有限区域卫星云图资料变分分析的试验研究

EXPERIMENT AND DESIGN OF THE VARIATIONAL ANALYSIS SYSTEM FOR THE SATELLITE CLOUD PICTURE DATA IN THE LIMITED AREA

资料分析在数值预报中的重要性受到越来越多的关注，鉴于目前常规探测网的时空局限性，利用分辨率较高的非常规资料势在必行。该文利用一个有限区域中尺度模式ＭＭ４，采用变分分析技术对有限区域的常规探空资料和非常规云图资料进行变分分析和数值模拟。试验结果表明，加进卫星云图的变分分析资料后，可改进初始温度场和湿度场。若仅加进湿度场的变分分析资料，可以改善降水量的预报，而对雨区的预报没有明显改善；若仅加进温度场的变分分析资料，可以明显地改善雨区的预报；

Nowadays,greater attention has been drawn to the importance of data assimilation in numerical prediction. It is necessary to use the nonconventional data that has a high resolution due to the time-space limit of the conventional sounding system. In the paper,in terms of the variational analysis technique,variational analysis and numerical experiment have been done on the conventional sounding data and nonconventional cloud picture data in the limited area,with the mesoscale model MM4. Results show that the technique can efficiently analyse the conventional and nonconventional data. Case experiments in the temperature and moisture fields have been well made. Results of the mesoscale numerical simulation indicate that the variational analysis of the moisture field can improve the prediction of rainfall,but has no obvious improvement in rain area prediction while the variational analysis of the temperature field can apparently improve prediction of the rain area. If the both two fields are analysed at the same time,better results will be obtained. The research in this paper will provide a new efficient method for accurate rainfall prediction at the weather stations throughout the country.