胶东半岛海岸带土地利用变化及其水文效应--以夹河流域为例

在归纳和总结国内外关于土地利用和土地覆被变化(LUCC)及其水文效应研究大量文献的基础上，以胶东半岛海岸带的夹河流域为案例，利用1979、1990、2000和2009年四个时相的遥感影像信息进行分类，得到土地利用分布数据，对夹河流域土地利用分布与变化、土地利用变化驱动力、土地利用变化的模拟、预测及其水文效应等问题等进行了较为系统的研究。研究表明：夹河流域的土地利用以耕地、林地和草地为主；土地利用分布受高程、坡度、到河流距离、到居民点距离和政策等因素的影响显著，而且自1979年以来，流域内土地利用发生了很大的变化，最显著的特点是受人口增长、经济发展和城市化的影响，城镇、农村居民点以及独立工矿等建设用地的面积大幅增加。应用LTM模型和CA-Markov模型对夹河流域土地利用变化进行模拟、预测，并分析和比较两个模型的特征与精度水平，结果表明：CA-Markov模型的原理与技术均较明确，模拟精度整体较高；LTM模型的灵活性、可扩展性和可探索性较强，但模拟精度受驱动力选择、数据制备方法等因素的影响，因而案例区模拟结果的精度略低。基于N-SPECT水文分析模型，利用土壤分布数据、多时相土地利用数据和过去10年（2000~2009年）的年降水数据，以年径流量指标为代表，对土地利用变化的水文效应进行模拟及未来情景分析，结果表明，未来20年夹河流域土地利用变化具有促使流域年径流量及河口入海通量持续增加的趋势。通过研究认为，为服务于海岸带区域可持续发展的框架目标，宜于强化流域综合管理和海岸带综合管理的集成与衔接，科学规划、合理配置夹河流域土地资源的结构特征和空间布局，促进经济、社会和生态环境的协调发展。

TPDS-2000测试图形开发系统

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

抗辐射2000门阵列的设计及实现

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

Spatio-temporal changes in annual accumulated temperature in China and the effects on cropping systems, 1980s to 2000

Change in thermal conditions can substantially affect crop growth, cropping systems, agricultural production and land use. In the present study, we used annual accumulated temperatures > 10 degrees C (AAT10) as an indicator to investigate the spatio-temporal changes in thermal conditions across China from the late 1980s to 2000, with a spatial resolution of 1 x 1 km. We also investigated the effects of the spatio-temporal changes on cultivated land use and cropping systems. We found that AAT10 has increased on a national scale since the late 1980s, Particularly, 3.16 x 10(5) km(2) of land moved from the spring wheat zone (AAT10: 1600 to 3400 degrees C) to the winter wheat zone (AAT10: 3400 to 4500 degrees C). Changes in thermal conditions had large influences on cultivated land area and cropping systems. The areas of cultivated land have increased in regions with increasing AAT10, and the cropping rotation index has increased since the late 1980s. Single cropping was replaced by 3 crops in 2 years in many regions, and areas of winter wheat cultivation were shifted northward in some areas, such as in the eastern Inner Mongolia Autonomous Region and in western Liaoning and Jilin Provinces.