Spatial patterns of terrestrial net ecosystem productivity in China during 1981–2000   总被引：1，自引：0，他引：1  

Tao Bo  Cao MingKui  Li KeRang  Gu FengXue  Ji JinJun  Huang Mei  Zhang LeiMing 《中国科学D辑(英文版)》2007,50(5):745-753

As the third largest country in the world, China has highly variable environmental condition and ecological pattern in both space and time. Quantification of the spatial-temporal pattern and dynamic of terrestrial ecosystem carbon cycle in China is of great significance to regional and global carbon budget. In this study, we used a high-resolution climate database and an improved ecosystem process-based model to quantify spatio-temporal pattern and dynamic of net ecosystem productivity (NEP) in China and its responses to climate change during 1981 to 2000. The results showed that NEP increased from north to south and from northeast to southwest. Positive NEP (carbon sinks) occurred in the west of Southwest China, southeastern Tibet, Sanjiang Plain, Da Hinggan Mountains and the mid-west of North China. Negative NEP (carbon sources) were mainly found in Central China, the south of Southwest China, the north of Xinjiang, west and north of Inner Mongolia, and parts of North China. From the 1980s to 1990s, the increasing trend of NEP occurred in the middle of Northeast China Plain and the Loess Plateau and decreasing trends mainly occurred in a greater part of Central China. In the study period, natural forests had minimal carbon uptake, while grassland and shrublands accounted for nearly three fourths of the total carbon terrestrial uptakes in China during 1981–2000. Supported by the Ministry of Science and Technology of China (G2002CB412507), the Major Program of the National Natural Science Foundation of China (Grant No.30590384), the “Hundred Talent” Program of the Chinese Academy of Sciences, and K C WONE Education Foundation  相似文献   

中国大陆黑碳气溶胶排放清单   总被引：1，自引：0，他引：1  

曹国良  张小曳  王亚强  Che Huizheng  Chen Dong 《气候变化研究进展》2007,3(Z1):75-81

The detailed high-resolution emission inventory of black carbon (BC) from China in the year 2000 was calculated. The latest fuel consumption data including fossil and biomass fuels, and socio-economic statistics used were obtained from government agencies, mostly at the county level, and some new emission factors (Efs) from local measurements were also used. National and regional summaries of emissions were presented at 0.2°×0.2°resolution. Total BC emission was 1499.4 Gg in 2000, mainly due to the burning of coal and biomass. The BC emission estimated here is higher than those in previous studies, mainly because the emissions from coal burning by rural industries and residences were previously underestimated. More BC aerosols were emitted from eastern China than western China. A strong seasonal dependence was observed for BC emissions, with peaks in January and December and low emissions in July and August; and this seasonality is mainly due to patterns in residential heating and the open burning of crop residues.  相似文献   

上海区域要素客观预报方法效果检验   总被引：5，自引：0，他引：5  

漆梁波  曹晓岗  夏立  陈春红  梁旭东 《气象》2007,33(9):9-18

数值模式的客观释用是数值模式在业务工作中发挥效能的重要环节。在对上海区域数值模式近5年的模式直接输出(DMO)进行检验的基础上,分别采用卡尔曼滤波释用(KLM)和最优化集成释用(OCF)的方法进行要素客观释用,总结出区域数值模式的预报性能,客观释用也取得令人鼓舞的结果:(1)近几年,上海区域数值模式的直接输出结果(DMO)对温度、湿度以及风向的预报改善不明显,甚至还有变差现象,风速的预报自2005年起有改善,但主要体现在预报的稳定性方面。(2)KLM方法较DMO在温度、相对湿度和风速的预报上均有明显提高,但是风向的预报无明显提高,预报准确率甚至略有下降。(3)OCF方法的预报性能较KLM方法略有提高。温度、相对湿度以及风向的预报准确率提高约2%,风速预报与KLM方法相当。在春季和冬季,OCF的预报水平已经与主观综合预报相当,如果主观综合预报能充分参考OCF的预报结果,主观综合预报"春季和冬季预报误差相对偏大"这一弱点能得到改善。检验结果能为数值模式的开发和调试者提供有益的参考,而最优化集成方法的成功业务尝试也佐证了集成预报在数值模式客观释用中的美好前景。  相似文献   

Mn content of reservoir calcite cement: A novel inorganic geotracer of secondary petroleum migration in the tectonically complex Junggar Basin (NW China)   总被引：1，自引：0，他引：1  

Cao Jian  Hu WenXuan  Yao SuPing  Zhang YiJie  Wang XuLong  Zhang YueQian  Tang Yong  Shi XinPu 《中国科学D辑(英文版)》2007,50(12):1796-1809

Electronic probe microanalysis(EPMA) results of reservoir calcite cement from fourteen core samples in the Junggar Basin show that Mn-content varies largely between different samples from below the detect limitation to 4.14%,while it displays a generally good correlation with oil-gas shows.This,therefore,likely indicates that concentration of the Mn-content of the calcite cement has a close rela-tion to the intensity of petroleum fluid charging during hydrocarbon secondary migration.In order to assess this hypothesis,oxygen and strontium isotopic measurements on sixteen calcite veins host in source sequences were carried out to investigate the feature of the oil-source petroleum fluid.Analytical results imply that during hydrocarbon generation and migration,deep hot fluid has dissolved volcanic minerals interlined between mudstone source rocks.As Mn is a kind of typical trace element enriched in volcanic rocks,it is reasonable to conclude that the petroleum fluid formed in the source sequences would be Mn-rich.Consequently,calcite cements precipitated from such Mn-rich petroleum fluid would be Mn-rich accordingly.Due to the geologic chromatographic effect during migration along reservoir rocks,the decreasing of the Mn-content of the reservoir calcite cements indicates the migration direction.Then,this novel geotracer was further successfully applied in the study of hydrocarbon migration in the Junggar Basin in combination with organic geochemical analyses during the hydrocarbon migration.The Mn content of the reservoir calcite cement appears promising as a novel inorganic geotracer for the petroleum migration.This paper represents a search for novel indicators of secondary petroleum migration in tectonically complex basins based on fundamentals of the reservoir fluid-rock interactions.  相似文献   

自动气象站维护及操作技巧   总被引：1，自引：0，他引：1  

栾永卫  曹兴锋 《山东气象》2007,27(4):51-52

对自动气象站软件、硬件及网络通信三个方面的主要故障现象进行了总结,介绍了使用维护注意事项和技巧,提出了故障排除方法。  相似文献   

交互式数据语言在气象数据可视化中的应用          下载免费PDF全文

曾财兴  曹长尧 《气象科技》2007,35(B12):65-66,94

科学计算可视化是20世纪80年代后期随着计算机图形学应用的拓广而发展起来的一个新的研究分支，受其推动，数字信息的可视化成为20世纪90年代研究的前缘。随着“数字地球”、“数字城市”、“数字油田”等概念的提出，气象工作者迫切需要更加精确地了解各种气象数据和地形实体。而对于这些复杂的数据资料，目前人们已不能满足于等线图那样的平面描述，更需要建立三维图像，用更接近实际的方式去描述它，从各个不同角度观察它，三维可视化就是实现以上目标的有效手段。实体三维可视化技术是描绘和理解三维实体的一种重要计算机技术，它可以帮助使用者快速、准确理解和描述三维实体，并能协助快速选定感兴趣的目标，为分析、理解数据提供了有利工具。  相似文献   

雨涝灾害对舞钢市棉花生产的影响     

付世权  曹春田  臧学斌  朱柳松  王俊香  王丽英  王梅香 《河南气象》2007,(Z1)

通过田间调查,对2004-2006年棉花不同阶段雨涝情况对棉花生育及产量构成的影响进行了比较分析,并提出了相应的抗灾减灾对策。  相似文献   

GPS精密单点定位(静态)影响收敛速度的因素分析     

曹相  高成发 《现代测绘》2007,30(1):19-21

GPS精密单点定位是最近几年发展起来的一项GPS定位新技术,是目前GPS界研究的热点之一.本文简要介绍了GPS精密单点定位的原理,通过对实验数据的处理,计算出利用IGS分析中心提供的五种精密星历和卫星钟差进行单点定位所能达到的精度,又较为详细的分析了影响收敛速度的因素,得出COD的定位精度是最高的,其收敛速度也是最快的,另外减小对流层延迟和GDOP大小对提高收敛速度也是有效的方法.  相似文献   

Validating the Runoff from the PRECIS Model Using a Large-Scale Routing Model   总被引：4，自引：0，他引：4  

曹丽娟  董文杰  许吟隆  张勇 《大气科学进展》2007,24(5):855-862

The streamflow over the Yellow River basin is simulated using the PRECIS （Providing REgional Climates for Impacts Studies） regional climate model driven by 15-year （1979-1993） ECMWF reanalysis data as the initial and lateral boundary conditions and an off-line large-scale routing model （LRM）. The LRM uses physical catchment and river channel information and allows streamflow to be predicted for large continental rivers with a 1°×1° spatial resolution. The results show that the PRECIS model can reproduce the general southeast to northwest gradient distribution of the precipitation over the Yellow River basin, The PRECIS- LRM model combination has the capability to simulate the seasonal and annual streamflow over the Yellow River basin. The simulated streamflow is generally coincident with the naturalized streamflow both in timing and in magnitude.  相似文献   

Carbon isotopic composition of modern soil and paleosol as a response to vegetation change on the Chinese Loess Plateau   总被引：7，自引：0，他引：7  

LIU Weiguo  NING Youfeng  AN Zhisheng  WU Zhenghai  LU Huayu & CAO Yunning State Key Laboratory of Loess  Quaternary Geology  IEE  Chinese Academy of Sciences  Xi''''an  China Northwest Sci-Tech University of Agriculture  Forest  Yangling  China 《中国科学D辑(英文版)》2005,48(1):93-99

The relationship between the carbon isotopic composition of paleosols and pale-ovegetation on the Loess Plateau is still unclear. One of the main reasons is that we are short of knowledge about the characteristics of the carbon isotopic composition of modern soil in this area. A preliminary investigation of the carbon isotopic compositions of the modern soil and the loess/paleosol sequence on the Loess Plateau shows that the carbon isotopic composition of modern soil is consistent with the distribution of modern plants on the Loess Plateau, where the ecosystem is dominated by a mixture of C4 and C3 plants. Comparing the δ13C values of modern soil and loess-paleosol sequences from the Xunyi profile, we conclude that C3 plants dominated the landscape during loess sediment stages, while C4 plants expanded during paleosol stages.  相似文献