The Vertical Characteristics of Temperature and Humidity Inside Convective and Stratiform Precipitating Clouds in the East Asian Summer Monsoon Region and Indian Summer Monsoon Region

Based on the daily precipitation dataset of 395 gauge stations in eastern China and the JRA-55 reanalysis rainfall (HR) and their associated large-scale circulation anomalies were investigated. The mutational analysis of summer HR occurrence frequency and contributing percentage showed that there were two significant changes of summertime HR-one around the late 1970s and another in the early 1990s, both exhibiting meridional three-cell (tripole for short) anomalies in spatial terms. The period from 1960 to 1979 is referred to as P1, from 1980 to 1991 as P2, and from 1992 to 2011 as P3. A positive (negative) tripole pattern can be defined as follows:negative (positive) anomalous signs in southern China;positive (negative) anomalous signs in the Sichuan Basin and Yangtze-Huaihe River basin;negative (positive) anomalous signs in the Huanghe-Huaihe valleys and North China. In other words, the interdecadal change of summertime HR around the late 1970s (early 1990s) was characterized by a positive (negative) tripole distribution in the average difference of summertime HR frequency or percentage between the periods P2 and P1(P3 and P2), and the two interdecadal changes were almost exactly opposite. Correspondingly, the interdecadal evolution of summertime HR anomalies can be divided into three phases, as follows:a negative tripole distribution in the P1 phase;a positive tripole distribution in the P2 phase;and a dipole distribution-known as the ‘southern flood/northern drought’ pattern-in the P3 phase. Further results show that the factors responsible for the positive (negative) tripole changes of summertime HR in eastern China around the late 1970s (early 1990s) might have been associated with anomalous large-scale circulation, as follows:a weakening (strengthening) of the East Asian summer monsoon;a southwards retreat (northwards march) of the western Pacific subtropical high, which continually strengthens and extends westwards;a southwards shrinking (eastwards expansion) and weakening (strengthening) of the South Asia high;and strong cyclonic (anticyclonic) circulation anomalies in the mid-low troposphere over the Mongol highlands.