基于动态特征的强对流云团追踪

Severe Convective Cloud Tracking Based on Dynamic Features

利用FY-2E卫星数据获取的强对流云团面积、重心、长短轴比、重心与形心距离、移动速度、移动角度和最低亮温等属性的变化可作为动态特征,利用慢特征分析方法提取云团中具有一定连续性和稳定性的动态特征对强对流云团不同阶段进行识别和追踪。结果表明,动态特征与强对流云团的不同发展阶段具有很好的对应关系:在初生阶段,云团的移动方向和速度不稳定,但是面积呈现出缓慢增长态势,云顶亮温缓慢下降,此时云团的慢特征为面积和云顶亮温;在成熟阶段,云团的移动路径趋于稳定,云顶亮温达到最低,云团重心和形心基本重合;在消散阶段,存在云团分裂和云团的重心与形心分离特征。云团长短轴比的变化与云团最低亮温的变化趋势一致,移速缓慢的对流云团更容易造成集中强降水,快速移动的对流云团大多造成地面大风。

Using the of cloud area, the center of gravity, the ratio of long and short axes, the distance of gravity center and centroid, moving speed angle and the lowest brightness temperature from FY-2E satellite data as dynamic features, the convective cloud in different phases were recognized and tracked using the slow feature analysis method extracting the successive and stable dynamic features. The results show that the dynamic features and convective cloud have a well corresponding relationship at the different development stages. The moving direction and speed of cloud are instable at the primary stage, but the cloud area presents slow growth and the cloud top brightness temperature drops slowly, so cloud area and cloud top brightness temperature are slow feature of cloud cluster. At the mature stage, the moving path of cloud is more stable, the cloud top brightness temperature reaches the minimum, the gravity center and centroid coincidence. At the decay stage, there is detach feature of the clouds split and the gravity center and centroid.