GPS气象观测应用的研究进展与展望

ADVANCE AND PROSPECT ON RESEARCH OF GPS AT MOSPHERIC SOUNDING AND ITS APPLICATION

ＧＰＳ（ＧｌｏｂａｌＰｏｓｉｔｉｏｎＳｙｓｔｅｍ）是美国第二代卫星导航系统。它的出现带来了当今世界上军事、民用导航技术的全面革新，在许多科学研究领域得到了极为重要的应用。同样地，在气象科学研究和业务应用方面也展示了广阔的前景。地基和空基的ＧＰＳ气象探测已被看成为支持２１世纪ＷＭＯ计划的一种新的全球综合高空观测系统。美国气象学会第７８届年会有不少相关研究报告，集中反映了欧美ＧＰＳ气象应用的开发研究最新进展，可概括为以下３方面：（１）由ＵＣＡＲ（ＵｎｉｖｅｒｓｉｔｙＣｏｒｐｏｒａｔｉｏｎｆｏｒＡｔｍｏｓｐｈｅｒｉｃＲｅｓｅａｒｃｈ）主持的ＧＰＳ／气象学（ＧＰＳ／ＭＥＴ）计划已经取得了成功。１９９５年４月３日发射了一颗低轨卫星（ＭＬ－１），利用低轨卫星对ＧＰＳ卫星进行掩星观测，可以获得５～４５ｋｍ高度范围内高分辨率的温度廓线（误差１～２℃）以及在５ｋｍ高度以下大气层的温度分布已知的条件下（精确到２℃），确定这一层中水汽压垂直分布。更具吸引力的应用是将大气折射率或射线偏转角这些基本物理量直接同化到高分辨率的全球或中尺度天气预报模式中去，以提高预报的准确性。只要发射８颗低轨卫星，总费用约１亿美元，便可以为天气业务预报?

Up to date,the remarkabl advances in a series of GPS/MET experimental programs to demonstrate potentiality and feasibility of GPS Sounding of atmospheric temperature profiles,precipitable water and wind have been acquired in different countries。It has been shown that active limb sounding of atmosphere using Global position system (GPS) radio signal received in low earth orbit is able to offer the data sets of temperature profiles with the precision of 1-2℃ between 5-45 km,and to calculate the water vapor pressure from the measured refractivity if an temperature profile can be estimated independently。The measuring accuracy of atmospheric precipitable water (PW) from a GPS PW network with high precision is better than 1-2 mm,and the observation is relatively unaffected by rain,cloud and aerosol.The advanced GPS windfinding system has also been tested by a few of country,and when the radar windfinding was used as a reference the average deviation was about 0.5 m/s for GPS and 0.8 m/s for loran c。Finally,the prospects for the wide application of the GPS sounding of atmosphere to meteorological research and operations are given,in addition the strategy to develop the technology of GPS remote sensing in China and to promote international cooperation is also presented in this paper。