中文摘要：

选用CMIP5的9个模式的输出资料,分析了北半球海陆间大气质量的季节变化及其驱动因子。结果表明：模式模拟的北半球海陆间的大气质量存在显著的季节性迁移。太平洋和大西洋上的大气质量1月达全年最小,太平洋上的大气质量7月堆积达最大,而大西洋上的大气质量6月堆积达最大（比再分析资料揭示的结果晚1个月）。欧亚大陆上的大气质量12月堆积达全年最大,7月达全年最小。整层积分的大气质量流具有明显的季节变化特征,其中气柱上下层变化呈相反倾向,从而影响纬向垂直环流的季节反转和海陆间大气运动和质量输送。整层水汽质量的季节变化与大气质量的季节变化相反,它在北半球海陆间出现明显的纬向偏差,从而改变大气密度及纬向压力梯度,有利于推动海陆间大气质量的迁移。1月平均地面温度自西向东呈＂负—正—负—正＂交替分布,7月分布情形与之相反,表明季节变化过程中海陆间热力因素差异推动了大气质量在海陆间迁移。

英文摘要：

Based on the multi-model output data in CMIP5,the seasonal cycle of air mass（ AM） migration between land and sea in the Northern Hemisphere（ NH） and its driving factors are investigated. Results show that the land-sea exchange of AM in NH exhibits notable seasonal variation. The annual minimum AM deficit of the Pacific Ocean and the Atlantic Ocean happens in January. The annual maximum AM pile-up of the Pacific Ocean happens in July,while the annual maximum AM pile-up of the Atlantic does in June,one month later than the result explored by the reanalysis data. The annual maximum AM pile-up of the Eurasian continent happens in December,while the minimum appears in July. Consistent with the seasonal variation of AM,the vertically integrated air mass fluxes also emerge notable seasonal cycle. In particular,there is an anti-phase variation between the low and upper level columnar-integrated AM fluxes,which affects the seasonal inversion of zonal vertical circulation and the atmospheric motion and masstransport between land and sea. The columnar water vapor shows a contrast seasonal variation compared to the AM,and its spatial distribution shows a clear zonal deviation between land and sea in NH. This implies that the corresponding changes of air density and zonal pressure gradient may be favorable for the land-sea exchange of AM. In addition,the climatology of surface air temperature in January（ July） exhibits a negative-positive-negative-positive（ positive-negative-positive-negative） pattern from west to east in NH,suggesting that the heating contrast between land and sea drives the land-sea exchange of AM during the seasonal change.