【摘要】 用2001年和2003年NCEP/NCAR再分析资料,计算了亚洲季风区两年逐日的大气热源汇〈Q1〉,再用谐波分析方法对〈Q1〉作带通滤波,得到了准30~70 d的〈Q1〉低频分量,并分析了两年夏季大气热源汇和其低频振荡变化特征的差异,然后研究了一些“关键”区〈Q1〉低频分量的变化与我国降水的关系。结果表明:在2001年和2003年夏季的亚洲季风区,一方面应该有这样一种过程,大气热源汇低频分量经向和纬向传播的差异→江淮流域旱涝期东亚地区大气热源汇低频分量南北配置的差异→东亚地区大气热源汇本身的南北分布不同。另一方面,夏季的5~8月期间,高原中南侧有较强的低频热源(热汇)时,可导致其后期江淮流域降水偏多(少);中国南海的作用则正好相反,南海有较强的低频热源(热汇)时,不仅可导致其后期江淮流域降水偏少(多),还可导致其后期青藏高原东部降水偏少(多)。因此,夏季亚洲季风区热源、热汇季节内变化特征的不同可导致我国江淮流域异常的旱涝发生。更多还原

【Abstract】 Drought and flood are the main disasters of Eastern China.During the summers of 2001 and 2003,the severe drought and flood occurred respectively in the Yangtze River-Huaihe River basin.In order to investigate the causes,the daily atmospheric heating source/sink 〈Q₁〉 over Asian monsoon area is computed by using the thermodynamic equation and the NCEP/NCAR re-analyses data of 2001 and 2003,and then its quasi-30-70-day low-frequency oscillation（LFO） is got by the Fourier transform according to the significance periodic variation of the 〈Q₁〉 which is got using the spectral analysis in three key areas.Then the differences of the 〈Q₁〉 and its LFO in the two summers are analyzed,furthermore the relationship between the 〈Q₁〉 LFO in some key areas and the delayed rainfall in China is investigated in the summer of 2003.The result shows that: On the one hand,the process should is that the meridional and zonal propagation of the 〈Q₁〉 LFO is different → the North-South scheme of the 〈Q₁〉 LFO over East Asia is different during the drought/flood periods of the Yangtze River-Huaihe River basin → the North-South distribution of the 〈Q₁〉 is also different in the summers of 2001 and 2003.On the other hand,there are the significance correlations between the changes of the 〈Q₁〉 LFO over the middle-southern Tibetan Plateau and the South China Sea from May 1 to August 6 and the delay rainfall of the Yangtze River-Huaihe River basin from May 11 to August 16.While the stronger heating source/sink of the 〈Q₁〉 LFO is over the middle southern Tibetan Plateau,the heavier/lighter rainfall maybe appears in the Yangtze River-Huaihe River basin,but it is reverse over the South China Sea.At one time,the heating source/sink of the 〈Q₁〉 LFO over the South China Sea is also significantly negatively correlated with the rainfall in the eastern Tibetan Plateau in summer.Therefore,the difference of the characteristics of 〈Q₁〉 LFO over Asian monsoon area can lead to the abnormal summer drought/flood in the Yangtze River-Huaihe River valley of China.更多还原