春季北支脊变化特征及其对中国气候的影响

论文利用NCEP/NCAR再分析资料和中国160个站月降水量和气温资料,通过小波、相关分析等方法,讨论了春季北支脊的变化特征及其对中国同期降水和气温的影响。结果表明：春季北支脊缓慢增强,存在2~3 a和准6 a的周期;纬向位置略向东移,具有准3 a和12 a的周期。春季北支脊偏强（弱）,黄河流域到江南地区的降水量偏少（多）,东北、西南和华南地区的降水量偏多（少）;春季北支脊纬向位置偏东（西）,中国北方大部分地区的降水量偏多（少）,西南和江南大部分地区的降水量偏少（多）;中国大部分地区的升（降）温显著。当春季北支脊纬向位置显著偏东（西）时,且强度偏强（弱）,淮河流域降水偏少（多）,东北、西南和华南地区的降水偏多（少）,中国大部分地区气温明显偏高（低）。通过对相应的环流和物理量场的分析,能较合理地解释中国春季气候异常的原因,对中国短期气候预测有一定帮助。

Variation of Springtime Northern Branch Ridge and Its Impact on Climate in China

The variation of springtime northern branch ridge (SNBR) and its impact on precipitation and temperature in China are analyzed using NCEP/NCAR reanalysis data and the observational precipitation and temperature data at the 160 stations of China, with the methods of wavelet analysis, correlation analysis, etc. The results indicate that SNBR is gradually strengthening with periods of 2-3 years and quasi-6 years. Its position is moving eastward slightly with quasi-periods of 3 years and 12 years. When the SNBR is stronger (weaker), the spring precipitation from the Yellow River basin to south of the Yangtze River decreases (increases) obviously, while the spring precipitation rises (drops) in Northeast, Southwest and South China. When SNBR is eastward (westward), the spring pecipitation increases (decreases) in most part of the northern China and drops (rises) in most part of the southwest and southeast of China. Meanwhile, the springtime mean temperature in most part of China is higher (lower) than normal. When SNBR locates more westward (eastward), the precipitation decreases (increases) in the Huaihe River Basin, and rises (drops) in Northeast, Southwest and South China when the SNBR is strong (weak). The springtime mean temperature in most part of China is higher (lower) than normal. The relationship between the SNBR and the variation of the circulation can explain the climate change in China and improve the short-term climate forecasting.