The FY-2C geostationary satellite performed its first rapid regional scan test in 2011,yielding high temporal resolution data.The mean observation frequency is about 10 min.Observational test data were used to analyze a strong convective cloud development process that appeared on June 28-29,2011,in Guangdong Province.The results show that the parameter difference between high-frequency observations can be used to monitor the initial development of convective clouds.The parameters can be selected as the brightness temperature at the infrared window channel and the brightness temperature difference between the infrared window channel and water vapor channel.At the initial phase of convective cloud formation,the cloud top first appeared strong cooling at the infrared window channel.Then,the brightness temperature difference between the infrared window and water vapor channels decreased,demonstrating that the height of the cloud top developed considerably.Accompanied by the development of convective clouds,the minimum brightness temperature continued to decrease,and the number of cold cloud pixels increased gradually,indicating that the cloud continued to develop.Hourly precipitation data at the surface are classified into three levels:smaller than 5 mm,between 5 mm and 10 mm,and larger than 10 mm.According to the different precipitation levels,the statistical distribution of the brightness temperature in the infrared window channel was analyzed.The results show that the cold cloud top is the main property producing strong precipitation during a strong convective cloud process.The colder the cloud top is,the stronger the precipitation is that appears on the surface.A HovmOller diagram is used to show the evolving properties of the cloud cold core in high-frequency observation mode.Combined with hourly precipitation data,it can show good agreement between the location of the cold cloud core and the center of maximum precipitation.Because there are six observations during 1 h during the high-frequency rapid regional scan,the standard deviation in the brightness temperature is calculated.A smaller standard deviation in the brightness temperature during 1 h indicates fewer changes in the cloud top properties.When heavy precipitation appears on the surface,the cloud not only has a colder top temperature,but also the colder cloud top should remain for a certain time period.On the basis of the above analysis,a high-frequency rapid regional scan can capture the features of evolving convective cloud properties,providing technological support to forecast the initial stages of a convective cloud mass.%利用我国首次获取的静止气象卫星平均10分钟观测间隔的高时间分辨率数据对2011年6月28日～29日发生的一次强对流云团特征进行分析.Hovmǒ11er分析图清晰地展示出在高时间分辨率观测条件下云团中心冷核的演变特征.高时间分辨率卫星资料与地面降水量进行联合分析,可推知对流云团中冷核的演变与地面小时降水量大值的落区间有很好的一致性；10分钟雨量资料联合前推1小时内7次平均10分钟观测间隔的卫星红外1通道亮温,分析可知地面雨量较大时,云顶像元亮温具有持续降低或维持低温状态的特点.反映出在对流性强降水中,冷且具有一定稳定性的云顶是产生大降水的主要特征.研究结果显示,静止气象卫星的高时间分辨率观测可很好地捕捉到强对流云团发展的演变特征,利用FY-2C静止气象卫星红外1通道亮温、红外1通道与水汽通道亮温差在高时间分辨率观测中的时差特征变量,可实现对强对流云团初生的有效监测,为强对流云团的预测预报提供支撑.
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