Research On The Application Of Spaceborne Radar In Improving The Data Quality Of Networked Radar

The top-down observation mode of space-borne radar makes its observation,not limited by the surface conditions.Space-borne radar can cover areas that are difficult to be observed by other observation methods,such as oceans and mountains.Previous researches have demonstrated the stability and accuracy of the reflectivity measurements of the space-borne radar.About two decades of well-calibrated and wide-coverage reflectivity measurements have been obtained since the successful launch of the TRMM satellite in1997.The space-borne radar provides a good comparison reference for all ground-based weather radars within its coverage.It is of practical significance to make full use of measurements of the space-borne radar and explore its application in improving the data quality of ground-based radar.In this paper,the reflectivity measurements of TRMM PR were selected to match those of the ground-based radar.Based on the measurements of TRMM PR,the results of the non-precipitation echo identification algorithm and the beam blocking identification algorithm were analyzed and evaluated from the perspective of comparison of measurements between TRMM PR and the ground-based radar.The results of the above quality control algorithms were evaluated and analyzed to provide data availability for the matching and comparison of the measurements between the space-borne radar and ground-based radars.This further improved the accuracy of the comparison between the two kinds of radar.It also provided a new idea for the objective and quantitative evaluation of the quality control algorithms of ground-based radar.Five-year reflectivity measurements of seven S-band weather radars in Shanghai and Jiangsu Province were selected to match the well-calibrated and stable measurements of TRMM PR,and the stability of measurements of the seven radars was analyzed based on the stable measurements of TRMM PR.The results showed that compared with the other six CINRAD SA radars,the reflectivity measurements of Nanhui WSR-88 D radar had a higher correlation with those of TRMM PR,and the fluctuation of the differences in the measurements between Nanhui radar and TRMM PR was smaller.This indicated that the measurements of Nanhui radar were more stable than those of the other radars,further analysis showed that the difference in stability lies in the radar calibration methods,which is helpful to the improvement of radar calibration methods.Considering the influence of typhoon wind speed on the rotation orientation of the rain drops,the relationship between Ku and S-band radar reflectivity values under typhoon precipitation was obtained by the T-matrix method,which improved the comparison results of reflectivity factor between the Ku and S-band radar.Based on the “floating column”comparison method,it was found that the echo intensity of Zhoushan radar was weaker than that of the other two radars during typhoon Ampil.The reflectivity measurements collected by the ground-based radar systems were corrected using the GPM Ku PR measurements as reference,and the results of the correction were verified by comparing quantitative precipitation estimations with rain gauge measurements.It was found that after the correction,the consistency of the reflectivity measurements of the multiple radar systems improved significantly,and the precipitation estimates based on the corrected reflectivity measurements were closer to the rain gauge measurements.The correction based on the GPM Ku PR measurements improved the availability of the multiple radar systems' reflectivity measurements in typhoon monitoring and quantitative precipitation estimation.