Major ion chemistry of Renuka Lake and weathering processes, Sirmaur District, Himachal Pradesh, India   总被引：2，自引：0，他引：2  

Brijraj K. Das  Parkash Kaur 《Environmental Geology》2001,40(7):908-917

Renuka Lake in the Lesser Himalaya, Himachal Pradesh is in a valley surrounded by mountains comprised of highly crumpled, shattered, crushed, folded and dislocated rocks consisting of carbonaceous shales-slates often pyrite-ferrous, limestone, quartzites, boulder beds, etc. A detailed and systematic study of the major ion chemistry of the lake, clay mineral composition of the bed and core sediments and the Pb²¹⁰ isotope estimation in the latter was conducted. The chemistry is dominated by carbonate weathering and (Ca + Mg) and (HCO₃ + SO₄) accounts for about 90% of the cations and anions. The SO₄ content is almost the same as the HCO₃. The low contribution of (Na + K) to the total cations and the (Ca + Mg) and HCO₃ data tends to indicate that silicate weathering has not been the potential source of major ions to the lake waters. This difference may be related to the increasing susceptibility to weathering of carbonate over silicate rocks exposed in the catchment and also seepage of water at the bottom. The high sulphate content in waters is derived from dissolution of pyrite-ferrous reduced black shales, which constitute a significant lithology in the catchment. The chemical index of alteration (CIA) value in core sediments is on an average 76, which is comparable with average shale (70-75) and the rate of sedimentation 3.3 mm/year based on measurement of Pb²¹⁰, indicating a fairly high weathering rate in the catchment. Illite is the dominant clay mineral (52-90%) in the bed and core sediments, chlorite constitutes 7-48% and the kaolinite-chlorite mixed silicate layer is l-2%. This is consistent with the shale-slate, sandstone lithology in the valley.  相似文献   

Total information content as an index of soil moisture     

R. N. Sahoo  M. Bhavanarayana  B. C. Panda  C. N. Arika  R. Kaur 《Journal of the Indian Society of Remote Sensing》2005,33(1):17-23

Accurate estimation of soil moisture through remote sensing technique has been a challenge till date. In optical and thermal remote sensing, there is no index developed to detect the changes in soil moisture levels. In microwave region, soil roughness and other target parameters equally affect the technique for soil moisture estimation. Therefore, a computational technique in C language based on Shannon’s Information Theory (Shannon, 1948) has been developed to calculate total information content from multispectral radiometer data. The total information content is a compressed single value, which quantifies the information content of soil spectral reflectance in the electromagnetic spectrum range (400–1100 nm) under study. This technique was tested over a wide range of soil moisture levels. The study revealed that as compared to other techniques total information content index is very sensitive to change in moisture content of soil. This technique could not only quantify the soil moisture content in optical and near infra red region, but also led to a simplified one dimensional separability and clustering analysis.  相似文献   

Satellite based study of land transformation in Ludhiana District, Punjab     

Minakshi P.K. Sharma  Amandeep Kaur  Vanita Shalley 《Journal of the Indian Society of Remote Sensing》2005,33(1):63-68

This study reveals the temporal changes in the land use/land cover of district Ludhiana from the years 1970 to 2001 and reports on the change that has occurred in land use/land cover as a result of change in cropping pattern. The changes were analysed through the data obtained from statistical abstract 1969–70, False Colour Composite (FCC) of IRS-IC LISS-III satellite data of March 2001 and ground truth. There has been a decrease in agricultural land by 2100 ha. but still it occupies 83.76% of the total geographical area (TGA). The wasteland shows a declining trend whereas forest cover has increased from 1.07 to 2.71% of TGA. Area under non-agricultural uses has increased from 10.13 to 12.50% of TGA. There has also been a great change in the cropping pattern of the district. Crops such as groundnut, gram and cotton have nearly disappeared and wheat and rice dominate the region. This change has substantially resulted in the decrease of area under wastelands.  相似文献   

Comparison of Kalpana-1 atmospheric motion vectors with other observations     

S. K. Deb  Inderpreet Kaur  C. M. Kishtawal  P. K. Pal 《Theoretical and Applied Climatology》2014,115(3-4):693-702

The operational derivation of atmospheric motion vectors (AMVs) using infrared (10.5–12.5 μm) and water vapor (6.3–7.1 μm) channels of successive geostationary satellite images started in the 1980s. Subsequently, AMVs have become an important component for operational numerical weather prediction throughout the globe for the last decade or so. In India, at the Space Applications Centre, Indian Space Research Organisation, the operational derivation of AMVs (infrared winds and water vapor winds) from the Indian geostationary satellite Kalpana-1 has been initiated a few years back. Recently, an L-band radar lower atmosphere wind profiler (LAWP) has been installed at the National Atmospheric Research Laboratory, Gadanki located at (13.58°N, 79.28°E) for continuous high-resolution wind measurements in the lower atmosphere. In this study, a comparison of Kalpana-1 AMVs with wind measurements from LAWP and radiosonde has been carried out for a period of one and a half years. The performances of Kalpana-1 AMVs are also assessed by a separate comparison of Meteosat-7 AMVs, derived at the European Organisation for the Exploitation of Meteorological Satellites, with wind measurements from LAWP and radiosonde. Both sets of comparison show that AMVs from Kalpana-1 and Meteosat-7 are comparable over the Indian Ocean region.  相似文献   

Height Assignment Improvement in Kalpana-1 Atmospheric Motion Vectors   总被引：1，自引：0，他引：1  

S. K. Deb  Steve Wanzong  C. S. Velden  Inderpreet Kaur  C. M. Kishtawal  P. K. Pal  W. P. Menzel 《Journal of the Indian Society of Remote Sensing》2014,42(4):679-687

The real-time operational use of atmospheric motion vectors (AMVs) at numerical weather prediction (NWP) centers in India are being adversely affected due to inaccurate height assignment of cloud tracers, especially in thin semi-transparent clouds. In India, the operational derivation of AMVs from the Indian geostationary satellite Kalpana-1 began few years ago. A statistical empirical method (SEM) of height assignment, based on a genetic algorithm, is currently used to estimate the height of the retrieved vectors from Kalpana-1. This method has many limitations. In this paper, attempts have been made to implement the widely used and well tested height assignment methods such as the infrared window (WIN) technique, the H₂O intercept, and the cloud base method in the Kalpana-1 AMV retrieval algorithm. The new height assignment algorithm significantly improves the statistics of the retrieved winds when compared to radiosondes, especially in high and mid levels winds.  相似文献   

Adsorption Kinetics,Isotherms, and Desorption of Monocrotophos and Dichlorvos on Various Indian Soils     

Paramjeet Kaur  Dhiraj Sud 《洁净——土壤、空气、水》2011,39(12):1060-1067

Pesticide sorption on to the soil has a significant role in deciding the fate and behavior of pesticides in soil and aquatic environment. The present study investigates the adsorption of monocrotophos (MCP) and dichlorvos (DDVP) on the three soils of Malwa region of Punjab, India under different conditions. Batch adsorption experiments were preformed in replicates using 2 g of air‐dried soil and varying concentrations of pesticides and 20 mL of 0.01 M CaCl₂ as background electrolyte. The results revealed high adsorption of MCP and DDVP in soil B with k_f‐values 0.1261 and 0.0498 and n‐values 2.7345 and 1.831, respectively. The adsorption isotherms obtained were analyzed and the data was subjected to classical Langmuir, Freundlich, and Temkin models. The experimental data best fitted to the logarithm form of Freundlich and Temkin model. Kinetics analyses were performed using pseudo‐first order, pseudo‐second order, and intraparticle diffusion models. The regression results showed that the experimental data fitted very well with the pseudo‐second order kinetic model as correlation coefficient value is very closer to 1 and also followed the intraparticle diffusion model, whereas, diffusion is not only the rate controlling step. The percentages desorption with tap and distilled water is 32–64% for MCP and 25–48% for DDVP.  相似文献   

Reduction in chlorophenolic compounds during bleaching of rice straw pulp by replacing elemental chlorine with chlorine dioxide     

D. Kaur  N. K. Bhardwaj  R. K. Lohchab 《International Journal of Environmental Science and Technology》2018,15(5):1113-1122

Speedy running down of forest cover has put great stress on paper industry for finding new fibrous raw materials. Rice straw is an abundantly available lignocellulosic material especially in wood-short countries and can be utilized as an alternate fibre resource by paper mills. Bleaching is a crucial step in papermaking that involves the chemical reactions to reduce the colour of the pulp and makes it brighter for manufacturing writing and printing grade paper. Contrary to this, bleaching results into the formation of toxic, biorefractory and carcinogenic chlorolignin compounds that pose serious health hazards to aquatic life and human beings. A study was carried out using rice straw soda-AQ pulp for bleaching with sequence based on elemental chlorine (CE_OPHH). Further, to reduce the wastewater pollution load, emphasis was given on replacement of elemental chlorine with chlorine dioxide at the first bleaching stage (C_D10E_OPHH C_D30E_OPHH and C_D50E_OPHH) and elemental chlorine-free (ECF) bleaching (DE_OPD). The study revealed that generation of chlorophenolic compounds was the highest in CE_OPHH sequence followed by C_D10E_OPHH C_D30E_OPHH and C_D50E_OPHH, i.e. 6047, 4765, 4247 and 3864 mg/t, respectively. In DE_OPD bleaching sequence, the generation of chlorophenolic compounds in wastewater was reduced to 421 mg/t. ECF bleaching had major impacts on reduction in chloroguaiacols (97%) and chlorophenols (92%) that were in the highest quantity in effluents of CE_OPHH bleaching sequence. DE_OPD bleaching was found to be a promising option for pulp and paper industry for cutting down the generation of chlorophenolic compounds in bleaching effluents.  相似文献   

Delineation of potential fluoride contamination zones in Birbhum,West Bengal,India, using remote sensing and GIS techniques     

Raju Thapa  Srimanta Gupta  Harjeet Kaur 《Arabian Journal of Geosciences》2017,10(23):527

Birbhum district in West Bengal, India, is one of the most severely affected districts by fluoride-contaminated groundwater. Fluoride content as high as 20.4 mg/L has been reported. Several cases of fluoride-related disorder such as dental fluorosis and skeletal fluorosis have been reported to be endemic in the district. Proper management of groundwater is very crucial. This contribution has been carried out for delineating potential fluoride-contaminated zones (PFCZ) in Birbhum district with the implementation of weighted overlay analysis in GIS environment. Twelve different potentially influential environmental parameters are integrated and evaluated. The final output map was categorised into two subclasses, i.e. ‘low’ and ‘high’, where the low region represents fluoride concentration of 1.5 mg/L and below and the high region represents fluoride concentration above 1.5 mg/L. The outcome reveals that approximately 24.35% of the study area falls under PFCZ, whereas about 75.65% of the study area falls under the safe zone with respect to potential fluoride contamination. On validation of the PFCZ, the reported fluoride contamination data in groundwater shows an overall 87.50% accuracy in prediction via superimposition method and 89.06 and 85.85% success and prediction rates, respectively, when validated with success and prediction rates.  相似文献   

Ground validation of an algorithm for estimating surface suspended sediment concentrations from multi-spectral reflectance data     

Ravinder Kaur  Sunita Rabindranathan 《Journal of the Indian Society of Remote Sensing》1999,27(4):235-251

Pollution of water resources by sediments eroded from degraded watersheds is a critical concern around the world. Current methods for locating these eroding areas and off-site damage to water resources through visual observations and field sampling with subsequent laboratory analysis are time consuming and expensive. There is thus, a justified interest in developing algorithms for quick estimation of suspended sediment concentrations in large water-bodies from remotely sensed data. This paper presents the results of a ground validation study on characterization and quantification of surface suspended sediment concentrations (SSC) in sediment laden water bodies through an n-waveband specific numerical index, total information content. A comparison of SSC-predictive potential of the proposed new index, derived from four broad (100–300 nm) Landsat MSS, five broad (40–300 nm) Landsat TM and eight narrow (20–40 nm) IRS-P4 OCM spectral bands, with that of the conventional (NIR-Red and NIR+Red) indices, computed from the same spectral band data, is also presented. The study reveaied that at SSCs 250 mg/1, the proposed index (derived from either broad / narrow landsat MSS/TM or IRS-P4 OCM spectral data) could lead to SSC predictions (with mean errors within 20%) comparable with those obtained with the conventional indices (derived from the same spectral band data). It could further be observed that, in general, lower sediment concentrations (i.e. SSCs 150 mg/1) were associated with higher prediction inaccuracies. A comparison of the mean errors of predictions associated with the proposed and the conventional (NIR-Red and NIR+Red) indices computed from broad and narrow band data for SSCs 150 mg/I, revealed that an increase in number of wavebands (from 4 MSS to 5 TM or 8 OCM bands) and a decrease in the bandwidth of these wavebands (from broad MSS/ TM bands to narrow OCM bands) led to a significant increase in the prediction accuracy of the proposed new index. These prediction accuracies were observed to be the highest with the proposed index calculated from narrow OCM-P4 spectral data. However this could not be observed with the conventional indices at any of the SSC ranges and with the proposed index at SSCs 250 mg/l. This shows that the lower SSC-predictive potential of proposed index was a significant function of both the number and the bandwidth of spectral bands used for its computation. In fact in one of the cases, lower SSC (150 mg/l) -predictive accuracy of the proposed index was found to be significantly higher than that of the conventional (NIR+R) index. The proposed algorithm could thus compress the information contained in the entire reflectance spectrum of the sediment laden water bodies to their sediment type and concentration specific characteristic values. This characteristic of the proposed index was not shared by any of the conventional indices, based on only two waveband data. In fact the proposed index appears to be the only mean of completely compressing and quantifying the information contained in all the information channels of a narrow band spectrometer (consisting of 200 wavebands) to be shortly launched by ISRO for satellite based inventory of natural resources.  相似文献   

Comparative evaluation of water quality zonation within Dwarka River Basin,India     

Raju Thapa  D. V. Reddy  Harjeet Kaur 《水文科学杂志》2018,63(4):583-595

This study evaluates the thematic representation of drinking water quality of 211 habitations along the Dwarka River Basin (DRB), West Bengal, India. The dominant water type is Ca–Mg–HCO₃. Statistical analysis of the spatial dataset indicates a clustering pattern (with a nearest-neighbour ratio of 0.368 and Z score of 29.774). Two different techniques, spatial interpolation of water quality index (WQI) and composite water quality index (WQI_C) of physico-chemical constituents, were implemented to compare their performance. The WQI_C indicates approximately 11.68% of the total study area is at non-permissible levels, whereas the normal WQI technique predicts about 1.64% of the area is in non-permissible zones. Spatial water quality zonation by means of the overlay technique was superior to the conventional WQI technique in precisely distinguishing the characteristics of the permissible area with respect to even a single WHO recommended water quality parameter.  相似文献