Seamless Detection of Cutoff Lows and Preexisting Troughs
Seamless Detection of Cutoff Lows and Preexisting Troughs
复制标题
无缝检测截止低点和预先存在的低谷
DOI：
10.1175/mwr-d-20-0255.1
复制
发表时间：
2021
影响因子：
3.2
通讯作者：
Yamazaki Akira
中科院分区：
文献类型：
--
作者：
Kasuga Satoru;Honda Meiji;Ukita Jinro;Yamane Shozo;Kawase Hiroaki;Yamazaki Akira
我们提出了一种基于位势高度场的新方案来检测从先前存在的低谷阶段开始的截止低点。从拟议的计划得出的强度和规模将使人们能够更好地了解截止低生命周期。这些截止低点经常伴随着中尺度扰动，导致与天气有关的不利事件，如强烈的暴雨和/或龙卷风。该方案从凹陷的水平高度剖面来量化凹陷的几何特征。局部与凹陷底部和最近切点(最佳斜率)相交的直线的高度斜率表示孤立凹陷的强度和规模。该方案的优点是，通过从位势高度场中去除局部背景高度斜率，将截止低点与其先前存在的低谷无缝地检测为相同的凹陷。图中显示了探测到的截止低点和先前存在的低谷的分布图，以及它们的强度、大小和从快照高度场估计的局部背景流。我们对截止低气压进行了气候学比较，以确定拟议方案的实用性。
We propose a new scheme based on geopotential height fields to detect cutoff lows starting in the preexisting trough stage. The intensity and scale derived from the proposed scheme will allow for a better understanding of the cutoff low life cycle. These cutoff lows often accompany mesoscale disturbances, causing adverse weather-related events, such as intense torrential rainfall and/or tornadoes. The proposed scheme quantifies the geometric features of a depression from its horizontal height profile. The height slope of a line intersecting the depression bottom and the nearest tangential point (optimal slope) locally indicates the intensity and scale of an isolated depression. The strength of the proposed scheme is that, by removing a local background height slope from a geopotential height field, the cutoff low and its preexisting trough are seamlessly detected as an identical depression. The distribution maps for the detected cutoff lows and preexisting troughs are illustrated along with their intensities, sizes, and local background flows estimated from snapshot height fields. We conducted climatological comparisons of cutoff lows to determine the utility of the proposed scheme.