A kinematic‐wave‐based distributed watershed model using FEM,GIS and remotely sensed data     

K. Venkata Reddy  T. I. Eldho  E. P. Rao  N. Hengade 《水文研究》2007,21(20):2765-2777

For the appropriate management of water resources in a watershed, it is essential to calculate the time distribution of runoff for the given rainfall event. In this paper, a kinematic‐wave‐based distributed watershed model using finite element method (FEM), geographical information systems (GIS) and remote‐sensing‐based approach is presented for the runoff simulation of small watersheds. The kinematic wave equations are solved using FEM for overland and channel flow to generate runoff at the outlet of the watershed concerned. The interception loss is calculated by an empirical model based on leaf area index (LAI). The Green‐Ampt Mein Larson (GAML) model is used for the estimation of infiltration. Remotely sensed data has been used to extract land use (LU)/land cover (LC). GIS have been used to prepare finite element grid and input files such as Manning's roughness and slope. The developed overland flow model has been checked with an analytical solution for a hypothetical watershed. The model has been applied to a gauged watershed and an ungauged watershed. From the results, it is seen that the model is able to simulate the hydrographs reasonably well. A sensitivity analysis of the model is carried out with the calibrated infiltration parameters, overland flow Manning's roughness, channel flow Manning's roughness, time step and grid size. The present model is useful in predicting the hydrograph in small, ungauged watersheds. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Radar Observations of Leonid Meteor Shower 2003     

Devulapalli Venkata Phani Kumar  Kammadhanam Chenna Reddy  Ganji Yellaiah 《Astrophysics and Space Science》2006,306(4):235-239

Observations carried out during Leonid meteor shower 2003, by using Indian MST radar (13.46^N, 79.18^E; dip 12.5^N) are used to determine the number density of meteoroids through the cross section of the meteor streams. Cross sections are calculated for a number of classes of echo duration (particle size). They are also used to determine the relative flux of the shower in particle size ranges producing radar meteor echoes having durations <0.4 s, 0.4–1 s and >1 s. Mean activity profiles along the Earth's passage through the stream show a systematic change of the peak activity and the width of the stream depending on the distribution of echo durations across the stream. The patterns of mass distribution index s are presented and discussed.  相似文献   

Soil erosion assessment in Rangit catchment,India through a process-based model in the geospatial environment     

Hari Venkata Durga Rao Korada  Venkateshwar Rao Vala 《国际地球制图》2013,28(5):507-519

The accurate assessment of soil erosion in the spatial environment can give valuable input in designing reservoirs and for preparing watershed management action plans. Rangit River in northeastern India is affected by severe soil erosion, causing reduction in its reservoir capacity. The main aim of the paper is to estimate the soil erosion in the Rangit catchment, India through a process-based soil erosion model that integrates remote sensing and field data in the geospatial domain, and also to identify the problem areas for further watershed management action plans. Various topographic parameters that were derived from land use, soil texture and a digital elevation model were used for the estimation of soil erosion. The Morgan, Morgan and Finny model was used to compute soil erosion. Based on the drainage pattern, the catchment was divided into eight sub-catchments for detailed study. Annual soil erosion was estimated for four years from 2002 to 2005 using the corresponding year’s meteorological data. Estimated soil erosion was compared with the field data in each year and found very good correlation.  相似文献   

‘Thermohaline front’ off the east coast of India and its generating mechanism     

Panangattu Viswanathan Hareesh Kumar  Basil Mathew  Madathiparambil Ranganatha Ramesh Kumar  Akula Raghunadha Rao  Puvvala Surya Venkata Jagadeesh  Kalarickal Gopalan Radhakrishnan  Thiyyadi Nandakumar Shyni 《Ocean Dynamics》2013,63(11-12):1175-1180

Physical oceanography measurements reveal a strong salinity (0.18 psu km^?1) and temperature (0.07 °C km^?1) front off the east coast of India in December 1997. T–S diagrams suggest lateral mixing between the fresh water at the coast and the ambient warmer, saltier water. This front seems to be the result of southward advection of fresh and cool water, formed in the northern Bay of Bengal during the monsoon, by the East Indian Coastal Current, as suggested by the large-scale salinity structure in the SODA re-analysis and the anti-cyclonic gyre in the northwestern Bay of Bengal during winter. The data further reveals an offshore front in January, which appears to be the result of a meso-scale re-circulation around an eddy, bringing cold and freshwater from the northern Bay of Bengal further away from the shore. Our cruise data hence illustrates that very strong salinity fronts can appear in the Bay of Bengal after the monsoon, as a result of intense coastal circulation and stirring by eddies.  相似文献   

Assessing the impact of various wind forcing on INCOIS-GODAS simulated ocean currents in the equatorial Indian Ocean     

Sanikommu Sivareddy  Muthalagu Ravichandran  Madathil Sivasankaran Girishkumar  Koneru Venkata Siva Rama Prasad 《Ocean Dynamics》2015,65(9-10):1235-1247

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Evaluation of atmospheric corrections on hyperspectral data with special reference to mineral mapping   总被引：1，自引：0，他引：1  

Nisha Rani  Venkata Ravibabu Mandla  Tejpal Singh 《地学前缘(英文版)》2017,8(4):797-808

Hyperspectral images have wide applications in the fields of geology, mineral exploration, agriculture, forestry and environmental studies etc. due to their narrow band width with numerous channels. However, these images commonly suffer from atmospheric effects, thereby limiting their use. In such a situation, atmospheric correction becomes a necessary pre-requisite for any further processing and accurate interpretation of spectra of different surface materials/objects. In the present study, two very advance atmospheric approaches i.e. QUAC and FLAASH have been applied on the hyperspectral remote sensing imagery. The spectra of vegetation, man-made structure and different minerals from the Gadag area of Karnataka, were extracted from the raw image and also from the QUAC and FLAASH corrected images. These spectra were compared among themselves and also with the existing USGS and JHU spectral library. FLAASH is rigorous atmospheric algorithm and requires various parameters to perform but it has capability to compensate the effects of atmospheric absorption. These absorption curves in any spectra play an important role in identification of the compositions. Therefore, the presence of unwanted absorption features can lead to wrong interpretation and identification of mineral composition. FLAASH also has an advantage of spectral polishing which provides smooth spectral curves which helps in accurate identification of composition of minerals. Therefore, this study recommends that FLAASH is better than QUAC for atmospheric correction and correct interpretation and identification of composition of any object or minerals.  相似文献   

Delineation of ground water potential zones in a hard rock terrain of Mysore district, Karnataka using IRS data and GIS techniques     

N. Lokesha  G. S. Gopalakrishna  H. Honne Gowda  A. K. Gupta 《Journal of the Indian Society of Remote Sensing》2005,33(3):405-412

In the present study, the ground water prospect of Mysore district has been delineated using remotely sensing data, base map of GSI, ground truth data, and geographic information system. Based on these integrated studies, it has been noticed that the lithology of the area mainly represents by amphibolite schists, hornblende-biotite gneiss, chamockite, quartzite and granite belonging to Archean to Lower Proterozoic. Resent alluvial deposits mainly occur as valley fills. Major lineaments are mainly confined to valley regions. Structurally the erosional and depositional landforms are occurring as hills, ridges, weathered pediments, weathered pediplains and valley fills. Geonaorphology, lineaments, drainage density, type of lithology and surface water bodies are directly influencing the ground water conditions and it is very good iu valley regions and in remaining area, it is moderate to poor.  相似文献   

Intraseasonal variability of subsurface ocean temperature anomalies in the Indian Ocean during the summer monsoon season     

Konda  Gopinadh  Gulakaram  Venkata Sai  Vissa  Naresh Krishna 《Ocean Dynamics》2023,73(3-4):165-179

Ocean Dynamics - The present study focuses on the variability of subsurface ocean temperature and associated planetary waves (oceanic Kelvin and Rossby waves) in the Indian Ocean during the boreal...  相似文献   

Structure and dynamics of undercurrents in the western boundary current of the Bay of Bengal     

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   

High-resolution flood hazard mapping based on nonstationary frequency analysis: case study of Ho Chi Minh City,Vietnam     

Le Thi Hoa Binh  E. Venkata Rathnam 《水文科学杂志》2019,64(3):318-335

Flood modelling inputs used to create flood hazard maps are normally based on the assumption of data stationarity for flood frequency analysis. However, changes in the behaviour of climate systems can lead to nonstationarity in flood series. Here, we develop flood hazard maps for Ho Chi Minh City, Vietnam, under nonstationary conditions using extreme value analysis, a coupled 1D–2D model and high-resolution topographical data derived from LiDAR (Light Detection and Ranging) data. Our findings indicate that ENSO (El Niño Southern Oscillation) and PDO (Pacific Decadal Oscillation) influence the magnitude and frequency of extreme rainfall, while global sea-level rise causes nonstationarity in local sea levels, having an impact on flood risk. The detailed flood hazard maps show that areas of high flood potential are located along river banks, with 0.60 km² of the study area being unsafe for people, vehicles and buildings (H5 zone) under a 100-year return period scenario.  相似文献