The Interannual Variation in Monthly Temperature over Northeast China during Summer

摘要

The interannual variations of summer surface air temperature over Northeast China(NEC) were investigated through a month-to-month analysis from May to August. The results suggested that the warmer temperature over NEC is related to a local positive 500-hPa geopotential height anomaly for all four months. However, the teleconnection patterns of atmospheric circulation anomalies associated with the monthly surface air temperature over NEC behave as a distinguished subseasonal variation, although the local positive height anomaly is common from month to month. In May and June, the teleconnection pattern is characterized by a wave train in the upper and middle troposphere from the Indian Peninsula to NEC. This wave train is stronger in June than in May, possibly due to the positive feedback between the wave train and the South Asian rainfall anomaly in June, when the South Asian summer monsoon has been established. In July and August, however, the teleconnection pattern associated with the NEC temperature anomalies is characterized by an East Asia/Pacific(EAP) or Pacific/Japan(PJ) pattern, with the existence of precipitation anomalies over the Philippine Sea and the South China Sea.This pattern is much clearer in July corresponding to the stronger convection over the Philippine Sea compared to that in August.