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91.
Anil V. Kulkarni Sunil Dhar B. P. Rathore Babu Govindha Raj K. Rajeev Kalia 《Journal of the Indian Society of Remote Sensing》2006,34(1):39-46
Himalayas possess one of the largest resources of snow, ice and glaciers that act as a huge freshwater reservoir. Monitoring
the glaciers is important to assess the overall reservoir health of the Himalayas. Samudra Tapu is one of the largest glaciers
in Chandra basin of district Lahaul and Spiti, Himachal Pradesh. Based on the field investigations and the remote sensing
techniques. features such as accumulation area, ablation area snowline/equilibrium line, moraine-dammed lakes and permanent
snowfields were mapped. The glacial terminus was identified using moraine-dammed lake, as lake is located at down streamside
of the terminus. The total recession of glacier during the period of 38 years (1962–2000) is about 742 m with an average rate
of 19.5 m/yr. In addition, glacial extent is reduced from 73 to 65 km2 between 1962 and 2000. suggesting overall deglaciation of 11%. During field investigation. three stages of glaciation using
terminal moraine were identified. These moraines were mapped by merging LISS-II1 and PAN data. At the peak of glaciation.
the glacial terminus was extended 3.18 km downstream of terminus position in year 2000. Total area during peak of glaciation
period has been observed to be 77.67 km2, which is 12.67 km2 higher than the present glacier extent. 相似文献
92.
Anil Kumar Y J Bhaskar Rao V M Padma Kumari A M Dayal K Gopalan 《Journal of Earth System Science》1988,97(1):107-114
Palaeomagnetic, geochemical and geochronological studies have been conducted on a set of dolerite dykes intruding the Peninsular
gneisses near Huliyurdurga town, Karnataka, as a reconnaissance survey indicated a Cretaceous age for them. The dykes are
mainly tholeiitic in composition with their 87Sr/86Sr ratios tightly clustered around 0·7045. Their palaeomagnetic data (D
m
=329°,I
m
=−55°) and the corresponding palaeopole coordinates (λ
p
= 34°S,L
p
=108°E) are strikingly close to those of the Deccan Traps to the north. Whole rock K-Ar ages of these dykes ranging between
69 and 84 Ma are also similar to the range of K-Ar ages of the Deccan basalts. The chemical, palaeomagnetic and temporal coherence
between the dykes and the Deccan basalts indicate that they may indeed be tectonically related events. 相似文献
93.
An effective procedure is summarized without derivation for estimating the maximum response of a class of torsionally-coupled, multi-storey buildings due to earthquake ground motion characterized by response spectra. The analysis procedure is shown to be efficient and to provide insight into torsional coupling effects because the maximum response of such a torsionally-coupled, N-storey building in its njth mode of vibration is determined exactly by analysing (i) the response in the jth vibration mode (j = 1,2, N) of the corresponding torsionally-uncoupled, N-storey system; and (ii) the response in the nth vibration mode (n = 1, 2 for a one-way symmetric plan) of an associated torsionally-coupled, one-storey system. It is also demonstrated that an earlier, simpler approach in which the total (considering all vibration modes) response of the building is determined from the total response of the two simpler systems is strictly valid only under restrictive conditions, which are identified, but the simpler approach leads to results that are accurate to a useful degree. 相似文献
94.
Man has had to live with floods since the very inception of his existence. Fury of flood causes heavy damages to both life and property. Accurate flood inundation data is one of the essential requirements for effective management of flood problem. Remote Sensing methods are well suited for acquiring flood inundation data because of synoptic, repetitive coverage of the satellite data. This paper briefs on an attempt to map flood inundated areas in a part of Mahanadi river basin using remote sensing data. 相似文献
95.
The mechanical properties of particulate systems are studied from a micromechanics point of view. Two approaches, namely, computer simulation and micro-structural continuum modelling are used. The computer simulation method is used to study the uniformity of the strain field and effect of particle rotations. These results are then used to evaluate the applicability of the micro-structural continuum model. Potential applications of the micro-structural continuum model in the study of mechanical properties of soils are discussed. 相似文献
96.
A detailed water quality analysis was carried out in the quaternary aquifer system of the marginal alluvial plain (Ganga Plain)
in Bah Tahsil, Agra district, India. The electrical conductivity of 50 samples each from dug wells, hand pumps and tube wells
was analysed for the study of salinity levels in shallow, intermediate and deep aquifers. Out of 50, 20 samples of each were
also analysed for other chemical constituents such as Na+, K+, Cl−, F− and TDS. The analyses show drastic changes in the salinity levels of shallow, intermediate and deep aquifers. The deep aquifers
are more saline compared to the shallow and intermediate aquifers. On the contrary, the concentration of chemical constituents
such as Na+, K+, Cl− and F− was more in the shallow aquifers compared to the deep aquifers. Moreover, there is an indication that the salinity and concentration
of the above chemical constituents also escalate with time in each aquifer. The chemical constituents such as Na+, K+, Cl−, F− and TDS range from 51 to 165 mg/l, 1 to 14 mg/l, 224 to 1,459 mg/l, 0 to 1.5 mg/l and 750 to 2,650 mg/l, respectively. Over
a 3-year period, the salinity levels have sharply increased and the average F level has increased by 0.1–0.3 mg/l. An attempt
has been made here to discuss the factors causing the variation and escalation of chemical constituents and salinity in the
water of the three aquifers. 相似文献
97.
New statistical models for long-range forecasting of southwest monsoon rainfall over India 总被引:2,自引:0,他引:2
The India Meteorological Department (IMD) has been issuing long-range forecasts (LRF) based on statistical methods for the
southwest monsoon rainfall over India (ISMR) for more than 100 years. Many statistical and dynamical models including the
operational models of IMD failed to predict the recent deficient monsoon years of 2002 and 2004. In this paper, we report
the improved results of new experimental statistical models developed for LRF of southwest monsoon seasonal (June–September)
rainfall. These models were developed to facilitate the IMD’s present two-stage operational forecast strategy. Models based
on the ensemble multiple linear regression (EMR) and projection pursuit regression (PPR) techniques were developed to forecast
the ISMR. These models used new methods of predictor selection and model development. After carrying out a detailed analysis
of various global climate data sets; two predictor sets, each consisting of six predictors were selected. Our model performance
was evaluated for the period from 1981 to 2004 by sliding the model training period with a window length of 23 years. The
new models showed better performance in their hindcast, compared to the model based on climatology. The Heidke scores for
the three category forecasts during the verification period by the first stage models based on EMR and PPR methods were 0.5
and 0.44, respectively, and those of June models were 0.63 and 0.38, respectively. Root mean square error of these models
during the verification period (1981–2004) varied between 4.56 and 6.75% from long period average (LPA) as against 10.0% from
the LPA of the model based on climatology alone. These models were able to provide correct forecasts of the recent two deficient
monsoon rainfall events (2002 and 2004). The experimental forecasts for the 2005 southwest monsoon season based on these models
were also found to be accurate. 相似文献
98.
Shusaku Inoue Anil C. Wijeyewickrema Hiroyuki Matsumoto Hiroyuki Miura Priyantha Gunaratna Manoj Madurapperuma Toru Sekiguchi 《Pure and Applied Geophysics》2007,164(2-3):395-411
The December 26, 2004 Sumatra-Andaman earthquake that registered a moment magnitude (Mw) of 9.1 was one of the largest earthquakes in the world since 1900. The devastating tsunami that resulted from this earthquake
caused more casualties than any previously reported tsunami. The number of fatalities and missing persons in the most seriously
affected countries were Indonesia - 167,736, Sri Lanka - 35,322, India - 18,045 and Thailand - 8,212. This paper describes
two field visits to assess tsunami effects in Sri Lanka by a combined team of Japanese and Sri Lankan researchers. The first
field visit from December 30, 2004 – January 04, 2005 covered the western and southern coasts of Sri Lanka including the cities
of Moratuwa, Beruwala, Bentota, Pereliya, Hikkaduwa, Galle, Talpe, Matara, Tangalla and Hambantota. The objectives of the
first field visit were to investigate the damage caused by the tsunami and to obtain eyewitness information about wave arrival
times. The second field visit from March 10–18, 2005 covered the eastern and southern coasts of Sri Lanka and included Trincomalee,
Batticaloa, Arugam Bay, Yala National Park and Kirinda. The objectives of the second visit were mainly to obtain eyewitness
information about wave arrival times and inundation data, and to take relevant measurements using GPS instruments. 相似文献
99.
Bianchi Type I magnetized Cosmological model for perfect fluid distribution is investigated. The magnetic field is due to
an electric current produced along x-axis. The distribution consists of an electrically neutral perfect fluid with an infinite electrical conductivity. To get
a determinate solution, a supplementary conditionA = BC between metric potentials is used. The behaviour of the model in presence and absence of magnetic field is also discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
100.