关键词: 中国夏季降水, 自组织映射(SOM), 经验正交函数(EOF)

Abstract:

Based on SOM (self-organizing maps) and EOF (empirical orthogonal function) methods, the dailymean and seasonal-mean summer precipitation patterns in Eastern China are analyzed and compared. Results show that the SOM method, compared with EOF, describes precipitation distributions more realistically. The spatial structures of summer precipitation patterns can be well explained by 850 hPa wind anomaly and 700 hPa specific humidity anomaly. As a posterior problem, 850 hPa height anomaly can well explain the corresponding precipitation area. However, as a prediction problem, due to other conditions such as moisture and temperature anomaly, the negative height anomaly in the numerical weather forecasting does not always indicate strong precipitation.

Key words: China summer precipitation, self-organizing maps (SOM), empirical orthogonal function (EOF)