002213   Jayaraman A;Joshi P C;Ramesh R (NO, National Atmospheric Research Laboratory, Gadanki-517 112, Email: jayaraman@narl.gov.in) : Developments and achievements in atmospheric sciences and space meteorology in India. Curr Sci 2007, 93(12), 1779-90.

Space research in India began in the early sixties, with the establishment of the Thumba Equatorial Rocket Launching Station. Indigenously developed rocket payloads were carried in foreign rockets and flown for studying various atmospheric parameters, which are unique to the tropics. In the seventies, Indian-made rockets became available. Since then, there has been rapid progress in the technical advancement, which helped the atmospheric scientists in taking up more challenging and contemporary problems, related to mesospheric winds, ionospheric irregularities, stratospheric ozone, role of aerosols in atmospheric radiative transfer, etc. India entered into the satellite era in 1975, with the development of the Aryabhatta satellite, the first Indian experimental satellite, followed by Bhaskara-1 in 1979, which carried a microwave radio meter for retrieval of atmospheric water vapour and cloud liquid water contents. Since then, there have been several satellites, such as the INSAT series for meteorology and communication, Indian Remote Sensing (IRS) satellite series, and Stretched Rohini Satellite System (SROSS) for in situ observation of the ionosphere, which are all built in India and launched from Indian soil. High quality data being obtained from these satellite missions are helping scientists in taking up problems that are of regional and global scales and in studying the changes that are taking place in the earth atomsphere system, in a more holistic way. This paper attempts to provide an overview of the scientific developments and highlights some results.

12 illus, 1 tables, 65 ref

002212   Ganguly N D (Physics Dep, St. Xavier's College, Ahamedabad-380 009, Email: nanditad@icenet.net) : Trend of tropospheric ozone in Indian forest from 1980 to 2000. Curr Sci 2007, 93(12), 1835-9.

Seasonal and yearly trends of troposphcric ozone for a few Indian forests from 1980 to 2000 have been studied using ozone data obtained from the troposphcric ozone residual method. The season in which peak value of ozone concentration is observed has been found to depend on the type of vegetation. The tropospheric ozone in Indian forests is observed to exhibit an overall increasing trend both seasonally and yearly over the period of these 20 years.

5 illus, 2 tables, 15 ref

002211   Ganeshaiah K N (School of Ecology and Conservation, Agricultural Sciences Univ, GKVK, Bangalore-560 065, Email: kng@vsnl.com) : Thalakaadu phenomenon: a miracle or an ecological disaster?. Curr Sci 2007, 93(11), 1495-1500.

Thalakaadu curse has established itself in the folklore as a miracle since the early part of 16th century because of two strange events visible even to date: (i) Thalakaadu, an historically vibrant city, is now being submerged under sand dunes several meters deep, and (ii) the Mysore royal fam-ily have faced problem in having a rightful heir to the throne since 1600s. Both these events linked to an apparent curse by a pious lady have defied logic. Based on the data from diverse sources and field studies, I have reconstructed the possible chronology of events of this acclaimed miracle. I argue that the Thalakaadu phenomenon represents an ecological disaster unintentionally wrought on to a vibrant civilization at this place and in this sense the curse per se is an intelligently inserted story as an overlay. Using this example I discuss the possible process through which the miracles or myths of this kind survive in a society.

10 illus, 12 ref

002210   Chaturvedi A K;Vashistha R K;Prasad P; Nautiyal M C (NO, High Altitude Plant Physiology Research Centre, H N B Garhwal Univ, Srinagar, Garhwal-246 174, Email: mcnautiyal@gmail.com) : Need of innovative approach for climate change studies in alpine region of India. Curr Sci 2007, 93(12), 1648-9.

4 ref

002209   Bidyananda M;Deomurari M P (Geological Sciences Dep, Gauhati Univ, Guwahati-781 014, Email: bmaibam@yahoo.com) : Geochronological constraints on the evolution of Meghalaya massif, northeastern India: an ion microprobe study. Curr Sci 2007, 93(11), 1620-3.

²⁰⁷Pb-²⁰⁶Pb isotope systematic of zircons from quart-zofeldspathic gneisses and metasediments belonging to the basement gneiss and Shillong group of the Megha-laya massif has been investigated using an ion micro-probe. The zircon age of the gneissic samples revealed the existence of multiple protolith components ranging in antiquity between ~1.5 and 2.6 Ga. The age distribution of the detrital metasedimentary zircons is similar to the range of the gneissic protoliths. Zircons from a charnockite sample yielded ages of 1.0-1.3 Ga, presumably recording the global Grenvillian orogeny. Our data suggest that crust formation in the Meghalaya massif started during the Archaean and experienced a protracted and episodic evolution that has some similarity with the Eastern Ghats Province.

3 illus, 1 table, 27 ref

002208   Bangar K S;Tiwari S C;Verma S K;Khandkar U R (All India Coordinated Research Project on Management of Salt Affected, College of Agriculture, Indore-452 001, Email: bangarks59@rediffmail.com) : Quality of ground water used for irrigation in Ujjain district of Madhya Pradesh, India. J envir Sci Engng 2008, 50(3), 179-86.

The ground water samples collected from different tehsils of Ujjain district were analysed in the laboratory for electrical conductivity (EC), pH, cations (Na⁺, K⁺, Ca²⁺ and Mg²⁺) and anions (CO_{3^2-, HCO3^-, Cl^- and SO4^2-). The water samples were categorized as per criterion developed by Central Soil Salinity Research Institute, Karnal, Haryana, India. Out of 712 samples, 105, 144, 150, 84, 68, 111 and 50 samples belong to Ujjain, Mahidpur, Khachrod, Tarana, Barnagar, Nagda and Ghatia tehsils of the district respectively. 80% samples indicated good water quality at the district as a whole, whereas 14 % were found saline (marginally saline (B1) - 9%, saline (B2) - 4%, high SAR saline (B3) -1%) and 6 % as alkali (marginally alkali (C1) - 5%, and alkali (C2) -1%) categories. In general, these waters were of Ca-Na-Mg type with the dominance of Cl followed by HCO3 and CO3 in case of good quality waters. The poor water quality belonged to categories of B1, B2, B3, C1 and C2, which were either having accumulation of salts (high EC) or high sodium adsorption ratio (SAR) and residual sodium carbonate (RSC). High significant negative correlation coefficient between pH and SO4 was observed. The sodium (Na⁺) content showed significant positive correlation coefficient with EC. Similarly, HCC3^- showed a significant positive correlation with RSC content. The ground water quality map of the district was generated using ERD AS-IMAGINE 8.7 Software showing different categories.}

3 illus, 4 tables, 7 ref

002207   Bably Prasad;Mondal K K (NO, Central Institute of Mining and Fuel Research, Barwa Road, Dhanbad-826 001, Email: drbablyprasad@yahoo.com) : Heavy metals leaching in Indian fly ash. J envir Sci Engng 2008, 50(2), 127-32.

Fly ash is an industrial waste generated from thermal power plants. Fly ash constitutes 80-85% of the total ash produced. A small part of fly ash is utilised in some sectors such as construction materials, building engineering, road, back fill, agriculture, selective engineering and processing useful materials. A large part of fly ash produced is disposed of with very high environmental risk. Laboratory leaching test has been used to determine the potential mobility of Pb, Cd, Cr, Cu, Zn, Fe, Mn and Ni in fly ash samples, collected from Chandrapura Thermal Power Plant, Jharkhand and Ramagundam Super Thermal Power Plant, Andhra Pradesh, in order to assess their leachability when these wastes are disposed of. A cascade-leaching test was used at liquid-to-solid ratio (L/S) ranging between 20 and 100. Both fly ash samples exhibited neutral reactions, as indicated by pH values <11.75 and >7.0 at L/S=10 and contact time of 10 minutes. The percentage of leached amounts found to follow the trend Zn>Fe>Mn>Cr<62>Pb>Cu>Ni>Cd for fly ash from Chandrapura and Fe>Zn>Cu>Mn<62>Cr>Ni>Pb>Cd for fly ash from Ramagundam. Effect of pH on metals released from ash surface in aqueous solution followed a predictable pattern of decreasing release with increasing pH.

6 illus, 2 tables, 26 ref

002206   Ashton P (Arnold Arboretum, Harvard Univ and Royal Botanic Gardens, Kew, England, Email: pashton@oeb.harvard.edu) : Asia's tropics are the most intensively used: contrasting conservation strategies between south and east. Curr Sci 2007, 93(11), 1538-43.

The Asian tropics have been by far the most densely populated, due to the early invention and dissemination of complex and inherently fragile socio-political and religious systems that permitted irrigation-based civilizations to expand almost to continental scale. Over the last half-century, many have become prosperous, while a few, notably Myanmar, Cambodia, Nepal and to a lesser extent the Philippines have yet to realize their economic potential while facing increasing populations pressures. Ancient understanding of the interdependence of nature and man has persisted to varying degree throughout the region, but weakened under the mercantile onslaught from the West. Forest and wildlife conservation initiatives and institutions were started in colonial times, but directed at commercial and elite interests. Now, public concern and effective political action is growing in the more successful economies, but successful conservation of biodiversity will be a close call.

1 illus, 1 table, 2 ref

001194   Tiwari A K;Nayak G N (National Centre for Antarctic and Ocean Research, Head Land sada, Vasco da Gama, Goa-403 804) : Water abundance and effect of glacier melting at priyadarshini lake in antarctica. J Instn Engrs-Pt EN 2007, 88(Sept), 27-32.

Priyadarshini lake also called Zub lake covers an area of 0.29 km² and forms the major source of water supply to the Maitri. The consumption of water at Maitri is relatively more in austral summer compared to the rest of the year and it fluctuates between 1. 70 m³/day in winter and 5. 7 m³/day in summer. Although the inflow volumes to the lake can vary widely from one summer to another owing to temperature differences, changes of annual losses over both summer and winter take place. Melt, water runoff from surrounding glaciers during the short austral summers is the only significant source of water that maintains the lake. Using the paddle boat, marked string with weight and GPS, depth and boundary line was recorded. The maximum recorded depth was 7.2 m. From 2nd January to 29th January, 2000 the water level recorded continuously has shown the increase in water level. The total area of the lake was estimated is around 2 76 944 m² after accumulation of feed water, which is 4.49% less than the GPS monitored area. Further volume calculated is 650358 m³. The average water consumption at Maitri is around 900 m³/year. The inflow of water due to annual glacial melt is around 61132 m³. Therefore even in the winter period sufficient water is available to be consumed by Maitri. This water abundance through Priyadarshini Lake will sustain for many years even if there is no inflow of water. The water quality of the lake is unchanged by the intrusion of seepage water channel from the wastewater pond due to less quantity and high dilution ratio and due to replenishment of water from glacial melt.

4 illus, 4 tables, 6 ref

001193   Sharma G K;Bora J (Geology Dep, Kumaun Univ, Nainital-263 002) : Pleistocene radiolaria from the kerguelen plateau, leg 119, sections 1H and 2H. J Palaeont Soc India 2007, 52(1), 27-38.

Twenty core samples from the Leg 119 Site 745 (Sections 1H to 2H) on the Kerguelen-Heard Plateau in the Southern Ocean region yielded, thirty-eight well-preserved radiolarian taxa which were studied and illustrated. The systematics, biostratigraphy, distribution in the core and comparison with radiolarian occurrences from other regions are presented. Two radiolarian zones are established viz. Psi and Omega in the sections. Ten new species are described but not formally named. The primary purpose is to present a first detailed Antarctic Pleistocene radiolarian data and refined biozone boundaries for comparative studies with other parts of the Antarctic region.

2 illus, 1 table

001192   Rai S P;Kumar V;Singh O;Jain S K (NO, National Institute of Hydrology, Jal Vigyan Bhawan, Roorkee-247 667) : Hydrochemical characteristics of mansar lake, Jammu and Kashmir in India. J Instn Engrs-Pt EN 2007, 88(Sept), 16-22.

An attempt has been made to study the chemical characteristics of the Mansar lake in Jammu region. The depthwise variation of temperature, pH, electrical conductivity, dissolved oxygen, hardness and alkalinity show that Mansar lake undergoes two distinct stages, such as, complete mixing stage in the months of January to February and stratified in remaining months of the year. Chemical analysis of lake water reveals that the; Ca and Mg account 70% to 85% of the cations and HCO₃ accounts for 77% to 91% of the total anion, and equivalent ratio of Ca:Mg varies from 0.45 to 6.40. The average (Ca+Mg)/HCO₃ equivalent ratio of 1.04, major contribution of (Ca+Mg) to total cations and high (Ca+Mg)/(Na+K) ratio indicate that, weathering of calcareous sandstone and mudstone of the Siwalik group is the primary source of major ions in the water. Phosphate concentration more than 0.03 mg/l shows that the lake has been entered into eutrophic stage.

4 illus, 13 ref

001191   Pathak D B (Geology Dep, Banaras Hindu Univ, Varanasi-221 005) : Jurassic/cretaceous boundary in the Spiti Himalaya, India. J Palaeont Soc India 2007, 52(1), 51-7.

The Jurassic/Cretaceous boundary in the Spiti region of the Tethys Himalaya, was identified near the contact of the Spiti Shale with the Guimal Sandstone Formation, being marked by the first appearance of the genera Odontodiscoceras and/or Neocosmoceras and last appearance of the genus Virgatosphinctes.

5 illus, 22 ref

001190   Khare N;Chaturvedi S K (NO, National Centre for Antarctic and Ocean Research Ministry of Earth Sci, Headland Sada, Vasco-Da-Gama, Goa-403 804) : Latitudinal variations in the abundance of planktic foraminifera along the Indian ocean sector of the southern Ocean. J Palaeont Soc India 2007, 52(1), 45-9.

During the 199C and 200th (also known as Pilot expedition to Southern Ocean) cruises of ORV Sagar Kanya between 9.69° N and 55.01° S latitude and 80° E and 40° E longitude, nineteen surface sediment samples were considered for present study, for which we simultaneously collected salinity data at near surface, 50 m and 100 m depths, using CTD. The planktic population is dominated by species such as Globigerina bulloides, Globigerinoides ruber, G. sacculifer, G. conglobatus, Orbulina universa, Neogloboquadrina pachyderma, Globorotalia menardii, etc. However, for the present purpose, the total planktic foraminiferal population was estimated in one gram dry sediments to assess the changes in their abundance along the north-south transect in the Indian Ocean Sector of Southern Ocean. Attempts are made to establish inter-relationship of planktic foraminiferal population vis-a-vis salinity and other allied factors such as nutrient (phosphate) content of the ambient water masses.

3 illus, 1 table, 31 ref

000299   Thakkar A K;Dhiman S D (Civil and Structural Engineering Dep, G.H. Patel of College of Engineering and Technology, Vallabh Vidyanagar-388 120, Email: dhimansanjay18@hotmail.com) : Morphometric analysis and prioritization of miniwatersheds in Mohr watershed, Gujarat using remote sensing and GIS techniques. J Indian Soc Remote Sens 2007, 35(4), 313-21.

Morphometric analysis and prioritization of the eight miniwatersheds of Mohr watershed, located between Bayad taluka of Sabarkantha district and Kapadwanj taluka of Kheda district in Gujarat State. India is carried out using Remote Sensing and GIS techniques. The morphometric parameters considered for analysis are stream length, bifurcation ratio, drainage density, stream frequency, texture ratio, form factor, circularity ratio, elongation ratio and compactness ratio. The Mohr watershed has a dendritic drainage pattern. The highest bifurcation ratio among all the miniwatersheds is 9.5 which indicates a strong structural control on the drainage. The maximum value of circularity ratio is 0.1197 for the miniwatershed 5F2B5b3. The miniwatershed 5F2B5a2 has the maximum elongation ratio (0.66). The form factor values arc in range of 0.29 to 0.34 which indicates that the Mohr watershed has moderately high peak flow for shorter duration. The compound parameter values are calculated and prioritization rating of eight miniwatersheds in Mohr watershed is carried out. The miniwatershed with the lowest compound parameter value is given the highest priority. The miniwatershed 5F2B5b2 has a minimum compound parameter value of 3.12 is likely to be subjected to maximum soil erosion hence it should be provided with immediate soil conservation measures.

4 illus, 5 tables, 14 ref

000298   Shankar D;Shetye S R;Joseph P V (NO, National Institute of Oceanography, Dona Paula, Goa-403 004, Email: shankar@nio.org) : Link between convection and meridional gradient of sea surface temperature in the Bay of Bengal. J Earth Syst Sci 2007, 116(5), 385-406.

Uses daily satellite estimates of sea surface temperature (SST) and rainfall during 1998-2005 to show that onset of convection over the central Bay of Bengal (88-92°E, 14-18°N) during the core summer monsoon (mid-May to September) is linked to the meridional gradient of SST in the bay. The SST gradient was computed between two boxes in the northern (88-92°E, 18-22°N) and southern (82-88° E, 4-8° N) bay; the latter is the area of the cold tongue in the bay linked to the Summer Monsoon Current. Convection over central bay followed the SST difference between the northern and southern bay (ΔT) exceeding 0.75°C in 28 cases. There was no instance of AT exceeding this threshold without a burst in convection. There were, however, five instances of convection occurring without this SST gradient. Long rainfall events (events lasting more than a week) were associated with an SST event (ΔT ≥ 0.75°C); rainfall events tended to be short when not associated with an SST event. The SST gradient was important for the onset of convection, but not for its persistence: convection often persisted for several days even after the SST gradient weakened. The lag between AT exceeding 0.75°C and the onset of convection was 0-18 days, but the lag histogram peaked at one week. In 75% of the 28 cases, convection occurred within a week of ΔT exceeding the threshold of 0.75°C. The northern bay SST, T_N, contributed more to AT, but it was a weaker criterion for convection than the SST gradient. A sensitivity analysis showed that the corresponding threshold for T_N was 29°C. Authors hypothesises that the excess heating (~ 1°C above the threshold for deep convection) required in the northern bay to trigger convection is because this excess in SST is what is required to establish the critical SST gradient.

12 illus, 15 tables, 45 ref

000297   Sayed S;Dodagoudar G R;Rajagopal K (Civil Engineering Dep, Indian Institute of Technology Madras, Chennai-600 036, Email: sajna@small.iitm.ac.in) : Reliability analysis of reinforced soil walls. Indian Geotech J 2008, 38(1), 49-67.

Highlights the importance of considering the uncertain parameters explicitly in the evaluation of stability of a reinforced retaining wall. The results of the reliability calculations have been obtained using FOSM method, FORM and PEM. For five units increase in coefficient of variation of friction angle and mean values of unit weight and interaction angle of soils, the results of sensitivity analysis show the variation in reliability index as 1.92, 0.64 and 1.18 for pullout and rupture modes of failure, and for external sliding, respectively. System reliability analysis reveals that the probability of failure of the retaining wall is 0.05 which is more than 0.001 (failure rate for earth retaining structures). It has been found that the friction angle of the soil is the most sensitive random variable affecting both the external and internal stability of the reinforced retaining wall. Interaction angle between soil and reinforcement and unit weight of soil are also found to affect the stability of the reinforced retaining wall. It is to be noted that these parameters have to be quantified rationally using probability theory so that the reliability of the retaining wall system can be assessed quantitatively.

10 illus, 9 tables, 27 ref

000296   Sasibhushana Rao G (NO, University College of Engineering, Andhra Univ, Visakhapatnam-530 003, Email: sasi_gps@yahoo.co.in) : GPS satellite and receiver instrumental biases estimation using least squares method for accurate ionosphere modelling. J Earth Syst Sci 2007, 116(5), 407-11.

The positional accuracy of the Global Positioning System (GPS) is limited due to several error sources. The major error is ionosphere. By augmenting the GPS, the Category I (CAT I) Precision Approach (PA) requirements can be achieved. The Space-Based Augmentation System (SBAS) in India is known as GPS Aided Geo Augmented Navigation (GAGAN). One of the prominent errors in GAGAN that limits the positional accuracy is instrumental biases. Calibration of these biases is particularly important in achieving the CAT I PA landings. In this paper, a new algorithm is proposed to estimate the instrumental biases by modelling the TEC using 4th order polynomial. The algorithm uses values corresponding to a single station for one month period and the results confirm the validity of the algorithm. The experimental results indicate that the estimation precision of the satellite-plus-receiver instrumental bias is of the order of ± 0.17 nsec. The observed mean bias error is of the order -3.638 nsec and -4.71 nsec for satellite 1 and 31 respectively. It is found that results are consistent over the period.

3 illus, 1 table, 9 ref

000295   Sasi Kumar V;Sampath S;Vinayak P V S S K; Harikumar R (Atmospheric Sciences Div, Centre for Earth Science Studies, Thiruvananthapuram-695 031) : Rainfall intensity characteristics at coastal and high altitude stations in Kerala. J Earth Syst Sci 2007, 116(5), 451-63.

Rainfall intensities measured at a few stations in Kerala during 2001-2005 using a disdrometer were found to be in reasonable agreement with the total rainfall measured using a manual rain gauge. The temporal distributions of rainfall intensity at different places and during different months show that rainfall is of low intensity (<10 mm/hr), 65% to 90% of the time. This could be an indication of the relative prevalence of stratiform and cumuliform clouds. Rainfall was of intensity < 5 mm/hr for more than 95 of the time in Kochi in July 2002, which was a month seriously deficient in rainfall, indicating that the deficiency was probably due to the relative absence of cumuliform clouds. Cumulative distribution graphs are also plotted and fitted with the Weibull distribution. The fit parameters do not appear to have any consistent pattern. The higher intensities also contributed significantly to total rainfall most of the time, except in Munnar (a hill station). In this analysis also, the rainfall in Kochi in July 2002 was found to have less presence of high intensities. This supports the hypothesis that the rainfall deficiency was probably caused by the absence of conditions that favoured the formation of cumuliform clouds.

16 illus, 3 tables, 9 ref

000294   Saikia K;Sarkar B C (Applied Geology Dep, Indian School of Mine, Dhanbad-826 004, Email: bhabesh_sarkar2003@yahoo.co.in) : EXGID- a prototype exploration geological information system for Jharia Coalfield, India. J scient ind Res 2007, 66(7), 513-16.

A prototype exploration geological information system (EXGID) has been developed to provide, a quick and user-friendly means for rapid access, search and retrieval of various geological and exploration information in respect of various mine blocks and coal seams of Jharia coalfield. EXGID consists of three sub-systems (Geological. Mine Exploration Block and Coal Seam), each of which is further segmented into several information categories to provide detail information in respect of the coalfield. Core program of EXGID system has been developed in Visual Basic environment (Version 6.0) and database management part of the system has been developed using Microsoft Access. EXGID system comprises a visual basic executable file (EXGID.exe). two microsoft access datafiles (geostruc.mdb, seanistat.mdb) and a number of BMP' files for visualization of location map of various mine exploration blocks of Jharia coalfield. It provides a facility (or rapid search and retrieval of user's required geological and exploration information ensuring minimum redundancy.

3 illus, 1 tables, 6 ref

000293   Saha D;Chakraborti S (NO, Indian Statistical Institute, Geological Studies Unit, 203 B. T. Road, Kolkata-700 108, Email: dsaha@isical.ac.in) : Advective heat transfer and fabric development in a shallow crustal intrusive granite-the case of Proterozoic Vellaturu granite, south India. J Earth Syst Sci 2007, 116(5), 433-50.

Syntectonic plutons emplaced in shallow crust often contain intermediate- to low-temperature deformation microstructures but lack a high-temperature, subsolidus deformation fabric, although the relict magmatic fabric is preserved. The Proterozoic Vellaturu granite emplaced at the eastern margin of the northern Nallamalai fold belt, south India during the late phase of regional deformation has a common occurrence of intermediate- to low-temperature deformation fabric, superimposed over magmatic fabric with an internally complex pattern. But high-T subsolidus deformation microstructure and fabric are absent in this pluton. The main crystal plastic deformation and fluid enhanced reaction softening was concentrated along the margin of the granite body. Resulting granite mylonites show Y-maximum c-axis fabric in completely recrystallized quartz ribbons, dynamic recrystallization of perthites, and myrmekite indicative of fabric development under intermediate temperature (~500-400°C). The weakly-deformed interior shows myrmekite, feldspar microfracturing and limited bulging recrystallization of quartz. The abundance of prism subgrain boundaries is indicative of continuing deformation through low-temperature (~300°C). The relative rates of cooling influenced by advective heat transfer and deformation of the pluton seem to control the overall subsolidus fabric development. The rapid advective heat transfer from the interior in the early stages of subsolidus cooling was followed by slow cooling through intermediate temperature window as a well-developed phyllosilicate rich mylonitic skin around the granite body slowed clown conductive heat loss. Low-T crystal plastic deformation of quartz was effected at a. late stage of cooling and deformation of the shallow crustal granite body emplaced within the greenschist fades Nallamalai rocks.

11 illus, 2 tables, 62 ref

000292   Rachna Raj (Geology Dep, Faculty of Science, M.S. Univ of Baroda, Vododara-390 002, Email: naveenrachna@gmail.com) : Strike slip faulting inferred from offsetting of drainages: lower Narmada basin, western India. J Earth Syst Sci 2007, 116(5), 413-21.

The detailed analysis of landforms, drainages and geology of the area between the rivers Amaravati and Karjan was carried out in order to understand the tectonic history of the lower Narmada basin. Movement along the various faults in the area was studied on the basis of the drainage offsetting. Horizontal offsetting of stream channels was found quite demonstrable along NNW-SSE trending transverse faults. Tectonic landforms including systematic deflection of stream channels and ridges, alignment of fault scarp and saddles and displacement in the basement rocks and alluvial deposits show that the area is undergoing active deformation driven by the NSF system.

6 illus, 34 ref

000291   Negi H S;Thakur N K;Mishra V D (Snow&Avalanche Study Establishment, , Chandigarh-160 036, Email: negi_hs@yahoo.com) : Estimation and validation of snow surface temperature using MODIS data for snow-avalanche studies in NW-Himalaya. J Indian Soc Remote Sens 2007, 35(4), 287-99.

Snow avalanche studies require different snow-meteorological parameters for avalanche forecasting. Snow surface temperature is one of the major parameters, which is responsible for the evolution of snow pack characteristics. The snow surface temperature was estimated using TERRA satellite based - Moderate resolution imaging spectroradiometer (MODIS) sensor for NW-Himalayas. Ground data observed by automatic weather stations (AWS) was used to calibrate the brightness temperature obtained by MODIS thermal bands data into the actual snow surface temperature data through regression analysis. A split window technique has been implemented for the estimation of snow surface temperature. The multi-date satellite derived snow surface temperature was validated with ground data of winter 2004-05 and 2005-06 collected at various observation stations located in different ranges of NW-Himalaya. Good correlations were observed for Upper Himalaya (0.98, 0.98), Middle Himalaya (0.92, 0.96) and Lower Himalaya (0.88, 0.82) for 2004-05 and 2005-06 winter respectively. Further, estimated snow surface temperature was also verified with snow-cover information collected by manned observatories and area delineated by thematic maps of snow surface temperature was validated with the different snow climatic zones of NW-Himalaya.

8 illus, 1 table, 18 ref

000290   Mishra A K;Krishnamurti T N (Meteorology Dep, Florida State Univ, Tallahassee, Florida-323 306, USA, Email: dkhil@io.met.fsu.edu) : Current status of multimodel superensemble and operational NWP forecast of the Indian summer monsoon. J Earth Syst Sci 2007, 116(5), 369-84.

In the last thirty years great strides have been made by large-scale operational numerical weather prediction models towards improving skills for the medium range time-scale of 7 days. Illustrates the use of these current forecasts towards the construction of a consensus multimodel forecast product called the superensemble. This procedure utilizes 120 of the recent-past forecasts from these models to arrive at the training phase statistics. These statistics are described by roughly 10⁷ weights. Use of these weights provides the possibility for real-time medium range forecasts with the superensemble. Shows the recent status of this procedure towards real-time forecasts for the Asian summer monsoon. The member models of our suite include ECMWF, NCEP/EMC, JMA, NOGAPS (US Navy), BMRC, RPN (Canada) and an FSU global spectral forecast model. Shows the skill scores for day 1 through day 6 of forecasts from standard variables such as winds, temperature, 500 hPa geopotential height, sea level pressure and precipitation. In all cases noted that the superensemble carries a higher skill compared to each of the member models and their ensemble mean. The skill matrices use include the RMS errors, the anomaly correlations and equitable threat scores. For many of these forecasts the improvements of skill for the superensemble over the best model was found to be quite substantial. This real-time product is being provided to many interested research groups. The FSU multimodel superensemble, in realtime, stands out for providing the least errors among all of the operational large scale models.

6 illus, 1 table, 32 ref

000289   Madhavi Latha G;Sitharam T G (Civil Engineering Dep, Indian Institute of Science, Bangalore, Email: madhavi@civil.iisc.ernet.in) : Effect of particle size and gradation on the behaviour of granular materials simulated using DEM. Indian Geotech J 2008, 38(1), 68-88.

The effect of particle size and gradation on the stress-strain and volume change behaviour of granular soils is studied through systematic series of numerical experiments. Results from numerical triaxial tests on samples with uniform size particles and also on parallel graded samples indicated that the particle size has no effect on the strength of granular materials. Irrespective of the initial void ratio, samples with particles of same size exhibit same shear strength. The volume change response of samples during isotropic compression is independent of the particle size. However, Samples with bigger size particles exhibit higher compressibility resulting in slightly higher load carrying capacity at any particular deviatoric strain during triaxial tests and also the failure strain increase slightly with increase in particle size. Gradation of the particles significantly influences the strength and volume change behaviour of granular soils. Widening the gradation curve by keeping same minimum or maximum particle size increases the shear strength irrespective of the initial density of the sample. The volume change behaviour during isotropic compression is also different for different gradations, the volumetric compression for any value of mean isotropic compressive stress being small for wider gradations due to low initial void ratio resulting from compact packing because of large range of particle sizes available. Also the compressibility of samples and the failure deviatoric strain increased for wider gradations. Initial void ratio of the samples is the major factor that influences the shear strength of granular soils. The φ values of samples with the initial void ratio of the samples follow a unique nonlinear trendline, suggesting that initial void ratio is the single parameter that can effectively replace the individual effects of size and gradation of the granular soils.

18 illus, 3 tables, 36 ref

000288   Das J D;Dutta T;Saraf A K (Earthquake Engineering Dep, Indian Institute of Technology Roorkee, Roorkee, Email: jddasfeq@iitr.ernet.in) : Remote sensing and GIS application in change detection of the Barak river channel, N.E. India. J Indian Soc Remote Sens 2007, 35(4), 301-12.

Rivers flowing through the alluvium invariably have very low gradient forcing the river to flow slowly in a meandering and zigzag path. Nature and intensity of meandering is governed by the geological and tectonic conditions of the river basin. Barak River in tectonically active south Assam (Northeast India) exhibits intense meandering and shifting of the river course. Topographic data of two different years and satellite images of 4 different years covering a section of the Barak River have been investigated to verity the nature of changes undergone by the river through limes. This study reveals active northward shift of the river and a prominent neck-cut off in the initial part of the study area. Northward shift of the river also occurred in the area west of Silchar. But, in the western part the river has shifted both towards north and south. Oscillatory shifting in the river channel has also been noticed. The river has shown a overall northward shift which is probably due to uplift of the southern part of the Barak River valley.

11 illus, 10 ref

000287   Chattopadhyay A;Ghosh N (Geology Dep, Delhi Univ, Delhi-110 007, Email: ng1704@rediffmail.com) : Polyphase deformation and garnet growth in pelitic schists of Sausar group in Ramtek area, Maharashtra, India: a study of porphyroblast-matrix relationship. J Earth Syst Sci 2007, 116(5), 423-32.

Polyphase deformation and metamorphism of pelitic schists of Chorbaoli Formation of Sausar Group in and around Ramtek area, Nagpur district, Maharashtra, India has led to the development of garnet and staurolite porphyroblasts in a predominantly quartz-mica matrix. Microstructural study of oriented thin sections of these rocks shows that garnet and staurolite have different growth histories and these porphyroblasts share a complex relationship with the matrix. Garnet shows at least two phases of growth - first intertectonic between D₁ and D₂ (pre-D₂ phase) and then syn-tectonic to post-tectonic with respect to D₂ deformation. Growth of later phase of garnet on the earlier (pre-D₂) garnet grains has led to the discordance of quartz inclusion trails between core and rim portion of the same garnet grain. Staurolite develops only syn-D₂ and shows close association with garnet of the later phase. The peak metamorphic temperature thus coincided with D₂ deformation, which developed the dominant crenulation schistosity (S₂), regionally persistent in the terrain. The metamorphic grade reached up to middle amphibolite facies in the study area, which is higher than the adjoining southern parts of Sausar Fold Belt.

6 illus, 37 ref