利用气温与云顶亮温差值检测云方法研究

利用2005年7-12月卫星资料、地面观测资料、探空资料和地形资料,统计分析了无云条件下气温与云顶亮温的差值,结果表明：无云情况下气温与云顶亮温差值平均为5.04℃,且具有较大的日变化性。由此提出了按时次分别求取阈值用以检测云。通过个例对比分析,初步得出该方法检测云具有以下特点：可用于全天候云检测;不受地形地貌等因素的影响;该云检测方法应用于反演计算,不仅反演的中、高云区域与实测的比较一致,而且反演的低云区域与实测结果也比较一致。

Research on the Cloud Detection Method of Using the Difference Between the Temperature and the Cloud Top Temperature

By using satellite data,ground observation data,sounding observation data and geograph-ic data from July to December 2005,the difference between the temperature and the cloud top tempera-ture was analyzed. The results showed that： the average difference between the temperature and the cloud top temperature in the cloudless condition was 5. 04 ℃,and the diurnal change of the difference was great. Thus the method which selected threshold of different time to detect cloud was proposed. By stud-ying the contrast analysis of a case,the characteristics of the method were followed： the method can be used in all-weather cloud detection,avoided the influences of topography and other factors. In the inverse calculation of this method,not only in the high and middle cloud area,but also in the low cloud area the results were consistent with the real observation results.