The Assimilation Experimentation Of Observational Data Of GPS Radio Occultation

Meteorological satellite remote sensing data can provide large-scale, high time-resolution observations of atmospheric information, especially added observational information of marine, highland and desert areas with scarce conventional data distribution .In numerical prediction, remote sensing observations play an important role on improving the initial of numerical prediction. Therefore, satellite data assimilation study attracts more and more attention. At present numerical weather prediction of the meteorological satellite data assimilation mainly refers to conditions for a clear sky, a large number of meteorological satellite data influenced by clouds and precipitation was discarded outside of analysis system, being not fully utilized. However, perceptible cloud area often is the sensitive region with a significant impact on forecasting, the regional meteorological satellite observation contains more meaningful weather information, having a more direct relationship with weather analysis and forecasting system. The use of perceptible cloud area satellite data may be one technological way to improve the numerical prediction accuracy rate continually. Different from the remote sensing data by infrared remote sensing and microwave radiation, the way of GPS radio occultation observation is a temporary observation, the radio signal can pass through Thick Cloud and Precipitation, whose observation is less affected by Cloud and Precipitation, weather condition wouldn't impact GPS radio occultation observation, it has high data accuracy and vertical resolution, it just can cover flaws of available data. So, assimilation study on GPS radio occultation observation is of great significance.This paper firstly analysis COSMIC data of the temperature, wet profile test data inversed by GPS radio occultation, do assimilation experiment with global / regional data assimilation and prediction system (GRAPES), evaluate its value in the numerical prediction, and investigate the existing problems in the use of GRAPES , which lay a foundation in application of COSMIC in the Global Business Forecasting .Following is the paper's main research and conclusions Summary:1. Check out COSMIC information : Full verification of the GPS radio occultation inversion information can be applied to all data assimilation system to improve the quality of initial field model through COSMIC data by calculating the temperature and height of the RMS error.2. The influence of COSMIC data on the path forecasting of"Sepat"typhoon: COSMIC data at 12:00 on August 17, 2007 and Conventional data are used in GRAPES-3DVAR system assimilation test, then an analysis got and be used in the regional model of GRAPES to make a 2d forecast. The results show that the COSMIC data is helpful to enhance the capacity of the Typhoon path forecasting.3. The preliminary research on COSMIC data used in GRAPES global three-dimensional variational assimilation system: COSMIC data and Conventional data are used in GRAPES Global Assimilation System to make a Continuous cycle of assimilation test, then the anomaly correlation coefficient of GRAPES analysis field and NCEP is got. The GRAPES analysis field is used to make a 5d forecast, the result shows that it is helpful to enhance GRAPES global forecasting capability.4. The sparseness of COSMIC data: sparse COSMIC data and Conventional data are used in GRAPES Global Assimilation System to make a Continuous cycle of assimilation test, and then the anomaly correlation coefficient of GRAPES analysis field and NCEP is got. The GRAPES analysis field is also used to make a 5d forecast, the result shows that the sparse COSMIC data is helpful to enhance GRAPES global forecasting capability, especially for the northern hemisphere.