GNSS数据质量评估软件的实现及验证分析     

吴丹  王利  张勤  付文举  舒宝  范丽红 《测绘科学技术学报》2015,(4):344-348

近些年卫星导航系统的飞速发展,使得导航定位用户获取多模GNSS数据已成为一种趋势。而目前尚无一种能够同时检测GPS/BDS/GLONASS/Galileo数据质量的软件。针对新一代RINEX格式的GNSS数据,深入研究数据质量检测的方法。用C语言开发了与TEQC数据质量检测功能相近的软件QC,并对其正确性进行了验证。在此基础上,对iGMAS站的数据质量进行了分析,发现目前的多模GNSS接收机易发生钟跳;在多路径效应方面,BDS卫星的GEO卫星多路径效应的周期性较弱,信噪比也呈现出与GPS和GLONASS不同的特征。  相似文献   

贵州中西部冰雹云闪电活动特征及对降雹指示作用研究          下载免费PDF全文

曾勇  张淑霞 《中低纬山地气象》2020,44(6):44-50

利用VLF/LF三维闪电监测资料、CINRAD/CD雷达资料和地面降雹观测资料,对贵州中西部冰雹云闪电特征进行分析。结果表明：高原台地威宁平均POP和Z值均高于斜坡过渡带区域,两者平均POP值均高于贵州10a（2006—2015）平均POP统计特征值。斜坡过渡区域内总闪峰值平均为22次/（5 min）,威宁总闪峰值平均为13次/（5 min）。斜坡过渡带区域2σLFCR闪电跳跃信号和闪电频次峰值提前量平均为20 min和 13 min,威宁2σLFCR闪电跳跃信号和闪电频次峰值提前量平均为33.7 min和29 min。2σLFCR闪电跳跃信号指示降雹优于闪电频次峰值信号,在实际中可以综合利用闪电2σLFCR跳跃信号与峰值信号识别降雹。  相似文献   

地球化学模拟在南北古脊梁岩溶裂隙水系统划分中的应用   总被引：3，自引：1，他引：2       下载免费PDF全文

余秋生  张发旺  韩占涛  于艳青  薛忠岐 《地球学报》2005,26(4):375-380

南北占脊梁是贺兰山经向构造体系的核心部分,为一条SN向的震旦系、寒武系、奥陶系地层隆起。寒武系、奥陶系地层主要为灰岩和白云岩,其问赋存有较丰富的岩溶裂隙水。由于埋深大,构造情况复杂,南北古脊梁的岩溶裂隙水的分布和径流规律至今仍不是十分清楚。本文利用地球化学模拟的方法,对南北古脊梁深埋岩溶裂隙水的系统划分和各部分之间的水力联系进行了研究。认为：系统I和系统Ⅱ的边界应当在严湾和吕套之间,其边界为一条由第四系地下水补给形成的,地下水位较高的可移动地下分水岭;系统I和系统Ⅲ之间存在水力联系,系统I北端排泄口太阳泉的水量有46％来自系统Ⅲ的补给,在萌城泉和太阳泉之间可能存在一条导水断层形成的岩溶裂隙水的强径流带。  相似文献   

Simulating the intraseasonal variation of the East Asian summer monsoon by IAP AGCM4.0   总被引：5，自引：0，他引：5  

SU Tonghua  XUE Feng  ZHANG He 《大气科学进展》2014,31(3):570-580

ABSTRACT This study focuses on the intraseasonal variation of the East Asian summer monsoon （EASM） simulated by IAP AGCM 4.0, the fourth-generation atmospheric general circulation model recently developed at the Institute of Atmospheric Physics, Chinese Academy of Sciences. In general, the model simulates the intraseasonal evolution of the EASM and the related rain belt. Besides, the model also simulates the two northward jumps of the westem Pacific subtropical high （WPSH）, which are closely related to the convective activities in the warm pool region and Rossby wave activities in high latitudes. Nevertheless, some evident biases in the model were found to exist. Due to a stronger WPSH, the model fails to simulate the rain belt in southern China during May and June. Besides, the model simulates a later retreat of the EASM, which is attributed to the overestimated land-sea thermal contrast in August. In particular, the timing of the two northward jumps of the WPSH in the model is not coincident with the observation, with a later jump by two pentads for the first jump and an earlier jump by one pentad for the second, i.e., the interval between the two jumps is shorter than the observation. This bias is mainly ascribed to a shorter oscillating periodicity of convection in the tropical northwestern Pacific.  相似文献   

A Simple Model for Earthquake Instability     

Li Ping’en  Yin Youquan 《中国地震研究》2010,24(2):179-189

Based on the heterogeneity of fault plane strength,the macro rupture process of a fault plane can be treated as the rupture accumulation process of local micro-elements in the fault surface.Assuming that the strength of the local micro-elements follows the Weibull probability distribution,the macro-fault constitutive relationship of the complete load-deformation process is derived from a statistical mechanics viewpoint.Applying a one-dimensional earthquake mechanics model and using far-field displacement a as the control variable,the problem of earthquake instability is investigated by employing the stability theory.The results show that the system stiffness ratio(stiffness ratio of fault to surroun-ding rock) β is the important parameter that affects the occurrence of earthquakes.Earthquake instability occurs only when β < 1,and the sudden stress jump appears at the displacement turning point of the equilibrium path curve.The expression of three important parameters for earthquakes(fault half-dislocation distance after earthquake,earthquake stress drop and elastic energy release) is also given.When β≥1,the earthquake does not occur and the fault only slips slowly without an earthquake.  相似文献   

黄河三角洲近四十年的气候变化特征   总被引：1，自引：0，他引：1  

盖世民  徐启春 《海洋湖沼通报》1998,(2):1-5

采用了惠民、滨洲和垦利三站平均的１９５７－１９９６年冬季平均气温（＾－Ｔ）,春季平均风速（＾－Ｖ）和夏季降水量（＾－Ｒ）,表征黄河三角洲的气候变化状态。分析结果显示,近４０年来,该地区的气候变化具有以下特征：（１）长期变化趋势变,科季＾－Ｔ呈明显的增高;春季＾－Ｖ则呈明显的减少;夏季＾－Ｒ变化趋势不显著。（２）冬季＾－Ｔ、夏季＾－Ｖ、夏季＾－Ｒ变化存在着转折和跃变。跨变年份是１９８６年（＾－Ｔ）和  相似文献   

新疆百里风区强风中尺度特征分析          下载免费PDF全文

汤浩  周雅蔓  杨杰尧 《沙漠与绿洲气象(新疆气象)》2022,16(4):1-8

大尺度环流背景和天山山脉大地形共同作用形成新疆百里风区，其风力之大居全疆九大风区之首。为进一步研究百里风区强风中尺度特征及其与局地地形的关系，选取2018年5月6—8日百里风区强风天气过程，使用WRF模式进行中尺度模拟分析，形成以下结论：天山两侧气压梯度力驱动下冷空气翻越天山，经色皮山口狭管效应和过山波水跃下沉接力加速，在背风坡上空形成强风区，强风区接地形成百里风区地面大风；大风过程中，七角井盆地地形强迫引发有限振幅重力波，背风坡上空大风区之上的临界层吸收上层能量并向下传递，增大了大风区的风速，使得低空大风区的接地更加充分。低空大气稳定层结的强度与大风强度相对应。  相似文献