GPS折射角资料的变分同化试验

越来越多的新型观测资料为数值天气预报水平的进一步提高提供了许多新的机会。在各种新型的观测资料中,GPS(全球定位卫星系统)折射角资料无疑是非常重要的。GPS折射角资料具有分辨率高、全天候探测、覆盖全球等优点,实现对GPS折射角资料的变分同化,将具有非常重要的意义。文中介绍了如何获得及同化GPS折射角资料的原理。对GPS折射角资料的变分同化可以分为两种:间接同化和直接同化,文中对这两种方法都作了具体介绍。在变分同化的最小化过程中,计算效率无疑是最重要的,而优化步长的计算又直接关系到算法效率的成败。根据最小化算法的特点,通过数学推导,得出一种适合于各种最小化算法的计算优化步长的自适应方法。最后,还利用1995年10月11日的GPS折射角资料进行了数值试验,结果表明了变分同化方法和计算优化步长方法的有效性。     

The Northward Shift of Climatic Belts in China During the Last 50 Years and the Corresponding Seasonal Responses

Along the meridian of 105°E, the Chinese region are divided into two parts, east and west. The results show that in the east part of China the temperate extratropical belt, the warm extratropical belt,and the northern subtropical belt shift northward significantly, whereas the middle subtropical belt and the southern subtropical belt have less or no change. As for the northern subtropical belt, the maximal northward shift can reach 3.7 degrees of latitude. As for the warm extratropical belt, along the meridian of 120°-125°E, the maximal northward shift can reach 3-4 degrees. In the west part of China, each climatic belt changes little. Only in the Xinjiang area are the significant northward shifts. Correspondingly, it is found that in the last 50 years the traditional seasons have changed. For Beijing, Hailar, and Lanzhou, in general, summer becomes longer and winter shorter over the last 50 years. Summer begins early and ends late with respect to early 1950s. Contrary to the summer, winter begins la     

兰州地区深部电性结构的初步研究

利用兰州地区现有的大地电磁资料，对该区的深部电性结构进行了初步研究。结果表明，兰州地区各地质构造单元的电性差异较明显，与区域构造有较好的对应性。     

地震视应力用于震后趋势快速判定的可能性

对多次强震的地震视应力进行了计算，将各次强震的地震视应力的高低与强震发生后的后续地震的强度进行联系，探索它们之间的关系，进而提出将地震视应力用于强震震后趋势预测的可能性。对多次强震的地震视应力与其后续地震强度的关系的分析结果表明，低视应力的强震的后续地震的强度一般较低，即低视应力的强震发生后，震区发生较强的后续地震的可能性较小。     

Characteristics of the atmospheric heat source and moisture sink over the Qinghai-Tibetan Plateau during the second TIPEX of summer 1998 and their impact on surrounding monsoon

Summary ?Using the data of 6 automatic heat balance observation (AWS) stations and a data set of 52 surface observation stations over the Qinghai-Tibetan Plateau (“the Plateau”) and surroundings, the horizontal distribution is studied of “apparent atmospheric heat sources” 〈Q ₁〉 and of “apparent atmospheric moisture sinks” 〈Q ₂〉. The AWS stations were established during the period May to August 1998 of the Tibetan Plateau Meteorological Experiment (second TIPEX) by a cooperation of China and Japan. For this period the Plateau mean of 〈Q ₁〉 is positive. Its value of 74 W/m² is a little greater than a climate value and than values from MONEX and the first TIPEX in 1979, respectively. Also the corresponding 〈Q ₂〉 is positive. Hence during that time the Plateau is a heat source and a moisture sink. A day-to-day change of 〈Q ₁〉 and 〈Q ₂〉 is more pronounced over the middle and east part of the Plateau than over the west part. Diagnostics accompanied by numerical simulations are used to study the daily relationship between 〈Q ₁〉 over the Plateau and the weather over China and Asia for this summer. The results suggest that 〈Q ₁〉 may affect precipitation over northern China and position of the west Pacific subtropical high. Abnormal southward retreat of this Pacific high seems to have caused the second flood over the middle and lower Yangtse river basin in July. Received May 20, 2001; revised February 2, 2002     

陆面过程模式的改进及其检验

文中对陆面过程模式 (BATS)进行了改进 ,改进后的模式能较好地模拟地表物理量的年、季和日变化 ,它有两方面的特点 :采用热扩散方程模拟 7层土壤温度 ,模拟的温度可与实测值进行比较 ;在BATS的地表径流方案中 ,考虑了空间不均匀性的一般地表径流 (GVIC)过程 ,研究结果表明 :⑴模式能很好地模拟各层土壤温度的年、季和日变化。冬季土壤温度下层高于上层 ,而在夏季上层高于下层 ,这种上下层温度的转换时间大约在 4和 10月份 ,这与实测土壤温度的年变化非常一致。较为准确地模拟了各层土壤温度日变化的时滞效应。⑵用南京和武汉站的资料 ,将BATS地表径流方案模拟的地表水分分量与GVIC方案进行比较 ,BATS地表径流方案模拟的地表水分分量 ,与总水量的平衡相差较大 ,而GVIC模拟的效果相对较好 ,地表总水量基本上与降水总量达到了平衡     

ADP数字地震前兆综合观测台网系统的设计

介绍了ADP数字地震前兆综合观测台网系统的功能与结构。ADP系统已在广东省地震局连续运行，满足前兆台网综合化、数字化、自动网络化的要求。     

ADAPT数字遥测地震台网中传递函数的辨识

Adapt系统可以利用脉冲标定波形得到系统的传递函数，它将复杂的传递函数计算过程简化了，用户可以将传递函数的测定作为一种日常工作来做。     

The numerical simulation of thesource development of the Tangshan earthquake

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1995年7月12日云南孟连中缅边界7.3级地震中短临预报及前兆异常特征（3）

研究了孟连７．３级地震前云南全省及震中距６００ｋｍ范围内跨断层短水准、短基线、地倾斜、水氡、水位、水汞等１３类观测项目，５５个台站，１１个台项测值的中、短、临异常情况。结果表明，震前中、短、临异常台项目分比为３８％，并主要集中在２００－４００ｋｍ范围。中期异常特征为异常时间长、幅度大、短临异常特征为中期异常趋势结束或测反向，部分项目出现“巨变”东家主震中附近异常出现晚而外围出现早、随着地震临近其异