中文摘要：

为了探究与融雪、融冻过程相联系的青藏高原春季地表非绝热加热异常对东亚夏季风强度变化的影响,利用NCEP/NCAR Reanalysis I（NCEP-I）和欧洲中心（ERA-interim）全球月平均感、潜热通量等再分析资料,以及1961—2014年全国723个气象站逐月历史观测资料,首先定义一个与青藏高原地表非绝热加热相联系的新东亚夏季风指数,并分析新夏季风指数与中国夏季降水的关系,进而探讨青藏高原春季地表非绝热加热异常对东亚夏季风强度变化的影响。结果表明：（1）受青藏高原春季大气射出长波辐射减弱、地气温差发生突变影响,近36 a青藏高原春季地表感热、潜热通量先后在1997年、2003年左右经历了一次由增大转为减小的明显突变;（2）采用200 h Pa水平风速新定义的东亚夏季风指数具有良好、广泛的代表性和适用性,近50 a来新东亚夏季风指数强度呈减弱趋势,减弱速率为-0.73/10 a;（3）新东亚夏季风指数与长江流域夏季6—8月降水之间存在极为显著的负相关关系,即东亚夏季风出现增强（减弱）异常时,长江流域夏季6—8月降水会异常减少（增多）;（4）融雪、融冻过程引起的青藏高原春季前期地表潜热通量正（负）异常,会引起随后建立的东亚夏季风强度的减弱（增强）。与融雪、融冻过程联系紧密的青藏高原春季地表感、潜热通量存在显著的准3 a左右周期,其年代际变化对随后爆发的东亚夏季风和我国东部地区夏季降水准3 a左右周期的变化具有重要影响。

英文摘要：

The monthly average zonal wind, sensible and latent heat fluxes reanalysis data of the NCAR/NCEP Reanalysis I （NCEP - I） and European Centre for Medium - Range Weather Forecasts Center（ ERA - interim） , and the 723 stations observational precipitati-on and temperature data from 1961 to 2014 over China, were used to investigate the effects of Qinghai - Xizang Plateau,s （ QXP） spring surface diabatic heating anomalies, which were associated with snowmelt and thawing processes, on the East Asian summer mon-soon intensity changes. Firstly, the inter - annual variation characteristics of QXP surface diabatic heating in spring that closely related with the thawing of snow and thawing - freezing processes of soil were analyzed and diagnosed. Meanwhile, a new East Asian summer monsoon index （EASMI） was defined, which has intimately associated with the spring surface diabatic heating and large - scale atmos-pheric circulation over QXP. Based on the above, the relationships between EASMI and the summer precipitation over China were re-searched, and the effects of QXP,s spring surface diabatic heating anomalies on the East Asian summer monsoon intensity change were also investigated and analyzed. The results are as follows ： （ 1） Due to the atmospheric outgoing long wave radiation decreasing and the surface - atmosphere temperature difference （Ts - Ta） mutation, the spring surface sensible and latent heat fluxes had successively ex-perienced significant mutation from increasing to decreasing around 1997, 2003 during the past 36 years. （ 2 ） The new EASMI that was defined by the 200 hPa zonal wind speed in this paper had a good, wide representation and application. It showed a weakening tenden-cy in recent 50 years with the rate of - 0. 73 （ 10a） 1. （ 3 ） There was a significant negative correlation between the new EASMI and the entire Yangtze River basin’ s summer precipitation,i. e. when the new EASMI appeared a positive （ negative） anomalies, t