Can Regional Climate Models Represent the Indian Monsoon?
Can Regional Climate Models Represent the Indian Monsoon?
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DOI：
10.1175/2011jhm1327.1
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发表时间：
2011-10-01
影响因子：
3.8
通讯作者：
Hagemann, Stefan
中科院分区：
文献类型：
--
作者：
Lucas-Picher, Philippe;Christensen, Jens H.;Hagemann, Stefan
四个区域气候模式（RCMs），以代表印度季风的能力进行了验证，在1981-2000年期间使用45年的欧洲中期天气预报中心（ECMWF）再分析（ERA-40）作为横向边界强迫数据的一致框架。在季风期间，区域气候模型能够捕捉到降水的空间分布，在印度的中部和西部海岸最大，但在孟加拉国和缅甸的印度东海岸的区域尺度上有重要的偏差。与观测结果相比，印度北部的大多数模型都太温暖了。这对RCM模拟的平均海平面压力产生了影响，与ERA-40相比，一般来说太低了。这些偏差扰乱了驱动季风动态的陆海温度和压力对比，结果导致高估风速，特别是海上风速。季风爆发的RCMs的时间是在很好的协议，从观测为基础的网格数据集，而季风撤退是不太好的模拟。Hovmoller图表示的降水的平均年周期表明，降水的纬向运动的RCMs模拟的是一个观察到的，但降水量和区域分布有很大的不同的四个RCMs之间。总之，区域气候模型之间在区域尺度上的分布表明，在最先进的区域气候模型中，重要的反馈和过程很少考虑或没有考虑。
The ability of four regional climate models (RCMs) to represent the Indian monsoon was verified in a consistent framework for the period 1981-2000 using the 45-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) as lateral boundary forcing data. During the monsoon period, the RCMs are able to capture the spatial distribution of precipitation with a maximum over the central and west coast of India, but with important biases at the regional scale on the east coast of India in Bangladesh and Myanmar. Most models are too warm in the north of India compared to the observations. This has an impact on the simulated mean sea level pressure from the RCMs, being in general too low compared to ERA-40. Those biases perturb the land sea temperature and pressure contrasts that drive the monsoon dynamics and, as a consequence, lead to an overestimation of wind speed, especially over the sea. The timing of the monsoon onset of the RCMs is in good agreement with the one obtained from observationally based gridded datasets, while the monsoon withdrawal is less well simulated. A Hovmoller diagram representation of the mean annual cycle of precipitation reveals that the meridional motion of the precipitation simulated by the RCMs is comparable to the one observed, but the precipitation amounts and the regional distribution differ substantially between the four RCMs. In summary, the spread at the regional scale between the RCMs indicates that important feedbacks and processes are poorly, or not, taken into account in the state-of-the-art regional climate models.