青藏高原积雪对亚洲夏季风影响的诊断及数值研究

通过对青藏高原多、少雪年的合成分析及数值试验，研究了青藏高原积雪对亚洲 夏季风和我国东部气候异常的影响。结果表明:青藏高原积雪造成亚洲大气环流较大的年际变化。高原积雪改变了高原陆面春、夏季的热状况，使亚洲夏季风爆发推迟20天左右。高原积雪通过以下物理过程影响亚洲夏季风和我国东部气候:高原积雪多(少)→高原春、夏季的感热弱(强)→感热加热引起的上升运动弱(强)，高原强(弱)环境风场→不利(有利)于高原感热通量向上输送→高原上空对流层加热弱(强)→高原对流层温度低(高)→高原南侧温度对比弱(强)→造成亚洲夏季风弱(强)→我国长江流域易涝(旱)。

The Influences of Snow Cover over the Tibetan Plateau on Asian Summer Monsoon

The influences of snow cover over the Tibetan Plateau on Asian summer monsoon are stu died by composed analyses and conducting numerical experiments. The main conclusions are as follows:the snow cover over the Tibetan Plateau changes the characteristics of surface heating and directly in fluences on the Asian summer monsoon and climate of the eastern China. The possible mechanism link ing snow cover over the Tibetan Plateau and anomalous Asian summer monsoon is that more (less)snow cover over the Tibetan Plateau→weak (strong) surface heating in spring and summer→weak (strong) upward motion and strong (weak) environmental wind→unfavorable (favorable) condition for transporting surface sensible heating from near-surface layers to upper layers→weak (strong)tropospheric heating→low (high) tropospheric temperature surrounding the Tibetan Plateau→weak (strong) tropospheric temperature contrast south of the Tibetan Plateau in spring and summer→weak (strong) Asian summer monsoon.