中国西北干旱区年降雨量的时空变化

通过对中国西部地区６８个站３０年年降雨量的分析，把中国西部划分为６个降雨量性质不相关的区。通过对西北３个区的分析，把年降雨量划分为８种不同的空间分布类型。分析表明，控制中国西北干旱区的天气系统主要为西风系统。在过去的３０年间，西北干旱区的气候并非都是变得越来越干，不同的地区变化情况不同。     

春季一次特殊的暴雨天气过程分析

对2000年春季一次高空槽快速移动影响的暴雨天气过程发生的特殊性进行分析,寻找这次暴雨过程发生的前期特征.     

THE STUDY OF STORM RAINFALL CAUSED BY INTERACTION BETWEEN THE NON-ZONAL HIGH LEVEL JET STREAK AND TYPHOON IN THE DISTANCE

In this paper, statistics were analyzed concerning correlation between the storm rainfall far from typhoon and non-zonal upper-level jet stream. The results show that the jet stream at 200 hPa is constantly SW (90.2 %) during the period in which storm rainfall occurs. Rainfall area lies in the right rear regions of the jet axes. While the storm intensifies, the jet tends to be stronger and turn non-zonal. With the MM4 model, numerical simulation and diagnosis were carried out for Typhoon No.9711 (Winnie) on August 19 to 20, 1997. The distant storm rainfall is tightly correlative to the jet and low-level typhoon trough. The divergence field of jet is related to the v component. The upper level can cause the allobaric wind convergence at low level. This is the result of the form of low-level typhoon trough and the strength of the storm. By scale analysis, it is found that there is a branch of middle scale transverse inverse circulation in the right entrance regions behind the jet below the 300-hPa level, which is very important to the maintenance and strengthening of storm rainfall. This branch of inverse circulation is relative to the reinforcement of jet's non-zonal characteristics. From the field of mesoscale divergence field and non-zonal wind field, we know that the stronger symmetry caused by transverse circulation in the two sides of the jet, rainfall’s feedback and reinforcement of jet’s non-zonal characteristics had lead to positive feedback mechanism that was favorable of storm rainfall’s strengthening.     

一个区域气候模式对ENSO衰减年夏季中国东部降水的模拟

The performance of the Climate version of the Regional Eta-coordinate Model (CREM), a regional climate model developed by State Key Laboratory of Nu- merical modeling for Atmospheric Science and Geophysical Fluid Dynamics/Institute of Atmospheric Physics (LASG/IAP), in simulating rainfall anomalies during the ENSO decaying summers from 1982 to 2002 was evaluated. The added value of rainfall simulation relative to reanalysis data and the sources of model bias were studied. Results showed that the model simulated rainfall anomalies moderately well. The model did well at capturing the above-normal rainfall along the Yangtze River valley (YRV) during El Nio decaying summers and the below and above-normal rainfall centers along the YRV and the Huaihe River valley (HRV), respectively, during La Nia decaying summers. These features were not evident in rainfall products derived from the reanalysis, indicating that rainfall simulation did add value. The main limitations of the model were that the simulated rainfall anomalies along the YRV were far stronger and weaker in magnitude than the observations during El Nio decaying summers and La Nia decaying summers, respectively. The stronger magnitude above-normal rainfall during El Nio decaying summers was due to a stronger northward transport of water vapor in the lower troposphere, mostly from moisture advection. An artificial, above-normal rainfall center was seen in the region north to 35°N, which was associated with stronger northward water vapor transport. Both lower tropospheric circulation bias and a wetter model atmosphere contributed to the bias caused by water vapor transport. There was a stronger southward water vapor transport from the southern boundary of the model during La Nia decaying summers;less remaining water vapor caused anomalously weaker rainfall in the model as compared to observations.     

Assimilation of Polarimetric Radar Data Using an Ensemble Kalman Filter for the Analysis and Forecast of Tropical Storm Ewiniar

This study explores the potential for directly assimilating polarimetric radar data (including reflectivity Z and differential reflectivity ZDR) using an ensemble Kalman filter (EnKF) based on the Weather Research and Forecasting (WRF) model to improve analysis and forecast of Tropical Storm Ewiniar (2018). Ewiniar weakened but brought about heavy rainfall over Guangdong, China after its final landfall. Two experiments are performed, one assimilating only Z and the other assimilating both Z and ZDR. Assimilation of ZDR together with Z effectively modifies hydrometeor fields, and improves the intensity, shape and position of rainbands. Forecast of 24-hour extraordinary rainfall ≥250 mm is significantly improved. Improvement can also be seen in the wind fields because of cross-variable covariance. The current study shows the possibility of applying polarimetric radar data to improve forecasting of tropical cyclones, which deserves more researches in the future.     

降雨条件下考虑饱和渗透系数变异性的边坡可靠度分析

土体饱和渗透系数表现为天然的变异性,为此基于Green-Ampt模型建立了考虑饱和渗透系数变异性的降雨入渗物理模型,并藉此模型确定了坡体湿润锋深度和含水率分布。然后结合无限长非饱和土边坡稳定模型得到解析形式的反映边坡稳定性的极限状态函数。采用Monte Carlo法对饱和渗透系数进行随机抽样并最终建立降雨条件下考虑饱和渗透系数变异性的边坡概率分析框架。针对一假想边坡,探讨了饱和渗透系数的变异系数、降雨持时和降雨强度对边坡破坏概率以及破坏发生时间概率分布的影响,结果表明：在降雨初期,边坡的破坏概率随饱和渗透系数变异性的增强而逐渐增加,但随着降雨的持续,破坏概率开始随变异性的增强而显著降低;滑坡最可能发生时间的大小并不受饱和渗透系数变异性的影响,而是直接取决于降雨强度;滑坡最可能发生时间所对应的概率却随变异性的增强而逐渐减小。     

无隔水管泥浆回收钻井技术控制系统功能设计

无隔水管泥浆回收钻井技术（RMR）作为双梯度钻井工艺之一,具有绿色环保、井身结构简易、工程成本低和安全程度高等优点。但是RMR作为新兴钻井工艺,虽然国外应用较为成熟,但国内目前尚无工程应用,缺乏相关使用经验。最关键的是RMR控制系统功能复杂,对可靠性、准确性及灵敏性等要求高,面对复杂工况时,要求控制系统能够及时准确的做出应对处理。因此,为发展国内无隔水管泥浆回收钻井技术（RMR）,拉近甚至超越国外钻井工艺水平,迫切需要对控制系统做出相对完善的设计。本文针对无隔水管泥浆回收钻井过程中的几类典型工况,分析不同工况下控制系统所具备的功能,设计控制功能具体的实现形式。通过对无隔水管泥浆回收钻井技术控制系统的功能设计与实现的研究,以期为今后同类研究提供有益的借鉴。     

地理信息可视化中的二元方法论

作为一种方法论的探索,以二元分析为基本方法,初步探讨和形成了地理信息可视化二元概念模型 ,力求构建一个简单的、易于被人们理解和接受的地理信息可视化理论框架。文章首先从地理学、语言学、哲学等方面阐述了二元方法论的理论基础,然后以符号语言学为范式,从地理信息可视化的所指与能指两个方面展开,阐述地理信息可视化二元方法论的主要内容;最后得出结论。研究表明:①地理信息具有二元性,它包括时间与空间二元 、瞬时与历时二元、空间几何与空间属性二元、定性与定量二元;②地图设计也具有二元性,它们是地图整体样式与个体符号二元、符号外观与内在二元、形状与尺寸二元、色彩与纹理二元。     

工科GIS专业建设若干问题辨析

本文分析了地理信息学科和我国GIS高等教育发展的特点,就工科背景下GIS专业建设的指导思想、专业特色和课程设置等问题进行了分析研究。本文认为:工科GIS专业应在完善地理信息学科建设的基础上,适当开设工科特色课程,优化课程体系及课程内容配置,着重培养学生利用地理空间思维解决工科问题的能力。     

泰州市海陵区城镇地籍调查技术方法探讨

江苏范围内城镇地籍调查工作开展了很多年,取得了大量的地籍调查成果和地籍调查经验。为满足泰州市海陵区土地管理和城市建设的需要,泰州市国土资源局海陵分局区委托作者及其单位实施了海陵区城镇地籍调查,该项目采用综合利用江苏省全球导航卫星连续运行参考站综合服务系统（Jiangsu Continuously Operating Refer-ence Stations,JSCORS）、全球定位系统（Global Positioning System,GPS）以及性能优越的TOPCON免棱镜全站仪,根据测区不同区域的地形地貌特点针对性的进行地籍测量,即好又快的为该项目的顺利完成提供了优良的技术保障。本文通过对泰州市海陵区地籍调查、地籍测量工作方法进行了总结,旨在进一步提高城镇地籍测量的成果质量与工作效率。