Changes in the Frequency of Cool Season Lake Effects within the North American Great Lakes Region
Changes in the Frequency of Cool Season Lake Effects within the North American Great Lakes Region
复制标题
北美五大湖地区冷季湖泊效应频率的变化
DOI：
10.1080/24694452.2020.1785270
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Joseph B. Bahret
中科院分区：
文献类型：
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作者：
A. Ellis;Michael L. Marston;Joseph B. Bahret
北美五大湖影响顺风的地面天气，尤其是在冬季，当向南迁移的冷空气经过相对温暖的湖泊时。对有利于湖泊效应的天气大气模式的研究集中在湖泊效应降雪，这是湖泊最具影响力的影响。虽然这些模式有利于湖泊效应，但它们实际上可能不会对顺风表面天气产生明显的改变。本研究使用天气类型的历史每日数据（1964-1965年至2017-2018年）来检测五大湖逆风的冷干空气对东部（伊利，安大略）和西部（密歇根州，上级）湖泊顺风的冷湿空气的凉爽季节（11月至4月）修改。整个地区的天气类型的空间安排，以确定个别天的湖泊效应的特点。在有记录以来的前三分之一时间里，湖泊影响的频率有所增加，但此后有所减少，自20世纪90年代末的一个变化点以来，这种情况最为严重，东部湖泊的情况更为突出。在湖泊的下风处，结果是改变了冷季水文气候，湖泊效应降水量和频率以及归因于湖泊效应的季节性降水量和频率的百分比下降了54年。
The North American Great Lakes influence surface weather downwind, distinctly in winter when southward migrating cold air passes over relatively warm lakes. Study of the synoptic atmospheric patterns favorable for lake effects has focused on lake-effect snowfall, the most impactful effect of the lakes. Although the patterns are conducive to lake effects, they might not actually yield discernible modification of downwind surface weather. This study uses historical daily data (1964–1965 through 2017–2018) of weather types to detect cool season (November–April) modification of cold, dry air upwind of the Great Lakes to cool, moist air downwind of the eastern (Erie, Ontario) and western (Michigan, Superior) lakes. A spatial arrangement of weather types across the region is shown to identify individual days characterized by a lake effect. The frequency of lake effects increased through the first one third of the record, but it has since decreased, most profoundly since a change point in the late 1990s and more prominently for the eastern lakes. At stations immediately downwind of the lakes, the result is a changed cool season hydroclimate, with fifty-four-year declines in lake-effect precipitation amount and frequency and in the percentages of seasonal precipitation amount and frequency attributed to lake effects.