地基GPS水汽反演及水汽层析研究

发布时间：2018-09-04 12:18

【摘要】：GPS气象学为GPS探测大气水汽奠定了理论基础,地基GPS大气水汽监测网和GPS连续观测站为地基GPS水汽反演提供了绝好的条件,当前气象学正在从技术研究逐步走向业务化应用。所以地基GPS水汽反演精度提高、气象应用和三维层析精度提高均是当前研究的热点。本文针对以上内容,利用香港连续观测站以及探空数据进行了地基GPS水汽反演,主要内容如下:1、依据香港地区2014年-2016年10月份探空数据,建立了香港地区加权平均温度模型。实验后发现,本地化模型计算10月份的加权平均温度误差基本保持在3.4度以内,造成的PWV误差保持在1mm以内。2、在依据GPS观测站坐标信息进行地势拟合时,发现3次模型虽然拟合误差小,但是对于未参与拟合测站的误差较大,所以在地势拟合过程中需根据实际地势情况进行模型确定。本文通过PWV拟合研究发现,香港地区地势拟合以2次模型为最佳,平面方向梯度因子对于PWV拟合精度并没有显著提高。3、本文基于地势拟合模型进行了 PWV香港地区的拟合,并发现当地势拟合模型误差在1km以内时能够保证PWV误差控制在1mm以内。在基于地势拟合的PWV平面拟合时序分析图中发现,使用平面PWV拟合不仅在精度上有所保证,而且能通过该方法对水汽走势、运动状态有明显的判断。4、针对传统层析方法中采用平面分层而不能顾及测站之间高差的问题,本文提出使用基于地势拟合的三维层析方案,并分别从滤波次数、平面格网划分长度和地势拟合模型进行考虑。结果表明基于地势拟合的三维层析方法在低层3km以下和高层6km以上区域较传统层析方法解算的水汽密度有明显的精度提高,但是在中层3km-6km区域精度较传统平面层析结果较差。最后提出使用组合方案对水汽密度进行计算,结果证明该方法能够有效提高结果精度。
[Abstract]:GPS meteorology has laid a theoretical foundation for GPS to detect atmospheric water vapor. Ground-based GPS atmospheric water vapor monitoring network and GPS continuous observation station provide excellent conditions for ground-based GPS water vapor inversion. Currently, meteorology is gradually moving from technical research to operational application. Therefore, the precision of ground-based GPS water vapor inversion is improved, meteorological application and three-dimensional tomography accuracy is improved. The main contents are as follows: 1. Based on the sounding data of Hong Kong from 2014 to October 2016, a weighted mean temperature model for Hong Kong region is established. The local model is used to calculate October. The weighted average temperature error is kept within 3.4 degrees, and the PWV error is kept within 1 mm. 2. When the terrain is fitted according to the coordinate information of GPS observatories, it is found that although the fitting error of the third model is small, the error of the unfitted stations is large, so the actual terrain situation should be considered in the process of terrain fitting. Through the study of PWV fitting, it is found that the quadratic model is the best for terrain fitting in Hong Kong, and the plane direction gradient factor does not improve the precision of PWV fitting significantly. The difference is controlled within 1 mm. In the time series analysis chart of PWV plane fitting based on the ground fitting, it is found that the plane PWV fitting can not only guarantee the precision, but also judge the water vapor trend and movement state obviously by this method. 4. In view of the problem of plane stratification in traditional tomography method, the difference between stations can not be considered. In this paper, a three-dimensional tomographic scheme based on terrain fitting is proposed, and the filtering times, the length of planar grid division and the terrain fitting model are considered respectively. The results show that the three-dimensional tomographic method based on terrain fitting can improve the water vapor density in the region below 3 km and above 6 km in the upper layer more precisely than the traditional tomographic method. But the accuracy in the middle layer of 3km-6km region is worse than that in the traditional plane tomography. Finally, a combination scheme is proposed to calculate the vapor density, and the results show that the method can effectively improve the accuracy of the results.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P228.4;P407

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