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Impact of Drought on Agriculture in the Indo-Gangetic Plain,India

Advances in Atmospheric Sciences 2017年第3期34卷 335-346页

作者： reshmita nath Debashis nath Qian LI Wen CHEN Xuefeng CUI Center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China School of System Sciences Beijing Normal UniversityBeijing 100875China Key Laboratory of Middle Atmosphere and Global Environmental Observations Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Meteorology and Climate Unit School of Mathematical ScienceUniversity College DublinDublin 4Ireland

In this study, we investigate the spatiotemporal characteristics of drought in India and its impact on agriculture during the summer season （April-September）. In the analysis, we use Standardized Precipitation Evapotranspiration Index （SPEI） datasets between 1982 and 2012 at the six-monthly timescale. Based on the criterion SPEI 〈 -1, we obtain a map of the number of occurrences of drought and find that the humid subtropical Upper Middle Gangetic Plain （UMGP） region is highly drought-prone, with an occurrence frequency of 40%-45%. This UMGP region contributes at least 18%-20% of India＇s annual cereal production. Not only the probability of drought, but the UMGP region has become increasingly drought-prone in recent decades. Moreover, cereal production in the UMGP region has experienced a gradual declining trend from 2000 onwards, which is consistent with the increase in drought-affected areas from 20%-25% to 50%-60%, before and after 2000, respectively. A higher correlation coefficient （-0.69） between the cereal production changes and drought-affected areas confirms that at least 50% of the agricultural （cereal） losses are associated with drought. While analyzing the individual impact of precipitation and surface temperature on SPEI at 6 month timescale [SPEI （6）] we find that, in the UMGP region, surface temperature plays the primary role in the lowering of the SPEI. The linkage is further confirmed by correlation analysis between SPEI （6） and surface temperature, which exhibits strong negative values in the UMGP region. Higher temperatures may have caused more evaporation and drying, which therefore increased the area affected by drought in recent decades.

关键词： drought agriculture SPEI Indo-Gangetic Plain temperature precipitation potential evapotranspiration

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Identification of Black Dragon forest fire in Amur River Basin Using Satellite Borne NDVI Data and Its Impact on Long Range Transport of Pollutants:A Case Study

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Journal of Atmospheric Science Research 2019年第3期2卷 6-10页

作者： Ankita nath reshmita nath Vivekananda College West Bengal State UniversityIndia Department of Earth System Science/Institute for Global Change Studies Tsinghua UniversityBeijing100084China

The Greater Hinggan Forest was the world’s largest stand of evergreens,along the Black Dragon River(also known as Amur),which forms the border between Chinese Manchuria and Soviet *** Dragon fire ranks as one of the worst environmental disasters of the 20th century and it burned about 18 million acres of conifer *** the 2nd week of May,1987,we observe more than 10K rise in brightness temperature over a wide region in the China-Russia *** weekly mean NDVI data shows the changes in greenness after the forest fire broke *** NDVI value is positive with persistent greenness and vegetation in the Amur River valley,but from the 2nd week of May onwards the reddish patch appears to spread over the entire region,indicates the burned *** addition,we observe the impact of Black Dragon forest fire on tropospheric ozone concentration,aerosol index away from the location over North Pacific Ocean.A clear increase in atmospheric pollutants can be noticed after the forest fire event and the long range transports are confirmed with 72 hours NOAA HYSPLIT forward trajectory analysis.

关键词： Black Dragon forest fire NDVI Ozone Aerosol Transport HYSPLIT model

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基于分层分区法的中国历史耕地数据的网格化重建

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地理学报 2016年第7期71卷 1144-1156页

作者：魏希文缪丽娟江源 nath reshmita 崔雪锋北京师范大学资源学院北京100875 南京信息工程大学地理与遥感学院南京210044 中国科学院大气物理研究所季风系统研究中心北京100029 北京师范大学系统科学学院北京100875

网格化历史耕地数据集能为历史时期耕地变化研究提供更精确的支持,并且为全球环境气候变化研究模型模拟提供驱动数据。本文综合考虑了中国历代土地利用开发的特点及自然人文因子对耕地的影响,设计了一套对中国耕地先分区再分层分配的网... 详细信息

网格化历史耕地数据集能为历史时期耕地变化研究提供更精确的支持,并且为全球环境气候变化研究模型模拟提供驱动数据。本文综合考虑了中国历代土地利用开发的特点及自然人文因子对耕地的影响,设计了一套对中国耕地先分区再分层分配的网格化方法。基于国内3个主流区域耕地数据研究成果,采用上述方法建立了1820年(清仁宗嘉庆二十五年)和1936年(民国二十五年)中国10 km×10 km分辨率的耕地数据集,并绘制了分布图。本文还利用国内具有代表性的区域数据集对重建结果进行对比验证。结果表明,该方法可以保证耕地数量的权威性,并且建立具有区域性的高精度历史耕地数据集。

关键词：中国历史耕地分区分层网格化重建

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应用生态网络分析方法评价中国经济系统的可持续性

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生态学报 2016年第24期36卷 7942-7950页

作者：胡科刘晓磊魏希文 nath reshmita 崔雪锋西北师范大学地理与环境科学学院兰州730070 北京师范大学全球变化与地球系统科学研究院地表过程与资源生态国家重点实验室北京100875 中国科学院大气物理研究所季风系统研究中心北京100029

将生态网络分析方法应用于中国经济系统的可持续性分析。依据1987—2010年的投入产出数据,构建中国经济系统的货币网络流,用生态网络指标量化经济系统的网络特征和变化情况,探讨中国经济系统中增长与发展的变化及其可持续性。主要结论有... 详细信息

将生态网络分析方法应用于中国经济系统的可持续性分析。依据1987—2010年的投入产出数据,构建中国经济系统的货币网络流,用生态网络指标量化经济系统的网络特征和变化情况,探讨中国经济系统中增长与发展的变化及其可持续性。主要结论有:(1)1987—2010年间中国经济系统的总吞吐量呈指数增长趋势,网络规模不断增长。(2)1987—2010年间中国经济的系统效率在波动中呈增加趋势,但增长幅度较小。从长期阶段看,1997—2010年间的系统效率和组织能力比1987—1995年间有明显提高,表明经济系统在后期获得了一定程度的发展。但系统效率在2002年达到高点后呈现下降趋势。(3)1987—2010年间中国经济系统的上升性和发展能力都在持续提高,但主要来自规模增长。增长和发展的量化结果表明,1987—2010年间中国经济系统上升性的提高,90%来自总吞吐量(增长),只有10%来自效率改进(发展)。(4)1987—2010年间的中国经济系统的α平均值为0.138,远小于0.37或0.33的可持续性最优平衡点,系统处于缺乏效率的不可持续的状态。要提高经济系统的可持续性,需要提高经济系统的效率(结构)和组织能力。

关键词：生态网络分析中国经济系统增长发展可持续性

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中国生猪生产耗水及影响因素分析

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资源科学 2016年第1期38卷 110-118页

作者：刘晓磊栾一博胡科 reshmita nath 崔雪锋北京师范大学全球变化与地球系统科学研究院地表过程与资源生态国家重点实验室北京100875 中国科学院大气物理研究所季风系统研究中心北京100029

随着城市化的发展和人均收入的提高,中国居民对猪肉的需求日益增长。猪肉生产耗水量大,其包括饲料作物生长所消耗的水,也包括生猪生产过程所消耗的水。本文从生猪生产的角度计算了2001-2012年生猪生产耗水,结果表明生猪生产水足迹由200... 详细信息

随着城市化的发展和人均收入的提高,中国居民对猪肉的需求日益增长。猪肉生产耗水量大,其包括饲料作物生长所消耗的水,也包括生猪生产过程所消耗的水。本文从生猪生产的角度计算了2001-2012年生猪生产耗水,结果表明生猪生产水足迹由2001年的3.39m^3/kg下降到2012年的3.31m^3/kg,但生猪生产耗水却从2001年的1910亿m^3上升到2012年的2650亿m^3,增长了38.95%。运用对数平均迪氏指数法(Logarithmic Mean Divisia Index,LMDI)对影响生猪生产耗水的因素进行了分析。在影响生猪生产耗水的3个因素中,人口的增长和猪肉消费量的增加导致生猪生产耗水的增加,而生猪生产水足迹的降低则会降低生猪生产耗水,三者中,猪肉消费量对生猪生产耗水的贡献最大。同时,农场耗水所占比例不断增加。本研究第一次揭示了长时间尺度,中国大、中、小规模化及散养养殖情况下,生猪生产水足迹的变化以及生产耗水。这有助于处理中国生猪产业的快速发展和耗水量不断增加的关系,促进生猪产业的可持续发展。

关键词：水足迹生猪生产规模化粮食安全

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Perspectives on Higgs boson and supersymmetry

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Frontiers of physics 2013年第3期8卷 294-301页

作者： Pran nath Department of Physics Northeastern University Boston MA 02115-5005 USA

We review the recent discovery of the Higgs like particle at - 125 GeV and its implications for par- ticle physics models. Specifically the implications of the relatively high Higgs mass for the discovery of supersymmetry are discussed. Several related topics such as naturalness and supersymmetry, dark matter and unification are also discussed.

关键词： 125 GeV Higgs supersymmetry (SUSY) dark matter unification

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Propagation of a strong cylindrical shock wave in a rotational axisymmetric dusty gas with exponentially varying density

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Research in Astronomy and Astrophysics 2010年第5期10卷 445-460页

作者： Gorakh nath Department of Mathematics National Institute of Technology Raipur G. E. Road Raipur-492010 India

Non-similarity solutions are obtained for one-dimensional isothermal and adiabatic flow behind strong cylindrical shock wave propagation in a rotational ax-isymmetric dusty gas, which has a variable azimuthal and axial fluid velocity. The dusty gas is assumed to be a mixture of small solid particles and perfect gas. The equi-librium flow conditions are assumed to be maintained, and the density of the mixture is assumed to be varying and obeying an exponential law. The fluid velocities in the ambient medium are assumed to obey exponential laws. The shock wave moves with variable velocity. The effects of variation of the mass concentration of solid particles in the mixture, and the ratio of the density of solid particles to the initial density of the gas on the flow variables in the region behind the shock are investigated at given times. Also, a comparison between the solutions in the cases of isothermal and adia-batic flows is made.

关键词： shock wave — equation of state — stars: rotation — radiative transfer — interplanetary medium

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Efficient contraflow algorithms for quickest evacuation planning

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Science China Mathematics 2018年第11期61卷 2079-2100页

作者： Urmila Pyakurel Hari Nandan nath Tanka nath Dhamala Central Department of Mathematics Tribhuvan University Department of Mathematics Bhaktapur Multiple Campus Tribhuvan University

The optimization models and algorithms with their implementations on flow over time problems have been an emerging field of research because of largely increasing human-created and natural disasters *** an optimal use of transportation network to shift affected people and normalize the disastrous situation as quickly and efficiently as possible,contraflow configuration is one of the highly applicable operations research(OR)*** increases the outbound road capacities by reversing the direction of arcs towards the safe destinations that not only minimize the congestion and increase the flow but also decrease the evacuation time *** this paper,we sketch the state of quickest flow solutions and solve the quickest contraflow problem with constant transit times on arcs proving that the problem can be solved in strongly polynomial time O(nm^2(long n)~2)where n and m are number of nodes and number of arcs,respectively in the *** contraflow solution has the same computational time bound as that of the best min-cost flow ***,we also introduce the contraflow approach with load dependent transit times on arcs and present an efficient algorithm to solve the quickest contraflow problem *** the claim,our computational experiments on Kathmandu road network and on randomly generated instances perform very well matching the theoretical *** a sufficiently large number of evacuees,about double flow can be shifted with the same evacuation time and about half time is sufficient to push the given flow value with contraflow reconfiguration.

关键词： evacuation planning contraflow flow over time quickest flow load dependent transit time

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Development and experimental investigation of duplex turning process

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Advances in Manufacturing 2017年第2期5卷 149-157页

作者： Ravindra nath Yadav Department of Mechanical Engineering BBD National Institute of Technology and Management Lucknow 226028India

The aim of the present study was to develop a novel turning process with the simultaneous application of two cutting tools in place of a single cutting tool during machining of rotating surfaces. This process is referred to as duplex turning, and is used to eliminate the need for a secondary final cut operation following the turning process. To achieve this, a secondary （auxiliary） tool post is mounted on the cross slide of the centre lathe machine after fabrication. The secondary tool post is used to hold a secondary cutting tool that penetrates the workpiece from opposite side of the primary cutting tool to perform the finish cut operation during turn machining of the cylin- drical workpiece. The performance of the developed process was tested on AISI 1040 alloy steel, using two single point cutting tools made of high speed steel. The effects of cutting velocity, feed rate, primary depth of cut and secondary depth of cut were analyzed and discussed with regard to average surface roughness, and were also compared with normal turning process. From the results, it was concluded that duplex turning process was capable of providing better surface finishes compared to those generated by normal turning. It was also found that higher cutting velocity yielded better surface finishes within the determined ranges of the selected parameters.

关键词： Cutting Design of experiment Machining Surface roughness Turning

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Investigating the Dominant Source for the Generation of Gravity Waves during Indian Summer Monsoon Using Ground-based Measurements

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Advances in Atmospheric Sciences 2013年第1期30卷 153-166页

作者： Debashis nath 陈文 Center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of Sciences

Over the tropics, convection, wind shear （i.e., vertical and horizontal shear of wind and/or geostrophic adjustment comprising spontaneous imbalance in jet streams） and topography are the major sources for the generation of gravity waves. During the summer monsoon season （June August） over the Indian subcontinent, convection and wind shear coexist. To determine the dominant source of gravity waves during monsoon season, an experiment was conducted using mesosphere-stratosphere-troposphere （MST） radar situated at Gadanki （13.5°N, 79.2°E）, a tropical observatory in the southern part of the Indian subcontinent. MST radar was operated continuously for 72 h to capture high-frequency gravity waves. During this time, a radiosonde was released every 6 h in addition to the regular launch （once daily to study low-frequency gravity waves） throughout the season. These two data sets were utilized effectively to characterize the jet stream and the associated gravity waves. Data available from collocated instruments along with satellite-based brightness temperature （TBB） data were utilized to characterize the convection in and around Gadanki. Despite the presence of two major sources of gravity wave generation （i.e., convection and wind shear） during the monsoon season, wind shear （both vertical shear and geostrophic adjustment） contributed the most to the generation of gravity waves on various scales.

关键词： convection wind shear gravity waves MST radar radiosonde

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