喜马拉雅中部甘达基河流域尼泊尔国鸟(棕尾虹雉)生境分布变化     

Raju RAI  Basanta PAUDEL  谷昌军  Narendra Raj KHANAL 《资源与生态学报(英文版)》2020,11(2):223-231

甘达基河流域(Gandaki River Basin,GRB)是喜马拉雅中部地区的一部分,该地区栖息着许多珍稀的野生动物。由于气候和人类活动的影响,许多珍稀保护物种的生境处于危险之中。本研究基于最大熵(MaxEnt)模型,运用生物气候、土地覆被和DEM数据,分析各环境要素对棕尾虹雉(Lophophorusimpejanus)的生境适宜性的影响,评估棕尾虹雉现在状况和未来栖息地分布的变化。研究表明,目前棕尾虹雉的高度适宜栖息地面积约为749 km^2,主要分布在流域北部、东部和西部,尤其是郎塘国家公园、马纳斯卢峰自然保护区和安纳布尔纳峰自然保护区等保护区内。到2050年,棕尾虹雉的高度适宜栖息地面积将减少至561 km^2,主要在流域北部和西北部(即Chhyo,Tatopani,Humde和Chame地区)。未来环境变化的模拟表明,由于适宜栖息地面积的减少,棕尾虹雉面临的生存风险将增加。  相似文献   

Standal,Karina. Challenges of Gender,Power and Change in Solar Energy Interventions in Rural India: Imagined Beneficiaries and the Making of Women’s Empowerment in the Village Electrification Project     

Joy S. Clancy  Saraswati Raju 《Norsk geografisk tidsskrift. Norwegian journal of geography》2020,74(1):66-68

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Density and temperature diagnostics of solar emission lines from NeV/MgV and SiVII/MgVII Ions     

Anita Mohan  B. N. Dwivedi  P. K. Raju 《Journal of Astrophysics and Astronomy》1999,20(1-2):51-65

We present NeV/MgV and SiVII/MgVII theoretical line intensity ratios as a function of electron densityN _e and temperatureT _e . These are shown in the form of ratio-ratio diagrams, which should in principle allow bothN _e andT _e to be deduced for the emitting region of the solar plasma. We apply these diagnostics in the solar atmosphere, and discuss the available observations made from space. In most cases, however, we deduceN _e andT _e from the computed absolute line intensities in a spherically symmetric model atmosphere of the Sun. Possible future applications of this investigation to spectral data from the Coronal Diagnostic Spectrometer (CDS) on the Solar and Heliospheric Observatory (SOHO) are briefly discussed.  相似文献   

Geobotany of red sanders (Pterocarpus santalinus) – a case study from the southeastern portion of Andhra Pradesh     

K. K. Raju  A. Nagaraju 《Environmental Geology》1999,37(4):340-344

 RedSanders in their natural distribution occur almost exclusively in quartzites and shales. This indicates the geobotanical response to these rock types in the semi-arid tract of the southeastern portion of Andhra Pradesh in the tropical dry deciduous forests of Chittoor, Cuddapah and Nellore districts. Thus Red Sanders are important from a commercial point of view and also a useful tool to demarcate stratigraphic formations. Received: 27 April 1998 · Accepted: 21 July 1998  相似文献   

Detection of ionospheric scintillation effects using LMD–DFA     

Raghavendra Vishnu Tadivaka  Bhanu Priyanka Paruchuri  Sridhar Miriyala  Padma Raju Koppireddi  Venkata Ratnam Devanaboyina 《Acta Geophysica》2017,65(4):777-784

The performance and measurement accuracy of global navigation satellite system (GNSS) receivers is greatly affected by ionospheric scintillations. Rapid amplitude and phase variations in the received GPS signal, known as ionospheric scintillation, affects the tracking of signals by GNSS receivers. Hence, there is a need to investigate the monitoring of various activities of the ionosphere and to develop a novel approach for mitigation of ionospheric scintillation effects. A method based on Local Mean Decomposition (LMD)–Detrended Fluctuation Analysis (DFA) has been proposed. The GNSS data recorded at Koneru Lakshmaiah (K L) University, Guntur, India were considered for analysis. The carrier to noise ratio (C/N₀) of GNSS satellite vehicles were decomposed into several product functions (PF) using LMD to extract the intrinsic features in the signal. Scintillation noise was removed by the DFA algorithm by selecting a suitable threshold. It was observed that the performance of the proposed LMD–DFA was better than that of empirical mode decomposition (EMD)–DFA.  相似文献   

Dynamical downscaling approach for wintertime seasonal-scale simulation over the Western Himalayas     

Pushp R. Tiwari  Sarat C. Kar  Uma C. Mohanty  Sagnik Dey  Palash Sinha  P. V. S. Raju  M. S. Shekhar 《Acta Geophysica》2014,62(4):930-952

The performance of RegCM4 for seasonal-scale simulation of winter circulation and associated precipitation over the Western Himalayas (WH) is examined. The model simulates the circulation features and precipitation in three distinct precipitation years reasonably well. It is found that the RMSE decreases and correlation coefficient increases in the precipitation simulations with the increase of model horizontal resolutions. The ETS and POD for the simulated precipitation also indicate that the performance of model is better at 30 km resolution than at 60 and 90 km resolutions. This improvement comes due to better representation of orography in the high-resolution model in which sharp orography gradient in the domain plays an important role in wintertime precipitation processes. A comparison of model-simulated precipitation with observed precipitation at 17 station locations has been carried out. Overall, the results suggest that 30 km model produced better skill in simulating the precipitation over the WH and this model is a useful tool for further regional downscaling studies.  相似文献   

Physical and elastic properties of marine sediments off Bombay,India     

L. V. Subba Raju  Y. V. Ramana 《Marine Georesources & Geotechnology》2013,31(4):359-375

Abstract

Keeping in view the paucity of information as to the nature of the marine sediments from the continental shelf adjoining the Indian subcontinent, a number of shallow seismic surveys were carried out, nearshore and offshore Bombay between 18°45'N and 21°00'N. Representative core samples preserving their natural state were also retrieved from the region in the water depths ranging from 5 to 70 m for the determination of physical properties in the laboratory. Data on the physical, acoustic, and elastic properties of the sediment cores are reported for the first time. Useful individual least‐squares relations are presented for acoustic impedance, reflection coefficient, and bulk modulus against density; for the dependence of rigidity and bulk moduli on the constrained modulus; for the association between impedance and field sediment velocity against P‐velocity; and for rigidity against Poisson's ratio. Results indicate that the bulk modulus and Young's modulus are higher for silty clay and clayey silt samples than for the clay samples. Similarly, the acoustic impedance, reflection coefficient, and constrained modulus of silty clay and clayey silt are also higher than clay. The results are found to be comparable to the North Atlantic and Bay of Bengal sediments.  相似文献   

East-west mafic dyke in Aravallis – a post-depositional event deciphered by aeromagnetic studies     

A. K. Pathak  M. Sridhar  Y. Harsha  A. Markandeyulu  B. V. S. N. Raju  A. K. Chaturvedi 《Journal of the Geological Society of India》2017,89(6):675-678

Aravalli fold belt has witnessed major tectonism resulting in intense deformation and associated mafic magmatism. Recently acquired high resolution aeromagnetic data over central Aravalli fold belt brought out a conspicuous E-W trending magnetic anomaly extending for more than 35 km in length cutting across the whole succession of Aravalli Supergroup. This anomaly on ground is manifested as undeformed basic dyke intruding into metasediments of Aravalli Supergroup. The E-W trend and undeformed nature of these dykes suggest that they represent post Aravalli mafic magmatism which are emplaced sympathetic to the axial plane of F₃ folding.  相似文献   

Preparation of Visible Light Active Ag‐ and N‐Doped KVMoO6: Photodegradation of Methylene Blue          下载免费PDF全文

Jitta Raju Reddy  Sreenu Kurra  Naveen Kumar Veldurthi  Prathapuram Shrujana  Ravinder Guje  Muga Vithal 《洁净——土壤、空气、水》2016,44(11):1584-1590

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Delineation of coalfield surface fires by thresholding Landsat TM-7 day-time image data     

Ashwani Raju  Anupma Prakash 《国际地球制图》2013,28(4):343-363

Surface fires are common in coalfields where coal is mined or exposed to sunlight for long durations of time. The heat energy emitted from these fires affects the signal recorded by sensors operating in the shortwave infrared regions of the electromagnetic spectrum. The Landsat TM/ETM+ band-7 is sensitive to solar reflected radiation as well as emitted radiation from a target. The ‘maximum solar reflection threshold’ method proposed in this study uses the highest spectral radiance that can be attributed to solar reflection as the conservative threshold to segregate the pixels with emitted component from those with reflected component of the EM energy. Investigations with Landsat TM/ETM+ data indicate a reflectance value of 0.23–0.25 as the most representative highest reflectance (threshold) in coal mining areas. The method apparently has the advantage that it is based on the reflectance characteristics of materials (sandstone-shale mixtures) typically found in coal mining areas.  相似文献