A Hydrogeophysical Survey Using Remote-Sensing Methods from Kawaihae to Kailua-Kona, Hawaii     

William M. Adams  Frank L. Peterson  Surendra P. Mathur  Larry K. Lepley  Clifton Warren  Richie D. Huber 《Ground water》1971,9(1):42-50

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Field based spectral reflectance studies to develop NDSI method for snow cover monitoring     

A V Kulkarni  J Srinivasulu  S S Manjul  Mathur P 《Journal of the Indian Society of Remote Sensing》2002,30(1-2):73-80

Snow is highly reflective in the visible region of the electromagnetic spectrum making it possible to easily distinguish on a satellite image. However, cloud cover and mountain shadows pose a serious problem in the identification of snow in a mountainous region. Therefore, to identify snow in such an environment, a Normalized Difference Snow Index (NDSI) has been applied. The NDSI is based on the high reflectance of snow in the visible region and its low reflectance in the SWIR region, whereas, reflectance of cloud remains high compared to snow in the SWIR region. Efforts have been made to carry out field observations on reflectance of various land features near Manali in Himachal Pradesh (HP) to develop NDSI values for identifying snow. Field data have been collected using three field radiometers, viz., Multi-band Ground Truth Radiometer (GTR) operating in the 12 spectral bands ranging from visible to near-infrared wavelengths, Near-Infrared Ground Truth Radiometer (NIGTR) operating in the SWIR range, and Ratio-Radiometer (RR) operating in two spectral bands, one in the visible range, and another band in the SWIR range. All these three field radiometers have been designed and developed indigenously at the Space Applications Centre (ISRO), Ahmedabad. NDSI values for all types of snow, such as, fresh, clear, patchy and wet, have been found to be in the range 0.9 to 0.96. In addition, the NDSI value for snow under mountain shadow is found to be more than 0.9. This suggests the use of NDSI method for snow cover monitoring under mountain shadow. NDSI values for other land features such as soil, vegetation, and rock were substantially different than snow. However, water bodies have NDSI values close to snow and they need to be masked during snow cover delineation using NIR band.  相似文献   

Change detection study for snow covered mountains using remote sensing and ground based measurements     

H. S. Negi  V. D. Mishra  P. Mathur 《Journal of the Indian Society of Remote Sensing》2005,33(2):245-251

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Qualitative and quantitative analysis of snow parameters using passive microwave remote sensing     

V. D. Mishra  P. Mathur  R. P. Singh 《Journal of the Indian Society of Remote Sensing》2005,33(3):381-393

Snow cover is an important variable for climatic and hydrologic models due to its effect on surface albedo, energy, and mass balance. Satellite observations successfully provide a global and comprehensive hemispheric-scale record of the short-term, as well as inter-seasonal variations in snow cover. Passive microwave sensors provide an excellent method to monitor temporal and spatial variations in large-scale snow cover parameters, overcoming problems of cloud cover. Using microwave remote sensing data, snow parameters (snow surface temperature, snow water equivalence, scattering index, emissivity, snow depth) have been retrieved to integrate with the snow cover simulation model developed by SASE for avalanche risk assessment on regional basis. Multispectral and multitemporal brightness temperature data obtained from the Special Sensor Microwave Imager (SSM/I), flown onboard the DMSP satellites, for the period November 2000 to April 2001 and from November 2001 to February 2002 have been analysed. A comparative data set on snow measurements and meteorological observations of a region covering large area of Pir-Panjal and the Greater Himalayan range, available on near real time basis from SASE field observatories were also used. Model calculations were carried out to study the effects of atmospheric transmission on the microwave radiation emitted from the snow covered and snow free ground and atmosphere. The sensitivity of combinations of the SSM/I channels at 19, 37 and 85 GHz, in both horizontal and vertical polarizations, in respect to snow depth, surface temperature of the snowpack have been carried out. Decision rule based algorithms are developed to identify snow cover and non-snow area.  相似文献   

On the oscillation of Balat river,district Khasi and Garo Hills,Meghalaya     

Suresh Chopra  A. K. Mathur 《Journal of the Indian Society of Remote Sensing》1984,12(2):71-73

Balat River has abandoned its westerly course and followed an old course to the east during the recent past. This has lead to the recognition of an oscillation pattern for this river with its periodic shift where the course if confined to the zone bounded by the two channel courses.  相似文献   

Improvements in seismic reflection techniques for studying the lithosphere in Australia     

S.P. Mathur 《Tectonophysics》1984,105(1-4)

Over the last 25 years the Australian Bureau of Mineral Resources (BMR) has attempted to record seismic reflection data in several parts of Australia to determine if good quality near-vertical reflections could be obtained from the deep crust and upper mantle. Data recorded prior to 1976, using analogue instruments and large shots, did obtain good to fair quality deep events, but the short lengths of the traverses recorded did not allow discrimination between primary reflections and the coherent noise. The high cost of the special effort prevented recording of long traverses, and hence the study of the true nature of the deep reflections. From 1976 onwards, with the advent of digital recording and processing equipment and techniques, it became possible to obtain good quality deep reflection data on long traverses with the parameters such as small charges, short spreads, etc. which are normally used for recording good sedimentary reflections. The recent data allow better identification of reflections and study of their character, and provide a higher resolution picture of the nature and structure of the deep crust and upper mantle, than had been possible before. BMR is, therefore, now recording good deep reflection data on all traverses during normal sedimentary basin surveys, and accumulating the information necessary for studying the evolution of lithosphere in Australia.  相似文献   

Toxicity assessment of popular baby skin care products from Indian market using microbial bioassays and chemical methods     

A. Nepalia  A. Singh  N. Mathur  S. Pareek 《International Journal of Environmental Science and Technology》2018,15(11):2317-2324

Specialized cosmetic products for infant use are gaining a lot of popularity in the Indian as well as global market, as these products have become an inseparable part of modern urban lifestyle. Baby cosmetics are available in a wide range. They claim to be milder than similar products meant for adult use. However, these products need to be checked for their safety through a battery of assays based on biological systems, along with the ones based on chemical and physical protocols. This study attempts to test different baby cosmetic products using one prokaryotic and one eukaryotic assay system. Chemical protocols prescribed by cosmetic product controlling organizations of India are also used to estimate the quantity of harmful heavy metals like arsenic, lead and cadmium if present in the samples. Few of the products tested have shown significant toxicity as well as heavy metal content. The results hold a lot of importance keeping in mind the extra sensitivity of an infant body. It is further suggested that studies using cell based and in vivo test systems should be done to confirm the findings.  相似文献   

Geology and Re-Os Geochronology of Mineralization of the Miduk Porphyry Copper Deposit, Iran     

Nader Taghipour    Alijan Aftabi  Ryan Mathur 《Resource Geology》2008,58(2):143-160

The Miduk porphyry copper deposit is located in Kerman province, 85 km northwest of the Sar Cheshmeh porphyry copper deposit, Iran. The deposit is hosted by Eocene volcanic rocks of andesitic–basaltic composition. The porphyry‐type mineralization is associated with two Miocene calc‐alkaline intrusive phases (P1 and P2, respectively). Five hypogene alteration zones are distinguished at the Miduk deposit, including magnetite‐rich potassic, potassic, potassic–phyllic, phyllic and propylitic. Mineralization occurs as stockwork, dissemination and nine generations (magnetite, quartz–magnetite, barren quartz, quartz‐magnetite‐chalcopyrite‐anhydrite, chalcopyrite–anhydrite, quartz‐chalcopyrite‐anhydrite‐pyrite, quartz‐molybdenite‐anhydrite ± chalcopyrite ± magnetite, pyrite, and quartz‐pyrite‐anhydrite ± sericite) of veinlets and veins. Early stages of mineralization consist of magnetite rich veins in the deepest part of the deposit and the main stage of mineralization contains chalcopyrite, magnetite and anhydrite in the potassic zone. The high intensity of mineralization is associated with P2 porphyry (Miduk porphyry). Based on petrography, mineralogy, alteration halos and geochemistry, the Miduk porphyry copper deposit is similar to those of continental arc setting porphyry copper deposits. The Re‐Os molybdenite dates provide the timing of sulfide mineralization at 12.23 ± 0.07 Ma, coincident with U/Pb zircon ages of the P2 porphyry. This evidence indicates a direct genetic relationship between the Miduk porphyry stock and molybdenite mineralization. The Re‐Os age of the Miduk deposit marks the main stage of magmatism and porphyry copper formation in the Central Iranian volcano‐plutonic belt.  相似文献   

Assessment of forest fragmentation in the conservation priority Dudhwa landscape,India using FRAGSTATS computed class level metrics   总被引：1，自引：0，他引：1  

N. Midha  P. K. Mathur 《Journal of the Indian Society of Remote Sensing》2010,38(3):487-500

The Dudhwa landscape, a priority conservation area representing Terai ecosystem (woodland-grassland-wetland complex) has witnessed a sea change in past 150 years or so on account of long history of forest management, changes in land use, and rapid economic development. We assessed fragmentation in two constituent protected areas (Dudhwa National Park-DNP and Katerniaghat Wildlife Sanctuary-KAT) of the landscape due to forest management activities (clear cutting, development of rail and road network, and plantations) and compared the magnitude among them using select metrics at the forest class level. We applied FRAGSTATS spatial pattern analysis software (ver.3.3) on different forest classes deciphered by land use/ cover maps generated using IRS P6 LISS IV digital data. Study amply revealed that the forests in DNP are less fragmented and of better habitat quality than forests of KAT. The set of seven metrics (patch density, mean patch size, edge density, mean shape index, mean core area, mean nearest neighbour, and interspersion and juxtaposition index) at the class level quantified in the present study are simple and proved useful for quantifying complex spatial processes and can be used as an effective means of monitoring in Dudhwa landscape.  相似文献   

Soil erosion modeling of a Himalayan watershed using RS and GIS   总被引：5，自引：1，他引：4  

Ashish Pandey  Abhisekh Mathur  S. K. Mishra  B. C. Mal 《Environmental Earth Sciences》2009,59(2):399-410

Employing the remote sensing (RS) and geographical information system (GIS), an assessment of sediment yield from Dikrong river basin of Arunachal Pradesh (India) has been presented in this paper. For prediction of soil erosion, the Morgan-Morgan and Finney (MMF) model and the universal soil loss equation (USLE) have been utilized at a spatial grid scale of 100 m × 100 m, an operational unit. The average annual soil loss from the Dikrong river basin is estimated as 75.66 and 57.06 t ha⁻¹ year⁻¹ using MMF and USLE models, respectively. The watershed area falling under the identified very high, severe, and very severe zones of soil erosion need immediate attention for soil conservation.  相似文献