提高GNSS掩星低层大气参数反演精度的NMAR算法研究

项目名称： 提高GNSS掩星低层大气参数反演精度的NMAR算法研究

项目编号： No.41504035

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 天文学、地球科学

项目作者： 李莹

作者单位： 中国科学院测量与地球物理研究所

项目金额： 22万元

中文摘要： GNSS无线电掩星探测技术是一种重要的地球大气探测手段。然而由于水汽模糊度的问题，掩星技术提供的低层大气参数反演的准确度较低，严重影响了掩星技术在大气与气象学等方面的研究与应用效能。为此，本项目提出一种能显著提高GNSS掩星低层大气参数反演精度的NMAR算法。该方法克服了传统方法粗略估算观测量和背景量误差信息的方法，在顾及误差与经纬度、高度和时间的相关性的前提下，通过统计和数学建模的方法准确的计算反演所需变量的误差信息，并用于掩星参数的反演，从而显著提高低层大气参数的计算效果。本项目的研究成果不仅可望改善低层大气参数反演的质量、提升大气掩星技术应用于气候监测和数值天气预报等方面的效能，也将提升我国自主建设的低轨地球卫星星座掩星反演研究与应用的能力与水平。

中文关键词： 全球卫星导航系统；地基/空基GNSS大气探测；精度和可靠性；水汽；误差改正

英文摘要： GNSS Radio Occultation (RO) technique is an important atmospheric sounding technique for the Earth's atmosphere. However, due to the effects of water vapour ambiguity, the RO technique cannot provide accurate atmospheric information at low atmosphere. Therefore, the applications of the RO technique in atmospheric study are limited. This project proposes a new NMAR algorithm to improve the accuracy of GNSS retrievals at low atmosphere. The new algorithm uses statistical calculation and mathematical modeling methods to calculate error information of background and observed variables, accounting for their variations with latitude, longitude, altitude and time. The new algorithm overcomes the weaknesses of current algorithms that only use rough estimations of error information. The newly estimated error information are then used in RO retrieval in low atmosphere to improve the retrieved accuracy. It is expected that the outcome from this project will not only improve the quality of the RO retrievals in low atmosphere, but will also improve the ability of the RO technique in its use in climate monitoring and numerical weather prediction. It is also expected that the new algorithm can help to improve the capability of the RO technique of our country.

英文关键词： GNSS;ground-based/spaced-based atmospheric sounding;accuracy and reliability;water vapour;error correction