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21.
The once and future pulse of Indian monsoonal climate 总被引：3，自引：1，他引：2
K. Krishna Kumar K. Kamala Balaji Rajagopalan Martin P. Hoerling Jon K. Eischeid S. K. Patwardhan G. Srinivasan B. N. Goswami Ramakrishna Nemani 《Climate Dynamics》2011,36(11-12):2159-2170
We present a comprehensive assessment of the present and expected future pulse of the Indian monsoon climate based on observational and global climate model projections. The analysis supports the view that seasonal Indian monsoon rains in the latter half of the 21th century may not be materially different in abundance to that experienced today although their intensity and duration of wet and dry spells may change appreciably. Such an assessment comes with considerable uncertainty. With regard to temperature, however, we find that the Indian temperatures during the late 21st Century will very likely exceed the highest values experienced in the 130-year instrumental record of Indian data. This assessment comes with higher confidence than for rainfall because of the large spatial scale driving the thermal response of climate to greenhouse gas forcing. We also find that monsoon climate changes, especially temperature, could heighten human and crop mortality posing a socio-economic threat to the Indian subcontinent. 相似文献
22.
N. V. Nanda Kumar S. Ameer Basha M. Rajasekhar T. Ramakrishna 《Journal of the Indian Society of Remote Sensing》2001,29(1-2):37-40
Jerdon’s courser (Cursorius bitorquatus) considered as lost bird is found in Sri Lankamalleswaram Sanctuary, Cuddapah District, Andhra Pradesh. It is listed in Red data book as endangered bird. Analysis of satellite imagery of 1989, 1996, 1998 and ground information have revealed an improvement of Jerdon courser’s habitat after declaration of area as sanctuary in 1988. Large open grounds show a decrease, white small open grounds surrounded by scrub plants offering protection and food cover increase. Analysis of satellite imagery shows core niche covering 4 x 3 km area and larger area of sanctuary (7.3 x 13.1 km) having various land cover classes. Comparison of satellite imagery from 1989 to 1998 shows degradation of larger area of sanctuary where birds are not seen. 相似文献
23.
Preliminary analysis of seismograms recorded by a wide band high dynamic range digital seismograph installed under a collaborative
research programme between IPG, Paris and NGRI, Hyderabad, indicates that the crust and upper mantle structure below the Indian
continent are characterized by high velocity up to a depth of 500 km. Both the group and phase velocities in the period range
of 100–350s are found to be faster by 3–4% and 1–3% respectively compared with global models such as the preliminary reference
earth model. 相似文献
24.
I. V. Radhakrishna Murthy P. Rama Rao P. Ramakrishna 《Pure and Applied Geophysics》1989,130(4):711-719
The exponential decrease in the density contrast of anomalous bodies is equated to a quadratic function. The three-dimensional body is divided into a series of parallel vertical polygonal sections of unit thickness each. The gravity effect of each side of the vertical polygonal cross-section with a quadratic density variation is derived in closed form. Gravity effects of a few equispaced and representative cross-sections are integrated to obtain the gravity anomaly of the entire body. When used in modelling gravity data, the method of considering vertical cross-sections has the unique advantage of easily allowing changes in theZ-coordinates of polygonal sections. 相似文献
25.
Nellipudi Nanaji Rao Ramakrishna S. S. V. S. Podeti Srinivasa Rao Rao B. Ravi Srinivasa Yesubabu V. Rao V. Brahmananda 《Natural Hazards》2022,114(1):495-519
Natural Hazards - In this study, an attempt is made to analyze the sensitivity of land surface process and the associated moisture budget characteristics of the cyclonic storm Yemyin (2007), which... 相似文献
26.
Francis Pavanathara Augustine Jithin Abraham Kaduvathazham Chatterjee Abhisek Mukherjee Arnab Shankar Doraiswamy Vinayachandran Puthenveettil Narayanamenon Ramakrishna Surireddi Satya Venkata Siva 《Ocean Dynamics》2020,70(3):387-404
Ocean Dynamics - The structure and variability of undercurrents in the East India Coastal Current (EICC), which is the western boundary current system in the Bay of Bengal (BoB), and the mechanisms... 相似文献
27.
Achanta Ramakrishna RAO Bimlesh KUMAR Gopu SREENIVASULU 《国际泥沙研究》2007,22(3):218-227
The design of an alluvial channel for critical conditions requires information about four basic parameters, i.e., particle size d, water depth y, energy slope Sf and average velocity u. Most of the investigators use a standard or modified form of the critical Shields’ parameter to define the incipient motion of a particular grain size. Shields’ diagram describes an iterative process of determining the incipient motion parameters. To design a process that does not require iteration, one must know the resistance relationship. The absence of a universal resistance equation increases the difficulty of defining the model. Metamodelling techniques are widely used in engineering designs to simulate a complex system. This article describes a Metamodel, which employs the radial basis function (RBF) network to predict the average velocity u and energy slope Sf based on experimental data of incipient condition. With the help of the Metamodel generated by the RBF network, design curves have been presented to predict the u and Sf based on known values of the particle size and water depth. It has been found that this model improves the predictability of incipient motion. 相似文献
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29.
G. Bala Sujith Krishna Devaraju Narayanappa Long Cao Ken Caldeira Ramakrishna Nemani 《Climate Dynamics》2013,40(7-8):1671-1686
Increasing concentrations of atmospheric CO2 influence climate, terrestrial biosphere productivity and ecosystem carbon storage through its radiative, physiological and fertilization effects. In this paper, we quantify these effects for a doubling of CO2 using a low resolution configuration of the coupled model NCAR CCSM4. In contrast to previous coupled climate-carbon modeling studies, we focus on the near-equilibrium response of the terrestrial carbon cycle. For a doubling of CO2, the radiative effect on the physical climate system causes global mean surface air temperature to increase by 2.14 K, whereas the physiological and fertilization on the land biosphere effects cause a warming of 0.22 K, suggesting that these later effects increase global warming by about 10 % as found in many recent studies. The CO2-fertilization leads to total ecosystem carbon gain of 371 Gt-C (28 %) while the radiative effect causes a loss of 131 Gt-C (~10 %) indicating that climate warming damps the fertilization-induced carbon uptake over land. Our model-based estimate for the maximum potential terrestrial carbon uptake resulting from a doubling of atmospheric CO2 concentration (285–570 ppm) is only 242 Gt-C. This highlights the limited storage capacity of the terrestrial carbon reservoir. We also find that the terrestrial carbon storage sensitivity to changes in CO2 and temperature have been estimated to be lower in previous transient simulations because of lags in the climate-carbon system. Our model simulations indicate that the time scale of terrestrial carbon cycle response is greater than 500 years for CO2-fertilization and about 200 years for temperature perturbations. We also find that dynamic changes in vegetation amplify the terrestrial carbon storage sensitivity relative to a static vegetation case: because of changes in tree cover, changes in total ecosystem carbon for CO2-direct and climate effects are amplified by 88 and 72 %, respectively, in simulations with dynamic vegetation when compared to static vegetation simulations. 相似文献
30.
Snehasis Tripathy Ramakrishna Bag Hywel Rhys Thomas 《Geotechnical and Geological Engineering》2014,32(4):749-763
The effects of post-compaction residual lateral stress and salt concentration in the hydrating fluid on swelling pressures of compacted MX80 bentonite is brought out in this paper. In order to release the residual lateral stresses, following the static compaction process during preparation of specimens, compacted bentonite specimens were extruded from the specimen rings and then inserted back prior to testing them for swelling pressures in isochoric condition. The swelling pressure tests were carried out at several dry densities of the bentonite with distilled water and solutions of NaCl (0.1 and 1.0 M) as the hydrating fluids. With water, the test results showed that specimens that underwent extrusion and insertion processes exhibited about 10–15 % greater swelling pressures as compared to the specimens those that were compacted and tested. The influence of saline solutions was found to reduce the swelling pressure of the bentonite, but their impact was less significant at high compaction dry densities. 相似文献