午夜欧美大片免费观看,欧美激情综合五月色丁香,亚洲日本在线视频观看,午夜精品福利在线

Based on the observed data from 1960 to 2011, the Heating Degree Days (HDD) and Cooling Degree Days (CDD) in China are calculated and analyzed by using the MannKendall test. The results show that an abrupt change of winter temperature in the northern China and its adjacent plateau region occurred at around 1987, along with the decreasing HDD on the background of climate warming. The summer temperature in the southern China changed abruptly around 1997, with CDD increasing after that. The circulation characteristics before and after the climate warming are further analyzed by using the NCEP/NCAR reanalysis data and the circulation index data. It is found that the Arctic Oscillation (AO) index is negatively correlated with HDD in the northern China and its adjacent plateau region. When the AO index is stronger (weaker) than normal, the heavy cold air events decrease (increase), along with the decreasing (increasing) HDD. On the other hand, the Subtropical High Area (SHA) index has a significantly positive correlation with CDD in southern China. When the SHA index is stronger (weaker) than normal, the fair weather with high temperature will increase (decrease), along with the increasing (decreasing) CDD.