017221   Mahajan K K;Ashok Kumar;Lodhi N K (Radio & Atmospheric Sciences Div, National Physical Laboratory, Dr K S Krishnan Road, New Delhi-110 012) : Long-term trends in the upper atmosphere and ionosphere: Models and observations. Indian J Radio Space Phys 2007, 36(6), 543-55.

Theoretical models predict a 10 K cooling in the mesosphere and 50 K cooling in the thermosphere in response to doubling of CO₂ and CH₄ from present day mixing ratios. In the mesosphere this cooling is expected to bring-in considerable changes in the individual ion concentration, but no significant change in the total ion density. In the thermosphere, atmospheric density would decrease and the heights of the ionospheric E- and F2-layers will drop by about 2 and 20 km, respectively. There would be little change in the critical frequency of these layers but electron density will decrease in the topside and increase in the bottomside ionosphere due to this lowering. Early results from some individual ionosonde stations showed the predicted decrease in the height of the F2-peak, but statistical analysis of ionospheric data from stations spread all over the globe did not indicate any significant trend in this parameter, as well as in the height of the E-layer and density of the F2-layer. The E and F1 layers peak densities, however, showed negative trends. Satellite drag data have provided convincing evidence of decrease in atmospheric density in the thermosphere during the last few decades. Better statistical methods are needed to filter out long-term solar activity and magnetic activity influences for detecting long-term trends in the F2 layer. Measurements of low frequency reflection heights from 1959 to 2003 at the mid-latitude station Kuhlungsborn show a long-term decreasing trend, an observation in agreement with the expected cooling in the mesosphere.

017220   Kurian S;Shenoy D M;Gauns M;Roy R;Narvenkar G;Pratihary A K;Paul J T (NO, National Institute of Oceanography, Dona Paula-403 004) : Water column characteristics following the September 2004 stench event off southern Malabar coast. Indian J Mar Sci 2007, 36(3), 199-205.

Unusual stench emanated from the coastal waters of southwest coast India during September 2004 associated with an algal bloom. Water samples collected from 14 stations from the affected area after three weeks of the event, revealed that phytoplankton were dominated by holococcolithophorids (max 27x10⁶cells l^-1) in the coastal stations in comparison with the offshore stations (max 8000 cells l^-1), which contained mainly diatoms. Slightly low oxygen concentration (81-191 μM) associated with relatively lower temperature and high nutrients indicated the prevalence of weak upwelling in the region. Chlorophyll a to phaeopigments ratio at the coastal stations indicated that the bloom was in the degrading phase. Resultant microbial activities perhaps led to higher ammonia concentration in the study region. The holococcolithophorids seem to be uncommon to this region, but upon availability of right conditions, presumably temperature and nutrients formed massive bloom and consequently a stench affecting coastal population.

017219   Jaiswal R S;Geetha P;Uma S (Physics Dep, Sona College of Technology, Salem-636 005, Email: senoritta_in@yahoo.co.in ) : Estimation of cross-polarisation due to rain over some stations in India. Indian J Radio Space Phys 2007, 36(5), 379-82.

Attempt has been made to compute cross-polarization of millimeter waves in the 30-35 GHz frequency range due to rain. Laws and Parson's drop size distributions for oblate spheroid drops at 20°C ITU-R (2002) model has been used to predict cross-polarization discrimination (XPD) for circular polarization. The study includes a number of earth stations in India, namely, Ahmedabad, Calcutta, Delhi, Gangtok and Jodhpur. Variations of co-polar attenuation with XPD have been shown. Cumulative time distribution of XPD has also been presented. The study reveals that cross-polarization depends on frequency, co-polar attenuation and rainfall rate. Comparison with measurement does not show good agreement although the two show the same trend. Extensive work on cross-polarization is required in the millimeter wave frequency range over a large number of earth stations in India using different drop size distributions and different polarizations.

017218   Jain S L;Kulkarni P S;Arya B C;Arun Kumar; Ghude S D;Pankaj Singh (Radio and Atmospheric Sciences Div, National Physical Laboratory, New Delhi 110 012, Email: sljain@mail.nplindia.ernet.in) : Altitudinal variation of surface aerosol with change in site: A comparative study. Indian J Radio Space Phys 2007, 36(6), 571-5.

The study of size distribution of atmospheric aerosols is an important tool in understanding and managing aerosol effects on health, visibility and climate. The measurements of surface aerosols, both mass-size distribution and mass concentration, were carried out in the campaign mode at Leh (34°09'N, 77°34'E, 3441 m asl), Hanle (32°47›N, 78°58›E, 4517 m asl) and Delhi (28°39'N, 77°13'E, 220 m asl) during July 2003 to examine their variation with altitudinal and anthropogenic activity. A 15 channel portable particle size aerosol spectrometer GRIMM was used for carrying out the experiment. The aerosol spectrometer is equipped with class 3-B laser as the light source and uses a light scattering technology for single particle counts in the range <62> 0.3 μm to > 20.0 μm. During the period of observation at all three sites, the pattern of total mass concentration was found to be influenced by supermicron range mass concentration. The higher values of aerosol mass concentration observed at Delhi as compared with those observed at Leh and Hanle on all the channels show a large amount of anthropogenic activity taking place around Delhi vis-a-vis the other two sites. It is further observed that the mass-size distribution changes with the change in altitude and anthropogenic activity.

017217   Hussain S M;Ganesan P;Ravi G;Mohan S P; Sridhar S G D (Geology Dep, School of Earth and Atmospheric Scineces, University of Madras, Guindy Campus, Chennai-600 025, Email: smhussain7@hotmail.com) : Distribution of Ostracoda in marine and marginal marine habitats off Tamil Nadu and adjoining areas, southern east coast of India and Andaman Islands: Environmental implications. Indian J Mar Sci 2007, 36(4), 369-77.

Ostracods successfully inhabit almost all types of aquatic environment, from deep oceans to brackish water lagoons, estuaries and even freshwater streams, lakes, etc. The major controlling factors governing ostracod population and distribution in estuarine environments and continental shelf zones are water temperature, salinity and substrate. The distribution and ecology of marine ostracoda in relation to the environmental parameters such as temperature, salinity, dissolved oxygen of the bottom waters, organic matter, and CaCO₃, along with the sand-silt-clay ratio of sediments from the inner shelf sediment region off Karikkattukuppam (near Chennai), off Rameswaram, off Tuticorn and Andaman Islands is discussed. Additionally, similar studies on the brackish water ostracods from the Adyar estuary, Pitchavaram mangroves and Tamiraparani estuary have also been presented. The work pertaining to the statistical parameters of ostracoda such as carapace/valve ratio, ornamentation and grain size to infer the environment of the study area, from the Indian region is also discussed.

017216   Harinarayana T (National Geophysical Res Inst, , Uppal Road, Hyderabad) : Electrical structure of the upper crust of central Indian suture zone Narmada-son lineament deccan traps, Southern granulite region and Eastern Dharwar craton. J Geophys 2007, 28(3-4), 111-20.

Cratons and mobile belts are the major tectonic features in Indian peninsular continental crust. To study the crustal structure, major initiatives are taken by DST under Deep Continental Study (DCS) programme. As a part of such a programme NGRI, besides other studies, has taken up wide band magnetotellurics, to map the electrical structure of the upper crust on a regional scale. Long geotraverses have been covered in Southern Granulite Terrain (SGT), Deccan Trap (DT) region, Central Indian Shear (CIS) zone, Narmada-Son Lineament (NSL) zone and Eastern Dharwar Craton (EDC). It is observed that upper crustal characters are different in these regions. Continent-Continent collision tectonics is evidenced in SGT, distinct resistivity changes is observed across CIS in upper crust, correlation of surface faults with conductive features are seen in NSL region and thrustal signature in EDC. Additionally, these studies have brought out a relation between upper crustal rocks and the development of seismicity in the region. In the present paper, the upper crustal signatures of the above five different regions are compared and the importance on the study of electrical resistivity of crustal rocks is discussed to understand the seismotectonics of the region.

10 illus, 1 table, 12 ref

017215   Gupta P K;Khem Singh;Dixit C K;Nahar Singh; Sharma C;Sahai S;Jha A K;Singh D P;Tiwari M K;Garg S C (NO, National Physical Laboratory, Dr K S Krishnan Marg, New Delhi 110 012, Email: prabhat@mail.nplindia.ernet.in) : Spatial distribution in aerosol mass and size characteristics between Delhi and Hyderabad during land campaign in February 2004. Indian J Radio Space Phys 2007, 36(6), 576-81.

Mass and size distribution of aerosols was studied using different measurement techniques, along Delhi-Hyderabad land corridor, to understand the spatial variability of aerosols over north central Indian region, from Delhi to Hyderabad and back, in the month of February 2004. Aerosol mass loading of Quartz Crystal Microbalance (QCM) derived up to PM25, PM10, PM2.5, PM1 size fractions, were found to be in the range of 17-56, 16-54, 8-44 and 5-37 μg m-3, respectively. The QCM derived up to PM10, PM2.5 and PM1 with respect to total aerosol mass (PM25) are 90%, 80% and 70>%, respectively, which indicate the dominance of finer particles. The PM10 aerosol concentrations measured by High Volume Respirable Dust Sampler (HV-RDS) had an average value of 48 μg m^-3 with the range of 27-75 μg m^-3. Aerosol average concentrations by HV-RDS were observed to be 54 <145>-3 near urban areas, 48 ± 2 μg m-3 in forest area and 44 <145>-3 in rural areas along the land corridor.

017214   Defraigne P;Banerjee P;Lewandowski W (NO, Royal Observatory of Belgium, Ringlaan 3, B-1180 Brussels, Belgium) : Time transfer through GPS. Indian J Radio Space Phys 2007, 36(4), 303-12.

Commonly available GPS receivers have, these days, hardware outputs of 1 pps. These receivers normally have the time accuracy within 100 ns. But if these are not calibrated in advance, they cannot be recommended for precise on-line applications. However, common view mode GPS time transfer using single satellite is in use for the generation of Coordinated Universal Time (UTC) by ensembling more than 40 clocks scattered all over the world. Use of carrier phase in common view mode is being explored. The initial results are quite encouraging. The paper reviews the current status of these time transfer techniques via GPS.

017213   Das Gupta A;Paul A;Das A (S K Mitra Center for Research in Space Environment, University of Calcutta, 92 A P C Road, Calcutta 700 009, Email: adg1bkpr@hotmail.com) : Ionospheric total electron content (TEC) studies with GPS in the equatorial region. Indian J Radio Space Phys 2007, 36(4), 278-92.

Deals with the effects of equatorial ionization anomaly gradient on space-based navigation systems like GPS. The equatorial region of the ionosphere, which extends about ñ30odip about the magnetic equator, is characterized by a steep latitudinal gradient, not only in the maximum ionization but also in the total electron content (TEC), through a major part of the day. This region also accounts for about one-third of the global electron content. The high ambient TEC results in large range errors for a major part of the day, affecting navigation and position-fixing using GPS. The gradient of the equatorial ionization anomaly between the trough and the crest is very sharp, which results in large temporal and spatial variation of the ionospheric electron content. A prediction of the range error introduced by the ionosphere in the equatorial zone is very difficult. Identification of a suitable ionospheric model for prediction of these errors in the geophysically sensitive equatorial region is necessary prior to the introduction of Indian SBAS network, GAGAN (GPS And Geo Augmented Navigation). For this purpose, ionospheric TEC measured from Calcutta, situated underneath the northern crest of the equatorial anomaly, has been compared with values generated by models like PIM1.6 and IRI-95 during 1977-1990. The equatorial anomaly gradient not only extends in the horizontal direction but with altitude also. Problems related to conversion of vertical to slant TEC and vice versa, as required for ionospheric range error corrections in satellite-based navigation with GPS, have been indicated and diagnostics suggested. It has been observed that sharp latitudinal gradient of TEC during the afternoon hours of equinoctial months of high sunspot number years is usually followed by generation of irregularities over the magnetic equator in the form of 'bubbles' or depletions. These depletions have sharp edges resulting in large range error rates on GPS links. Characteristics of bubbles, namely, amplitude and leading and trailing edge slopes, have been studied using GPS TEC data recorded at the Giant Meterwave Radio Telescope (GMRT) site during the vernal equinox of 2004. Use of GPS TEC measurements as a tool for studying ionospheric response to earthquakes has also been indicated.

017212   Chakravarty S C;Datta J (NO, ISRO Headquarters, Antariksh Bhavan, New BEL Road, Bangalore-560 094) : Mesospheric backscatter echoes as observed by the Indian MST Radar Facility at Gadanki. Indian J Radio Space Phys 2007, 36(6), 489-501.

The Indian Mesosphere Stratosphere Troposphere (MST) radar facility at Gadanki (13.5<167>N, 79.2<167>E) has been utilised to characterise the mesospheric backscattered signals by considering already available results and new analysis of past and recent data sets. Individual days data as well as continuous and long term Common Mode Observation (CMO) data have been used to study (1) the basic features of mesospheric return echoes, (2) scattering layer heights, (3) relation to mesospheric turbulence governed through weather phenomena, (4) spatial and temporal variability, (5) seasonal patterns and, (6) inter-annual changes. While the present results have been found to be consistent, with the earlier results, some new aspects have been brought out. A broad theoretical background is provided relevant to turbulent scattering of radar waves so that the results are interpreted from this perspective. The main results of the mesospheric studies with the Gadanki radar include the very intermittent nature of echoes varying with radar beam directions and time. Temporal variations of the radar returned signals are found to be related to the growth and decay of eddies, generated by atmospheric turbulence. The mean height of mesospheric scattering layer is around 72 km and the life period of the turbulence patches generally lies in the range 10-20 min. In the months of June-July and September-October of 2003, the intensity of radar returned signals were stronger compared to other months and there is an elevation of the mean scattering layer by <126> km with the decrease in solar activity between 2003 and 2005.

017211   Birbal Singh (Electronics and Communication Engineering Dep, Faculty of Engineering, R B S College, Bichpuri, Agra-283 105) : Forty years of whistler research in India. Indian J Radio Space Phys 2007, 36(6), 466-73.

An up to date review of whistler research in India has been presented which is an extension of previous reviews by Somayajulu et al. [Indian J Radio Space Phys, 1 (1972) 102], and Singh [Indian J Radio Space Phys, 22 (1993) 139]. In this review efforts have been made to highlight the recent advancements in technology adopted for recording and analysis of whistlers, re-interpretations of some old data, general consensus in propagation mechanism, and effects of ionospheric irregularities on whistler propagation in the low latitude ionosphere. Some new results of existence of ELF emissions in the low latitude ionosphere as determined from the satellite DEMETER data and Trimpi/TLE phenomena in the low latitude ionosphere as observed from phase and amplitude monitoring of VLF transmitter signals have been presented.

017210   Bhattacharya R;Das R;Guha R;Deb Barman S; Bhattacharya A B (Physics Dep, University of Kalyani, Kalyani-741 235) : Variability of millimetrewave rain attenuation and rain rate prediction: a survey. Indian J Radio Space Phys 2007, 36(4), 325-44.

Reviews the literature on attenuation of mm-wave due to rain and rain rate prediction methods to analyze the performance of the various systems proposed by different workers at different parts of the globe under varying meteorological and topographical conditions with an emphasis on the observational reports made in the tropics, particularly in the Indian subcontinent. In this comprehensive review, besides considering the various features related to rain rate, the various methods proposed for prediction of rain attenuation have been examined and thereby a comparison of those prediction methods is made. Finally, scopes for future investigation have been critically focused.

017209   Bhaskara Rao D;Satyanaryana K V V;A Praveen Kumar (Andhra Univ, , Visakhapatnam) : Gravity and magnetic surveys in the northern part of the cauvery basin. J Geophys 2007, 28(3-4), 137-43.

The gravity and magnetic data along three profiles across the northern part of Cauvery basin have been collected and the data is interpreted for basement depths. The first profile (1) runs from Cuddalore to Villupuram, and the second (2) starts from Port Novo and ends at Neyveli and the third (3) runs from Tarangambadi to Vridhachalam. Gravity profiles are interpreted using density varying with depth. The density contrast function with depth has been constructed using well log density data obtained from ONGC, Chennai. From the Bouguer anomaly, the residual anomaly is constructed by graphical method with well data as control. The residual anomaly profiles are interpreted using prismatic as well as polygonal models. The maximum depths to the basement are obtained as 3.0 km, 3.8 km and 4.6 km for the first, second and third profiles respectively. Magnetic anomaly profiles are also interpreted using the dyke model. The total field magnetic anomaly profiles, in general, consist of number of peaks corresponding intrusive bodies into the sedimentary basin using dyke models.

8 illus, 10 ref

017208   B V S N Raju;Abhinav Kumar;Goswami A; Chaturvedi A K;C Shanti Kumar (Atomic Minerals Directorate, , Begumpet, Hyderabad-500 016) : Delineation of uranium potential zones in Gwalior basin, India using multi-sensor data sets. J Geophys 2007, 28(3-4), 105-10.

Gwalior basin forms an E- W trending elongated basin covered by Gangetic Alluvium in the north and east, by Kaimur Group sediments in the west and underlain by Bundelkhand granite in the south. IRS LISS3 and PAN Satellite images were used for the interpretation of geomorphology, geology and structure of the Basin. Airborne radiometric and magnetic survey data was processed, images generated and interpreted. The output data has been organized in to vector, raster and tabular data. The maps showing geology, structure and uranium occurrences were digitised as vector data and georeferenced. The data related to map features were tabulated and made interactive by using unique ID for each feature. Digital enhanced satellite, Airborne gamma ray spectrometric (AGRS) and magnetic images were incorporated in the form of raster data. Atomic Minerals Directorate for Exploration and Research (AMD) has intensified uranium exploration activities in Proterozoic basins of India. The Proterozoic Gwalior basin was evaluated for uranium potential by the integration of available data sets using Arc GIS. Thematic Maps on detailed scale (l:25000) were generated by integration of the geology, structure, ground uranium occurrences and AGRS uranium anomaly zones. Based on the thematic maps and uranium exploration knowledge Uranium potential zones were delineated.

1 illus, 2 tables, 6 ref

017207   Ashok Kumar;Lodhi N K;Mahajan K K (Radio and Atmospheric Sciences Div, National Physical Laboratory, New Delhi-110 012) : Near-terminator Martian ionosphere during sunspot cycle 23 from Mars Global Surveyor radio science measurements. Indian J Radio Space Phys 2007, 36(6), 457-65.

Radio Science experiment on the Mars Global Surveyor (MGS) has measured a large number of electron density profiles in the near-terminator Martian ionosphere, from December 1998 to March 2005, thus covering rising, maximum and declining phase of sunspot cycle 23. More than a dozen data sets, EDS 1 to EDS 13, are now available at the public website and these sets contain profiles numbering from a few tens in some sets to several hundreds in others. On any one day, several profiles were measured at a constant solar zenith angle (χ) but at different longitudes. However, χ varied considerably during each data set and in this paper about 2000 profiles have been analysed to study the height (h_m) and density (Nm) of the primary peak as a function of solar zenith angle. A significant decrease of N_m is seen with increasing χ, but h_m starts increasing at χ above 80° only. To examine how close the Martian primary peak is to an ideal Chapman layer, values of exponent, k and sub-solar peak density, N_o in the equation N_m = N_o (cos χ)^k were obtained by using the largest number of profiles employed ever before. A value of 0.45 for the exponent k deduced is somewhat smaller than the value of 0.5 expected for an ideal Chapman layer. Value of N_o was found to be 1.75 x 10¹¹ m^-3. Anomalous features in the Mars ionosphere seen in the earlier MGS data are found to be present in the latest data also.

017206   Ashok Kumar;Gupta V B;Dutta H N;Ghude S D (School of Future Studies and Planning, Devi Ahilya University, Indore-452 017, Email: ashok_kumarg@yahoo.com) : Mathematical modelling of katabatic winds over Schirmacher region, East Antarctica. Indian J Radio Space Phys 2007, 36(3), 204-12.

A one-dimensional mathematical model for flow of katabatic winds over Schirmacher region of East Antarctica has been developed. The model is based on momentum and sensible heat transport to the ice slope surface under calm conditions. A relationship of potential air temperature with the height and elevation of the reference state is suggested and used in the model. The model parameters were estimated using the measurements of surface based meteorological parameters and high resolution maps of pressure contours. The wind velocities have been computed using the model on actual terrain slope around 130° in which direction maximum katabatic flow moves towards the periphery of the continent , the ratio of mean bulk coefficients (C_H/C_M) and over large variations in slope angle (α), potential temperature difference between air parcel and slope surface (θ), and slope length (l). The results suggest that the inclination angle or terrain slope and the distance at which inversion forms, control the speed of katabatic winds. At the same time, the direction of katabatic wind is controlled by the slope of the icy terrain.

017205   Acharya R;Nagori N;Jain N;Sunda S;Regar S; Sivaraman M R;Bandopadhyay K (NO, Systems & Applications Group, Satcom & IT Applications Area Space Appl, Ahmedabad-380 015, Email: rajat_acharya@sac.isro.gov.in) : Ionospheric studies for the implementation of GAGAN. Indian J Radio Space Phys 2007, 36(5), 394-404.

Satellite Based Augmentation System (SBAS), being developed by Indian Space Research Organization (ISRO) in collaboration with Airports Authority of India (AAI) is known as "GPS Aided GEO Augmented Navigation" (GAGAN). It is expected to offer better accuracy and integrity of navigation service than with GPS alone by providing correction terms to the GPS signals. This is achieved by modelling a Near Real Time Grid Based Ionospheric Delay Model for correcting propagation delay at 1575.42 MHz (L1) using measurements at 1575.42 and 1227.6 MHz (L2). Existing algorithms are replaced by Kriging based model to meet the requirement of correction with 0.5 m maximum residue over Indian region. Details of the data collection and pre-processing, including estimation of the Total Electron Content (TEC), which is a measure of ionospheric delay, has been described. Kriging algorithm and some preliminary results of studies are also presented in this paper. This includes the spatial decorrelation of the stochastic random field over the deterministic variation of ionospheric TEC. Its variation with time and locations are investigated and a temporal dependence found to exist. Large scale ionospheric irregularities and depletions that cause severe amplitude and phase scintillations are also studied. Their impacts on GAGAN are also shown. Some major scientific studies required to be carried out over Indian region to improve the GAGAN performance is discussed.

016298   Ziari K (NO, Yazd University, YAZD, Iran) : County-wise levels of development in Iran. Trans Inst Indian Geogr 2007, 29(1), 55-82.

Attempt has been made to measure the levels of development of 253 counties of Iran on the basis of 38 selected indices. The method of research uses a quantitative approach to measure development (factor analysis, HDI, CV) and computer software of SPSS. On the basis of 38 blended factors, 22 counties fall in the category of `developed', 116 counties `partially development' and I I4 are `undeveloped'. The important point to note is that the precedence of Tehran and its incongruency with respect to the other counties is due to the greater facilities of development provided to it, being the official and political centre for more than two centuries and the metropolitan city for half a century. On the other hand, e.g. Tehran, Mashad, Isfahan, Shiraz and Tabris have emerged as growth poles especially after the land reform in 1962 as the result of political economy. Neglecting people's participation in the formulation of development plans, the centralised policy has stimulated the growth of few centres, brought to them the benefits from oil earnings and surplus and thus added to the regional inequality. These growth poles have developed due to the provision of facilities from the peripheral counties, using national resources but without disseminating much growth to the periphery. Discusses the results of the different factors analysed, while the second part t looks for the causes of the regional imbalance in Iran.

7 illus, 17 ref

016297   vinoth Kumar J A;Pathan S K;Bhanderi R J (Land Use Planning and Photogrammetric Div, Forestry, Land Use and Photogrammetric Group, Space Applications Centre (ISRO), Ahmedabad-380 015) : Spatio temporal analysis for monitoring urban growth a case study of Indore city. J Indian Soc Remote Sens 2007, 35(1), 11-20.

Urban sprawl is characterized by haphazard patchwork of development, which leads to an improper development in any city. To prevent this kind of sprawl in future, it is necessary to monitor the growth of the city. Hence, an attempt has been made in the present study to monitor the urban growth over a period of time by employing Remote Sensing and Geographic Information System techniques in conjunction with Shannon entropy. Shannon entropy is a measure to determine the compactness or dispersion of built-up land growth in the urban areas. The growth patterns of urban built-up land have been studied initially by dividing the area into four zones. The observations have been made with respect to each zone. Then, the study area has been divided into concentric circles of 1 km buffers and the growth patterns have been studied based on urban built-up density with respect to each circular buffer in all four zones. These observations have been integrated with road network to check the influence of infrastructure on haphazard urban growth. It has been found from the study that Shannon entropy is a good measure to determine the spatial concentration or dispersion of built-up land in the city. The study also proved the potential of RS and GIS techniques in the spatio-temporal analysis of urban growth trends and their consequences in the lands adjoining to urban areas.

9 illus, 1 table, 18 ref

016296   Tigga A;Hema Malini B (Geography Dep, Andhra University, Visakhapatnam-530 003) : Analysis of climates of Jharkhand State - a thermal regime approach. Trans Inst Indian Geogr 2007, 29(1), 33-41.

Jharkhand State, with forested hills and dissected plateaus and low-lying river valley plains experiences varied climatic conditions across the State. In view of that, an attempt is made to classify the thermal climates of Jharkhand based on Thornthwaite's (1955) thennal regime. For that purpose, monthly temperature data of seven IMD stations with variable time scales ranging between 50 to 100 years have been collected to compute monthly Potential evapotranspiration (PE). The analysis of thermal efficiency has indicated that entire Jharkhand experiences Megathermal climate (A') with the thermal efficiency values ranges between 1271 mm to 1548 mm. In order to find out the seasonal variation, percentage of Summer Concentration of Thermal Efficiencies (SCTE) was worked out which indicated that thermal efficiency is highest during summer months. To understand the variation in the intensity within Megathermal climate, it was further classified into four sub categories namely A'₁a'₃, A'₂ a' ₃, A'₃a'₃ and A'₃a'₄. From the study it was revealed that Jharkhand experiences enormous thermal efficiencies that can support abundant vegetative growth if moisture availability is sufficient throughout.

3 illus, 4 tables, 13 ref

016295   Thirumalai P;Senthil J;Anand P H (Disaster Mangement, Government College (Autonomus) Kumbakonam, Tamil Nadu-612 001) : Impact of tsunami on aquaculture farms along the nagapattinam coast zone Tamil Nadu India. J Indian Soc Remote Sens 2007, 35(1), 67-72.

The tsunami waves triggered by underwater earthquake with a focal depth of 30 km near the Sumatra Island distressed the entire coast of Tamil Nadu. The worst affected coastal region is Nagapattinam. particularly from Nagoore to Vailankanni. The impact of tsunami had multidimensional effect, killing most of the fishermen communities, devastating the coastal huts and damaging the coastal aquaculture resources. The present study has been carried out to find the impact of tsunami on the aquaculture small farmland owners along the coast using pre (December 18, 2004) and post January 6, 2005) IRS P6 data. The study includes the extent of damage caused to the farms by saltwater intrusion; sand inundation, total destruction of farms The results indicate that, there have been incredible damage caused to the farmers beyond recovery in short span of time.

2 illus, 1 table, 13 ref

016294   Srivastava V K (Zoology Dep, Jawaharlal Nehru College, Pasighat. P O Hill -Top-791 103, Email: srivksl1@rediffmail.com) : River ecology in India: present status and future research strategy for management and conservation. Proc Indian Natn Sci Acad 2007, 73(4), 255-69.

Reviews the present ecological and biological conditions of the rivers in India, and also states management practices and conservational approach. Works on the various rivers of the country have been surveyed and analyzed so as to identify the constrains and problems related to management and conservation. For effective management, it is stressed to assess precisely the ecological impacts (through biomonitoring) caused by anthropogenic activities (i.e. any developmental project and policy) by segregating the natural variations from the actual impacts caused. It is also recommended to adopt appropriate sampling design and method (BACI, beyond BACI, Nested sampling, Rapid bioassessment etc.) and planned study for such segregation. Further, it has become pre-requisite to integrate the findings of ecological impact assessment (Eco IA) with the execution of projects so as to manage the sustainable lotic ecosystem with developmental activities. Author has also advocated for the study of functional attributes along with the structural parameters; so as to get the spectrum of variation in energy flow all along the channel and also in entire watershed. Studies related to riparian vegetation, floodplain ecology, longitudinal and transverse flow of organic matter and energy dynamics are still very sparse which is stressed to be undertaken. River regulation and its deleterious impact on functional state of river are needed to be considered more.

2 illus, 184 ref

016293   Srinivas Choudary V;Rau T K;Bhaskara Rao K S; Sridhar M;Sinha K K (Geological Survey of India, , OP: Andhra Pradesh, Southern Region, Hyderabad-500 068) : Timmasamudram kimberlite cluster, Wajrakarur kimberlite field, Anantapur District, Andhrapradesh. J Geol Soc India 2007, 69(3), 597-609.

A cluster of four kimberlite bodies was discovered on the left bank of the Penner river near Timmasamudram village. falling in the area known for alluvial dimond occurrences within the Wajakarur Kimberlite field (WKF), this cluster is located between the Kalyandurg Kimberlite Cluster in the west and Chigicherla Kimberlite cluster in the east. With the addition of kimberlite bodies in the present cluster, christened as the timmasamudram Kimberlite cluster (TKC), the total number of kimberlite bodies in WKF reaches to 27. Texturally, mineralogically and chemically, the kimberlite bodies in TKC match with the archetypal Group_I Kimberlites. Typically they fall in the non-micaceous kimberlite field. The mantle xenocrystic mineral chemistry shows conditions congenial for diamond formation in these pipes, which is further supported by actual microdiamond recovery from the soft kimberlitic yellow ground.

17 illus, 3 tables, 41 ref

016292   Srinivas Choudary V;Rau T K;Bhaskara Rao K S; Sridhar M;Sinha K K (Geological Survey of India, , OP: Andhra Pradesh, Southern Region, Hyderabad-500 068) : Timmasamudram kimberlite cluster, Wajrakarur kimberlite field, Anantapur District, Andhrapradesh. J Geol Soc India 2007, 69(3), 597-609.

A cluster of four kimberlite bodies was discovered on the left bank of the Penner river near Timmasamudram village. falling in the area known for alluvial dimond occurrences within the Wajakarur Kimberlite field (WKF), this cluster is located between the Kalyandurg Kimberlite Cluster in the west and Chigicherla Kimberlite cluster in the east. With the addition of kimberlite bodies in the present cluster, christened as the timmasamudram Kimberlite cluster (TKC), the total number of kimberlite bodies in WKF reaches to 27. Texturally, mineralogically and chemically, the kimberlite bodies in TKC match with the archetypal Group_I Kimberlites. Typically they fall in the non-micaceous kimberlite field. The mantle xenocrystic mineral chemistry shows conditions congenial for diamond formation in these pipes, which is further supported by actual microdiamond recovery from the soft kimberlitic yellow ground.

17 illus, 3 tables, 41 ref

016291   Singh R D;Purnima Singh (Regional Planning and Economic Growth and Evironmental Management Prog, Barkatullah University, Bhopal-462 026, Email: rd_singh54@yahoo.com) : Geo-tectonic movement and natural hazards: strategy for disaster preparedness and mitigation. J Indian Geophys Union 2007, 11(3), 171-3.

In India, the incidence of natural hazards have increased in recent times and their intensity and impacts have increased. Though the natural hazards like earthquake in Indian sub-continent cannot be prevented, because of the active tectonic disturbances and resulting incidence of earthquake of different intensities in sensitive zones, with a better preparedness and mitigation plan, the loss of ife and property can be minimised to a greater extent. Though the scientific and technological knowledge is available for disaster preparedness and mitigation in different disaster prone regions of the world, the lack of disaster management system in disaster prone regions is causing collateral damages causing enormous environmental costs in form of loss of life and property and the cost of rehabilitation. The neglect of the development of disaster management system for minimisation of the impact of such disasters have caused a huge cost, even a fraction of which could help in disaster management capacity building in disaster prone regions. dentifies the regional pattern of disaster sensitive zones, the causal relation of tectonic movement on sismicity and resultant cummulative impacts of earthquake, landsliding, changes in landforms and meandering of rivers causing floods and other cummulative human interface. On the basis of such analysis, the model framework is suggested for disaster preparedness and mitigation plan in the sensitive zones.

6 ref

016290   Sharma R;Murthy V V S;Nagaraju B V;Gouda H C; Singh R K (Geological Survey of India, GMC Div., , ASME Wing,Vasudha Bhavan, Kumaraswamy Layout, Bangalore-560 078) : Interpretation of aeromagnetic data of Panna and adjoining area, parts of M.P. & U.P., for evaluation of structural patterns favourable for emplacement of depths of magnetic bodies. J Geol Soc India 2007, 69(3), 653-63.

The rocks of vindhyan Supergroup overlying Bundelkhand Granites host the diamondiferous Kimberlite diatremes in Kaimur Group and Diamondiferous conglomerates with the Rewa Group. The region, collectively referred as the `Panna Diamond Belt' was flown by the Geological survey of India aircraft during the years 2001-2002 and the aeromagnetic data generated are interpreted here. The survey was carried out at an altitude of 150 m above groundlevel with traverse spacing of 500 m. The International Geomagneic Reference Field (IGRF) corrected aeromagnetic data was brought to a plane at 600 m above msl and was subjected to terrain correction. Interpretation of this area yielded several structural trends in NE-SW, ENE-WSW, nearly E-W, nearly N-S and NW-SE directions in the form of magnetic discontinuities and linears, which are indicative of structural patterns like formational contacts/faults/fractures and body axes. The study area is characterized by a strong magnetic linear feature trending in ENE-WSW direction with intersections in nearly N-S direction representing transverse faults at some places and also intersected by two prominent features on either side, one aroung Majhagaon and the other towards north of Usrar. This prominent ENE-WSE trending magnetic feature is seen to fall along the contact of Vindhyan Supergroup with the adjacent Bundelkhand Granite Complex (BGC) and strong magnetic closures along this feature represent the intrusive activity at depth. In the northern partof the area occupied by BGC. Prominent magnetic features are obtained in the direct of NE-SW and few in N-S and E-W directions represent the fracture system. The quantitative interpretation of aeromagnetic data employing radial power spectrum, matched filtering, 2-D, 3-D and contact modeling indicated the depths of causative sources. The radial power spectrum indicated three magnetic interfaces at 380 m, 1.3 km and 5.3 km from the plane of observation.

7 illus, 4 tables, 15 ref

016289   Scott Smith Barbara H (NO, , 2555 Edgemont Boulevard, North Vancouver, B.C., Canada V7R 2M9) : Lamproites and kimberlities in India. J Geol Soc India 2007, 69(3), 443-65.

New petrographic and mineral chemistry data are presented to show that the Majhgawan and Hinota pipes are olivine lamproite lapilli tuffs and not kimberlites as suggested elsewhere. These bodies, therefore, comprise a newly reognized province of diamondiferous olivine lamproites. Other intrusions in India have been proposed in the literature as being lamproites or kimberlites. Available information for these localities is discussed and, where possible, augmented by new data (Wajrakarur/Lattavaram, Angor, Jungel, Chelima). the Wajrakarur/Lattavaram bodies are classified here as kimberlites. Although two of these bodies appear to be extreme varieties they do not represent a different rock type and are not lamproites. The Chelima and gondwana coalfields dyke swarms could include lamproites. There are no data to support suggestions of other lamproites or kimberlites in India. This study highlights the need for further detailed petrological investigations of many of these localities.

10 illus, 4 tables, 100 ref

016288   Sastry R G;Jose M K (Earth Sciences Dep, I.I.T., Roorkee-247 667) : Analytical computation of hydraulic potentials due to point, line and areal sources over three-layered aquifer system. J Indian Geophys Union 2007, 11(1), 47-58.

Steady state analytical expressions for hydraulic potentials and streamlines of a three-layered aquifer system due to a point source recharging have been derived. By applying appropriate convolution techniques, respective expressions for a finite-length line and areal sources are arrived at. Then, the computational algorithms (i) 3LPNT- for a point source, (ii) 3LLIN- for a finite length line source and (iii) 3LARL- for an areal source have been designed. The simulation results for these three different sources, when compared with those by standard numerical groundwater flow model, MODFLOW indicate the cost-effectiveness of our approach both in terms of accuracy and computational speed.

11 illus, 3 tables, 17 ref

016287   Sarma A A L N;Lakshmi Kumar T V (Meteorology and Oceanography Dep, Andhra University, Visakhapatnam-530 003, Email: aalnsarma_met@rediffmail.com) : Rainfall and soil wetness response to ENSO and soil wetness estimation from remote sensing data. J Indian Geophys Union 2007, 11(2), 91-100.

Studies on water budget elements are of great importance in the context of geo-hydrological scenario. The estimation and analysis of soil wetness for a particular region is helpful in understanding the various mechanisms involved in the land surface hydrology. The present study attempts to understand the daily rainfall and soil wetness variations with respect to the geophysical indices of ENSO phases such as NINO 3 sea surface temperature and Southern Oscillation Index. The parameter soil wetness is derived from the water balance model on a daily basis. The study has been performed for the monsoon seasons of 1999 to 2002 over selected stations of Andhra Pradesh (12°-20°N; 76°-86°E). The study then proceeds in estimating the soil wetness using the brightness temperature data of Multichannel Scanning Microwave Radiometer of IRS-P4. As the study region consists of different types of soils such as medium black, redloam and laterite soils, the investigation makes use of the brightness temperature variations with reference to soil category in relation to soil wetness.

6 illus, 4 tables, 17 ref

016286   Sapkale J (Geography Dep, Shivaji University, Kolhapur-416 004) : Shifts in Tarali river channel, a tributary of Krishna, in post-monsoon low flow condition. Trans Inst Indian Geogr 2007, 29(1), 43-53.

Channel geometry in section or plan is basically the result of the interaction between the channel forming materials and the discharge that is passing through them. This is more evident in the areas where channels exist in alluvial materials which are highly erodibile. Catastrophic events of high floods are well known for their devastating effects as well as for causing shifts in channel beds. The excessive deposition, within the channel and / or intensive erosion along the channel banks, changes the channel geometry both in plan and section. However, it is not necessary that always such changes are the results only of catastrophic events. Slow but definite erosion selectively along one of the banks' may also eventually lead to shift of channel. Changes in the bed of the channel leading to its shift can also be introduced by anthropogenic factors. Human interventions in natural processes are increasingly causing such effects and at times assume such magnitude of scale that they are beyond the limits of corrective mechanism of normal, natural processes. Removal of river alluvium as building materials in the form of coarser bed load (sands) or finer components of alluvial material for brick manufacturing is one such intervention, which leads to changes in channel geometry. The author of this paper has been monitoring the effect of such an activity along the lower reaches of River Tarali, a tributary of Krishna in its upper reaches. An attempt was made to highlight the effects of human interventions on the channel geometry.

3 illus, 3 ref

016285   Saluja V;Niwas S (Earth Sciences Dep, Indian Institute of Technology, Roorkee-247 667, Email: vikaspes@yahoo.com ) : Estimation of permeability of shaly sand from induced polarization relaxation time spectra. J Indian Geophys Union 2007, 11(3), 135-42.

Singular Value Decomposition (SVD) method is used to invert induced polarization (IP) decay curve for the IP relaxation time spectrum. A nonnegative restriction is added during inversion for meaningful solution of the amplitude of the relaxation spectrum. The analysis of the experiment design, by comparing results in different range, shows that the appropriate number of relaxation arrangement points in data inversion lies with 32 to 64. The attenuation of noise in this range is better and resolution is good. IP relaxation spectrum indicates the pore size distribution that in turn indicates the permeability of shaly sand reservoir. Combining the average relaxation time (geometric average time) with the porosity can improve the accuracy of estimation of the permeability in comparison to that obtained using total porosity from core measurements.

4 illus, 3 tables, 14 ref

016284   Ravi S;Rau T K;Reddy N S;Nayak S S (Geological Survey of India, , Southern Region, Hyderabad-500 068, Email: iyers_ravi@redifmail.com) : Tungabhadra Kimberlite Field Kurnool District, Andhra Pradesh. J Geol Soc India 2007, 69(3), 611-18.

The diamondiferous Upper Proterozoic conglomerates and the associated sandstone beds display sedimentary structures that are suggestive of provenance in the northwest, i.e. towards the Tungabhadra river drainage basin Multidisciplinary surveys in this region have led to the discovery of a kimberlite body (350 m x 470 m), concealed under alluvial soil spread on the left bank of the Tungabhadra river near Mantralayam. The study area, represented by the granitoids of Peninsular Gneissic Complex with remnants of Gadwal schist belt, presents a domal upwarp that plunges into the river. The domal surface displays intense fracturing with prominent NW-SE/WNW-ESe and subordinate NE-SW trends, which show marked preponderance and dilation on the northern low angle plunge parts. Traverses coupled with extensive stream sediment sampling and the study of specific mineral chemistry is suggestive of presence of kimberlite, which is supported by actual recovery of micro-diamonds from the yellow ground. The kimberlite contains mantle nodules of phlogopite-bearing websterite and siliceous mica-garnet-chrome diopside bearing lherzolite; the selective non-silicification of interstitial chrome diopside in the latter being enigmatic. The silicification of these mantle nodules could be due to the emplacement of kimberlite into a surface water body and subsequent action of silica-saturated groundwater.

9 illus, 3 tables, 6 ref

016283   Ravi S;Rau T K;Reddy N S;Nayak S S (Geological Survey of India, , Southern Region, Hyderabad-500 068, Email: iyers_ravi@redifmail.com) : Geological Survey of India. J Geol Soc India 2007, 69(3), 611-18.

The diamondiferous Upper Proterozoic conglomerates and the associated sandstone beds display sedimentary structures that are suggestive of provenance in the northwest, i.e. towards the Tungabhadra river drainage basin Multidisciplinary surveys in this region have led to the discovery of a kimberlite body (350 m x 470 m), concealed under alluvial soil spread on the left bank of the Tungabhadra river near Mantralayam. The study area, represented by the granitoids of Peninsular Gneissic Complex with remnants of Gadwal schist belt, presents a domal upwarp that plunges into the river. The domal surface displays intense fracturing with prominent NW-SE/WNW-ESe and subordinate NE-SW trends, which show marked preponderance and dilation on the northern low angle plunge parts. Traverses coupled with extensive stream sediment sampling and the study of specific mineral chemistry is suggestive of presence of kimberlite, which is supported by actual recovery of micro-diamonds from the yellow ground. The kimberlite contains mantle nodules of phlogopite-bearing websterite and siliceous mica-garnet-chrome diopside bearing lherzolite; the selective non-silicification of interstitial chrome diopside in the latter being enigmatic. The silicification of these mantle nodules could be due to the emplacement of kimberlite into a surface water body and subsequent action of silica-saturated groundwater.

9 illus, 3 tables, 6 ref

016282   Rau T K (Geological Survey of India, , Southern Region) : Panna diamond belt, Madhya Pradesh - a critical review. J Geol Soc India 2007, 69(3), 513-21.

The Panna Diamond Belt (PDB) occupying the northern margin of the Vindhyan Basin in Panna district, Madhya Pradesh hosts the primary, secondary and tertiary sources of diamond. It comprises the basement Bundelkhand granitoids to the north overlain by Vindhyan Supergroup of rocks (Mid to Upper Proterozoic) to the south. The diamond mining activity is confined mainly to the Baghain plateau and to a lesser extent to the Gahadra plateau. The two kimberlite pipes known in PDB are Majhgawan and Hinota pipes (<126>1100Ma), emplaced in Baghain Sandstone lying to the west of PDB. The basal conglomerate interbeds of Jhiri Shale (Upper Rewa) and Itwan Sandstone (Lower Rewa) have been extensively mined for diamond in the past. The alluvial and colluvial (Quaternary and Recent) placer diamond workings, both ancient and present, spread over the Baghain plateau mainly between Panna town in the west and Paharikhera in the east. Exploration indicated significantly higher incidence (<126>30 cpht) of diamond with high percentage of gem quality diamonds.

^ccr1 illus, 1 table, 20 ref

016281   Ram B;Singh N P;Murthy A S K (Geophysics Dep, Banaras Hindu University, Varanasi-221 005, Email: drbram_bhu@yahoo.co.in) : Qualitative appraisal of aeromagnetic image of Chhattisgarh basin. J Indian Geophys Union 2007, 11(3), 129-33.

Qualitative appraisal of aeromagnetic image of Chhattisgarh region has been carried out to study the geology of the region. The study area comprises of Chhattisgarh basin, one of the seven-purana basins of Peninsular India. The aeromagnetic anomaly map of the area has been used as input for interpretation to extract the geologic information from the mapped and imaged anomalies in a systematic way that makes a positive contribution to the geology of the area. On the basis of aeromagnetic anomalies, Chhattisgarh basin can be divided into the northern low anomaly zone and the southern high anomaly zone. The northern portion of the main Chhattisgarh basin has been further divided into two sub-basins namely Hirri sub-basin (HRSB) in the west and Baradwar sub-basin (BRSB) in the east by NW-SE trending Sonakhan greenstone belt with maximum negative amplitude. The positive magnetic anomaly zone east of 81.5° E and bounded by 19.5° and 21.0° N latitude is due to Dongargarh granites and their equivalents. The greenstone belt, Dongargarh granite, granulites/gneisses occurrences in the region and intrusive bodies are clearly demarcated in the inferred geological map.

3 illus, 10 ref

016280   Radhakrishna B P (Geological society of India, , Bangalore-560 019, Email: kitts@bgl.vsln.net.in) : Diamond exploration in India: retrospect and prospect. J Geol Soc India 2007, 69(3), 419-42.

India was the first country in the world to recognize diamond as the hardest mineral which could be used to polish and pierce holes even in the hardest rocks. Its use as a gem with a brilliant lustre came to be recognized later. Its fame spread all over the world by travelers like Pliney, Marco Polo, Nikitin, Nicolas Konti and others. The most famous of them was the French traveler Tavernier, who made six voyages to India, personally visited many mines in operation, collected diamonds and introduced them to Europe. Venetian cutters, who were expert gem cutters, enhanced their attraction by their brilliance and extraordinary lustre. It became the gem of royalty. With increasing demand from all parts of the world, Indian diamond industry reached its zenith in the 15^th and 16^th centuries. The very attraction of diamonds and their phenomenal value brought hordes of invaders whose only object was loot and plunder. A great countrywhich was the pride of the East was ruined and its people reduced to poverty. With the fall fo Indian royalty, the diamond industry became virtually dead, most of the mines abandoned, and today India does not find a place in the list of diamond producing countries.

94 ref

016279   Paul D K;Crocket J H;Reddy T A K;Pant N C (Dep of Geology, Presidency College, College Street, Calcutta-700 073, Email: abhijeetmukherjee_2000@yahoo.com) : Petrology and Geochemistry including planting. J Geol Soc India 2007, 69(3), 577-96.

A suite of potassic ultramafic rocks occurs in the Krishna district in the southern Indian craton along with clusters of kimberlite. The principal minerals include olivine, pyroxene, amphibole and phlogopite. Compositional variation exists in the phlogopite of the different occurrence of the region. Mg number varies from 0.37 to 0.56 and the groundmass phlogopies are enriched in Fe and Ti and poor in Al compared to the phenocrysts. Major and trace element data indicate enrichment of LILE and LREE (La/Yb = 24 - 104; Gd/Yb = 3.8 - 8.02). Ba contents vary from 132 to 5327 ppm, which is rather low compared to literature values for lamproite. However, the abundances of Zr(<62>500ppm), Sr(<62> 1000ppm) and La(<62>200 ppm) are similar to those in the lamproite. The potassic ultramafic rocks have variable but high U/Pb (2-37, average 17.2) and Th/U (4.6-10.7) ratios. Concentrations of Platinum Group Elements (PGE) are quite variable with Ir, Pt and Pd varying by <62>9, 21 and 15 times respectively over the suite. Significant features included differences in fractionation between PGE and enrichment of cu relative to the mantle source region. Some of the samples are not ultrapotassic and peralkaline. However, combining their mineralogical and geochemical properties, these rocks of the Krishna region may be considered as a member of the lamproite clan. There is no evidence of significant crustal contamination, but fractional crystallisation of olivine and perovskite is suggested from the geochemical relations. Available isotopic age data indicate that the ca. 1220 Ma old Krishna lamproite preceded kimberlite emplacement in the region by about 160 million years. Partial melting of a mantle metasomatically enriched in Ti and Fe would yield the Krishn lamproite magma. Amphibole contributed to the emlt, but the HREE abundance data preclude garnet involvement. The depth of melt formation was likely to be shallower than that of kimberlites.

15 illus, 5 tables, 9 ref

016278   Pandey V K;Pandey A C (K. Banerjee Centre of Atmospheric and Ocean Studies, Institute of Interdisciplinry Studies, University of Allahabad, Allahabad-211 002, Email: vivekkpandey@rediffmail.com) : Trubulent kinetic energy and its dissipation rate of the Indonesian throughflow region via Lombok and Savu straits. J Indian Geophys Union 2007, 11(2), 117-22.

Turbulent kinetic energy (TKE) and its dissipation rate are estimated at Lombok (115° 50'E, 8° 30°S) and Savu (122°E, 9° 30° S) strait of Indonesian Throughflow (ITF), in the upper and middle layers. It is the region having most complicated geometry of the world ocean. TKE is of the order of 10^-3 m²s^-2 in the upper layer whereas it is 10^-4 m²s^-2 in the middle layer. Corresponding values of TKE dissipation rate are of the order of 10^-6 m²s^-3 and 10^-8m²s^-3.

4 illus, 24 ref

016277   Narkhedkar S G;Sinha S K;Kulkarni P L; Kulkarni J R;Mahajan P N (NO, Indian Institute of Tropical Meteorology, Dr. Homi Bhabha Road, Pashan, Pune-411 008, Email: narkhed@trompmet.res.in) : Diagnostic study of monsoon depression and examination of energetics produced by two schemes (2-D NVA and 3-D NVA) over Indian region. J Indian Geophys Union 2007, 11(1), 29-45.

Following Sasaki (1958) two objective analysis schemes viz. two dimensional Numerical Variational Analysis (2-D NVA) and three dimensional Numerical Variational Analysis (3-D NVA) have been developed by Sinha, Narkhedkar & Rajamani (1998); Sinha et al., (2003) and Narkhedkar & Sinha (2000) over India and adjoining region. NVA is the scheme that produces the analysed data in balance. The 2-D NVA uses geopotential height and wind data simultaneously to produce analysed height and wind field at grid points whereas 3-D NVA allows temperature data to influence the analysis of height and wind fields. Both the schemes have been tested for two to three synoptic situations and have performed well in depicting the systems. In the study the performances of these two analysis schemes in context with energetics have been assessed in depicting the features of the synoptic scale systems viz. Tropical Easterly Jet, Sub Tropical Westerly Jet etc. prevailing over Indian and adjoining region in the monsoon season. The analyses produced by these two schemes have been examined to study the energetics of a monsoon depression which formed over head Bay of Bengal. The energy terms viz. available potential and kinetic energy (both zonal and eddy part) and their conversion terms have been computed. The analyses of these terms for both schemes showed that they are in well accordance with the earlier studies made by other researchers over Indian region. The analyses produced by both the schemes were able to depict the system very well in context with the energy terms that have been computed from the analysed field produced by them. However, due to the inclusion of temperature field 3-D NVA scheme has produced higher values of energy terms compared to 2-D NVA scheme. The influence of analysed upper and lower tropospheric temperature fields on the energy terms in generation of the energy and maintaining the circulation patterns have been studied critically. It has been observed that during the period of depression the north-south temperature gradient was prominent at upper levels.

11 illus, 19 ref

016276   Nambiar A R (Geological Survey of India, , Marine Wing, Email: nambiar_ar@yahoo.co.in) : (NULL). J Geol Soc India 2007, 69(3), 641-52.

A swarm of alkaline and mafic dykes occurs in the Archaean Gneissic Complex of western Meghalaya, Northeastern India, spatially associated with a N-S trending deep-seated fault-Nongcharm Fault. Lamprophyre constitutes the dominant member among the alkaline dyke rocks; other petrological variants include tinguaite, ijolite, trachyte and orthoclasite. Rare carbonatitie is also present. Lamprophyre contains country rock fragments, as well as mantle derived ultramafic nodules, aggregated megacrysts and lapilli like structures. A feature characteristic of most lamprophyre dykes of the area of the presence of ocelli, commonly zoned, with carbonate-rich (rarely analcime) inner zone and outer zone rich in alkali felspars, mica, proxens and opaque minerals. Petrographically, the lamprophyres of the area are classified as camptonite, but they have some affinity towards ultramafic and carbonatitic lamprophyres. Field and petroraphic studies suggest that the lamprophyre and carbonatite of Nongcharm Fault zone (NFZ) are genetically linked to a common parental magma, which differentiated by the process of liquid immiscibility to carbonate and silicate fractions, leading to the emplacement of discrete bodies. The best candidate for the parental magma appears to be mantle-derived alkali basalt magma. Lamprophyre and other sodic alkaline rocks and carbonatite in NFZ indicate rift-controlled magmatism triggered by a mantle plume. The spatial and temporal distribution of lamprophyre dykes (107 ma) of the region with ultramafic-mafic-alkaline-carbonatite complexes of Assam-Meghalaya and Kerguelen-related Sylhet-Rajmahal-Bengal Basin basalts (105-118 Ma) suggest their genetic link with early Kerguelne hotspot magmatism.

12 illus, 1 table, 79 ref

016275   Nagaraj H;Murthy K (Geography Dep, University of Mysore, Mysore) : Geographical analysis of regional dispariteis - Chitradurga district, Karnataka. Trans Inst Indian Geogr 2007, 29(1), 76-82.

Analyses the regional disparities of the nine talukas of Chitradurga district in Karnataka with the help of thirty-seven social, economic and demographic indicators. The identification of the regional disparities is made with the help of Kendall's ranking coefficient method for the years 1988-89 and 1998-99. The talukas show different degrees of development ranging from `low' to `very' highly developed regions. In 1998-99, two talukas showed less disparity as compared to the earlier period.

1 illus, 3 tables, 7 ref

016274   Murthy B S R (NO, GSI, 273 Indraprastha Colony, Baghamberpet, Hyderabad-500 013) : Airborne geophysics and the Indian scenario. J Indian Geophys Union 2007, 11(1), 1-28.

24 illus, 67 ref

016273   Mukherjee A;Ch. Sravan Kumar;Krishna Reddy K; Siddiquie S N;Chaturvedi L (National Mineral Development corporation Ltd., , Khanj Bhavan, Masab Tank, Hyderabad-500 028, Email: abhijeetmukherjee_2000@yahoo.com) : Two new kimberlites in Bommaganapall area, Anantapur district, Andhra Pradesh, based on systematic stream sediment sampling and ground magnetic survey. J Geol Soc India 2007, 69(3), 625-40.

Two Kimberlite pipes in Bommaganapalli area, Kalyandurg, Anantapur district are reported based on stream sediment sampling yielding HIM's viz. garnets (`G 9' iherzolitic, `G 10' harzburgitic and eclogitic with Na₂O(<62>0.07 wt%), Cr-diopsides (from garnet peridotites), spinels and ilmenites. Ground magnetic survey indicated magnetic anomaly of about 280 nT in KL-5 and an anomaly of 100 n T over KL-6. The anomaly over KL-5 was dipolar. The `Maturation Index' (MI) of 9.8 and MgO content 8.08 of the calcrete over this area indicate their kimberlitic nature. Analysis indicates that the chrome spinels fall in the diamond stability field. Garnets suggest they are of the nature of 'G 10" harzburgitic garnets.

15 illus, 5 tables, 9 ref

016272   Mukherjee A;Ch. Sravan Kumar;Krishna Reddy K; Siddiquie S N;Chaturvedi L (National Mineral Development corporation Ltd., , Khanj Bhavan, Masab Tank, Hyderabad-500 028, Email: abhijeetmukherjee_2000@yahoo.com) : Two new kimberlites in Bommaganapali area, Anantapur district, Andhra Pradesh, based on systematic stream sediment sampling and ground magnetic survey. J Geol Soc India 2007, 69(3), 625-40.

Two Kimberlite pipes in Bommaganapalli area, Kalyandurg, Anantapur district are reported based on stream sediment sampling yielding HIM's viz. garnets (`G 9' iherzolitic, `G 10' harzburgitic and eclogitic with Na₂O(<62>0.07 wt%), Cr-diopsides (from garnet peridotites), spinels and ilmenites. Ground magnetic survey indicated magnetic anomaly of about 280 nT in KL-5 and an anomaly of 100 n T over KL-6. The anomaly over KL-5 was dipolar. The `Maturation Index' (MI) of 9.8 and MgO content 8.08 of the calcrete over this area indicate their kimberlitic nature. Analysis indicates that the chrome spinels fall in the diamond stability field. Garnets suggest they are of the nature of 'G 10" harzburgitic garnets.

15 illus, 5 tables, 9 ref

016271   Mitchell R H (Dep of Geology, Lakehead Univ, 955 Oliver Road, Thunder Bay, Ontario, Canada P7B 5E1, Email: rmitchel@lakeheadu.ca) : Potassic rocks from the Gondwana coalfields of India: closing pandora's box of petrological confusion. J Geol Soc India 2007, 69(3), 505-12.

The nomenclature of potassic lamprophyres occurring in the Gondwana coalfields is discussed from a mineralogical-genetic viewpoint. The concept of a lamprophyre facies and the mineralogical character of calc-alkaline minette and peralkaline phlogopite sanidine lamproite is described. It is concluded that none of the Gondwana coalfields rocks represent calc-alkaline minettes and that there is no "majhgawan and the Mainpur region, are considered to be formed from differentiates of distinct magmas formed by the partial melting of metasomatic veins in the lithospheric mantle, and as such cannot be classified using nomenclatural schemes devised for other petrological provinces. The gondwana potassic rocks, which are the expression of potassic metasomatized lithospheric magmatism in the northern Singhbhum craton, are considered not to be Kaapvaal craton-type orangeites or Kimberley craton-type lamproites, but might be described as lamproites (var.Damodar). It is recommended that use of the terms:"minette-lamproites association", kimberlite-clan rocks"; and "lamprophyre clan rocks" be discontinued as they serve no useful petrogenetic purpose.

1 tables, 47 ref

016270   Minirani S;Kurup P G (NO, School of Marine Sciences, Cochin-682 016, Email: kuruppg@yahoo.co.uk) : Energy attenuation of sea surface waves through generation of interface waves on Visco-elastic bottom as in the mud banks, SW coast of India. J Indian Geophys Union 2007, 11(3), 143-6.

Mud banks present picturesque instances of large-scale natural damping of sea surface waves. When waves propagate on the surface of a layer of inviscid fluid overlying a visco-elastic bottom fluid of greater density, surface wave energy is dissipated by the coupling between the surface wave sand the waves generated at the interface. Using a dimensionally correct expression (Mac Phersonand Kurup, 1981) obtained from Gade's mathematical model (1958), the wave energy attenuation is calculated for different wave periods, water depths and fluid layer thickness. The predicted wave decays are comparable to those observed in the mud banks where the seabed is of soft viscous mud. The waves get almost completely attenuated over a distance of 5-10 wavelengths.

1 illus, 17 ref

016269   Lokesha N;Gopalkrishna G S;Mahesh M J (Karnataka State Remote Sensing Applications Centre, , Bangalore-560 032, Email: ka06r3683@yahoo.co.in) : Hydrogemorphological studies in kallambella watershed, Tumkur district, Karnataka state, India using remote sensing and GIS. J Indian Soc Remote Sens 2007, 35(1), 107-15.

4 illus, 2 tables, 20 ref

016268   Krishna Reddy D;Sarma A D;Pammi S R;Prasad M V S N (NO, Chaitanya Bharathi Institute of Technology, Hyderabad, Email: dkreddi@rediffmail.com) : Development of SMS-based G<. J Indian Geophys Union 2007, 11(3), 161-70.

Details of development and applications of a navigation system known as GPS-GSM Integrator (G²I) are presented. G²I system consists of two modules namely In Vehicle Module (IVM) and Control Room Module (CRM). The IVM is micro controller based system equipped with Global Positioning System (GPS) receiver and Global System for Mobile communication (GSM) modem. The CRM consists of a Personal Computer (PC) and GSM mobile phone. Relevant software is developed for obtaining position information of vehicle. Drive tests are conducted with G²I system (in different modes) for cellular coverage area determination and for developing comprehensive digital reference Geographical Information System (GIS) maps in real time vehicle tracking. During these tests, the Received Signal Strength Indications (RSSI) of the cellular signal at various locations (latitude and longitude) in urban and rural regions are recorded and coverage area classification is done. The developed G²I system would be helpful for implementation of Location Based Services (LBS) of Third Generation (3G) communications.

13 illus, 22 ref

016267   Kolvankar V G (Seismology Div, Bhabha Atomic Research Centre, Tombay, Mumbai-400 085, Email: vkolvankar@yahoo.com) : RF emissions, types of earthquake precursors: possibly caused by the planetary alignments. J Indian Geophys Union 2007, 11(3), 147-60.

Various research workers have reported EM emission prior to earthquakes or during an earthquake sequence. In few cases, these EM emissions were consistently found during certain hours of the day. EM emission in semi-diurnal pattern spaced in time domain from the local noontime was observed in many examples prior to earthquakes / volcanic eruption. Also such emission was observed in a very wide frequency band from VLF to Microwave range. Besides this semi diurnal type of pattern, some other type of EM emission had diurnal pattern. This type was witnessed in Valsad [1991] and Chilean earthquake sequence [1960], in which it preceded semidiurnal pattern found in these earthquake sequences. The cause of this type of EM emission seems to be completely different than that for semidiurnal type. Efforts are made here to check whether the gravitational forces of the planetary alignments caused these types of RF emission. Discusses all these examples in details and discusses an application for the development of reliable monitoring of Earthquake/ Volcanic eruption precursors in the high seismicity area.

15 illus, 3 tables, 14 ref

016266   Khare N;Saraswat R;Chaturvedi S K (NO, National Centre for Antarctic and Ocean Research (Ministry of Earth S, Headland Sada, Vasco-da-Gama, Goa-403 804) : On the intriguing relatinship between seawater salinity and δ<. J Indian Geophys Union 2007, 11(2), 73-77.

The δ¹⁸O variation in planktic foraminifera Globigerina bulloides from nineteen surface sediment samples, collected onboard ORV Sagar Kanya between 1.92°S and 55.01°S latitude in the Indian Ocean sector of Southern Ocean, have been analyzed to understand the relationship between oxygen isotopic fractionation and near surface seawater salinity. The initial intriguing results indicate that up to <126>31°S latitude, salinity may influence the oxygen isotopic composition of the foraminiferal tests. However, beyond 31°S (further south) latitude, salinity does not appear to influence the G.bulloides oxygen isotopic composition significantly.

3 illus, 15 ref