A Radar-Based Climatology of Mesoscale Convective Systems in the United States
A Radar-Based Climatology of Mesoscale Convective Systems in the United States
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DOI：
10.1175/jcli-d-18-0559.1
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发表时间：
2019-03-01
影响因子：
4.9
通讯作者：
Ashley, Walker S.
中科院分区：
文献类型：
--
作者：
Haberlie, Alex M.;Ashley, Walker S.
本研究将自动中尺度对流系统(MCS)分割、分类和跟踪方法应用于覆盖邻近美国(CONUS)的合成雷达反射率镶嵌图像，研究周期相对较长，为22年(1996-2017)。这些数据为MCS的季节和年际变化提供了一种新的评估。此外，还利用其中16年(2002-17年)的每小时降雨量数据，系统地研究了与雷达衍生的MCS事件有关的降雨量。文中还研究了横跨大陆分水岭以东的部分大陆控制区(ECONUS)的MCSs的属性和产状，以及作者定义的五个亚区--北部平原、高平原、玉米带、东北和中南部。结果表明，东太平洋有两个MCS活动的优先区域：1)中南部和墨西哥湾沿岸；2)中原和中西部。MCS的发生和MCS降水表现出明显的季节循环，大多数地区主要在温暖的季节(5-8月)经历这些事件。此外，MCS降水占ECONUS许多地区年降雨量和季节性降雨量的50%以上。尤其重要的是，农业用地高度利用(玉米带)和重要含水层补给特性(高平原)的地区暖季降雨量的大部分可归因于MCS。这些结果重申了MCSs是ECONUS水气候的一个重要方面。
This research applies an automated mesoscale convective system (MCS) segmentation, classification, and tracking approach to composite radar reflectivity mosaic images that cover the contiguous United States (CONUS) and span a relatively long study period of 22 years (1996-2017). These data afford a novel assessment of the seasonal and interannual variability of MCSs. Additionally, hourly precipitation data from 16 of those years (2002-17) are used to systematically examine rainfall associated with radar-derived MCS events. The attributes and occurrence of MCSs that pass over portions of the CONUS east of the Continental Divide (ECONUS), as well as five author-defined subregions-North Plains, High Plains, Corn Belt, Northeast, and Mid-South-are also examined. The results illustrate two preferred regions for MCS activity in the ECONUS: 1) the Mid-South and Gulf Coast and 2) the Central Plains and Midwest. MCS occurrence and MCS rainfall display a marked seasonal cycle, with most of the regions experiencing these events primarily during the warm season (May-August). Additionally, MCS rainfall was responsible for over 50% of annual and seasonal rainfall for many locations in the ECONUS. Of particular importance, the majority of warm-season rainfall for regions with high agricultural land use (Corn Belt) and important aquifer recharge properties (High Plains) is attributable to MCSs. These results reaffirm that MCSs are a significant aspect of the ECONUS hydroclimate.