IMPACT OF THE INTERANNUAL VARIABILITY OF THE LOW-FREQUENCY OSCILLATION INTENSITY IN THE TROPICS ON THE WINTERTIME RAINFALL IN EAST CHINA

Using the percentage of the low-frequency oscillation energy and the total energy as the low-frequency oscillation intensity index, the association of the interannual variability of low-frequency oscillation intensity with rainfall in the area of East China in the boreal winter is investigated based on NOAA outgoing longwave radiation(OLR) data, NCAR/NCEP data and observed precipitation data of 160 stations in China. The results demonstrated that when the tropical low-frequency oscillation intensity is high(low),the precipitation in East China is more(less). The results also showed that the interannual variability of low-frequency oscillation intensity is linked to the interannual variability of both subtropical wave trains and East Asian Winter Monsoon. In the high-value years of the low-frequency oscillation intensity, the North Africa trough and the Bay of Bengal trough deepen, East Asia trough and East Asian Winter Monsoon weaken, the south wind anomaly appears in East China, and the moisture increases, leading to more rainfall.In the low-value years of the low-frequency oscillation intensity, the North Africa trough and the Bay of Bengal trough weaken, East Asia trough and East Asian Winter Monsoon deepen, the north wind anomaly appears in East China, and the moisture decreases, resulting in less rainfall.