北极环极边界流研究及其主要科学问题   总被引：8，自引：1，他引：7       下载免费PDF全文

赵进平  史久新 《极地研究》2004,16(3):159-170

北极环极边界流是新近揭示的重要海洋现象 ,是对北冰洋海洋环流长期研究结果综合得到的概念。在本文中 ,详细介绍了北极环极边界流的主要结构和水团特征 ,论述了研究北极环极边界流的意义和前景 ,深入探讨了北极环极边界流面对的科学问题 ,指出了解决这些问题的关键科研工作。文章指出 ,从整体上研究北极环极边界流是非常重要的 ,需要全面考察北冰洋的质量和能量平衡、深层水通风过程以及水体的混合过程。在进一步的研究工作中需要更多的有针对性的现场观测、开展多学科协作研究。数值模拟仍然是北极环极边界流的重要研究手段 ,需要改善数值模式 ,提高数值模拟的质量。  相似文献   

太平洋入流及其与北冰洋异常变化的联系   总被引：13，自引：1，他引：12       下载免费PDF全文

史久新  赵进平  矫玉田  曲平 《极地研究》2004,16(3):253-260

太平洋水通过白令海峡进入北冰洋 ,对北冰洋的海冰、水团和环流产生重要影响。在过去的十几年中 ,北冰洋的海冰和海洋系统发生了前所未有的异常变化 ;与此同时 ,白令海峡太平洋入流水的流量和性质发生了改变 ,太平洋水在北冰洋中的运移路径和影响范围也有所不同 ,这些变化之间的关系有待于进一步的研究。本文综述了有关的研究进展 ,探讨了北冰洋异常变化与太平洋入流变化之间的可能联系。  相似文献   

Robust estimation for correlated observations: two local sensitivity-based downweighting strategies   总被引：1，自引：1，他引：0  

Jianfeng Guo  Jikun Ou  Haitao Wang 《Journal of Geodesy》2010,84(4):243-250

An iterative robust estimation procedure for correlated observations is proposed, in which the a-prior correlation coefficient matrix is not updated to alleviate the computational burden. Selection of the downweighting strategy plays a key role in the proposed method. Two local sensitivity-based strategies, one is based on the uniformly most powerful test statistics, the other is based on the standardized least squares residuals, are developed and analyzed. Monte Carlo simulations in the GPS network adjustment scenario demonstrate that, the two strategies can provide a certain resistance against the deteriorating effect of outlying observations on the parameter estimates; the former downweighting strategy is superior to the latter one, both in terms of robustness and computational efficiency.  相似文献   

基于水稻高光谱遥感数据的PLS波长选择研究   总被引：1，自引：0，他引：1  

宋沙磊  李平湘  龚威  汪金平 《武汉大学学报(信息科学版)》2010,(2)

对武汉地区不同生长状况下的水稻冠层进行了遥感监测,采用偏最小二乘(PLS)分析方法分别对水稻叶面氮含量、叶绿素含量进行了波长选择研究,并通过构建8种波长组合进行PLS水稻叶面氮含量反演分析和比较,选择出最合适的反演波长。多种波长(波段)组合进行叶面氮含量反演的验证表明,采用552 nm、675 nm7、52 nm7、76 nm的4波长组合是最适合叶面氮含量反演的波长选择结果,同时,采用光谱能量空间变换的形式能较好地改善波长选择的反演效果。  相似文献   

贵州喀斯特石漠化防治的国家重点生态功能区生态系统健康度评价     

邓欧  李亦秋  杨广斌  李若霜 《中国岩溶》2020,39(5):689-696

文章以桂黔滇喀斯特石漠化防治的国家重点生态功能区贵州区为研究对象,以2010、2015年遥感影像、基础地理信息、降水、土壤等数据资料为基础,集成3S技术和生态评估模型,对水源涵养、土壤侵蚀和石漠化进行定量和定位研究。结果表明:研究区4个亚区的水源涵养功能等级处于“中”、“高”等水平,2015年比2010年的水源涵养指数有所提高;威宁—赫章区、关岭—镇宁区和册亨—望谟区3个亚区的土壤侵蚀模数较大,水土保持功能等级处于“低”等,罗甸—平塘区的土壤侵蚀模数最低,其水土保持功能等级为“中”等;威宁—赫章区2010年中度以上石漠化比重达16.36%,2015年降为8.74%,生态系统健康度从“低”转为“中”;关岭—镇宁2010年和2015年中度以上石漠化比重分别为8.64%和4.49%,生态系统健康度从“中”转化“高”;册亨—望谟和罗甸—平塘的健康度均为“高”,2015年相比2010年均有所提升;4个亚区的石漠化恶化面积所占比重均不到1.00%,石漠化好转区域分别占27.00%、14.10%、10.24%和5.13%,石漠化得到了有效遏制。今后应继续因地制宜,恢复植被和生态系统,巩固和扩大石漠化防治成果。   相似文献   

Research Progress of Transportation Facilities Construction and Their Impact Assessment in the Qinghai Tibet Plateau     

Yi Miao  Haimeng Liu  Jinping Song  Teqi Dai 《地球科学进展》2020,35(3):308-318

The Qinghai Tibet Plateau (QTP) is an important ecological security barrier region and strategic resource reserve base in China. It is of great significance to explore the construction and impact of its transportation facilities. Through combing the relevant research, we found that: \mathrm{①} With the construction of macro regional policies and major transportation facilities, the relevant research has been growing rapidly since 2000, and the contribution of Chinese Academy of Sciences, transportation universities and research institutions is outstanding; \mathrm{②} The key research of QTP's transportation facilities construction includes the constraints and countermeasures of permafrost melting, sandstorm, erosion and geological disasters, the development process of modern comprehensive transportation system and its spatial characteristics, and the evolution of multi-scale regional traffic connection and accessibility; \mathrm{③} The regional impact assessment of traffic facilities mainly focuses on ecological environment and social economy. The former results are mainly negative effects such as disturbing ecosystem, cutting landscape pattern, destroying vegetation cover and disturbing the normal living habits of wild animals, while the latter ones are mainly positive effects like promoting macro regional development, changing the spatial structure of regional development, and driving the development of tourism and other related industries. In general, the positive and negative effects of multi-dimensional and multi-scale show the characteristics of differentiation and multiple feedbacks. With the implementation of the Second Comprehensive Scientific Investigation on the QTP and the construction of Third Pole National Park Group, Sichuan-Tibet Railway and Qinghai-Tibet Expressway, we should further focus on the breakthroughs in key relevant technologies, the balance of transportation system with national strategies and regional functions, the combination of travel perception and comprehensive traffic accessibility, combing the comprehensive impact mechanism from the perspective of coupling and the construction of analysis framework that is in line with regional reality, etc.  相似文献