Regional determinants of research and development institutions in India     

Sudhir K. Thakur  Edward J. Malecki 《GeoJournal》2015,80(4):533-554

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Dynamics of land use change in a mining area: a case study of Nadowli District,Ghana     

Laari Prosper BASOMMI  GUAN Qing-feng  CHENG Dan-dan  Sudhir Kumar SINGH 《山地科学学报》2016,13(4):633-642

In a developing country like Ghana, the study of land use and land cover change(LULCC) based on satellite imageries still remains a challenge due to cost, resolution and availability with less skilled man power. Existing researches are skewed towards the southerly part of Ghana thereby leaving the Northern sectors uncovered. The maximum likelihood classification(MLC) algorithm was employed for the LULCC between 2000 and 2014 in Nadowli: an area characterized by an upsurge in mining in the Northern belt of Ghana. A spatial-social approach was utilized combining both satellite imagery and socio economic data. Land use transition matrix, land use integrated index/degree indices was used to depict the characters of the change. A semi structured interview, pair wise ranking and key informant interviews were used to correlate the socio economic impact of the different LULC. Overall changes in the landscape showed an increase in bare ground by 19.22%, open savannah by 16.8% whereas closed savanna decreased by 50%. Land use change matrix showed increasing trends of bare ground at the expense of vegetation. The integrated land use index highlighted the bare ground and built up areas rising with a decreasing closed vegetation woodlot. Large farm size are shrinking whiles majority of the people view mining as the main socio economic activity affecting the environment and the reduction in vegetation. This study therefore provides a strategic guide and a baseline data for land use policy actors in the Northern belt of Ghana. This will aid in developing models for future land use change implications in surrounding areas where mining is on the rise.  相似文献   

On the abnormally high natural remanent magnetization of certain lavas     

Sudhir K. Dutt 《Pure and Applied Geophysics》1964,59(1):84-92

Summary The rock specimens found to have natural remanent magnetization of abnormally high intensity, have been generally from hill sides or tops, or from ridges high up from the local surroundings. A field of several hundred oersteds has been found sufficient to produce in some of the artificially demagnetized specimens an isothermal magnetization of the same order as the abnormal natural ones, and this magnetization has shown a similar degree of stability as the natural one. Variations in the direction and magnitude of the natural magnetic vector have been found over a distance of a few centimetres. Laboratory tests indicate a normal chemical composition for the specimens. The lightning discharge seems to be the plausible cause of abnormally high magnetization of rocks, which is generally isothermal and might have originated in the recent past, but the magnetization is sometimes complicated probably by the thermal effect of the discharge.  相似文献   

Satellite stereo data for dem surfaces and derivatives     

Pramod Kumar  Sudhir Kumar  M. L. Manchanda 《Journal of the Indian Society of Remote Sensing》2004,32(1):81-90

Various attributes can be derived from Digital Elevation Model (DEM), which are essential to analyze watershed physical characteristics. This paper discusses utility and accuracy of satellite DEM surfaces and their derivatives. Facilities available in various software packages were compared to generate DEM from satellite data and other sources. For test site at Chamba, Uttaranchal, DEMs produced from various algorithms were evaluated for accuracy of surface and its derivatives. Most of the algorithms have shown correlation coefficient of 0.99 and above but the desirable maximum error in spot height (1/5 of contour interval) is not achieved. Slope and aspect produced from various algorithms were comparable around 70-80%. Comparison of DEM surface and its derivatives were attempted for test sites at Shimla and Nahan using IRS-1C and SPOT PAN stereo pair, respectively. Model accuracy has shown that error in height is higher than planimetry. Surface derivatives from stereo DEM for Shimla and Nahan test sites have shown an overall accuracy of 56.5% and 59.2% for slope; 49.79% and 71.21% for aspect and 74.15% for topographic level slicing, respectively. Accuracy has improved when observed class value was lowered or put-up by one unit.  相似文献   

Alternative method to locate centre of rigidity in asymmetric buildings     

Dhiman Basu  Sudhir K. Jain 《地震工程与结构动力学》2007,36(7):965-973

Response of asymmetric buildup under earthquake excitation often involves lateral vibration coupled with torsional vibration. Floor slab is, in general, assumed as rigid along the in‐plane direction. Building code provisions to account for the torsional effect in static force procedure are based on centre of rigidity or shear centre of the building. A convenient procedure is developed here to locate the centre of rigidity or shear centre, which can be implemented, using any standard building analysis software. The procedure is applicable for orthogonal as well as non‐orthogonal building systems and accounts for all possible definitions of static eccentricity to compute the design response. An irregular building is analysed to illustrate the proposed methodology. Significant variation in member force resultants is observed due to different definitions of static eccentricity. Finally, a mathematical proof is presented to substantiate the applicability of the proposed procedure to a non‐orthogonal building. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Implications of ocean color in the upper water thermal structure at NINO3.4 region: a sensitivity study for optical algorithms and ocean color variabilities     

Hae-Cheol Kim  Sudhir Nadiga  Seunghyun Son  Avichal Mehra  Zulema Garraffo  Eric Bayler 《地理信息系统科学与遥感》2018,55(4):568-582

Chlorophyll a (Chl-a) has been the most commonly used biomass metric in biological oceanographic processes. Although limited to two-dimensional surfaces, remote-sensing tools have been successfully providing the most recent state of marine phytoplankton biomass to better understand bottom-up processes initiating daily marine material cycles. In this exercise, ocean color products with various time-scales, derived from Sea-Viewing Wide Field-of-View Sensor (SeaWiFS), were used to investigate how their bio-optical properties affect the upper-ocean thermal structure in a global ocean modeling framework. This study used a ¼-degree Hybrid Coordinate Ocean Model forced by hourly atmospheric fluxes from the Climate Forecast System Reanalysis at National Oceanic Atmospheric Administration. Three numerical experiments were prepared by combining two ocean color products – downwelling diffuse attenuation coefficients (K_dPAR) and chlorophyll a (Chl-a) – and two shortwave radiant flux algorithms. These three runs are: (1) KparCLM, based on a 13-year long-term climatological K_dPAR derived from SeaWiFS; (2) ChlaCLM, based on a 13-year long-term Chl-a derived from SeaWiFS; and (3) ChlaID, which uses the inter-annual time-series of monthly-mean SeaWiFS Chl-a product. The KparCLM experiment uses a Jerlov-like two-band scheme; whereas, both ChlaCLM and ChlaID use a two-band scheme that considers inherent (absorption (a) and backscattering (b_b) coefficients) and apparent optical properties (downwelling attenuation coefficient (K_d) and solar zenith angle (θ, varying 0–60°)). It is found that algorithmic differences in optical parameterizations have a bigger impact on the simulated temperatures in the upper-100 m of the eastern equatorial Pacific, NINO3.4 region, than other parts of the ocean. Overall, the K_dPAR-based approach estimated relatively low surface temperatures compared to those estimated from the chlorophyll-based method. In specific, this cold bias, pronounced in the upper 20–30 m, is speculated to be due to optical characteristics of the algorithm and K_dPAR products, or due to nonlinear hydrodynamical processes involving displacement of mixed-layer depth. Comparisons between each experiment against Global Ocean Data Assimilation System (GODAS; Behringer and Xue 2004) analyses find that KparCLM-based simulations have lower mean differences and variabilities with higher cross-correlation coefficients compared to ChlaCLM- and ChlaID-based experiments.  相似文献   

Study of hydro-chemical characteristics of Lake Nainital in response of human interventions,and impact of twentieth century climate change     

Dharmaveer Singh  Shive Prakash Rai  Bhishm Kumar  Sanjay K. Jain  Sudhir Kumar 《Environmental Earth Sciences》2016,75(20):1380

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Impact of land-use and land-cover change on groundwater quality in the Lower Shiwalik hills: a remote sensing and GIS based approach   总被引：2，自引：0，他引：2  

Sudhir Kumar Singh  Chander K Singh  Saumitra Mukherjee 《Central European Journal of Geosciences》2010,2(2):124-131

Human activities have exerted small to large scale changes on the hydrological cycle. The current scenario regarding groundwater resources suggests that globally there is a water crisis in terms of quantity (availability) and quality. Therefore there is a great need for the assessment and monitoring of quality and quantity of groundwater resources at local level. This paper presents a case study of the lower Shiwalik hills, in Rupnagar, Punjab, India, to trace land-use and land-cover changes during the past 17 years, with an emphasis on groundwater quality and quantity. This study was performed in alluvial and hilly terrain. The results show that the quantity of groundwater increased with the help of natural and artificial recharge due to change in land-use and land-cover pattern (increased area of fallow land). The quality of groundwater deteriorated due to input of fertilizers for enhancing the short-term soil fertility. Using a Remote Sensing and GIS based approach, we show the final results in map form. In particular we highlight a potential groundwater exploration site, which could be useful for district level planning. Our research shows that the change in land-use and land-cover affects the quantity and quality of groundwater.  相似文献