20km高分辨率全球模式对青藏高原夏季降水变化的预估

Projection of Summer Precipitation Change over the Qinghai-Tibetan Plateau with a 20 km High-resolution Global Climate Model

使用日本气象研究所(Meteorological Research Institute,MRI)大气环流模式在20 km分辨率下的国际大气模式比较计划(Atmospheric Model Intercomparison Project,AMIP)试验结果以及A1B温室气体排放情景下(简称A1B情景)的预估试验数据,预估了青藏高原夏季(6—8月)降水的变化,并讨论了降水变化的可能原因。在A1B情景下,青藏高原夏季降水量显著增加,中心位于青藏高原东南部,主要归因于来自印度洋和孟加拉湾的西南水汽,经90°E—100°E附近进入高原的水汽输送显著增加。同时,整个青藏高原夏季强降水出现概率增加,降水频率南部减少,北部增加。高原南部(北部)降水频率的减少(增加)是因为该地区降水强度的增加速率快(慢)于降水量的增加速率。高分辨率MRI模式预估的青藏高原夏季降水变化与较低分辨率的耦合模式预估结果基本一致,但提供了更详细的局地变化信息。

Projection of future summer precipitation change over the Qinghai-Tibetan Plateau is studied based on AMIP（the Atmospheric Model Intercomparison Project） and the A1 B scenario experiment results by a 20 km high-resolution global climate model,MRI. Under the A1 B scenario,the summer precipitation would increase significantly,with the biggest increasing center over the southeastern Qinghai-Tibetan Plateau. This is might attributed to the increasing southwest water vapor transportation to the Qinghai-Tibetan Plateau from the Indian Ocean and the Bay of Bengal. The probability of summer precipitation with high intensity is projected to increase over the whole Qinghai-Tibetan Plateau. The summer precipitation frequency over the southern（northern） QinghaiTibetan Plateau would decrease（increase）,as the increasing rate of precipitation intensity is faster（slower）than that of precipitation amount over the southern（northern） Qinghai-Tibetan Plateau. The precipitation change over the Qinghai-Tibetan Plateau projected by the high-resolution MRI model is almost consistent with coupled models with low-resolution,except for the detail information provided.