Analysis of temperature variability over north-west part of India for the period 1970–2000     

Monika Punia  Suman Nain  Amit Kumar  Bhupendra Pratap Singh  Amit Prakash  Krishan Kumar  V. K. Jain 《Natural Hazards》2015,75(1):935-952

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Shallow lithosphere-asthenosphere boundary beneath Cambay Rift Zone of India: Inferred presence of carbonated partial melt     

Prakash Kumar  Gautam Sen  Prantik Mandal  Mrinal K. Sen 《Journal of the Geological Society of India》2016,87(4):401-410

A vast area between Phalodi in Jodhpur and Pokaran in Jaisalmer district of western Rajasthan, is occupied distinctly by rocky, shallow gravelly surfaces and occasional hills. These surfaces exhibit quartz and quartzite pebbles, angular, sub-angular and few rounded sandstone gravels, have slightly convex outline and can be best described as desert pavements. Such land features assume significance because of their extent and variability under a dominantly dry aeolian environment. Morphology and distributional pattern of such formations indicate that sediments are either of in situ origin or may have been transported to a short distance. The present study is based on field level assessment of such surfaces in the above two desert districts. Over much of the area, the profile shows a surficial concentration of gravels followed by thick sand and silt mixed with gravels and then the parent material. There are also occasional rock outcrops of very low relief exhibiting vertical, horizontal and conchoidal pattern of fractures over these surfaces near Pokaran and north of Jaisalmer which indicate disintegration of rocks under extreme diurnal fluctuation of temperature. Such manifestations in the morphology indicate impact of both thermal as well as aeolian processes. In the east of Jaisalmer town near Basanpir and Bhojka, the pavement surfaces are found covered with abundant sub-rounded to rounded pebbles and cobbles. This type of condition would indicate a profound action by fluvial activities followed by wind sorting. Our study found significant spatial variability in the distribution of pavement surfaces, which carried imprints of climatic fluctuations and environment of deposition during Holocene.  相似文献   

Discrimination of explosions and earthquakes: An example based on spectra and source parameters of the 11<Superscript>th</Superscript> May 1998 Pokhran explosion and the 9<Superscript>th</Superscript> April 2009 earthquake     

Bandana Baruah  Prakash Kumar  M. Ravi Kumar 《Journal of the Geological Society of India》2016,88(1):13-21

We compare the P-, S- and Lg- spectra of the 11^th May, 1998 Pokhran underground nuclear explosion (NE) with those of an earthquake (EQ) of comparable magnitude that occurred in its vicinity (~100 km west) on 9^th April, 2009, utilizing the waveforms recorded by a Global Seismograph Network station at Nilore (NIL), Pakistan. The contiguous occurrence of these events and the similarity of the travel paths provided a good opportunity to discriminate the nature of the sources. Our results suggest that the Pn/Lg and Pn/Sn amplitude ratios of the explosion and earthquake waveforms exhibit distinct differences in the higher frequency window. Further, since the P-phases have high signal to noise ratio compared to their S counterparts, we utilize their spectra to derive the source parameters of the NE and EQ sources. Our results show that the seismic moment, corner frequency and source dimension of the explosion are ~1.58X10¹⁷ Nm, 1.18 Hz and ~0.793 km respectively. The moment magnitude (M_W) and surface wave magnitude (M_S) for the nuclear explosion are estimated to be ~5.4 and ~3.57 respectively. The values of M_W (5.3) and M_S (4.3) obtained by us for the earthquake are consistent with the estimates in the Harvard catalog and earlier published results. The estimate of M_W for the nuclear explosion was hitherto not available. Lastly, we estimate the yield of the NE to be ~50 kt from the surface wave magnitude and discuss the various limitations related to its estimation.  相似文献   

Prediction of daily modes of South Asian monsoon variability and its association with Indian and Pacific Ocean SST in the NCEP CFS V2     

Namendra Kumar Shahi  Shailendra Rai  D. K. Pandey 《Meteorology and Atmospheric Physics》2016,128(1):131-142

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Extratropical anticyclonic Rossby wave breaking and Indian summer monsoon failure     

Dhrubajyoti Samanta  M. K. Dash  B. N. Goswami  P. C. Pandey 《Climate Dynamics》2016,46(5-6):1547-1562

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Assessment of Kalpana-1 Rainfall Product over Indian Meteorological Sub-Divisions During the Summer Monsoon Season     

M. T. Bushair  Satya Prakash  Shashikant Patel  R. M. Gairola 《Journal of the Indian Society of Remote Sensing》2016,44(1):67-76

In this paper, Kalpana-1 derived INSAT Multispectral Rainfall Algorithm (IMSRA) rainfall estimates are compared with two multisatellite rainfall products namely, TRMM Multisatellite Precipitation Analysis (TMPA)-3B42 and Global Satellite Mapping of Precipitation (GSMaP), and India Meteorological Department (IMD) surface rain gauge (SRG)-based rainfall at meteorological sub-divisional scale over India. The performance of the summer monsoon rainfall of 2013 over Indian meteorological sub-divisions is assessed at different temporal scales. Comparison of daily accumulated rainfall over India from IMSRA shows a linear correlation of 0.72 with TMPA-3B42 and 0.70 with GSMaP estimates. IMSRA is capable to pick up daily rainfall variability over the monsoon trough region as compared to TMPA-3B42 and GSMaP products, but underestimates moderate to heavy rainfall events. Satellite-derived rainfall maps at meteorological sub-divisional scales are in reasonably good agreement with IMD-SRG based rainfall maps with some exceptions. However, IMSRA performs better than GSMaP product at meteorological sub-divisional scale and comparable with TMPA data. All the satellite-derived rainfall products underestimate orographic rainfall along the west coast, the Himalayan foothills and over the northeast India and overestimate rainfall over the southeast peninsular India. Overall results suggest that IMSRA estimates have potential for monsoon rainfall monitoring over the Indian meteorological sub-divisions and can be used for various hydro-meteorological applications.  相似文献   

Review of challenges of and practices for sustainable management of mountain flood hazards     

Desirée Tullos  Elizabeth Byron  Gerald Galloway  Jayantha Obeysekera  Om Prakash  Yung-Hsin Sun 《Natural Hazards》2016,83(3):1763-1797

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The geochemistry of uranium occurrences and speciation in groundwater of Chinnar sub basin,South India     

CS Suma  K Srinivasamoorthy  K Saravanan  S Gopinath  R Prakash  A Faizal Khan 《Arabian Journal of Geosciences》2016,9(18):703

An attempt has been made in Chinnar sub basin of Dharmapuri district, South India to isolate the geochemistry of uranium occurrences in groundwater. The geology of the area is mainly of charnockite and granite gneiss. Groundwater samples were collected for two different seasons post and pre monsoon in two different litho units (granite gneiss and charnockite) and analysed for major, minor and uranium concentrations. Higher uranium (18.45 μg L^?1) has been recorded during pre monsoon season in granite gneiss with increasing pH. The saturation index calculation for the groundwater isolated minerals like uaraninite, coffinite, haiweeite and soddyite to be precipitating and uranium oxides like UO_2.25, UO_2.25beta, UO_2.33beta as oversaturated. The Eh-pH diagram attempted represents solubility of uraninite within the pH range of 6.0 to 8.0. The study isolate uranium in groundwater of the study area is controlled by the presence of (U₄O₉) uranium oxide.  相似文献   

Comparative performance evaluation of physicochemical treatment processes for simulated dairy wastewater     

N. Prakash  A. Garg 《International Journal of Environmental Science and Technology》2016,13(11):2675-2688

In the present study, the effectiveness of physicochemical treatment processes (coagulation and Fenton’s oxidation) was investigated for simulated dairy wastewater (pH = 7.3, chemical oxygen demand (COD) = 3600 mg/l, 5-day biochemical oxygen demand (BOD₅) = 1950 mg/l, total Kjeldahl nitrogen (TKN) = 87 mg/l, and total phosphorous (TP) = 14 mg/l). Plain and ballasted coagulation runs were carried out in a jar apparatus, while Fenton’s oxidation was performed in a three-neck glass reactor. Ballasted coagulation caused an enhancement in the settling rate of sludge though no significant enhancement in the removal of organics was observed. Individually, coagulation and Fenton’s oxidation processes resulted in ~67 and 80 % COD removals, respectively, from the wastewater. The sequential treatment exploring coagulation followed by Fenton’s oxidation showed overall COD, BOD₅, TKN, and TP reductions of ~93, 97, 84, and 70 %, respectively, from the wastewater. However, a biological post-treatment would be required to achieve the effluent discharge standards. The removal of proteins, fats, and amino acids from wastewater was confirmed from Fourier transform infrared analysis of the settled sludge (obtained after coagulation process). Preliminary cost analysis suggested coagulation and the sequential treatment (i.e. coagulation followed by Fenton’s oxidation) as the preferred options.  相似文献   

Deformation behavior of migmatites: insights from microstructural analysis of a garnet–sillimanite–mullite–quartz–feldspar-bearing anatectic migmatite at Rampura–Agucha,Aravalli–Delhi Fold Belt,NW India     

Prakash  Abhishek  Piazolo  Sandra  Saha  Lopamudra  Bhattacharya  Abhijit  Pal  Durgesh Kumar  Sarkar  Saheli 《International Journal of Earth Sciences》2018,107(6):2265-2292

International Journal of Earth Sciences - In the present study we investigate the microstructural development in mullite, quartz and garnet in an anatectic migmatite hosted within a Grenvillian-age...  相似文献