbai-400 005) : Strength of the equatorial electrojet and geomagnetic activity control on VHF scintillations at the Indian longitudinal zone. Indian J Radio Space Phys 2001, 30(4), 163-71.

Amplitude scintillations on 244 MHz radio signals transmitted from geo-stationary satellite, FLEETSAT (73øE), were continuously recorded at a network extending from Ujjain (situated north of anomaly crest region) to the equatorial station, Trivandrum, by the Indian Institute of Geomagnetism, Mumbai. Parameters of geomagnetic activity like K-Alibag, Ap and electrojet strength are used to study the association of the amplitude scintillation recordings at the equatorial station, Trivandrum (dip 1° N) and a Mumbai (dip 26° N), a station south of a anomaly crest region during the high solar activity period 1989-1991. It is observed that an increase in geomagnetic activity (K-Alibag or Ap) suppress the occurrence of scintillation activity at both the stations, whereas the electrojet strength is found to have no association on the occurrence of scintillations. A total of 77 storms occurring during this period are classified into three types according to Aarons criterion. The time of the maximum intensity of ring current appears to play a role directly or indirectly in establishing the conditions necessary for the equatorial F-layer irregularity generation and inhibition which, in turn, manifests itself in scintillation activity. However, there is about 30-40% of scintillation activity unaccounted by the magnetospheric electric field alone.

7 illus, 1 table, 37 ref

005750   Bajpai V N;Roy T K S;Tandon S K (Dept Geol, Univ Delhi, Delhi-110 007) : Subsurface sediment accumulation patterns and their relationships with tectonic lineaments in the semi-arid Luni river basin, Rajasthan, Western india. J Arid Envir 2001, 48(4), 603-621.

Sediment accumulation patterns in the Luni basin have been studied on the basis of tubewell lithologs and Bouguer gravity anomaly profiles. East-West geologic transects using these data reveal several sediment-filled graben depressions, for example, the Digrana-Bhawal graben in the northern part, the Mangta-Sindari, Sindari-Bhiingoda, and Bhimgoda-Juna Motisara grabens in the central part; and the Dungari-Ratanpura and Ratanpura-Khanpur grabens in the southern part. Maximum sediment accumulation of more than 300 m is located in the southwestern part of the Luni basin, more specifically in the Ratanpura-Khanpur graben. Minor depressions also occur towards west of Jodhpur and east of Bhadrajun. Sediment filling in these graben depressions commenced with thick clay deposits followed by multistoried fining up sand and gravel sequences. Sediment accumulation centres are coincident with major tectonic lineaments and thus indicate that important loci of sediment accumulation are, possibly, a response to synsedimentary tectonics.

36 ref

004613   Upadhyay R (NO, Birbal Sahni Institute of Palaeobotany, Lucknow-226 007) : Middle cretaceous carbonate build-ups and volcanic seamount in the Shyok suture, Northern Ladakh, India. Curr Sci 2001, 81(6), 695-9.

Along the Shyok suture zone in northern India, a <126>200 m thick limestone succession has been identified as a carbonate platform margin with build-ups. This limestone succession is directly overlying volcanic rocks of island arc affinity. The partly recrystallized reefal limestone which rests on a volcanic seamount or ridge contains abundant rudists, corals, gastropods, algae and a rich orbitolinids assemblage of Late Aptian-Early Albian Age. This faunal assemblage reflects a shallow-water tropical environment for the carbonate build-ups and also shows a close affinity with those recorded from the Yasin Group in north-western Pakistan. The presence of Late Aptian Horiopleura, Radiolitidae and different forms of Orbitolinae and other microfaunal assemblage in the reefal limestone, dates the underlying volcanic edifice as Middle Cretaceous or older. Rudists, nerineids, corals and foraminifers of Lower Cretaceous age are widely distributed as a reefal framework all along the tropical and subtropical Euro-African-Asiatic regions of the northern margin of the Tethys. However, prior to our findings, the Cretaceous carbonate build-ups associated with submarine volcanism have only been reported in the Caribbean, Sicily in Italy, Yasin in Pakistan and from dredged samples from a seamount in the central pacific region.

4 illus, 20 ref

004612   Simon B et al (Meteorology and Oceanography Group, Space Application Centre, Indian S, , Ahmedabad-380 015) : Monsoon onset-2000 monitored using multi-frequency microwave radiometer on-board oceansat-1. Curr Sci 2001, 81(6), 647-51.

^ssc4 illus, 1 table, 15 ref

003471   Satyanarayana A N V;Mohanty U C;Niyogi D S; Raman S;Lykossov V N;Warrior H;Sam N V (Centre for Atmospheric Sciences, Indian Institute of Technology, New Delhi-110 016) : Marine boundary layer processes in the ITCZ and non-ITCZ regimes over Indian ocean with INDOEX IFP-99 data. Curr Sci 2001, 80(Apr), 39-45.

One-dimensional numerical planetary boundary layer (PBL) model was applied to simulate the dynamical and thermodynamical characteristics of the tropical Indian Ocean under varying convective regimes. Using sounding as well as surface meteorological data obtained during the INDOEX field phase, the PBL was validated for three different regions within the INDOEX domain. The three regions identified were, a coastal location representing suppressed convection, an open ocean region with medium convection, and a region of intense convection in the vicinity of the Inter-Tropical Convergence Zone (ITCZ). The model was integrated using observed sounding as initial as well as lateral boundary conditions, for a period up to 48 h. The model simulated surface fields as well as vertical profiles were compared with observations for the three cases. In general the model performance was good. The one-dimensional model cloud not simulate the dynamical features associated with advection and winds satisfactorily. However, the convective regimes are well simulated. As such, the PBL processes near the ITCZ were better simulated compared to the coastal regions. Results suggest that such a model can be used as a tool to develop high resolution, time-varying profiles over data-sparse regions to enhance mesoscale analysis.

8 illus, 2 tables, 8 ref

003470   Sarkar A K;Jain M;Parashar D C;Mitra A P; Kulshrestha U C;Cachier H (National Physical Laboratory, , New Delhi-110 012) : Measurement of carbonaceous aerosols at urban and remote marine sites. Curr Sci 2001, 80(Apr), 176-9.

Concentrations of total carbon (TC) and black carbon (BC) in ambient air at Delhi (urban site) and over Indian Ocean (remote marine) were determine as a part of INDOEX programme. Over Indian Ocean, the TC and BC concentrations varied from 1.81 to 10.05 μg/m³ and 0.13 to 1.36 μg/m³ respectively during FFP-98. During the same season at Delhi, the TC and BC ranged from 7.50 to 40.27 μg/m³ and 0.49 to 2.84 μg/m³ respectively. In addition, at Delhi, the TC and BC concentrations were noticed very low during the monsoon season. However, the percentage BC during monsoon season was very high compared to winter season. High concentrations of TC were observed due to high organic carbon (OC) which might be due to biomass burning of various kinds. Similar to Delhi, near Indian coast, the concentration of OC was very high while towards ITCZ and across ITCZ, OC content was relatively lower.

2 illus, 3 tables, 11 ref

003469   Sam N V;Mohanty U C;Satyanarayana A N V;Raju P V S (Centre for Atmospheric Sciences, Indian Institute of Technology, New Delhi-110 016) : Air-sea exchange processes and conserved variable analysis over the Indian ocean with INDOEX IFP-99 data. Curr Sci 2001, 80(Apr), 46-54.

Air-sea interaction processes were studied by computing the radiation fluxes (short-wave and long wave) and the turbulent heat fluxes (sensible heat and latent heat) using semi-empirical models. Over ITCZ region a net heat loss was found which can be attributed to large convergence, strong convective activity and dense cloud cover, leading to drastic reduction in short-wave radiation. Latitudinal and longitudinal variation of surface meteorological parameters and turbulent fluxes were studied to establish a link with the prevailing convective and clear weather regimes along the cruise tracks. A conserved variable analysis of the conserved variable such as potential temperature, virtual potential temperature, saturation equivalent potential temperature and specific humidity is carried out at every point of upper air observation from Ronald H. Brown. The values are estimated up to a maximum of 3 km to cover the boundary layer. In the ITCZ region due to the convective mixing deeper boundary layers are formed, where a double structure is observed. The Marine Boundary Layer Height is also estimated using thermodynamic profiles.

11 illus, 16 ref

003468   Roswintiarti O;Raman S;Mohanty U C;Niyogi D S (State Climate Office of North Carolina and Department of Marine Earth, North Carolina State University, Raleigh NC 27695, USA) : Performance of a triple nested mesoscale model for tropical Indian ocean during INDOEX. Curr Sci 2001, 80(Apr), 77-84.

Triple nested version of the fifth generation PSUNCAR Mesoscale Model (MM5) was used over the INDOEX domain. A 3-dimensional model study over the tropical Indian Ocean was performed. The domain extended from 40.12°N-32.04°S; 32.10°E-117.90°E for the outer most grid (horizontal resolution of 180 km), while the inner most grid (20 km horizontal resolution) extended from 19.81°N-13.92S; 56.20°E-91.64°E, with 17 vertical δ levels. The model was integrated for 48 h starting from 00 UTC 5 March 1999. The model results were validated against analysis for large-scale characteristics (circulation pattern, ITCZ location and rainfall). MM5 was able to realistically simulate these large-scale features. In addition to this validation, objective evaluation of the model performance was undertaken by comparing GPS sonde vertical soundings obtained from RV Ronald H. Brown for the times of model integration. MM5 results were in good agreement with both dynamical (wind components) and thermodynamical (temperature and humidity) fields over the INDOEX domain.

9 illus, 2 tables, 11 ref

003467   Roswintiarti O;Raman S;Mohanty U C;Niyogi D S (State Climate Office of North Carolina and Department of Marine, Earth, North Carolina State University, Raleigh, NC 27695, USA) : Application of three-dimensional triple nested mesoscale model for assessing the transport and boundary layer variability over the Indian ocean during INDOEX. Curr Sci 2001, 80(Apr), 69-76.

The model simulated significant variability in the MBL heights both spatially and temporally. During the daytime, the continental boundary layer was <126> 1500 m deep while over the ocean, the MBL was shallow (<126> 300 m) near the coast, and it increased steadily towards the ITCZ where MBL heights of <126> 1000 m were encountered. During night there was a reversal with the continental boundary layer heights averaging less than 500 m while over the ocean, particularly over the ITCZ, the MBL heights were <126> 1000 to 1500 m. This variability in the MBL heights significantly affected the transport pattern over the INDOEX region. Both the backward and forward trajectories showed distinct characteristics depending on the source region (eastern or western coastal landmass, equator, or near ITCZ). Near the coast, there was an evidence for localized circulation in which the air parcels were trapped along the coast. For the open oceans (both near the ITCZ as well as equator) the air parcel trajectories continued over a significant distance. Results suggest that MM5 can be successfully applied for diagnostic studies related to INDOEX, and that the boundary layer heights and the variations in the air parcel transport need to be considered for interpreting the surface measurements.

6 illus, 2 tables, 9 ref

003466   Ravikumar;Chaudhury S;Peshin S K;Srivastava s K;Mandal T K;Mitra A P (National Physical Laboratory, Dr K.S. Krishnan Road, New Delhi-110 012, ) : First time observation of latitudinal and vertical distribution of infra-red radiative flux using radiometer sonde over Indian ocean during the INDOEX IFP-1999 and its comparison with other Indian stations. Curr Sci 2001, 80(Apr), 209-15.

Latitudinal distribution of radiative flux at different layers has been measured for the first time over the Indian Ocean from 15°N to 20°S during intensive field phase of INDOEX 1999. Simultaneously measurements have been made over three Indian ground stations, viz. Delhi, Pune and Trivandrum. The basic feature of radiative flux over the Indian Ocean, Delhi, Pune and Trivandrum is similar, i.e. the radiative flux increases with altitude and reaches a maximum value at 15 km and after that the increasing rate slows down. The most striking feature of this observation is the existence of radiative flux between 12 and 15 km of height near the equator (1.75°N, 62.98°E) which may be due to the combined effect of partly cloudy sky, presence of aerosol and ozone. In addition, at 13.3°N, 60.5°E a similar feature has been observed at a height of 14-15 km, which may be due to the increment of ozone by 25 Dobson Unit (D.U.) during the onword journey since no aerosol was observed. During the return journey, at 12°S, 60.4°E global warming is also observed at a height of 13-15 km, which may also be due to the combined effect of partly cloudy sky and the presence of aerosol and increment of ozone.

10 illus, 1 table, 17 ref