Sensitivity of the Asian summer monsoon to the horizontal resolution: differences between AMIP-type and coupled model experiments
Sensitivity of the Asian summer monsoon to the horizontal resolution: differences between AMIP-type and coupled model experiments
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DOI：
10.1007/s00382-006-0183-z
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发表时间：
2006-09
期刊：
影响因子：
4.6
通讯作者：
A. Cherchi;A. Navarra
中科院分区：
文献类型：
--
作者：
A. Cherchi;A. Navarra
利用Echam 4大气GCM在三种不同水平分辨率（T30、T42和T106）下进行了一系列SST观测强迫试验。这些试验被用来研究模拟的亚洲夏季风（ASM）的水平分辨率的敏感性。ASM在所有分辨率下都被Echam 4模型合理地模拟。特别是对亚洲夏季风的主要表现形式--低层西风气流的捕捉较好，对降水的模拟在强度和空间形态上都比较合理。由于更高的分辨率模式的主要改进与降水的区域方面，例如西高止山脉降水更好地再现。亚洲季风区降水和风场的年际变率似乎受水平分辨率增加的影响比平均气候学的影响小。一个可能的原因是前者主要是SST强迫的。此外，在不同的水平分辨率实现与Echam 4模式耦合到全球海洋模式的实验的可用性允许的可能性，以比较这些模拟与先前描述的实验。这一分析表明，耦合模式是能够再现一个现实的季风，作为基本动力学的现象被捕获。大气分量水平分辨率的提高对模拟季风的影响与强迫试验相同。进一步研究了亚洲夏季风的年际变化及其与ENSO的关系等基本特征。
A set of experiments forced with observed SST has been performed with the Echam4 atmospheric GCM at three different horizontal resolutions (T30, T42 and T106). These experiments have been used to study the sensitivity of the simulated Asian summer monsoon (ASM) to the horizontal resolution. The ASM is reasonably well simulated by the Echam4 model at all resolutions. In particular, the low-level westerly flow, that is the dominant manifestation of the Asian summer monsoon, is well captured by the model, and the precipitation is reasonably simulated in intensity and space appearance. The main improvements due to an higher resolution model are associated to regional aspects of the precipitation, for example the Western Ghats precipitation is better reproduced. The interannual variability of precipitation and wind fields in the Asian monsoon region appears to be less affected by an increase in the horizontal resolution than the mean climatology is. A possible reason is that the former is mainly SST-forced. Besides, the availability of experiments at different horizontal resolution realized with the Echam4 model coupled to a global oceanic model allows the possibility to compare these simulations with the experiments previously described. This analysis showed that the coupled model is able to reproduce a realistic monsoon, as the basic dynamics of the phenomenon is captured. The increase of the horizontal resolution of the atmospheric component influences the simulated monsoon with the same characteristics of the forced experiments. Some basic features of the Asian summer monsoon, as the interannual variability and the connection with ENSO, are further investigated.