To assess the effects of spatial resolutions of regional climate models that are used for the simulation of summer surface air temperatures (SATs) over China, the regional climate model RegCM3 is employed for a 5-year (2000 - 2004) long simulation of summer SATs over a fixed domain within China by choosing 3 horizontal resolutions (30, 60 and 90 km) and 3 vertical resolutions (14, 18, and 23 layers). The assessment is carried out in terms of several parameters, e. G. , simulated bias, root mean square error, and spatial correlation coefficient, and major conclusions are obtained as follows: (1) Simulated 5-year-mean summer SATs generally show a sensitivity to spatial resolutions for the whole China, where the subareas of North China and Northwest China are most affected with maximum resolution-induced differences of over 1 ℃, due mainly to the arid climate. (2) Increasing resolutions lead to an increasing sensitivity of simulated SATs to resolutions for the subareas above. (3) With higher horizontal resolutions, the model gives more detailed information for SATs, and better simulations of the temperatures at the regions with steep topography, and thus improves, as a whole, the SAT distributions over the subareas of China. However, increasing vertical resolution shows little effect on the SAT distributions. (4) SAT simulations do not always get closer to observations as resolutions increase. Proper configuration of horizontal and vertical resolutions is very important for a better simulation. In addition, increasing resolutions to quite a high level is necessary even for the regional climate research at the scale of South China and Northwest China. (5) Effects of resolutions on simulated temperatures do not show complete consistency with those on simulated precipitations. Although the influence of model resolutions may not be larger than that of model physics, this study still reveals the importance of choosing appropriate model resolutions as well as some uncertainties when a regional climate model is applied for the SAT simulation.%为评估区域气候模式中分辨率对中国夏季气温模拟的影响,选用区域气候模式RegCM3,针对中国范围同一区域设置3种水平分辨率(30、60和90 km)和3种垂直分辨率(14、18和23层)就2000-2004年夏季地表气温进行模拟试验,采用模拟偏差、均方根误差、空间相关系数等多种参数,评估了气温模拟对分辨率的敏感性.结果表明:模拟多年夏季平均地表气温对水平和垂直分辨率的提高总体上是敏感的,其中华北及西北地区模拟气温对分辨率最为敏感,不同分辨率可导致模拟气温1℃以上的差异,这与两地区较为干旱的气候是密切相关的;对考察子区域,分辨率的提高意味着模拟温度对分辨率敏感性的提高;水平分辨率越高,则模拟温度分布的细节更多,也越能改善陡峭地形附近的温度分布形势的模拟,从而有助于改善各子区域模拟形势,但垂直分辨率的提高对形势模拟改善不明显;并非分辨率越高气温模拟得越好,水平和垂直分辨率的合理配置非常重要,即使考察文中诸如华南、西北等子区域尺度的气候,提高分辨率到一定的较高程度也非常必要;季节尺度上模拟气温受分辨率提高的影响与模拟降水不完全一致.尽管分辨率的影响未必超出模式物理方案,文中结果还是揭示了区域气候模式模拟气温时选取合适分辨率的重要性及模拟中的不确定性.
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