BVR photometry of the three RS CVn binary stars: V711 Tau,UX Ari and IM Peg

Differential BVR photometric observations of the three RS CVn binary stars: V711 Tau, UX Ari and IM Peg obtained during the period November 26, 1994–February 24, 1995 using the 0.35 m reflector telescope equipped with photoelectric photometer are presented. Analysis of light curves shows significant changes in shape, amplitude as well as the phases of minimum light of all the three binaries. The amplitude of IM Peg, in particular, is found to have reached a larger value in the present epoch of observation than reported earlier.     

Inventory of degraded lands of Palamau district, Bihar — A remote sensing approach

In this study, an attempt has keen made for the identification, categorisation and mapping of degraded lands in Palamau district of Bihar using remotely sensed data (IRS-1A, raise colour composite, on 1:50,000 scale), It was observed that water erosion is the main cause of land degradation affecting 6.27 per cent area of the district, of which 5.22 per cent is subjected to severe to very severe erosion and remaining 1.05 per cent is moderately to severely gulleid land Degradation due to rock quarries, mine spoils and dumps accounted for only 0.01 per cent of the district area. Degraded lands were mostly confined to agricultural areas (4.76%) follwed by forest lands (1.10%) and opert-scrub/pastures (0.42%), respectively, Subdivision-wise categorisation of degraded lands was also attempted for efficient location-speeific reclamation planning and easy monitoring.     

Ocean Model Simulation of Southern Indian Ocean Surface Currents

The dynamic importance of the Southern Indian Ocean (SIO) lies in the fact that it connects the three major world oceans: the Pacific, Atlantic, and Indian Oceans. Modeling study has been used to understand the circulation pattern of this very important region. Simulation of SIO (10°N-60°S and 30°E-120°E) is performed with z-coordinate Ocean General Circulation Model (OGCM) viz; MOM3.0 and the results have been compared with observed ship drift data. It is found that except near coastal boundaries and in equatorial region, the simulated current reproduce most well known current pattern such as Antarctic Circumpolar Current (ACC), South Equatorial Current (SEC) etc. and bears a resemblance to that of the observed data; however the magnitude of the surface current is weaker in model than the observed data, which may be due to deficiency in the forcing field and boundary condition and problem with observed data. The annual mean wind stress curl computed over the oceanic domain reveals about ACC and its similar importance. The way in which the ocean responds to the windstress and vertically integrated transport using model output is fascinating and rather good.     

Eddy Detection Over Southern Indian Ocean Using TOPEX/POSEIDON Altimeter Data

Mesoscale eddies constitute the most energetic component of the variability of ocean currents. An attempt has been made for the detection of oceanic mesoscale eddy signatures over the Southern Indian Oceanic (SIO) regions using the dynamic topography derived from TOPEX/POSEIDON (T/P) altimeter data, by the signal processing technique, called matched filtering. After applying all the ocean and atmospheric corrections, data of a complete cycle of T/P over SIO has been used for detection of eddy signatures. The geoid undulations are removed from the data of corrected sea surface height from T/P and the resulting dynamic topographic data are passed through a matched filter designed to detect a generic eddy signature of Gaussian signal embedded in noise. The filter is optimized to detect eddies with amplitude 20 to 30 cm and diameters roughly 100?250 km. Out of all the analyzed data of T/P orbits over SIO a few examples are presented for brevity. Qualitative verification of eddies is done with some independent T/P sea level anomaly data over the region. The analysis shows that the matched filtering technique is most suitable for monitoring eddy signatures along the subsatellite track instantly over the remote and most hostile regions of the southern global oceans.     

Groundwater prospects evaluation based on hydrogeomorphological mapping using high resolution satellite images: A case study in Uttarakhand

Water is the most important natural resource which forms the core of the ecological system. The advent of remote sensing has opened up new vistas in groundwater prospect evaluation, exploration and management. The groundwater resources of the study area, Rishikesh region of Garhwal Himalayas, are under threat due to population pressure caused by expanding tourism in this region. This entails sustainable and judicious use of this precious resource. The groundwater prospect evaluation in Rishikesh region has been attempted based on hydrogeomorphological mapping of the area consisting of thematic maps of hydrogeomorphology, geology, drainage, lineament, slope and relief using high resolution IRS-1C LISS III and PAN merged satellite images. The Rishikesh region exhibits diverse hydrogeomorphological conditions where the groundwater regime is controlled mainly by topography and geology. A probability-weighted approach has been applied during overlay analysis in ArcMap GIS environment. The overlay analysis allows a linear combination of weights of each thematic map with respect to ground water potential. Good groundwater prospects dominate in the area with more than 50% of the study area showing moderate to excellent potential. The study shows that the remote sensing and geoinformatics techniques can be applied effectively for groundwater prospect evaluation.     

Plane-symmetric magnetofluid cosmological models

The solutions of the Einstein and Einstein-Maxwell equations for magnetofluid with cosmological constant are obtained for plane-symmetric space-time. We recover the results of Hojman and Santamarina in a special case when the magnetic field is made to vanish. It has also been shown that under a suitable transformation the cases =0 and 0 are mathematically equivalent.     

M<Subscript>w</Subscript> 6.7 earthquake of Manipur,NE India: Some Insights

Late Maastrichtian through middle Eocene planktic foraminiferal biostratigraphy and erosion patterns from three Cauvery basin wells are compared with the Krishna-Godavari basin, Madagascar and South Atlantic Site 525A. Maastrichtian sedimentation appears continuous at DSDP site 525A and substantially complete in the Cauvery basin and Madagascar for the interval from ~70.3 to 66.8 Ma (zones CF6-CF3). But the latest Maastrichtian through early Paleocene record is fragmented, except for some Krishna-Godavari and Cauvery basin wells protected from erosion by Deccan traps or graben deposition, respectively. Hiatuses are observed correlative with sea level falls at 66.8, 66.25, 66.10, 65.7, 63.8 and 61.2 Ma with erosion amplified by local tectonic activity including doming and uplift due to Deccan volcanism.     

Morphometric analysis of Usri River basin,Chhotanagpur Plateau,India, using remote sensing and GIS

A geomorphic unit Usri drainage basin (latitude: 24° 04′00″ N to 24° 34′00″ N and longitude 86°05′00″E to 86°25′00″E) lies in north-eastern parts of Chhotanagpur Plateau, India, has been selected for morphometric analysis. Digital elevation model (DEM) has been generated by Cartosat stereo pair data at 10-m resolution. The morphometric parameters considered for the analysis includes the linear, areal, and relief aspects of the basin. Morphometric analysis of the river network and the basin revealed that the Usri Basin has sixth-order river network with a dendritic drainage pattern. The dendritic drainage pattern indicates that the basin has homogeneous lithology, gentle regional slope, and lack of structural control. The bifurcation ratio between different successive orders varies but the mean ratio is low that suggests the higher permeability and lesser structural control. The low drainage density, poor stream frequency, and moderately coarse drainage texture values of the basin indicate that the terrain has gentle slope, is made up of loose material, and hence has good permeability of sub-surface material and significant recharge of ground water. The shape parameters indicate that the basin is elongated in shape with low relief, high infiltration capacity, and less water flow for shorter duration in basin. The 50 % of the basin has altitude below 300 m and gently sloping towards the southeast direction. All the morphometric parameters and existing erosional landforms indicated mature to early old stage topography.