摘要
利用水平分辨率接近0.7°×0.7°、垂直方向60层的ERA-Interim再分析资料,分析了2011年夏季江淮区域水汽汇的演变及各项的贡献,研究了与水汽辐合项有关的水汽输送及相应的月平均环流和天气尺度扰动。结果表明:(1)ERA-Interim再分析资料对江淮区域夏季水汽平衡有较好的描述能力。由水汽辐合项与水汽局地变化项计算的水汽汇值和用降水与蒸发求得的水汽汇值高度一致,说明该资料可用于研究江淮区域的水汽汇。(2)2011年夏季江淮区域整体处于水汽汇区,且水汽汇值具有明显的2~6天的天气尺度振荡。降水对水汽汇的贡献远大于蒸发,而水汽辐合项与水汽局地变化项对水汽汇均有较大贡献,并且对水汽汇具有超前1~2天的指示作用。(3)月平均环流和天气尺度扰动均通过与水汽输送密切相关的水汽辐合项对江淮区域水汽汇产生显著影响。月际尺度的水汽汇变化与大尺度大气环流尤其是副高有密切关系;而江淮流域及西南地区的天气扰动对江淮区域水汽汇的天气尺度振荡起到至关重要的作用。
The summer moisture sink and its components in the Yangtze–Huaihe River basin(YHRB) in 2011 were investigated using high-resolution ERA-Interim reanalysis data at a horizontal resolution of approximately 0.7°×0.7°with 60 σ vertical levels. The associated large-scale general circulation and synoptic disturbances were also investigated.The results can be summarized as follows. 1) Summer water vapors over the YHRB are well matched based on the water vapor balance equations used for the ERA-Interim data. The moisture sink derived from water vapor convergence minus the local moisture tendency is highly consistent with its counterpart derived from precipitation minus evaporation(P E),indicating good performance of the ERA-Interim reanalysis in describing moisture sinks for the YHRB region. 2) On a monthly mean basis, the YHRB area was a moisture sink in summer 2011, and its evolution exhibits a pronounced2–6-day synoptic fluctuation. The contribution of precipitation to the moisture sink is notably larger than that of evaporation during the rainy season. Conversely, both moisture convergence and the local moisture tendency play an important role in the moisture sink, with a 1–2-day predictable skill for its daily change. 3) Combined with water vapor transport associated with moisture convergence, both the large-scale circulation and local synoptic weather systems contribute greatly to the YHRB regional moisture sink. In particular, the position of the western Pacific subtropical high is closely related to the regional moisture sink on a monthly mean basis, whereas local weather disturbances over the YHRB and southwestern China primarily impact the regional moisture sink on a synoptic basis.
出处
《大气科学》
CSCD
北大核心
2013年第6期1210-1218,共9页
Chinese Journal of Atmospheric Sciences
基金
国家重点基础发展计划项目2010CB428602
国家自然科学基金资助项目41205065
41005046
江苏高校优势学科建设工程项目
