An appraisal of groundwater quality in Seymour and Blaine aquifers in a major agro-ecological region in Texas,USA     

Sriroop Chaudhuri  Srinivasulu Ale 《Environmental Earth Sciences》2014,71(6):2765-2777

Aquifer-based groundwater quality assessment offers critical insight into the major hydrochemical processes, and aids in making groundwater resources management decisions. The Texas Rolling Plains (TRP), spanning over 22 counties, is a major agro-ecological region in Texas from where highest groundwater nitrate (NO₃ ^?) levels in the state have been reported. In this study, we present a comparative assessment of major hydrochemical facies pertaining to NO₃ ^? contamination and a host of species such as sulfate (SO₄ ^2?), chloride (Cl^?), and total dissolved solids (TDS) in different water use classes in the Seymour and Blaine aquifers, underlying the TRP. Aquifer-stratified groundwater quality information from 1990 to 2010 was obtained from the Texas Water Development Board and aggregated over decadal scale. High groundwater salinization was found in the municipal water use class in the Blaine aquifer with about 100, 87 and 50 % of observations exceeding the secondary maximum contaminant level for TDS, SO₄ ^2?, and Cl^?, respectively in the 2000s (2000–2010). The NO₃-contamination was more alarming in the Seymour aquifer with 82 and 61 % of observations, respectively, exceeding the maximum contaminant level (MCL) in the irrigation and municipal water use classes in the 2000s. Salinization was more influenced by SO₄ ^2? and Cl^? in the Blaine aquifer and by NO₃ ^? in the Seymour aquifer. High NO₃ ^? (>MCL) observations in the Seymour aquifer occurred in the Ca–HCO₃ and Ca–Mg–HCO₃ facies, the domains of fresh water recharge and anthropogenic influences (e.g., agricultural activities, waste disposal). High SO₄ ^2?, Cl^? and TDS observations in the Blaine aquifer dominated the Ca–Cl, Na–Cl, and mixed Ca(Mg)–SO₄(Cl) facies indicating evaporite dissolution, mixing and solute exchange, and lack of fresh recharge.  相似文献   

http://www.sciencedirect.com/science/article/pii/S1674987114000437     

Udeni Amarasinghe  Asru Chaudhuri  Alan S.Collins  Gautam Deb  Sarbani Patranabis-Deb 《地学前缘(英文版)》2015,6(3):453-463

The Pranhita-Godavari Basin in central eastern India is one of the Proterozoic "Purana" basins of cratonic India.New geochronology demonstrates that it has a vast depositional history of repeated basin reactivation from the Palaeoproterozoic to the Mesozoic.U-Pb laser ablation inductively coupled plasma mass spectrometry dating of detrital zircons from two samples of the Somanpalli Group—a member of the oldest sedimentary cycle in the valley-constrains its depositional age to ~1620 Ma and demonstrates a tripartite age provenance with peaks at ~3500 Ma,~2480 Ma and ~1620 Ma,with minor age peaks in the Eoarchaean(~3.8 Ga) and at ~2750 Ma.These ages are consistent with palaeocurrent data suggesting a southerly source from the Krishna Province and Enderby Land in East Antarctica.The similarity in the maximum depositional age with previously published authigenic glauconite ages suggest that the origin of the Pranhita-Godvari Graben originated as a rift that formed at a high angle to the coeval evolving late Meosproterozoic Krishna Province as Enderby Land collided with the Dharwar craton of India.In contrast,detrital zircons from the Cycle III Sullavai Group red sandstones yielded a maximum depositional age of 970±20 Ma and had age peaks of ~2550 Ma,~1600 Ma and then a number of Mesoproterozoic detrital zircons terminating in three analyses at ~970 Ma.The provenance of these is again consistent with a southerly source from the Eastern Ghats Orogen and Antarctica.Later cycles of deposition include the overlying Albaka/Usur Formations and finally the late Palaeozoic to Mesozoic Gondwana Supergroup.  相似文献   

Effect of neutrino emission in the sun and other main sequence stars     

Probhas Ray Chaudhuri 《Astrophysics and Space Science》1971,11(3):412-416

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Neutrino emission,population II stars and big-bang cosmology     

Probhas Ray Chaudhuri 《Astrophysics and Space Science》1971,12(2):325-328

The spectroscopic determination of the helium abundance in the oldest stars of the galaxy is supported by the theory of stellar evolution when neutrino emission is considered according to the photon-neutrino coupling theory, if it is assumed that the population II stars started their life with a low surface helium content.Receipt delayed by postal strike in Great Britain.  相似文献   

A composite stability index for dichotomous forecast of thunderstorms     

Sutapa Chaudhuri  Anirban Middey 《Theoretical and Applied Climatology》2012,110(3):457-469

Thunderstorms are the perennial feature of Kolkata (22° 32???N, 88° 20???E), India during the premonsoon season (April?CMay). Precise forecast of these thunderstorms is essential to mitigate the associated catastrophe due to lightning flashes, strong wind gusts, torrential rain, and occasional hail and tornadoes. The present research provides a composite stability index for forecasting thunderstorms. The forecast quality detection parameters are computed with the available indices during the period from 1997 to 2006 to select the most relevant indices with threshold ranges for the prevalence of such thunderstorms. The analyses reveal that the lifted index (LI) within the range of ?5 to ?12?°C, convective inhibition energy (CIN) within the range of 0?C150?J/kg and convective available potential energy (CAPE) within the ranges of 2,000 to 7,000?J/kg are the most pertinent indices for the prevalence thunderstorms over Kolkata during the premonsoon season. A composite stability index, thunderstorm prediction index (TPI) is formulated with LI, CIN, and CAPE. The statistical skill score analyses show that the accuracy in forecasting such thunderstorms with TPI is 99.67?% with lead time less than 12?h during training the index whereas the accuracies are 89.64?% with LI, 60?% with CIN and 49.8?% with CAPE. The performance diagram supports that TPI has better forecast skill than its individual components. The forecast with TPI is validated with the observation of the India Meteorological Department during the period from 2007 to 2009. The real-time forecast of thunderstorms with TPI is provided for the year?2010.  相似文献   

Role of Subsurface Brines in Salt Balance: The Case Study of the Caspian Sea and Kara Bogaz Bay     

Norbert Clauer  Marie-Claire Pierret  Sam Chaudhuri 《Aquatic Geochemistry》2009,15(1-2):237-261

The water level of the Caspian Sea fluctuated significantly during recent history, without consensus for the cause. The varied chemistry of the Caspian, Kara Bogaz and sediment a interstitial waters provides a further insight. Element concentrations and ⁸⁷Sr/⁸⁶Sr ratios of the interstitial waters were compared to those of Caspian and Kara Bogaz open waters, and of acid-leached extractable components. The ⁸⁷Sr/⁸⁶Sr ratios of the interstitial waters are explained by addition of subterranean waters similar to nearby spring waters. These subterranean waters yield chemical characteristics such as a Cl/SO₄, ⁸⁷Sr/⁸⁶Sr, Ca/Sr and K/Rb ratios of respectively 80, 0.7086, 250 and 1,800. However, their addition does not explain the large difference in the K/Rb ratio of the Caspian and Kara Bogaz waters, respectively at 7,630 and 17,550, which implies also a leaching of salt deposits by the upward migrating subterranean waters. The sediments of the southern Caspian basin, with low Na, Cl and SO₄ in their interstitial waters, deposited apparently in an anoxic environment. The related chemical changes in the waters are also indicative of a recent change in the hydrologic regime, possibly induced by a changing morphology of the drainage basin.  相似文献   

Implementation of intuitionistic fuzzy logic to assess the predictability of severe thunderstorms   总被引：1，自引：0，他引：1  

Sutapa Chaudhuri 《Asia-Pacific Journal of Atmospheric Sciences》2011,47(5):477-483

Thunderstorms are responsible for remarkable devastation when accompanied with lightning flashes, high wind gusts, torrential rain, hail and tornadoes. Weather hazards due to thunderstorms of such severe measure take place every year over Kolkata (22°32′N, 88°20′E), India during the pre-monsoon season (April–May). Prediction of severe thunderstorms is extremely important to cope with the devastations. However, forecasting severe thunderstorms is very difficult because the weather system is confined within a very small spatial-temporal scale. The network of observation systems is not adequate to detect such high frequency small scale weather. The purpose of the present study is to bring in the concept of Intuitionistic fuzzy logic as a decision — making technique to assess the predictability of severe thunderstorms over Kolkata in the premonsoon season. Different measures of entropies are used to extract the route of fuzziness. The intuitionistic fuzzy logic is implemented with ten years (1997–2006) observation of the occurrence/nonoccurrence of severe thunderstorms to assess the predictability. The result reveals that two consecutive severe thunderstorm days are highly probable after two consecutive non-thunderstorm days whereas the probability of severe thunderstorm is very less after three consecutive non-thunderstorm days during the pre-monsoon season over Kolkata. The result is compared with the box-and-whisker plot and validated with four years (2007–2010) observations of India Meteorological Department (IMD).  相似文献   

Nowcasting Bordoichila with a composite stability index     

Sutapa Chaudhuri  Jayanti Pal  Anirban Middey  Sayantika Goswami 《Natural Hazards》2013,66(2):591-607

In operational forecast, the stability indices either individually or in combination are utilized to assess the predictability of local severe storms over a region. The objective of the present study is to identify such stability indices to assess the predictability of Bordoichila of Guwahati, India, during the pre-monsoon season (April–May) aiming to formulate a composite stability index using the most pertinent indices for nowcasting Bordoichila with considerable precision. Bordoichila, meaning the angry daughter of Assam, represents local severe storms of Guwahati during the pre-monsoon season. Precise forecast of Bordoichila is essential to mitigate the associated catastrophe over Guwahati. The forecast quality detection parameters are computed with the available indices during the period from 1997 to 2006 to select the most relevant stability indices for the prevalence of Bordoichila. The method of normal probability distribution is implemented to identify the threshold ranges of the selected indices. The stability indices that are selected with appropriate ranges are lifted index, Showalter index (SI), cross total index (CTI), vertical total index, totals total, convective available potential energy, convective inhibition energy, SWEAT and bulk Richardson number. The forecast skill scores are estimated with the selected indices. The best predictor indices identified for the prevalence of Bordoichila are the cross total index (CTI) and Showalter index (SI). A composite stability index, Bordoichila prediction index, is formulated with CTI and SI with proper weightages. The forecast with BPI is validated with the observations of India Meteorological Department for the year 2007 and is implemented for real-time forecast for the years 2009 and 2011.  相似文献   

Transient and steady state supersaturation in a thermal diffusion cloud chamber     

Shri S. Chaudhuri 《Meteorology and Atmospheric Physics》1983,32(3):269-279

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On magnetoelastic disturbances in an aelotropic elastic cylinder placed in a magnetic field     

Chaudhuri  B. 《Pure and Applied Geophysics》1969,73(1):60-68

Summary The present note deals with the disturbances in an aelotropic elastic cylinder placed in an axial magnetic field, being acted upon by a mechanical force.  相似文献