【作者】 蒋光伟；

【导师】 张勤；

【作者基本信息】 长安大学 ， 大地测量学与测量工程， 2010， 硕士

【摘要】 水汽随时空的变化对气象预报特别是对水平尺度100km左右、生命史只有几小时的中小尺度灾害性天气(暴雨、冰雹、雷雨、大风、龙卷风等)的监视和预报有特别重要的指示意义。地基GPS作为一种新型的大气探测手段,其时间分辨率高、不需要标定、设备可综合利用,已成为大气探测手段的重要补充,且对完善气象预报预测业务系统,加强短时临近天气预报系统建设,做好灾害性、关键性、转折性重大天气预报警报和旱涝趋势气候预测具有极大的促进作用。地基GPS应用将使我国的防灾减灾、可持续发展上升到一个新的台阶,从而取得重要的社会经济效益。目前国内外已开展了大量地基GPS遥感水汽研究,并逐步走向业务运行,但目前地基GPS遥感水汽技术还没有在国内完全达到应用阶段,如何进一步提高地基GPS遥感水汽的精度以及实时监测大气水汽仍然需要对现有的理论算法进行进一步完善。本文针对目前地基GPS遥感水汽技术中影响天顶总延迟精度的若干因素、映射函数关键技术进行了分析和研究,并基于实时气象业务预报的需要研究了实时遥感水汽的方法。本文主要研究：1.详细地阐述了地基GPS遥感天顶水汽PWV的方法。重点介绍遥感天顶对流层总延迟获取、天顶湿延迟的方法及PWV获取的方法。2.分析了地基GPS遥感天顶水汽精度的若干因素。重点研究星历误差、大气荷载、大洋荷载、绝对天顶延迟获取因素进行了深入研究,并进行算例分析。3.重点介绍了对流层延迟中映射函数及其在低高度时的选择。首先介绍了常用的映射函数模型,其次结合MODIS影像水气变化图与GPS PWV分析了在低高度时对不同映射函数的选择,得出VMF1映射函数更能满足实时气象水汽变化的需要但其需要外部数据,且精度最高,GMF映射函数精度次之,其可在事后数据处理上代替VMF1映射函数,NMF映射函数精度最弱。4.根据气象预报的实时性需要针对实时获取PWV进行了研究。首先,针对目前湿延迟模型精度偏低,提出使用外部气象数据近实时反演湿延迟。对基于欧洲ECMWF水汽资料获取湿延迟的可靠性和插值算法进行了分析研究,并顾及了高差对插值算法的影响；其次对MODIS影像反演湿延迟,并将其与GPS获取的真值进行比较分析,拟合了二者之间的相关关系,并提出把外部气象资料求取湿延迟并将其融合,建立区域对流层近实时湿延迟模型用于单历元算法和精密单点定位(PPP)中；最后,研究基于地基GPS双差Kalman滤波的方法实时动态监测水汽变化的方法,并验证这种方法实时动态监测大气水汽变化的正确性和可行性。更多还原

【Abstract】 Water vapor changes in time and space weather forecasting especially around 100km horizontal scale, life history only a few hours of small-scale severe weather (rain, hail, thunderstorms, strong winds, tornadoes, etc.) monitoring and forecasting are particularly important implications. As a new foundation GPS atmospheric sounding instruments, its high time resolution, does not require calibration, device utilization, has become an important complement to atmospheric sounding instruments, and the weather forecast predicted on improving business systems, enhance short-term weather forecasts near system construction, good disaster, critical, major weather shifts and trends in drought and flood warning and forecast climate into the role great. Will allow our disaster prevention and mitigation, sustainable development to a new level, so as to achieve important social and economic benefits.At home and abroad have carried out a large number of ground GPS water vapor remote sensing research, and to business operations, but how to further improve the accuracy of ground GPS water vapor sensing and real-time monitoring of changes in atmospheric water vapor existing theories still need to further improve the algorithm.In this paper, the current GPS ground water vapor remote sensing technology in some of the key technologies of analysis and research, and based on real-time weather forecasting business needs of the real-time remote sensing of water vapor method.This paper studies:1. Detailed description of the ground water vapor PWV GPS zenith remote sensing methods. Focuses on remote sensing of total zenith tropospheric delay in the acquisition, the zenith wet delay means and methods of PWV obtained.2. Analysis of remote sensing ground GPS accuracy of the zenith water vapor number of factors. Focuses on ephemeris error, atmospheric loading, ocean loading, to obtain the absolute zenith delay factors in-depth research and analysis for example.3. Focuses on the tropospheric delay in the mapping function and its low height option. First introduced the commonly used mapping function models, followed by the combination of changes in water vapor image MODIS maps and GPS PWV analysis in the low-altitude mapping functions for different choices, come VMF1 real-time weather mapping function to better meet the changing needs of water vapor, but their needs external data, and the highest accuracy, GMF mapping function accuracy of the second, it can be replaced after the data processing VMF1 mapping function, NMF mapping function accuracy of the weakest.4. According to the weather forecast for the real needs of real-time access to PWV were studied. First, wet delay for the current model of low precision and made use of external inversion of wet weather data in near real time delay. Based on the European ECMWF water vapor data for the reliability of the wet delay and interpolation algorithm analysis, and taking into account the impact of elevation on the interpolation algorithm; followed by inversion of the MODIS images wet delay with GPS and access to the true value comparative analysis, fitting the relationship between the two and make the external meteorological data to calculate the wet delay and the integration of regional wet tropospheric delay model for near real-time single epoch algorithm, and precise point positioning (PPP) in; Finally, the research foundation based GPS double difference method of Kalman filter real-time dynamic monitoring of changes in the method of water vapor, and verify that this method changes in real-time dynamic monitoring of atmospheric water vapor the correctness and feasibility.更多还原