日极端气温的主客观预报能力评估及多模式集成网格释用

精细格点天气预报是我国未来几年天气预报业务发展重点。利用ECMWF、GRAPES等业务数值模式和广东站点观测资料,对日极端气温的主客观预报能力进行了多角度综合评估。统计结果表明,T_(max)、T_(min)的主客观预报误差均存在明显季节差异,在系统误差相对平稳的夏半年主观预报具有较明显订正能力,模式预报呈现一定流依赖特征,温度越高(低),负(正)偏差越明显;主客观预报误差空间分布均受地形影响,随着时效延长误差总体增幅不大,主观订正能力也较稳定。根据以上评估特征和网格预报特点,研究开发了一套多模式动态集成网格释用技术方案(McGF)。结果表明,相比单个模式的预报和主观预报,McGF较明显提升了T_(max)的预报技巧;T_(min)的模式预报偏差总体较T_(max)偏小,McGF提升幅度相对较小;网格释用后的广东区域预报能较合理反映气温空间和强度特征,较周边未经释用区域明显更优。     

真空预压法在珠江流域某冲填土场地的应用

依托珠江流域某冲填土场地工程实例,介绍了真空预压法的施工参数及应用效果,另对“薄弱部位”泥浆搅拌桩密封墙处地层的强度进行了定量分析,结果表明真空预压法适用于此类场地,加固效果明显,但密封墙位置强度降幅较大,需采取换填等措施二次处理后才能使用,可为其他类似工程提供参考经验.     

《测量学》教学实习的改革与实践

介绍了９５年至今我们对土建类专业测量教学实习的改革措施和积累的经验,它对相关专业的测量教学实习有一定的参考意义。     

利用GPS水准点精化局部CQG2000

CQG2000模型的精度仍不能满足中、大比例尺的测图需要,如何充分利用现有成果,提高其价值和实用性,是目前需要迫切解决的问题。本文提出了通过加密GPS水准点来提高现有CQG2000精度的方法,并研究了GPS水准点数目和分布对提高结果的影响。     

实验室测绘教学仪器的管理

在分析了当前测绘仪器管理存在问题的基础上，从仪器在实验室的管理体制、模式方面做了有益探讨和分析，提出了测绘仪器实行动态管理和开放使用的模式。     

基于通量均衡基准的地壳垂直形变场逼近的Fourier分析法

本文根据地壳运动的全球通量均衡假说建立了地壳垂直形变场的分析模型,分析了以往作者所研究的球谐函数和球冠谐函数模型的优缺点,着重推导了在密切平面坐标系下该模型的Fourier级数解,该模型一方面可以简单地应用于地壳垂直形变场的逼近,另一方面为采用谱分析法提取地壳垂直形变场信息提供了理论依据。     

多源遥感影像融合最佳波段选择及质量评价研究

本文选用了有蓝色波段和无蓝色波段两种遥感数据源,使用定量指标对各波段进行基本统计及分析,并计算各波段之间的联合熵、协方差、相关系数及最佳指数,确定四类遥感数据各自的最佳波段组合;并采用了几种融合方法将四种影像按照最佳波段组合融合,计算融合后影像与原始影像之间的相关系数,分析得到两类数据的最佳融合方法。     

一种快速地球大气效果3维绘制方法

介绍了地球大气模型,并回顾了国内外大气的3维绘制算法。在此基础上提出了一种基于简化模型的快速大气效果绘制算法。该算法综合利用Billboard与图形学雾化效果,逼真模拟出了地球大气的可视化效果。实验结果表明,该算法简单有效,避免了复杂的物理计算,大大提高了绘制效率。     

Definitions of natural-language spatial relations: Combining topology and directions

Because SQL for querying data from spatial databases is ineffective, the query based on natural or visual language becomes an attractive research field gradually. However, how to define and represent natural languages related to spatial data are still gigantic problems. Because existing models of direction relations can't describe by use of some common concepts. First of all, detailed direction relations are proposed to describe the directions related to the interior of spatial objects, such as “east part of a region”, “east boundary of a region”, and so on. Secondly, by integrating the detailed directions with exterior direction relations and topological relations, several NLSRs are defined, such as “a road goes across the east part of a lake”, “a river goes along the east boundary of a province”, etc. Finally, based on the NLSRs abovementioned, a natural spatial query language (NSQL) is formed to retrieve data from spatial databases.     

Spatial and Temporal Dynamics of Urban Heat Island and Their Relationship with Land Cover Changes in Urbanization Process: A Case Study in Suzhou, China

One of the significant environmental consequences of urbanization is the urban heat island (UHI). In this paper, Landsat TM images of 1986 and 2004 were utilized to study the spatial and temporal variations of heat island and their relationships with land cover changes in Suzhou, a Chinese city which experienced rapid urbanization in past decades. Land cover classifications were derived to quantify urban expansions and brightness temperatures were computed from the TM thermal data to express the urban thermal environment. The spatial distributions of surface temperature indicated that heat islands had been largely broadened and showed good agreements with urban expansion. Temperature statistics of main land cover types showed that built-up and bare land had higher surface temperatures than natural land covers, implying the warming effect caused by the urbanization with natural landscape being replaced by urban areas. In addition, the spatial detail distributions of surface temperature were compared with the distribution of land cover by means of GIS buffer analysis. Results show remarkable show good correspondence between heat island variations with urban area expansions.