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change of surface cover greenness in china between 2000 and 2010

Chinese s.ience Bulletin 2012年第22期57卷 2835-2845页

作者： LIU shuang1,4& GONG Peng1,2,31state Key Laboratory of Remote sensing s.ience, Jointly sponsored by institute of Remote sensing Applications of Chinese Academy of s.iences,and beijing Normal university, beijing 100101, china 2ins.itute for global change studies & center for earth system s.ience, tsinghua university, beijing 100084, china 3Department of Environmental s.ience, Policy and Management, university of California, Berkeley, CA94720, UsA 4Graduate university of Chinese Academy of s.iences, beijing 100049, china state Key Laboratory of Remote sensing s.ience Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing China Graduate university of Chinese Academy of s.iences Beijing China institute for global change studies & center for earth system s.ience Tsinghua University Beijing China Department of Environmental s.ience Policy and Management University of California Berkeley USA

surface greenness reflects the situation of vegetation *** index calculated from the Red and Near Infrared bands of remote sensing images,whose values indicate the level of photosynthetic activity,is monotonically related to surface greenness when vegetation canopy does not fully cover the background *** for desert regions,vegetation index is positively correlated with vegetation ***,vegetation index can be used to study the change in greenness of desert *** study collected MODIs Normalized Difference Vegetation Index (NDVI) data from 2000 to 2010 and analyzed their change over china in this *** results showed that an increasing trend of NDVI occurred over 66.84% (OLs fitting) or 64.27% (LAD fitting) of china,indicating that china's greenness is increasing ***,desertification of china *** showing large increase in greenness are found in shaanxi,shanxi,Ningxia,Henan,shandong,Qinghai,and Gansu while regions with large decrease in greenness are found in Northeast Inner Mongolia,south Tibet,Jiangsu,and *** of Qinghai,Gansu,Xinjiang and south Tibet could probably be driven by climate *** of greenness in Northeast Inner Mongolia was related to agricultural *** of greenness in Jiangsu and shanghai was related to rapid *** factors did not exhibit obvious correspondence to the large increase in greenness in shaanxi,shanxi,Ningxia and Gansu,indicating that the changes might have been caused by human *** reduction of desert areas in china could probably have been caused by human management and protection at the national scale.

关键词：中国地表覆盖归一化植被指数植被覆盖度沙漠地区 NDVI 西藏南部气候因素

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Maximum Wind speeds changes over china

Maximum Wind Speeds Changes over China

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第28届中国气象学会年会

作者： JIANG Ying1,LUO Yong2,3,ZHAO Zongci2,3 1 Public Weather service center of CMA,beijing 100081,china 2 center for earth system s.ience of tsinghua university,beijing,100084,china 3 National Climate center of china,beijing,100081

An intensive analysis is undertaken for the characteristics of maximum wind speed（WsMax） change for 1956-2004 across china based on the observed station data,with further study of the changes of WsMax for 2046-2065 and 2080-2099 as projected by three global climate models（GFDLM2,CCCMAGCM3 and MRIGCM2） and their ensembles which proposed in the IPCC Fourth Assessment Report（AR4） . It is found that the observed annual and seasonal WsMax and the number of gale days show obviously the declining trends. The annual WsMax and the gale days reduced by about-1.46 m/s per decade and-3.0 days per decade during the study period 1956-2004,respectively. The amplitudes of annual and seasonal WsMax decreases were bigger than that of annual and seasonal average wind speeds（WsAvg） . Under the weakening of both East Asian winter and summer monsoons,the distinct decreases of WsMax associated with the weakening of cold wave in china and the decreasing number（weakening intensity） of landing typhoons in the northwestern Pacific Ocean. The global climate models GFDLM2,MRIGCM2 and EBGCM（the ensemble of GFDLM2,MRIGCM2 and CCCMAGCM3） areto project consistently that the annual and seasonal WsMax reduce during 2046-2065 and 2080-2099 to compare with 1981-2000,i.e. the WsMax for 2046-2065 decreases by-3.0m/s relative to 1981-2000. It is also noticed that the WsMax decreases during 2046-2065 and 2080-2099 have a good relationship with both the cold wave weakening as corresponding to the winter monsoon weakening and the decreasing numbers of tropical cyclones over the northwestern Pacific Ocean in the summer of the 21st century.

关键词： maximum wind speed,change,projection,china

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Orbit determination and prediction accuracy analysis for a regional tracking network

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s.ience china(Physics,Mechanics & Astronomy) 2010年第6期53卷 1130-1138页

作者： ZHOU shanshi 1,2,3 ,HU XiaoGong 1 & WU Bin 1 1 shanghai Astronomical Observatory,Chinese Academy of s.iences,shanghai 200030,china 2 Graduate university of Chinese Academy of s.iences,beijing 100049,china 3 Research center of GNss,Wuhan 430079,china shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai China Graduate university of Chinese Academy of s.iences Beijing China Research center of GNss Wuhan China

china's COMPAss satellite navigation system relies on a regional tracking network to provide navigation services. Limited by its geographic border,the regional network is able to cover only 30% of the medium-earth-orbits(MEO). Accuracy of determined and predicted orbits is not able to satisfy system requirements if the tracking data processing strategy for global tracking network processing is used for the regional network. Two major error sources for orbital prediction are accuracy of initial orbital elements and dynamical modeling. To achieve better prediction accuracy,we propose a two-step orbit determination and prediction strategy. For step 1,only solar radiation pressure(sRP) parameters are estimated along with the orbital elements and other parameters; for step 2,all parameters are estimated but the sRP parameters are tightly constrained to their step 1 estimates. Experimenting with data from a regional GPs network,we conclude for orbital prediction using the proposed two-step strategy,the average user range error(URE) for 24-h prediction arcs is better than 0.6 m.

关键词： orbit determination and prediction regional tracking network URE

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Dynamical diagnosis of the breakup of the stratospheric polar vortex in the Northern Hemisphere

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s.ience china earth s.iences 2007年第9期50卷 1369-1379页

作者： WEI Ke1,2, CHEN Wen1 & HUANG RongHui1 1 center for Monsoon system Research, institute of Atmospheric Physics, Chinese Academy of s.iences, beijing 100080, china 2 Graduate university of the Chinese Academy of s.iences, beijing 100049, china center for Monsoon system Research Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100080 China Graduate university of the Chinese Academy of s.iences Beijing 100049 China center for Monsoon system Research Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100080 China

The research on climate change in polar regions, especially on the role of polar in the global climate system, has gain unprecedented level of interest. It has been the key scientific issue of the International Polar Year program (IPY, 2007—2008). In this paper, we dealt with the debate upon the breakup time of the stratospheric polar vortex in boreal spring. An observational study of the relation between stratospheric polar vortex breakup and the extra-tropical circulation was performed. The mean breakup date—when the winter westerly at the core of polar jet turns to summer easterly—is about April 10. The breakup time has large interannual variation with a time span of about 2 months. It also has a long-term trend with the 1990s and 2000s witnessing more and more late breakups of polar vortex. Composite of wind speed at the core of polar jet for the extremely early and late breakup years shows that late years have two periods of westerly weakening while early breakup years have only one. The flrst weakening in the late years happens in middle January with wind speed dropping sharply from more than 40 m s^(-1) to about 15 m s^(-1). This is accompanied with anomalous activities of planetary waves in both stratosphere and troposphere; while the second weakening in the late breaking years is mainly the results of diabatic heating with very weak wave activities. In early breakup years, the transition from westerly to easterly is rapid with wind speed dropping from more than 30 m s^(-1) to less than -10 m s^(-1) within a month. This evolution is associated with a strong bidirectional dynamical coupling of the stratosphere and troposphere. The circulation anomalies at low troposphere are also analyzed in the extremely early and late breakup years. It shows that there are significant differences between the two kinds of extreme years in the geopotential height and temperature composite analysis, indicating the dynamical coupling of stratosphere and troposphere with the evo

关键词： stratospheric polar vortex, wave-flow interaction, diabatic heating, final breakup, stratosphere-troposphere coupling

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Relationship and its instability of ENsO--Chinese variations in droughts and wet spells

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s.ience china earth s.iences 2007年第1期50卷 145-152页

作者： sU MingFeng1,2 & WANG HuiJun1 1 Nansen-Zhu International Research center, institute of Atmospheric Physics, Chinese Academy of s.iences, beijing 100029, china 2 Graduate university of Chinese Academy of s.iences, beijing 100039, china Nansen-Zhu International Research center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate university of Chinese Academy of s.iences Beijing 100039 China Nansen-Zhu International Research center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

Monthly data of self-Calibrated Palmer Drought severity Index (PDsI) from 1951 to 2000 are calculated using historical precipitation and temperature data for Chinese 160 stations. Temporal and spatial pat-terns of the first empirical orthogonal function (EOF) of the PDsI reveals a fairly linear trend resulting from trends in precipitation and surface temperature, which is similar to the linear PDsI trend during 1951―2000 calculated using all monthly data. The EOF analysis also reveals that the leading mode correlates significantly with ENsO events in time and space. The ENsO EOF shows that during the typical warm phase of ENsO, surface conditions are drier in most regions of china, especially North china, but wetter than normal in the southern regions of Changjiang River, and Northwest china. During the typical cold phase of ENsO, these anomalies reverse sign. From 1951 to 2000, there are large multi-year to decadal variations in droughts and wet spells over china, which are all closely related to strong El Nio events. In other words, when one strong El Nio event happens, there is a possible big variability in droughts and wet spells over china on the multi-year or decadal scale. studies also sug-gest that during the last 2―3 decades climate changes over china, especially North china's drying and northwest china's wetting, are closely related to the shift in ENsO towards warmer events and global warming since the late 1970s. The instability of the relationship is also studied. It is revealed that there is a good correlation between ENsO and Chinese variations in droughts and wet spells in the 3―8-year band, but the correlation between ENsO and Chinese variations in droughts and wet spells is instable. studies suggest that there are decadal changes in the correlation: the wavelet coherency between ENsO and Chinese variations in droughts and wet spells is high during 1951―1962 and 1976―1991, but low during 1963―1975 and 1992―2000.

关键词： PDsI variations droughts and wet spells ENsO instability.

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The relationship between spatial extent and duration of severe droughts in china over the last 50 years

The relationship between spatial extent and duration of seve...

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2010 second IITA International Conference on Geos.ience and Remote sensing (IITA-GRs 2010)

作者： ZHANG Da-quan College of Atmospheric s.iences Lanzhou university Lanzhou china 730000FENG Guo-lin Laboratory for Climate studies National Climate center china Meteorological Administration beijing china 100081

Correlation between spatial extent and duration of severe droughts process and its statistical law is analyzed using Palmer Drought severity Index （PDsI） through a newly developed system of drought process monitoring. Results indicate that during the period from late 1990s to early 2000s,the percentage of severe drought （PDsI＜-3.0） in china is unprecedented since 1960 under the background of global warming and the variation of the distributions of droughts coverage areas in different seasons is uneven. The distribution of spatial extent and durations of severe droughts follows a power-law,e.g. the spatial-temporal characteristics of severe droughts is independent to their scaling,namely,being scale free. In general the area of severe droughts is correlated closely with its duration,while the deviations of the linear fit from its correlation is also high.

关键词： drought duration distribution power-law

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Dependence of magnetic field just inside the magnetopause on subsolar standoff distance:global MHD results

Dependence of magnetic field just inside the magnetopause on...

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第十四届全国日地空间物理学术研讨会

作者： Wang Ming1,2 Lu JianYong1,2 Liu ZiQian3 Pei shiXin1 (1 College of Math & Physics, Nanjing university of Information s.ience & Technology, Nanjing 210044, china ) (2 National center for space Weather, china Meteorology Administration, beijing 100081, china ) (3 Chinese Academy of Meteorological s.ience, Graduate university of Chinese Academy of s.ience, beijing 100081, china )

The subsolar magnetopause is the boundary of solar wind and the earth’s magnetosphere where reduced solar wind dynamic pressure is equal to the magnetic pressure of the earth’s outer magnetosphere. We use a global MHD model to estimate the ratio （f） of the compressed magnetic field just inside the subsolar magnetopause to the purely dipolar magnetic field. We also compared our numerical results with a similar work by shue with the THEMIs data. Our results show that the ratio f is linearly proportional to the subsolar magnetopause standoff distance （r0） for both northward and southward interplanetary magnetic field, which in property is consistent with shue’s result but the proportionality constant is smaller, although previous theoretical studies show that the ratio f is nearly independent of the subsolar standoff distance. The global model results also show that the ratio f is smaller for the southward IMF under the same r0 and the proportionality constant for the southward IMF is larger than that for the northward IMF. Both conclusions agree with statistical results from observations by shue.

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基于Lorenz模型的集合预报与单一预报的比较研究

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物理学报 2018年第7期67卷 60-68页

作者：梁丁顾斌丁瑞强李建平钟权加南京信息工程大学空间天气研究所南京210044 中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室北京100029 南京信息工程大学物理与光电工程学院南京210044 北京师范大学全球变化与地球系统科学研究院北京100875

根据非线性局部Lyapunov向量方法和增长模繁殖方法,选取Lorenz63模型和Lorenz96模型的不同状态为例,对集合预报与单一预报的预报技巧开展了对比研究.结果表明:与单一预报比较,集合预报的均方根误差和型异常相关有明显改善,随预报时间推... 详细信息

根据非线性局部Lyapunov向量方法和增长模繁殖方法,选取Lorenz63模型和Lorenz96模型的不同状态为例,对集合预报与单一预报的预报技巧开展了对比研究.结果表明:与单一预报比较,集合预报的均方根误差和型异常相关有明显改善,随预报时间推移,改善效果越显著,且集合平均优于单一预报的实验个例数逐渐增多.就概率分布(f)而言,单一预报状态的f与真实状态基本一致,不随时间变化;而集合平均预报状态的f则随时间呈现出值域变窄、峰值变大的特点.表明随预报时间的延长,单一预报状态为混沌吸引子上的随机状态,而集合平均预报状态为吸引子子集上的随机状态,这可能是集合平均误差小于单一预报的原因.

关键词：非线性局部Lyapunov向量集合预报单一预报 Lorenz模型

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钢铁产业链全球物质流网络分析

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中国矿业 2018年第5期27卷 61-65,71页

作者：钟维琼代涛李丹中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室北京100037 中国地质科学院全球矿产资源战略研究中心北京100037 中国地质大学(北京)地球科学与资源学院北京100083

在经济全球化的背景下,一个国家的钢铁产业链并不是一个封闭的系统,其中的每一个环节都通过国际贸易进行内部系统与外部系统之间的物质交流,本文通过构建产业链关键环节的全球铁元素物质流复杂网络模型,分析了钢铁产业链不同环节的网络... 详细信息

在经济全球化的背景下,一个国家的钢铁产业链并不是一个封闭的系统,其中的每一个环节都通过国际贸易进行内部系统与外部系统之间的物质交流,本文通过构建产业链关键环节的全球铁元素物质流复杂网络模型,分析了钢铁产业链不同环节的网络整体特征,以及国家的进出口总量和国家在网络中对资源流动的控制力。主要结论有:铁矿石环节的全球贸易物质量最大,网络密度最小,国家之间联系最不紧密,集团性最不明显,全球化程度最低,其贸易量主要集中于少数国家和少数贸易关系;钢铁制品环节的全球贸易网络规模最大,国家数和贸易关系数都最多,国家之间的贸易紧密度最高,全球化程度最高;废料环节的全球贸易网络分化最明显,表现出了较强的贸易集团性;中国在铁矿石、生铁、粗钢和废料环节的贸易网络中的控制力都较高,但在钢材和钢铁制品网络中的控制力不高。

关键词：钢铁产业国际贸易物质流分析产业链

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北京东灵山树线处土壤细菌的PICRUst基因预测分析

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生态学报 2018年第6期38卷 2180-2186页

作者：厉桂香马克明中国科学院生态环境研究中心城市与区域生态国家重点实验室北京100085 中国科学院大学北京100049

树线变动会对生物多样性分布以及生态系统功能的维持造成深远影响,研究树线处土壤微生物群落及其功能,对预测高海拔生态系统响应气候变化具有重要价值。采用Mi seq高通量测序技术及PICRUst基因预测分析方法,对北京东灵山辽东栎林及树线... 详细信息

树线变动会对生物多样性分布以及生态系统功能的维持造成深远影响,研究树线处土壤微生物群落及其功能,对预测高海拔生态系统响应气候变化具有重要价值。采用Mi seq高通量测序技术及PICRUst基因预测分析方法,对北京东灵山辽东栎林及树线之上亚高山草甸的土壤细菌群落及功能进行对比研究,结果表明:土壤细菌物种多样性在树线处没有发生显著的变化,沿海拔也没有呈现出明显趋势,但细菌群落结构以及预测功能基因均发生了变化。在39个二级预测功能分类中有10个子功能的相对多度在森林和草甸中具有明显差异。其中,其他次生产物代谢的生物合成、转录、多糖生物合成和代谢、酶家族、信号分子及交互作用、环境适应、细胞生长和死亡等的功能基因在森林中明显高于草甸中;而维他命及辅因子代谢、膜运输、内分泌系统等的功能基因在草甸中偏高。

关键词：土壤微生物树线海拔功能基因

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