Regional climate model applications on sub-regional scales over the Indian monsoon region: The role of domain size on downscaling uncertainty
Regional climate model applications on sub-regional scales over the Indian monsoon region: The role of domain size on downscaling uncertainty
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DOI：
10.1029/2012jd017956
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发表时间：
2012-05
影响因子：
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通讯作者：
B. Bhaskaran;A. Ramachandran;Richard G. Jones;W. Moufouma‐Okia
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文献类型：
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作者：
B. Bhaskaran;A. Ramachandran;Richard G. Jones;W. Moufouma‐Okia
许多需要进行这些评估的国家和省份的面积只有20万平方公里，远远小于成功应用单向嵌套区域气候模式所需的理想区域。因此，分区域范围的评估（例如，河流流域）的气候变化模拟通常是利用对相对较大区域进行的气候变化模拟进行的。在这里，我们表明，季节平均水文循环和一天到一天的降水量变化的一个子区域内的模型域的大小是敏感的，即使在该地区的大尺度环流特征在很大程度上是不敏感的。在季节性时间尺度上，相对较小的域通过增加进入研究区域的水分净运输来加强水文循环，从而增强降水和水分的局部再循环。在每日的时间尺度上，模拟运行在较小的域产生更多的中等降水日数的子区域相对于相应的较大的域模拟。水汽和垂直速度的日变化的子区域内的评估表明，较小的域可能有利于更频繁的温和的隆升和随后的降水在该地区。结果仍然在很大程度上不敏感的模式的水平分辨率，表明鲁棒性域的大小对区域模式的解决方案的影响。这些域大小依赖的降水特性有可能增加一个更大的不确定性的缩小规模的预测。引文：Bhaskaran，B.，A.拉马钱德兰河Jones和W. Moufouma-Okia（2012），印度季风区次区域尺度上的区域气候模型应用：域大小对尺度缩小不确定性的作用，J. Geophys。结果：117，D10113，doi：10.1029/2012JD017956。
Many countries and provinces requiring these assessments are as small as 200,000 km 2 in size, significantly smaller than an ideal domain needed for successful applications of one-way nested regional climate models. Therefore assessments on sub-regional scales (e.g., river basins) are generally carried out using climate change simulations performed for relatively larger regions. Here we show that the seasonal mean hydrological cycle and the day-to-day precipitation variations of a sub-region within the model domain are sensitive to the domain size, even though the large scale circulation features over the region are largely insensitive. On seasonal timescales, the relatively smaller domains intensify the hydrological cycle by increasing the net transport of moisture into the study region and thereby enhancing the precipitation and local recycling of moisture. On daily timescales, the simulations run over smaller domains produce higher number of moderate precipitation days in the sub-region relative to the corresponding larger domain simulations. An assessment of daily variations of water vapor and the vertical velocity within the sub-region indicates that the smaller domains may favor more frequent moderate uplifting and subsequent precipitation in the region. The results remained largely insensitive to the horizontal resolution of the model, indicating the robustness of the domain size influence on the regional model solutions. These domain size dependent precipitation characteristics have the potential to add one more level of uncertainty to the downscaled projections. Citation: Bhaskaran, B., A. Ramachandran, R. Jones, and W. Moufouma-Okia (2012), Regional climate model applications on sub-regional scales over the Indian monsoon region: The role of domain size on downscaling uncertainty, J. Geophys. Res., 117, D10113, doi:10.1029/2012JD017956.