The effect of increased convective entrainment on Asian monsoon biases in the MetUM general circulation model
The effect of increased convective entrainment on Asian monsoon biases in the MetUM general circulation model
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DOI：
10.1002/qj.2371
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发表时间：
2014
影响因子：
8.9
通讯作者：
S. Bush;A. Turner;S. Woolnough;G. Martin;N. Klingaman
中科院分区：
文献类型：
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作者：
S. Bush;A. Turner;S. Woolnough;G. Martin;N. Klingaman
我们表明，夏季降水偏差在南亚季风域是敏感的增加对流参数化的夹带和detrainment率在气象局统一模式。我们探索这种敏感性，以提高我们的理解的偏见和通知努力，以改善对流参数化。我们进行了新的有针对性的实验，在这些实验中，我们增加了特别是大的降水偏差地区的夹带率和去除率。我们使用这些实验来确定是否在一个给定的位置的敏感性是对流的局部变化的结果，或者是一个远程响应的变化在其他地方。我们发现，局部变化导致不同的平均状态响应在可比区域。当夹带和去除率在全球范围内增加时，区域之间的反馈通常会加强局部反应。我们选择了两个热带上升区域，表现出不同的平均状态响应，西赤道印度洋和西北太平洋，并分析它们作为案例研究，以确定导致不同响应的机制。我们的研究结果表明，一个地区的平均状态的几个方面，包括水分含量，海面温度和环流，发挥作用，在当地的反馈，确定增加夹带和detrainment的响应。
We demonstrate that summer precipitation biases in the South Asian monsoon domain are sensitive to increasing the convective parametrization's entrainment and detrainment rates in the Met Office Unified Model. We explore this sensitivity to improve our understanding of the biases and inform efforts to improve convective parametrization. We perform novel targeted experiments in which we increase the entrainment and detrainment rates in regions of especially large precipitation bias. We use these experiments to determine whether the sensitivity at a given location is a consequence of the local change to convection or is a remote response to the change elsewhere. We find that a local change leads to different mean‐state responses in comparable regions. When the entrainment and detrainment rates are increased globally, feedbacks between regions usually strengthen the local responses. We choose two regions of tropical ascent that show different mean‐state responses, the western equatorial Indian Ocean and western north Pacific, and analyse them as case‐studies to determine the mechanisms leading to the different responses. Our results indicate that several aspects of a region's mean state, including moisture content, sea surface temperature and circulation, play a role in local feedbacks which determine the response to increased entrainment and detrainment.