China＇s Land Carrying Capacity Based on Man-grain Relationships

With population growth and increasing pressure on land resources, land carrying capacity （LCC） and food safety have been attracting great attention worldwide. From the point of man-grain relationship and by establishing LCC and land carrying capacity index （LCCI） models, this article firstly analyzes the spatial-temporal dynamics of LCC of China from 1949 to 2005 at county, provincial and national levels. Choosing 2005 as a representative year, this article then evaluates the LCC of 264 pastoral regions （semipastoral regions）, 663 urban regions and 592 poverty stricken regions of the country. The results show that： （1） from 1949 to 2005, with the increase of grain production, the LCC of China has been improved conspicuously, but due to the rapid population growth, the production can only maintain a low level grain consumption; （2） over the past 25 years （1980-2005）, the number of population overloading provinces decreased from 23 to 15 and the mangrain relationship has been improved gradually, but there were more overloading provinces than surplus provinces in China; （3） at county level, there were 1572 overloading counties in 1980 accounting for 68.26% of the total counties of the country and where were 649 million people lived, while in 1990, 2000 and 2005, the number of overloading counties were 1066, 1133 and 1087 respectively, which shows that the man-grain relationship has been improved obviously during the past 25 years; as for spatial distribution, the surplus counties were mainly concentrated in agriculture developed regions, such as Northeast Plain, North China Plain, middle and lower Reaches of the Yangtze River Plain, and overloading counties were mainly located in regions with poor natural environment and low grain production capacity, such as Northwest China, Tibetan Plateau and Loess Plateau and economically developed urban regions, such as Beijing, Tianjin and Shanghai; （4） animal husbandry improved greatly the LCC of pastoral and semi-pastoral regions, while urban regions were overloading for increasing population pressure and more than half of poverty stricken regions were overloading due to critical natural environment and poor economic conditions.     

1998年我国主要气象灾害综述

１９９８ 年, 我国气象灾害频繁, 洪涝、干旱、风雹、台风、低温冷冻及雪灾等不同程度发生, 特别是暴雨洪涝灾害尤为严重, 损失巨大。本文就上述几种主要气象灾害的发生特点和影响进行了分析和评述     

现代遥感技术在我国西部开发中的应用前景

西部开发是我国当前的热点所在。开发西部，不仅要借助国家政策的优惠和外来投资的倾斜，更重要的是要充分利用自身丰富的资源走自我发展的道路。因此，引入新的技术辅助西部开发，促使西部开发走上生态循环的道路，才是我们真正的目的。文章介绍了遥感作为新兴的信息技术手段在西部开发中的应用前景，以期能对地方决策部门提供参考。     

水分快速分析仪测定城市污泥的含水率

污泥含水率是污水处理、污泥处理及污泥处置利用等环节的重要评估指标。本研究采用快速测定法对不同类型城市污泥含水率进行测定,考察了污泥含水率、质量、颗粒度对测定结果影响,并与国标重量法进行比较。结果表明：污泥质量对快速法测定结果影响较小,原始污泥测定结果标准偏差在0.01%~0.05%之间,常规脱水污泥和生物沥浸脱水污泥测定结果标准偏差均为0.03%;相比国标法,脱水污泥含水率越低,快速法测定结果误差越大,常规脱水污泥和生物沥浸脱水污泥测定结果相对误差分别为-2.09%和-3.49%;脱水污泥颗粒度越大,快速法测定结果偏差越大,常规脱水污泥和生物沥浸脱水污泥总体样本标准偏差分别为0.43%和1.25%。另外发现,在相同干化条件下,生物沥浸脱水污泥相对于常规脱水污泥有较快的水分蒸发速度。针对城市污泥,为缩短测定时间和提高工作效率,待测污泥优选质量≤4 g和颗粒度≤3 mm,且建议只在生产运行中使用,室内科研实验优选国标法。     

DROUGH TREND IN NORTH CHINA IN RECENT FIFTY YEARS

Inrecentseveralyears ,abnormaldroughtoccursinthepartnorthernofChina .Itex ertssomeinfluenceonChina’snationaleconomyandhasarousedwideattentionfromallwalksoflife .Muchresearchindrought wetindexhasbeendonebothathomeandabroad .Theresultcanbeclassifiedintotwocategories:first,droughtindexdirectlyisdefinedbyprecipitationorothermeteorologicalfactors;second ,droughtindexisidentifiedbycalculatinggainingandlos ingoflocalwaterinaccordancewithequationofwaterbalance ,andsomealsoconsidertheim pactofdrought…     

中国台风灾害及其影响的研究

中国是世界上受热带气旋影响最严重的国家之一。本文对影响和登陆中国的热带气旋活动的特征、台风灾害特点及其形成规律作了分析，并讨论了台风灾害对中国社会和经济发展的影响。分析结果指出，影响中国的台风灾害具有发生频率高、突发性强、群发性显著、影响范围广、成灾强度大等特点，这类灾害主要由台风带来的狂风、暴雨、风暴潮及其引发的灾害链所造成。台风灾害不仅造成大批人员伤亡，而且对中国各个经济部门都有严重影响，它所     

Pros and cons of climate change in China

Climate change strongly affected the structure and functions of natural ecosystems,e.g.the vegetation productivity decreased in the Northeast permafrost region due to the higher temperature and less precipitation,whereas in the Tibetan Plateau,the vegetation productivity increased,owing to the improved thermal resource.Climate change led to reduced precipitation in North and Northeast China and thus the reduced surface runoff.The public needs for energy were changed because of climate change,e.g.the shorter heating period in winter.Climate change profoundly influenced human health,pathophoresis and major projects by increasing extreme events,including frequency and magnitude,and causing more serious water shortage.Under the background of climate change,although the improved thermal resources can be helpful for extending the crop growth period,more extreme events may resulted in more instability in agricultural productivity.Not only did climate change indirectly affect the secondary and tertiary industries through the impacts on agriculture and natural resources,but also climate change mitigation measures,such as carbon tax,tariff and trading,had extensive and profound influences on the socioeconomic system.Further analysis indicated that the impact of climate change presented significant regional differences.The impact had its pros and cons,while the advantages outweighed the disadvantages.Based on the above analysis on the impacts of climate change,we put forward suggestions on coping with climate change.First,scientifically dealing with climate change will need to seek advantages while avoiding the disadvantages of climate change in order to achieve the orderly adaptation to climate change,which is characterized with"Overall best,long-term benefit."Second,quantitative adaptation should be given more attention,e.g.proposing operational schemes and predictable goals and using uncertainty analysis on adaptation measures.Third,more active coping strategy should be adopted to enhance China's future comprehensive competitiveness.The strategies include but are not limited to gradually adjusting the industrial structure,intensifying the research and development(RD)of emission reduction technology and actively responding to the influence of carbon tax,tariff and trading on socioeconomic development in China.     

GIS在西部生态环境建设中的应用

GIS与西部生态环境建设的有机结合将是一项长期的、复杂的系统工程。在严格论证了该项目实施的可行性之后，在可持续发展理论的指导下，运用空间分析方法，提出了项目的实施方案。在该方案中，对生态环境信息数据进行了分类，详述了空间数据文件存贮结构，查询管理子系统的开发，最后得出生态环境地理信息系统的总体结构，并简述了其功能。     

华北地区主要农业灾害及灾情分析

本文分析了华北地区农业灾害发生的气象背景,并利用1981～1990年的农业统计资料分析了华北地区的农业灾情状况及因灾而造成的粮、棉损失量。华北地区单位耕地面积的受灾率及成灾率分别为47.3%和23.0%,大致相当于二年一遇灾和四年一成灾。华北地区因农业灾害而造成的粮、棉损失量平均每年为397.0和34.5万吨,粮、棉损失率分别为4.9%及15.3%。     

中国1990—1996年冰雹灾害及其时空动态分析

依据《中国减灾》公布的１９９０－１９９６年月灾情信息,建立了冰雹灾害数据库,在此基础上,划分了中国冰雹灾害的组合类型,并绘制出了冰雹灾害的空分布图和时间变化图。