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Three-year changes of surface albedo of degraded grassland and cropland surfaces in a semiarid area

Chinese Science Bulletin 2008年第8期53卷 1246-1254页

作者： LIU HuiZhi1↑, TU Gang2,3.& DONG WenJie4 1 State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chi- nese Academy of Sciences, beijing 100029, china 2 Laboratory of Research for Middle-High Latitude Circulation System and East Asia Monsoon, china {3. administration, Changchun 13.062, china 3.Institute of {3. Science of Jilin Province, Changchun 13.062, china 4 National Climate Center, beijing 100081, china State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Laboratory of Research for Middle-High Latitude Circulation System and East Asia Monsoon China Meteorological Administration Changchun China Institute of meteorological Science of Jilin Province Changchun China National Climate Center Beijing China

Diurnal, seasonal and interannual variations of surface albedo of degraded grassland and cropland surfaces at a semiarid area of Tognyu have been investigated based on the continuous three years observational data from 2003.to 2005. The changes of surface albedo with solar elevation angle and soil moisture have been discussed also. It has been found that surface albedo has almost the same diurnal and seasonal variations on degraded grassland and cropland surfaces in the semiarid area, while sur- face albedo is large in winter and small in summer. The diurnal variation of the surface albedo has re- lationship with the weather condition. The diurnal cycle of the surface albedo likes the "U" shape curve in sunny day, while it is low-high after the rain, and high-low after the snow. The surface albedo has large variation in cloudy day, while it has no any variation in overcast day. The large difference of the surface albedo can be 0.04 in winter between two land surfaces, because the snow has large effects on the surface albedo in winter. The rainfall is an important factor in summer on the surface albedo, while the difference of the surface albedo is 0.01 only between two land surfaces. The differences of the surface albedo can also be 0.04 in autumn due to vegetation growing. The seasonal-average surface albeo from 2003.2005 is 0.25, 0.22, 0.24, 0.3. respectively in spring, summer, autumn and winter on the degraded grassland surface,while it is 0.25, 0.21, 0.22, 0.3. respectively in spring, summer, autumn and winter on the cropland surface. The surface albedo becomes smaller with the increase of solar elevation angle. When the solar elevation angle is greater than 40°, the surface albedo changes very little and tends to be a constant. The surface albedo has negative exponent functions with soil moisture in the growing season.

关键词：半干旱地区表面反照率土壤湿度草地退化

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Numerical simulation of topography effects on the “00.7” severe rainfall in beijing

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Progress in Natural Science:Materials International 2005年第9期15卷 818-826页

作者： ZHANG Chaolin1**, JI Chongping1, KUO Yinghwa2, FAN Shuiyong1, XUAN Chunyi3.and CHEN Min1(1. Institute of Urban Meteorology, china meteorological administration, {3. 100089, china 2. Mesoscale and Microscale Meteorology Division, National Center for Atmospheric Research, Boulder, CO 803.7-3.00, USA 3. {3. meteorological Bureau, {3. 100089, china) Institute of Urban Meteorology China Meteorological Administration Beijing 100089 China Mesoscale and Microscale Meteorology Division National Center for Atmospheric Research Boulder CO 80307-3000 United States beijing meteorological Bureau Beijing 100089 China

In an effort to study the severe rainfall event of 4—5th July 2000 in beijing (with 24h accumulated precipitation of 240 mm), we perform numerical simulations to investigate this event using the MM5v3.6 model. The model is initialized with the MM5/WRF 3.VAR analysis, which incorporates the ground-based GPS precipitable water vapor, automatic and conventional meteorological observations in its assimilation step. For 24 h accumulated precipitation forecast, the threat scores are 0.72, 0.76, 0.67 and 0.63. for thresholds of 1, 5, 10, and 20 mm, respectively. Holding other factors unchanged, sensitivity experiments were conducted with different topographic resolutions of 110, 50 and 3.7 km to investigate the topographic effects on precipitation over the beijing area. In these sensitivity experiments, we attempt to preserve the realistic orographic distribution in the model topography under the condition of keeping the dynamic-thermodynamic consistency of the initial model atmosphere to the extent possible. Results indicate that the unique topographic distribution and variations in the beijing area play an important role in determining the location, distribution and intensity of heavy precipitation.

关键词： topography heavy rainfall 3.VAR ground-based GPS numerical simulation.

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Evaluation of a 3.VAR system for the South china Sea

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Progress in Natural Science:Materials International 2008年第5期18卷 547-554页

作者： Xianjun Xiao a,b, Dongxiao Wang a, Changxiang Yan c, Jiang Zhu c a LED, South china Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 5103.1, china b NCC, china {3. administration, beijing 100081, china c Institute of Atmospheric Physics, Chinese Academy of Sciences, beijing 100029, china LED South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou 510301 China NCC China Meteorological Administration Beijing 100081 China Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The authors evaluate a three-dimensional variational (3.VAR) system for the South china Sea (SCS) in this study. The assimilation method applied in the system takes into consideration error correlation along each ground track and uses recursive lter for optimiza- tion. Data from three R/V cruises during the spring and summer of 1998 and the summer of 2000 are used to evaluate the system. The root-mean-square error and bias are reduced signi cantly and when the altimeter data are assimilated, the distribution of the error is much closer to the Gaussian distribution. Precipitation and river discharge in the southwestern SCS are reproduced, and the variability of sea surface height is e ciently transferred to the subsurface. The 3.VAR system performs well for each of the three cruises, suggesting that it is steady for routine usage.

关键词： South china Sea Three-dimensional variational data assimilation Recursive lter

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Thermal Activation Analyses of Dynamic FractureToughness of High Strength Low Alloy Steels

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Journal of Materials Science & Technology 2001年第2期17卷 215-218页

作者： Cunjian LI and Shaohua LI Welding Research Department, Central Iron & Steel Research Institute, beijing 100081, china Yuqing DENG State administration of Metallurgical Industry, {3. 100711, china Dept. of Welding Res. Central Iron and Steel Res. Inst. Beijing 100081 China

A formula is derived for determining the influence of temperature and loading rate on dynamic fracture toughness of a high strength low alloy steel (HQ785C) from thermal activation analysis of the experimental results of three-point bend specimens as well as introducing an Arrhenius formula. It is shown that the results obtained by the given formula are in good agreement with the experimental ones in the thermal activation region. The present method is also valuable to describe the relationship between dynamic fracture toughness and temperature and loading rate of other high strength low alloy steels.

关键词： test GB Thermal Activation Analyses of Dynamic FractureToughness of High Strength Low Alloy Steels

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Three-dimensional decomposition method of global atmospheric circulation

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Science china Earth Sciences 2008年第3期51卷 386-402页

作者： LIU HaiTao1,2,3. HU ShuJuan4, XU Ming5 & CHOU JiFan6,7 1 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, beijing 100029, china 2 Graduate University of Chinese Academy of Sciences, beijing 100049, china 3.beijing Climate Center, beijing 100089, china 4 Department of Mathematics, Lanzhou University, Lanzhou 73.000, china 5 Shanghai Typhoon Institute, Shanghai 20003., china 6 Department of Atmospheric Sciences, Lanzhou University, Lanzhou 73.000, china 7 china meteorological administration {13. Center, beijing 100089, china State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Graduate University of Chinese Academy of Sciences Beijing China beijing Climate Center Beijing China Department of Mathematics Lanzhou University Lanzhou China Shanghai Typhoon Institute Shanghai China Department of Atmospheric Sciences Lanzhou University Lanzhou China china meteorological administration {3. Center Beijing China

By adopting the idea of three-dimensional Walker, Hadley and Rossby stream functions, the global atmospheric circulation can be considered as the sum of three stream functions from a global per- spective. Therefore, a mathematical model of three-dimensional decomposition of global atmospheric circulation is proposed and the existence and uniqueness of the model are proved. Besides, the model includes a numerical method leading to no truncation error in the discrete three-dimensional grid points. Results also show that the three-dimensional stream functions exist and are unique for a given velocity field. The mathematical model shows the generalized form of three-dimensional stream func- tions equal to the velocity field in representing the features of atmospheric motion. Besides, the vertical velocity calculated through the model can represent the main characteristics of the vertical motion. In sum, the three-dimensional decomposition of atmospheric circulation is convenient for the further in- vestigation of the features of global atmospheric motions.

关键词： three-dimensional decomposition of the global atmospheric circulation generalized Walker Hadley and Rossby stream functions existence and uniqueness vertical motion

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Progress and review of the studies on the end-Triassic mass extinction event

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Science china Earth Sciences 2005年第12期48卷 2049-2060页

作者： DENG Shenghui1,2, LU Yuanzheng1,2,3.& XU Daoyi4 1. Research Institute of Petroleum Exploration and Development, beijing 100083. china 2. Key Laboratory of Oil and Gas Reservoir of Petrochina, beijing 100083. china 3. china University of Geosciences, beijing 100083. china 4. Institute of Geology, china Earthquake administration, beijing 100029, china Research Institute of Petroleum Exploration and Development Beijing China Key Laboratory of Oil and Gas Reservoir of Petrochina Beijing China china University of Geosciences Beijing China Institute of Geology China Earthquake Administration Beijing China

The mass extinction at the end-Triassic is one of the five biggest in the Phanerozoic. However,it is the least well understood among these five events, and only till last decade it became a great academic interesting subject to geologists. The evidences for this event come obviously from bivalves, brachiopods, ammonites, corals, radiolaria, ostracods and foraminifera of marine habitats, and plants and tetrapods of terrestrial realm. By contrast, for some of other groups, such as marine gastropods and marine vertebrates, no mass extinction has been recog-nized yet. The extinction event is strongly marked at specific level but shown a complicated situa-tion at generic and family levels. Dramatic changing of the environment, such as the temperature raise due to the greenhouse effect, the marine anoxic habitats caused by a sudden transgression after the regression at the end of Triassic, has been claimed to be the main cause of the extinction. Many hypotheses have been suggested to demonstrate the mechanisms of the environment changing, among which two popular ones are the bolide impact and volcanic eruption. The Triassic-Jurassic (Tr-J) boundary mass extinction event is still poorly understood because no enough data have been obtained from the Tr-J boundary successional sections of both marine and terrestrial sediments, and most of these studies were regionally restricted. The basic aspects of the event and its associated environmental conditions remain poorly characterized and the causal mechanism or mechanisms are equivocal. Some authors even doubt its occurrence. china has many successionally developed terrestrial and marine Tr-J sections. Detailed studies of these sections may be important and significant for well understanding of the event.

关键词： progress, review, end-Triassic, mass extinction, mechanism, Tr-J boundary.

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Climate change tendency and grassland vegetation response during the growth season in Three-River Source Region

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Science china Earth Sciences 2010年第10期53卷 1506-1512页

作者： QIAN Shuan1,FU Yang2 & PAN FeiFei3.1 National meteorological Center,beijing 100081,{3. 2 Qinghai meteorological Research Institute,Xining 810001,{3. 3.Department of Geography,University of North Texas,Denton,TX 76203.USA National meteorological Center Beijing China Qinghai meteorological Research Institute Xining China Department of Geography University of North Texas Denton USA

Climate change,climate suitablity change for grassland vegetation,and grassland response to climate change during the growth season are studied systematically by using meteorological data of temperature,precipitation,and length of sunlight from 1961 to 2007,NOAA/AVHRR NDVI from 1982 to 2006,and observations of grass height,biomass,and coverage in enclosed grassland from 1994 to *** models are developed to evaluate climate change and the climatic suitability of grassland vegetation *** temperature,accumulative precipitation,and length of sunlight during the growth season increased from 1961 to 2007 at rates of 0.24°C/10 yr,2.3. mm/10 yr,and 2.81 h/10 yr,*** increase rates of ave-rage temperature between April and May,and between June and August are 0.17 and 0.3.°C/10 yr;accumulative rainfall between April and May increased at a rate of 2.80 mm/10 yr,and accumulative rainfall between June and August decreased at a rate of 0.3. mm/10 yr;the increase rates of accumulative length of sunlight between April and May,and between June and August are 2.15 and 1.2 h/10 *** climatic suitability of grassland vegetation growth showed an increasing trend,and the increase rate between April and May is greater than that between June and *** NDVI observations from 1982 to 2006 and measurements of grass height,dry biomass,and coverage from 1994 to 2006 show that the climate change has resulted in an increase in plant productivity of the grassland in Three-River Source *** some protection measures are taken as soon as possible,the deteriorated grassland in Three-River Source Region can recover.

关键词： climate change climate suitability change grassland vegetation Three-River Source Region

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Water-vapor source shift of Xinjiang region during the recent twenty years

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Progress in Natural Science:Materials International 2007年第5期17卷 569-575页

作者： Dai Xingang , Li Weijing , Ma Zhuguo and Wang Ping (Key Laboratory of Regional Climate-Environment for Temperate East Asia, Institute of Atmospheric Physics, Chinese Academy of Sciences, beijing 100029, china Laboratory for Climate Change, Chinese meteorological {3., beijing 100081, china) Key Laboratory of Regional Climate-Environment for Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Laboratory for Climate Change Chinese Meteorological Administration Beijing 100081 China

The aim of this paper is to investigate the climate water-vapor sources of Xinjiang region and their shifts during the past 20 years. First, the principle and steps are roughly regulated to seek the water-vapor sources. Second, the climate stationary water-vapor transport in troposphere is calculated to distinguish where the water vapor comes from by ERA-40 reanalysis. In addition, the collocation between the transport and the atmospheric column water vapor content is analyzed. The results show that the major vapor comes from the west side of Xinjiang for mid-month of seasons, apart from July while the water vapor comes from the north or northwest direction. The water vapor sources are different for different seasons, for example, the Caspian Sea and Mediterranean are the sources in January and April, the North Atlantic and the Arctic sea in July, and the Black Sea and Caspian Sea in October, respectively. In recent ten years more water vapor above Xinjiang comes from the high latitudes and the Arctic sea with global warming, and less from Mediterranean in comparison with the case of 1973.1986. In fact, the air over subtropics becomes dry and the anomalous water vapor transport direction turns to west or southwest during 1987—2000. By contrast, the air over middle and high latitudes is warmer and wetter than 14 years ago.

关键词： global warming water-vapor source water-vapor transport precipitable water Xinjiang climate inter-decadal change.

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Progress in china’s climate change study in the 20th century

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Journal of Geographical Sciences 2004年第S1期 5-13页

作者： ZHAI Panmao1,2, CHAO Qingchen1,2, ZOU Xukai1,2(1. Laboratory for Climate Studies, china meteorological administration,{3., china 2. National Climate Center, china meteorological administration,{3., china)

Studies on the 20th century climate change in china have revealed that under the background of global warming over the past century, climate in china has also experienced significant change with mean annual temperature increased by about 0.5 oC. More reliable results for the latter part of the 20th century indicate that the largest warming occurred in Northwest china, North china and Northeast china, and the warming in winter is most significant. Although no obvious increase or decrease trends were detected for mean precipitation over china in the past half century, regional differences are very distinct. In the middle and lower reaches of the Yangtze River, precipitation increased, while that in the Yellow River Basin markedly decreased. Studies suggest that climate change in china seems to be related not only with the internal factors such as ENSO, PDO, and the others, but also with the anthropogenic effects such as greenhouse gas emissions, and land use. The future climate change studies in china seem to be important in narrowing understanding the nature of china's climate change and its main causes, since it is significant for projection and for impact assessment of climate change in the future.

关键词： th century climate change china

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Association between ICU quality and in-hospital mortality of V-V ECMO-supported patients—the ECMO quality improvement action(EQIA)study:a national cohort study in china from 2017 to 2019

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Frontiers of Medicine 2024年第2期18卷 315-326页

作者： Wei Cheng Jieqing Chen Xudong Ma Jialu Sun Sifa Gao Ye Wang Longxiang Su Lu Wang Wei Du Huaiwu He Yujie Chen Zunzhu Li Qi Li Jianhua Sun Hongbo Luo Jinbang Liu Guangliang Shan Bing Du Yanhong Guo Dawei Liu Chang Yin Xiang Zhou on behalf of the china National Critical Care Quality Control Center-the ECMO quality improvement action(EQIA)study Department of Critical Care Medicine State Key Laboratory of Complex Severe and Rare DiseasesPeking Union Medical College HospitalChinese Academy of Medical Science and Peking Union Medical CollegeBeijing100730China Information Center Department/Department of Information Management State Key Laboratory of Complex Severe and Rare DiseasesPeking Union Medical College HospitalPeking Union Medical College&Chinese Academy of Medical SciencesBeijing100730China Department of Medical administration National Health Commission of the People’s Republic of ChinaBeijing100044China School of Population Medicine and Public Health Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing100730China Department of Epidemiology and Biostatistics Institute of Basic Medicine SciencesChinese Academy of Medical Sciences(CAMS)&School of Basic MedicinePeking Union Medical CollegeBeijing100730China National Institute of Hospital administration National Health Commission of the People’s Republic of ChinaBeijing100044China 不详

This cohort study was performed to explore the influence of intensive care unit(ICU)quality on in-hospital mortality of veno-venous(V-V)extracorporeal membrane oxygenation(ECMO)-supported patients in *** study involved all V-V ECMO-supported patients in 3.8 of 1700 tertiary hospitals from 2017 to 2019,using data from the National Clinical Improvement System and china National Critical Care Quality Control *** quality was assessed by quality control indicators and capacity *** the 2563.V-V ECMO-supported patients in 3.8 hospitals,a significant correlation was found between ECMO-related complications and *** reintubation rate within 48 hours after extubation and the total ICU mortality rate were independent risk factors for higher in-hospital mortality of V-V ECMO-supported patients(cutoff:1.5%and 7.0%;95%confidence interval:1.05–1.48 and 1.04–1.45;odds ratios:1.25 and 1.23.P=0.012 and P=0.015,respectively).Meanwhile,the V-V ECMO center volume was a protective factor(cutoff of≥50 cases within the 3.year study period;95%confidence interval:0.57–0.83.odds ratio:0.69,P=0.0001).The subgroup analysis of 864 patients in 11 high-volume centers further strengthened these ***,ICU quality may play an important role in improving the prognosis of V-V ECMO-supported patients.

关键词： veno-venous extracorporeal membrane oxygenation in-hospital mortality high-volume centers quality control intensive care unit capacity parameters

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