两斜交柱坐标系间谐波函数坐标变换的辅助平面方法.   总被引：1，自引：0，他引：1       下载免费PDF全文

马宏伟  陈文化 《地震学报》2011,33(5):683-690

针对利用波函数展开法进行三维地震响应研究中的坐标变换问题,提出了在两斜交柱坐标系间谐波函数空间坐标变换的辅助平面方法．通过建立与空间点对应的一系列辅助平面,将地震波三维散射研究中的谐波函数表达式从柱坐标系变换至辅助平面内的极坐标系,然后在辅助平面内运用Graf加法公式,将柱坐标系下的波函数表达式变换至与该柱坐标系斜交的另一柱坐标系下,从而将三维问题转换成二维问题进行处理,最终得到了斜交柱坐标系下内域问题和外域问题的坐标变换公式．   相似文献   

中尺度对流涡旋(MCV)近30a来的研究进展   总被引：3，自引：3，他引：0  

王金鑫  潘益农  束宇  吴文华 《气象科学》2014,34(3):343-354

中尺度对流涡旋(MCV)是近30 a来中尺度气象学研究的一个热点。经过近30 a的模拟和观测研究,MCV的理论已逐步完善。由于MCV自身的一些特征,MCV可以被看做是联系小尺度的对流活动和大尺度的天气系统的纽带。近十几年来,一些学者已成功地运用MCV来解释有组织的对流活动对热带气旋形成和爆发性温带气旋形成的作用。本文将从多个角度入手,介绍MCV近30 a来的研究进展。  相似文献   

2012年初欧洲严寒天气成因的分析   总被引：1，自引：1，他引：0  

陈雄  李崇银  谭言科  郭文华 《气象科学》2014,34(2):213-221

2012年初欧洲遭受了严重的低温严寒天气。分析表明:从对流层低层到高层持续的大气环流异常与此次严寒天气有着密切的联系,1、2月出现的北极涛动(AO)的强负异常是造成此次欧洲严寒天气的主要原因。AO负异常导致北大西洋副高异常偏强、偏东和偏北,使得暖湿空气沿副高北侧流向北极地区,极大减弱了欧洲暖湿空气的来源;同时使乌拉尔山高压强度偏强,位置偏西偏北,有利于上游偏强、偏北的大西洋副高的维持,并加强了极区冷空气南下西进,造成了南欧地区的严寒天气。AO负异常引起的地中海低压槽的加深,为北方冷空气的南下创造了有利条件,也使冷暖空气在地中海北岸交汇,从而导致亚平宁半岛和巴尔干半岛的暴雪天气。虽然La Nia事件对这次严寒天气也有一定的贡献,但AO负异常对这次严寒天气的作用远远大于La Nia事件的作用。  相似文献   

香港特区土地续期规定的经验借鉴     

郭文华 《国土资源情报》2014,(5):24-26

香港特区土地批租期满,但契约规定可续期的土地,续期内仅需缴纳象征性的少量定额租金。这对我国住宅用地70年到期后如何续期及续期内如何缴纳费用有一定借鉴意义。  相似文献   

国际上房地产税收制度的特征分析     

郭文华  曹庭语  陈静 《国土资源情报》2014,(7):26-31

本文主要分析了欧美、日韩、新加坡、中国香港和中国台湾等市场经济国家或地区的房地产税收制度,总结其在房地产税制设计、税基评估、税率确定、税收征管等方面的通行做法和特征,意在为我国房地产税收制度改革提供一定的借鉴和参考作用。  相似文献   

Forest ecosystem services and their values in Beijing   总被引：5，自引：3，他引：2  

Gaodi Xie  Wenhua Li  Yu Xiao  Biao Zhang  Chunxia Lu  Kai An  Jixing Wang  Kang Xu  Jinzeng Wang 《中国地理科学(英文版)》2010,20(1):51-58

As the most important ecosystem in Beijing, the forest supports a lot of ecosystem services to local and around communities, which plays a key role in the maintenance of urban ecological security.However, the valuation on the forest ecosystem services based on regional scale could not provide precise and reasonable values for forestry sector management.In this study, we estimated the magnitudes and economic values of the forest ecosystem services in Beijing at sublot level.The economic value of forest ecosystem services in Beijing was estimated to be 19 339.71×10 6 yuan(RMB) in 2004.Among all the ecosystem services indicators we estimated in this study, only fruit, timber and part of the recreation(which only include the tourism income from the forest parks and scenic areas, but not include that from other forest types) were measured in the social economic system.As estimated in this study, more than 82.19% of the economic value of forest ecosystem services could not be measured in the socio-economic statistical system.The importance of forest ecosystem services in Beijing to human welfare was underestimated by the socio-economic system.Therefore, the policies about the eco-compensation of forest ecosystem services should be established to maintain the sustainable supply of the forest ecosystem services in Beijing.  相似文献   

基于InVEST模型的西苕溪流域产水量分析(英文)   总被引：6，自引：1，他引：5  

张灿强  李文华  张彪  刘某承 《资源与生态学报(英文版)》2012,3(1):50-54

流域产水量的计算与分析对水资源的规划、管理以及水库建设具有重要意义。本研究将InVEST中的产水量模型应用于西苕溪小流域。该模型的数据需求主要包括土地利用/覆被,年均降雨量和潜在蒸发散,土壤深度,植被可利用水量。为验证模型的精确度,利用基期的降水径流关系,得到2003-2007年的平均自然径流量。经过反复校验,当Z系数为6.5时,产水量为8.3亿m3,与自然径流量最为接近,从流域产水量的分布来看,南部和西南部地区单位面积的产水量较高。  相似文献   

Intelligent optimization algorithms to VDA of models with on/off parameterizations     

方昌銮  郑琴  吴文华  戴毅 《大气科学进展》2009,26(6):1181-1197

Some variational data assimilation (VDA) problems of time- and space-discrete models with on/off parameterizations can be regarded as non-smooth optimization problems. Same as the sub-gradient type method, intelligent optimization algorithms, which are widely used in engineering optimization, can also be adopted in VDA in virtue of their no requirement of cost functions gradient (or sub-gradient) and their capability of global convergence. Two typical intelligent optimization algorithms, genetic algorithm (GA) and particle swarm optimization (PSO), are introduced to VDA of modified Lorenz equations with on-off parameterizations, then two VDA schemes are proposed, that is, GA based VDA (GA-VDA) and PSO based VDA (PSO-VDA). After revealing the advantage of GA and PSO over conventional adjoint methods in the ability of global searching at the existence of cost functions discontinuity induced by on-off switches, sensitivities of GA-VDA and PSO-VDA to population size, observational noise, model error and observational density are detailedly analyzed. Its shown that, in the context of modified Lorenz equations, with proper population size, GA-VDA and PSO-VDA can effectively estimate the global optimal solution, while PSO-VDA consumes much less computational time than GA-VDA with the same population size, and requires a much lower population size with nearly the same results, both methods are not very sensitive to observation noise and model error, while PSO-VDA shows a better performance with observational noise than GA-VDA. It is encouraging that both methods are not sensitive to observational density, especially PSO-VDA, using which almost the same perfect assimilation results can be obtained with comparatively sparse observations.  相似文献   

用物候与温度的相关性指导水稻生产     

郑新峰  姜文华 《黑龙江气象》2009,26(1)

通过多年对物候现象的观测,利用850农场科研站水稻多年分期播种及不同插秧期的试验资料,分析出最佳插秧期的温度指标,用物候现象与温度指标的相关性,指导水稻播种、插秧的最佳时间及最佳收获期,从而获得水稻的高产稳产.  相似文献   

Effects of Traditional Ecological Knowledge on the Drought- resistant Mechanisms of the Hani Rice Terraces System     

LI Jing  JIAO Wenjun  MIN Qingwen  LI Wenhua 《资源与生态学报(英文版)》2016,7(3):211-217

The Hani Rice Terraces System is one of the Globally Important Agricultural Heritage Systems (GIAHS) sites which can successfully resist extreme droughts. The reason is not only that the forests and terraces have the important function of water conservation, which provide and conserve adequate water resources for this complex ecosystem, but also that Hani traditional ecological knowledge plays an important role in the drought-resistance process. In this paper, drought-resistant mechanisms of the Hani Rice Terraces System have been analyzed first, then Hani traditional ecological knowledge has been analyzed based on a comprehensive literature review, a questionnaire survey and key informant interviews. The results show that the Hani nationality has developed knowledge of water management techniques, including water conserving construction, water allocation and ditch management. The Hani people are also highly conscious of water resources protection. There is a good deal of forest resource management knowledge and worship of forests, which have effectively helped in protecting the forest ecological system. In the reclamation and maintenance of Hani terraced fields, the Hani people have developed a series of farming systems, which have effectively protected the terrace ecosystem. Through analyzing this knowledge of water management, forest resource management and Hani terraced fields management, our paper confirms the important role that traditional ecological knowledge plays in maintaining stability of the system and realizing the efficient use of water resource. This is not only helpful for preserving cultural heritage, but is vital for protecting the Hani Rice Terraces System as a whole.  相似文献