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921.
922.
K. Kasturirangan U. R. Rao D. P. Sharma R. G. Rastogi S. C. Chakravarty 《Astrophysics and Space Science》1976,42(1):57-62
The paper presents the results on investigations of the ionospheric effects arising out of the transient celestial events at X-ray and gamma-ray energies such as that from X-ray novae and cosmic gamma-ray bursts. The VLF data recorded at Ahmedabad corresponding to the 164 kHz transmission from Tashkent are examined to see whether there are any observable effects time coincident with the transit of the X-ray novae Cen X-4 and Cet X-2 around their intensity maxima. Besides, the VLF data have also been examined in relation to the cosmic gamma-ray bursts detected by Vela, IMP-6 and OSO-7 satellites.Theoretical computations are carried out for estimating electron density enhancements using the available data on intensities and energy spectra for these events. Further, the observational resutls are explained in terms of these theoretical calculations.Presently at Indian Space Research Organization, Bangalore, India.Paper presented at the COSPAR Symposium on Fast Transients in X- and Gamma-Rays, held at Varna, Bulgaria, 29–31 May, 1975. 相似文献
923.
We have analysed three Indian meteorites — Bansur, Udaipur and Madhipura — for the elemental and isotopic composition of Ne, Ar, Kr and Xe and determined their radiation and gas-retention ages. It is found that Udaipur belongs to the group of unequilibrated ordinary chondrites and Madhipura probably belongs to the group of shocked hypersthene chondrites. 相似文献
924.
925.
M. G. Raghavendra Reddy G. P. Obi Reddy A. K. Maji K. Nageshwara Rao 《Journal of the Indian Society of Remote Sensing》2003,31(4):271-282
In the present study, an attempt has been made to analyse IRS-ID LISS-III satellite data in conjunction with field observations
for geomorphological mapping and pedo-geomorphological characterisation in Mohgaon area of Nagpur district, Maharashtra. Analysis
of satellite data reveals distint geomorphological units viz., plateau top, isolated mounds, linear ridges, escarpments, plateau
spurs, subdued plateau, rolling plains, pediments, narrow valleys and main valley floor. Soil profiles, studied on different
identified landforms, showed variation in site and morphological charactaristics. Moderate soil erosion occurs on plateau
top, isolated mouds, plateau spurs, rollinmg plains and pediments. Severe erosion was identified on escarpments and subdued
plateau and narrow valleys suffer very slight erosional hazards. Moderately well drained soils were found on rolling plains,
pediments, narrow valleys and main valley floor. Well drained soils were noticed on plateau top and plateau spurs. Very shallow
soils were found on the plateau top and isolated mounds. Shallow soils are found in linear ridges, escarpments, plateau spurs
and rolling plains. Moderately deep and deep soils are found on subdued plateau, pediments and main valley floor. The landform-soil
relatioinship reveals that the soils on the plateau top and isolated mounds are very shallow, well drained, clay textured.
The soils on the narrow valleys and main valley floor are deep, moderatly well drained, and clayey in texture. It also indicates
that landform-soil processes are governed by physiographic position, drainage, slope and erosion conditions of the area. The
present study reveals that the analysis of remotely sensed data in conjunction with field observations in GIS will be of immense
help in geomorphology mapping, analysis of landform-soil relationships and generation of their geo-spatial database. 相似文献
926.
A variety of masonry structures suffered damage during the recent Bhuj earthquake. Some of the traditional masonry structures
had no earthquake resistant features and suffered considerable damage. This paper attempts to evaluate the behaviour of masonry
structures based on the type of masonry used in places like Bhuj, Anjar, Bhachau, Morbi, Samakhyali and several other places.
Quite a few masonry buildings had used earthquake resistant features like lintel bands and corner reinforcements. The cracking
and failure patterns of such buildings have also been examined. The paper concludes with a discussion on the relevance of
the current codal provisions for earthquake resistance of masonry structures and the direction of further research in the
area. 相似文献
927.
928.
P. L. S. Rao U. C. Mohanty P. V. S. Raju Gopal Iyengar 《Journal of Earth System Science》2003,112(1):95-111
In this study, we present the mean seasonal features of the Indian summer monsoon circulation in the National Centre for Medium
Range Weather Forecasting (NCMRWF) global data assimilation and forecast system. The large-scale budgets of heat and moisture
are examined in the analyzed and model atmosphere. The daily operational analyses and forecasts (day 1 through day 5) produced
for the summer seasons comprising June, July and August of 1995 and 1993 have been considered for the purpose. The principal
aim of the study is two-fold. Primarily, to comprehend the influence of the systematic errors over the Indian summer monsoon,
secondarily, to analyze the performance of the model in capturing the interseasonal variability.
The heat and moisture balances show reduction in the influx of heat and moisture in the model forecasts compared to the analyzed
atmosphere over the monsoon domain. Consequently, the diabatic heating also indicates reducing trend with increase in the
forecast period. In effect, the strength of Indian summer monsoon, which essentially depends on these parameters, weakens
considerably in the model forecasts. Despite producing feeble monsoon circulation, the model captures interseasonal variability
realistically. Although, 1995 and 1993 are fairly normal monsoon seasons, the former received more rainfall compared to the
latter in certain pockets of the monsoon domain. This is clearly indicated by the analyzed and model atmosphere in terms of
energetics. 相似文献
929.
930.
Summary. ?Cyclone track predictions in the Indian seas (Bay of Bengal and Arabian Sea) with a quasi-Lagrangian model (QLM) have been
attempted. QLM has a horizontal resolution of 40 km and 16 sigma levels in the vertical. It is integrated in a domain of about
4400 × 4400 km2. A new initialization procedure to provide initial fields for running the model has been designed. The initialization procedure
consists of updating the global model forecasts, used as first guess, provided by the National Center for Medium Range Weather
Forecasting (NCMRWF), New Delhi. A new version of IMD’s operational optimum interpolation scheme has been created to suit
the QLM grid structure. Lateral boundary conditions are computed from the extended forecasts of NCMRWF. The track forecasts
in each case show a reasonable skill of the forecast model in predicting the direction of movement within acceptable limits
of forecast errors, which are comparable to some of the best models operated by advanced NWP centers of the world. Even the
recurving storms are well predicted. Evolution of the vertical motion fields are also studied which reveal some interesting
features, which are described in detail in the text. The composited vertical motion fields are projected against observed
rainfall distribution, which show a good spatial correspondence.
Received August 9, 2001; revised March 12, 2002; accepted June 17, 2002
Published online: May 8, 2003 相似文献