北冰洋海冰/气候系统及其对全球气候的影响

结合前人对北冰洋海冰、气候系统的研究成果和 1 999年 8月在北冰洋对海冰的现场观测 ,本文综述了海冰分布、厚度的变化 ,海冰表面特征、积雪变化及北冰洋天气、气候特征和分区。讨论了北极海冰与南极海冰的差异。文章认为 ,北冰洋与周围地区气候变化趋势的不一致 ,主要是由于夏季在北冰洋海冰与开阔水域的相间分布、海冰漂移、融化吸热 ,均衡了周围大气、海洋温度的变化。     

A Method of Analysing Stream Channel Response to Environmental Change: Gauge data for the Tully River

Gauging data are available from numerous streams throughout Australia, and these data provide a basis for historical analysis of geomorphic change in stream channels in response to both natural phenomena and human activities. We present a simple method for analysis of these data, and a brief case study of an application to channel change in the Tully River, in the humid tropics of north Queensland. The analysis suggests that this channel has narrowed and deepened, rather than aggraded: channel aggradation was expected, given the intensification of land use in the catchment, upstream of the gauging station. Limitations of the method relate to the time periods over which stream gauging occurred; the spatial patterns of stream gauging sites; the quality and consistency of data collection; and the availability of concurrent land-use histories on which to base the interpretation of the channel changes.     

邢台地震前地壳形变异常的可能性物理机制

将地壳介质视为麦克斯威尔体 ,运用差分法和三维有限元方法 ,探讨了邢台分层地壳结构模型 （含高速体和低速体及深大断裂 ）中深部断裂加速蠕滑时 ,平均应力、水平最大剪应力和地表面垂直位移随时间演化的特征 ,计算结果表明 :（1 ）在地壳中上部 1 1km处 ,深部断裂的加速蠕滑急剧加速了水平最大剪应力的增加速率 ,可达数百倍 ,深部断裂的加速蠕滑是邢台强地震成核过程的开始 ,可实现地壳下部的能量向地壳中上部快速转移 ;（2 ）深部断裂的加速蠕滑引起的地面垂直位移变化与邢台地震震前的地表面垂直位移变化非常一致 .说明邢台地震震前地壳表面垂直方向的位移不仅与岩石的膨胀有关 ,而且可能与地壳内深部断裂的加速蠕滑密切相关 .     

地震前油井动态变化机理的初步探讨

根据理想的水平层状含油层模型,分析研究了地震前油井动态变化的机理,认为由于地壳应力应变的作用,使得含油层内的孔隙流体压力发生变化,当应娄增大时,孔隙流体压力也随之增大,进而引起油井的产液量和产气量发生变化。     

砒砂岩区沟边线变迁遥感调查及影响因素分析

纳林川布尔洞流域位于黄河中游砒砂岩分布区,由于砒砂岩抗侵蚀能力差,而且当地夏季降雨集中,导致砒砂岩发生严重的水土流失,侵蚀沟边线持续不断地后退.本文运用高分辨遥感及GIS方法对当地砒砂岩侵蚀沟边线的蚀退距离进行了计算,并对蚀退影响因素进行了综合分析.     

基于多波段统计检验的土地利用变化检测

在将历史土地利用矢量图与新时期遥感影像结合研究的基础上,提出多波段统计检验差异法进行土地利用变化检测,有效避免了传统方法中阈值的不确定性.在黑龙江省佳木斯市开展的试验及精度分析表明,本方法可以在无人工干预的情况下较好地检测出土地利用变化,总体检测精度达到86.2%.     

应用遥感技术开展土地动态监测方法评述与定量评价研究

基于土地动态监测理论在国内外发展情况,文章具体分析了动态监测的几种常用方法原理,并汇总各种方法的优缺点,在理论分析基础上,给出了基于图斑的变化监测精度定量评价方法。在比较了几种方法的应用特点后,指出在土地利用中遥感动态监测需要注意的问题。     

Assessment of changes in urban green spaces of Mashad city using satellite data

Green spaces play important functions in urban environments. Reducing air pollution, providing shade and habitat for arboreal birds, producing oxygen, providing shelter against winds, recreational and aesthetic qualities and architectural applications are the main functions of urban green spaces. With the rapid change of urban area in Mashad city during the past decades, green spaces have been fragmented and dispersed causing impairment and dysfunction of these important urban elements. The objective of this study was to detect changes in extent and pattern of green areas of Mashad city and to analyze the results in terms of landscape ecology principles and functioning of the green spaces. In this research, we classified a Landsat TM and an IRS LISS-III image belonging to the years 1987 and 2006, respectively. We then used a post-classification comparison to determine the changes in green space areas of Mashad city during the 19 years covered by the images. Then, we applied landscape ecology calculations to derive metrics that quantified pattern of the changes in the green areas. The results showed that during 19 years from 1987, a significant decrease had occurred in the extent of urban green spaces with a concomitant fragmentation resulting in downgrading and destruction of the functions and services these areas provide. We conclude that the general quality of life in the central parts of the city has been diminished. We also state that a combination of remote sensing image classification, landscape metrics assessment and vegetation indices can provide a tool for assessing life quality and its trend for urban areas.     

中国近50年气温及降水量的变化趋势分析

通过对我同385个站的观测资料序列进行分析研究,得到我国气候变化的一些特征。近25年全国平均温度有明显的上升趋势,只有极少数测站有明显的降温趋势,华北及东北的广大地区是增温最快、范围最大的地区。全国平均降水量没有明显的变化趋势。逐站分析降水量的年际变化后发现,我国降水量的变化存在着明显的区域特征,新疆地区足降水量增加最快的地区;华中华北地区的降水则存在明显的减少趋势;这两个地区的、平均降水量都与全球海表温度距平有很好的相关性。文中还利用同期大气再分析资料(NCEP／NCAR)尝试分析了气候变化与大气环流特征的关系。     

濮阳市近40年气候变化及未来趋势

利用濮阳1961－1999年的气象资料，分析了濮阳气候变化趋势，结果表明，39年来，气温增高，降水减少，雷暴，大风，日照等天气要素指数均呈负上升状态。从39年的气候变化趋势可以看出，未来干旱有可能成为濮阳比较突出的气候问题，气候异常极端事件也可能会较多地出现，上述气候变化与城市建设的一定关系。