An Outline of the Late Quaternary Stratigraphy and Palaeoclimate of Ladakh Region     

H. S. Saini 《Journal of the Geological Society of India》2013,82(2):202-202

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Effect of Different Growing Environments on Population Dynamics of Sucking Pests in Relation to Various Spectral Indices in Cotton     

Naresh Kumar  Ram Niwas  M. L. Khichar  R. K. Saini  Barun Biswas 《Journal of the Indian Society of Remote Sensing》2013,41(2):309-317

Present study was designed to determine the effect of various growing environments on sucking pest population dynamics in cotton and to work out their relation with spectral indices. Crop spectral reflectance in four IRS bands was measured with ground truth radiometer during 1000–1200 h in all the treatment combinations. Incidence of sucking pest in cotton was found out to be highly influenced by growing environments. The leafhopper and whitefly population was highest in 15 May sown cotton crop and was lowest in 15 April sown crop. Cultivar HS-6 was highly affected by both the sucking pest than the other cultivar H-1226. The spectral indices (SR, NDVI and TVI) were highest in 15 April sown crop at all the phenophases and were lowest in 15 May sown crop. The cultivar H-1226 showed higher values of spectral indices as compared to HS-6. The relationship of pests’ population with various spectral indices was established. Multiple regression models based on spectral indices can be used for prediction of sucking pest population more than 69 and 74 % accuracy in leafhopper and whitefly, respectively in cotton crop.  相似文献   

Geomagnetic field variation during winter storm at localized southern and northern high latitude     

Babita Devi  Smita Dubey  Shailendra Saini  Rajni Devi  Rashmi Wahi  Ajay Dhar  S. K. Vijay  A. K. Gwal 《Journal of Astrophysics and Astronomy》2008,29(1-2):275-280

This paper presents the effect of geomagnetic storm on geomagnetic field components at Southern (Maitri) and Northern (Kiruna) Hemispheres. The Indian Antarctic Station Maitri is located at geom. long. 66.03° S; 53.21° E whereas Kiruna is located at geom. long. 67.52° N; 23.38° E. We have studied all the geomagnetic storms that occurred during winter season of the year 2004–2005. We observed that at Southern Hemisphere the variation is large as compared to the Northern Hemisphere. Geomagnetic field components vary when the interplanetary magnetic field is oriented in southward direction. Geomagnetic field components vary in the main phase of the ring current. Due to southward orientation of vertical component of IMF reconnection takes place all across the dayside that transports plasma and magnetic flux which create the geomagnetic field variation.  相似文献   

Effect of interplanetary magnetic field and disturb storm time on H component     

Rajni Devi  Smita Dubey  Shailendra Saini  Babita Devi  Ajay Dhar  S. K. Vijay  A. K. Gwal 《Journal of Astrophysics and Astronomy》2008,29(1-2):281-286

A fluxgate digital magnetometer is used to study the variation of magnitude of H component during geomagnetic storm events of April, July and November 2004 at southern subauroral localized region at “MAITRI” (geom. lat. 62°S, long. 52.8°E). We also study the effect of vertical component of interplanetary magnetic field (IMF) on the variation of the magnitude of H component during storm time of April, July and November 2004. Results show that before sudden storm commencement (SSC) time magnitude of H component and IMF show smooth variation but after SSC of first storm of 22 July 2004, the magnitude of the H component shows fluctuations and at 09:00 UT it increases, but during second storm of 24 July 2004, the magnitude of H component indicates large fluctuations and it increases rapidly at 04:00 UT.  相似文献   

Tectonics induced switching of provenance during the Late Quaternary aggradation of the Indus River Valley,Ladakh, India     

Ravish Lal  H.S.Saini  N.C.Pant  S.A.I.Mujtaba 《地学前缘(英文版)》2019,10(1):285-297

The Indus River flows through Ladakh, one of the driest and coldest places on earth, in a tectonically active domain. Fluvial, glaciofluvial, lacustrine and debris dominated sequences represent the Late Quaternary sedimentary record along the river course. Karakoram Fault, a major crustal scaled feature reported to be active during the Quaternary, is associated with the Indus River drainage. Linkages between a major, active fault and deposits formed during the activity period of the fault are explored using heavy mineral deduced provenance and Optically Stimulated Luminescence(OSL) chronology.Five deposits in a ~200 km long stretch of the Indus River have been examined for a ~80 ka period to decipher the climate linked aggradation history. Damming of the Indus River at ~79 ka and existence of the Spituk Lake for >30 ka is demonstrated. Using geology of the provenance in relation to the mineralogical attributes of the Quaternary deposits, the major drainage reorganization when the connection of the Tangtse Valley to the Indus was blocked, is inferred at ~73 ka. It is supported by the geologicalgeomorphological evidence. The study demonstrates the application of provenance linked mineralogy in terrestrial aggradation in a tectonically active region.  相似文献   

2008年中国南方低温雨雪冰冻灾害网络建模及演化机制研究   总被引：1，自引：0，他引：1  

李双双  杨赛霓  刘宪锋  刘焱序 《地理研究》2015,34(10):1887-1896

基于中国0.5°×0.5°逐日气温和降水格网数据,利用复杂网络分析方法,对2008年南方低温雨雪冰冻灾害综合致灾过程进行再认识,综合分析低温雨雪冰冻灾害在时空维度的网络特性。结果表明：2008年南方低温雨雪冰冻灾害是典型的多灾种叠加事件,低温与雨雪灾害叠加放大了致灾因子的危险性;基础设施设防水平低与春运高峰叠加增大了承灾体的脆弱性;低山丘陵区与人口聚集区叠加降低了孕灾环境的稳定性。低温冰冻雨雪灾害具有小世界特征和核心—边缘结构,具体表现为：在空间打击上具有集聚性,影响区域相对集中;在时间打击上具有连续性,间隔1天事件相对较少。在研究方法上,复杂网络是一种有效分析多灾种叠加的方法,可以进一步挖掘自然灾害的时空演化信息。  相似文献   

Arbitrary amplitude dust–ion acoustic solitary structures in electronegative plasma     

Ripin Kohli  N. S. Saini  T. S. Gill 《Astrophysics and Space Science》2018,363(9):193

In the present study existence domains of large amplitude dust–ion acoustic (DIA) solitary structures are analyzed in an unmagnetized and collisionless, electronegative plasma containing inertial positive and negative ions, inertialess superthermal electrons with two different temperatures and negatively charged stationary dust. Using the Sagdeev pseudopotential technique, the energy-balance equation has been derived and the critical values (lower and upper limits) of the Mach number are also determined. The effect of different physical parameters has been analyzed for the formation of these nonlinear structures. Also the critical values of different physical parameters have been determined to establish parametric regimes for the existence of positive/negative potential DIA solitary structures.  相似文献   

Static spherically-symmetric perfect fluids with pressure equal to energy density     

R. B. S. Yadav  S. L. Saini 《Astrophysics and Space Science》1991,186(2):331-336

The present Letter represents an exact, static, and spherically-symmetric solution of Einstein's field equations for a homogeneous perfect fluid core surrounded by a field of Zeldovich's fluid which is asymptotically homaloidal.  相似文献   

Inventory of degraded lands of Palamau district, Bihar — A remote sensing approach     

Sanjay K Gupta  M Hussain  M Ahmed  A S Pandey  P Singh  K M Saini  S N Das 《Journal of the Indian Society of Remote Sensing》1998,26(4):161-168

In this study, an attempt has keen made for the identification, categorisation and mapping of degraded lands in Palamau district of Bihar using remotely sensed data (IRS-1A, raise colour composite, on 1:50,000 scale), It was observed that water erosion is the main cause of land degradation affecting 6.27 per cent area of the district, of which 5.22 per cent is subjected to severe to very severe erosion and remaining 1.05 per cent is moderately to severely gulleid land Degradation due to rock quarries, mine spoils and dumps accounted for only 0.01 per cent of the district area. Degraded lands were mostly confined to agricultural areas (4.76%) follwed by forest lands (1.10%) and opert-scrub/pastures (0.42%), respectively, Subdivision-wise categorisation of degraded lands was also attempted for efficient location-speeific reclamation planning and easy monitoring.  相似文献   

Revealing the nature of dark energy using Bayesian evidence     

T. D. Saini  J. Weller  S. L. Bridle 《Monthly notices of the Royal Astronomical Society》2004,348(2):603-608

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