北极海冰的厚度和面积变化对大气环流影响的数值模拟

文中利用中国科学院大气物理研究所设计的两层大气环流模式 ,模拟研究了北极海冰厚度和面积变化对大气环流的影响 ,尤其是对东亚区域气候变化的影响。模式中海冰厚度处理趋于合理分布 ,导致东亚冬、夏季风偏强 ,使冬季西伯利亚高压和冰岛低压的模拟结果更趋合理 ;另一方面 ,海冰厚度变化可以激发出跨越欧亚大陆的行星波传播 ,在低纬度地区 ,该行星波由西太平洋向东太平洋地区传播 ;海冰厚度变化对低纬度地区的对流活动也有影响。冬季北极巴伦支海海冰变化对后期大气环流也有显著的影响。数值模拟结果表明 :冬季巴伦支海海冰偏多 (少 )时 ,春季 (4～ 6月 )北太平洋中部海平面气压升高 (降低 ) ,阿留申低压减弱 (加深 ) ,有利于春季白令海海冰偏少 (多 ) ;而夏季 ,亚洲大陆热低压加深 (减弱 ) ,5 0 0 h Pa西太平洋副热带高压位置偏北 (南 )、强度偏强 (弱 ) ,东亚夏季风易偏强 (弱 )。

NUMERICAL SIMULATIONS ON INFLUENCE OF SEA-ICE THICKNESS AND EXTENT VARIATION IN ARCTIC ON ATMOSPHERIC CIRCULATION

By using IAP 2L-GCM, the influence of variation of sea ice thickness and extent in Arctic on atmospheric circulation , especially on East Asian climate variations is investigated. The results indicate that an nearly reasonable distribution of sea-ice thickness in Arctic in the model leads directly to stronger winter and summer monsoon over East Asia, and improves the model's simulation results for Siberia High and Icelandic Low in winter. On the other hand, sea-ice thickness variation can excite the teleconnection wave trains across Asian Continent, and in the low latitude region, the wave propagates from the Western Pacific across the equator to the Eastern Pacific. In addition, variation of sea ice thickness also influences convective activities over Asian low latitude region . The effect of winter sea ice extent in the Kara and the Barents Seas on atmospheric circulation in the following spring and summer is also significant. The simulation result shows that when winter sea ice extent in the target region is larger(smaller) than normal, (1)in spring(from April to June), positive(negative)SLP anomalies occupy the northern central Pacific, which lead directly to weakened (deepened)Aleutian Low and light(heavy) sea ice in Bering Sea; (2)in summer, thermal depression in Asian Continent is deepened(weakened), and Subtropical High in the western Pacific shifts northward(southward) from its normal position and to be strengthened(weakened).