A quantitative assessment of the sensitivity of the downstream midlatitude flow response to extratropical transition of tropical cyclones
A quantitative assessment of the sensitivity of the downstream midlatitude flow response to extratropical transition of tropical cyclones
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DOI：
10.1002/2015gl065764
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发表时间：
2015-11
影响因子：
5.2
通讯作者：
C. Grams;S. Lang;J. Keller
中科院分区：
文献类型：
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作者：
C. Grams;S. Lang;J. Keller
在热带气旋（TC）的转型期（ET），中纬度气流的可预报性往往会降低。在这项研究中，我们评估的敏感性中纬度流量响应ET。为此，一个简单的新的度量，“等效预测小时差”，并引入和应用到最近的ET事件，其中TC已被删除或搬迁的实验模拟。在ET早期，中纬度气流响应对过渡TC下游的山脊形成很敏感。在强烈的洋脊形成和Rossby波触发的情况下，灵敏度仍然很高。中纬度气流响应对TC初始位置的误差更加敏感。这项研究新量化的下游中纬度流量响应ET的敏感性的高度。它证实了需要正确的热带气旋生成和TC路径预报，以改善ET期间的中纬度数值天气预报。
During extratropical transition (ET) of tropical cyclones (TC) reduced predictability for the midlatitude flow is often observed. In this study we assess the sensitivity of the midlatitude flow response to ET. To this end, a simple novel metric, the “equivalent forecast hour difference,” is introduced and applied to experimental simulations for eight recent ET events, in which the TC has been removed or relocated. Early during ET, the midlatitude flow response is sensitive to ridgebuilding directly downstream of the transitioning TC. In cases with strong ridgebuilding and Rossby wave triggering, the sensitivity remains high. The midlatitude flow response is even more sensitive to error in the initial position of the TC. This study newly quantifies the high degree of sensitivity of the downstream midlatitude flow response to ET. It corroborates the need for correct tropical cyclogenesis and TC track forecasts for improving midlatitude numerical weather prediction during ET.