SYNOPTIC MECHANISMS ASSOCIATED WITH SNOWFALL INCREASES TO THE LEE OF LAKES ERIE AND ONTARIO
SYNOPTIC MECHANISMS ASSOCIATED WITH SNOWFALL INCREASES TO THE LEE OF LAKES ERIE AND ONTARIO
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与伊利湖和安大略湖背风区降雪量增加相关的天气机制
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
A. Ellis
中科院分区：
文献类型：
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作者：
D. Leathers;A. Ellis
降雪是一个影响几乎社会各个领域的冰环变量。由于其社会重要性，降雪是一个逻辑变量，可用作潜在全球环境变化的指标。这项研究调查了美国东部五大湖地区观测到的大量降雪增加的机制。结果表明，从 1930 年至 1931 年的降雪季节到 1989 年至 1990 年的 60 年期间，纽约州西部和宾夕法尼亚州西北部部分地区的平均降雪量增加了 100 厘米。利用天气气候学方法来确定导致该地区降雪的一致天气尺度大气模式。九种天气类型被确定为研究区域产生大量降雪；其中五个具有表明湖泊效应降雪的天气特征，四个具有与气旋影响相关的降雪证据特征。
对九种天气类型的季节频率的检查表明，从 1950-1951 年到 1981-1982 年，五种湖泊效应天气类型的频率大幅增加，而气旋天气类型的数量长期减少。有关九种降雪天气类型中每种降雪的频率和强度趋势的信息被组合起来，以产生由于该时期的频率和强度变化而产生的降雪变化模型。与湖泊效应降雪相关的天气模式的频率和强度趋势解释了该地区观测到的大部分降雪增加。与气旋引起的降雪相关的天气类型的变化对于整个五大湖地区的降雪变化并不重要。讨论了湖泊效应天气类型的频率和强度增加的可能原因。
Snowfall is a cyrospheric variable that impacts nearly every sector of society. Because of its societal importance, snowfall is a logical variable to be used as an indicator of potential global environmental change. This study investigates the mechanisms responsible for large observed snowfall increases across the eastern Great Lakes region of the USA. Results indicate that mean snowfall amounts across sections of western New York and north-western Pennsylvania have increased by up to 100 cm over the 60-year period encompassing the snowfall seasons 1930–1931 through to 1989–1990. A synoptic climatological approach is utilized to identify consistent synoptic-scale atmospheric patterns responsible for snowfall across the region. Nine synoptic types are identified as producing significan t snowfall in the study area; five with synoptic characteristics indicative of lake-effect snowfall and four evidencing characteristics of snowfall associated with cyclonic influence.
An examination of the seasonal frequency of the nine synoptic types indicates a substantial increase in the frequency of the five lake-effect synoptic types and a long-term decrease in the numbers of cyclone synoptic types over the period 1950–1951 through to 1981–1982. Information concerning trends in the frequency and the intensity of each of the nine snowfall-producing synoptic types was combined to produce a modelled snowfall change due to frequency and intensity variations over the period. Trends in the frequency and intensity of the synoptic patterns associated with lake- effect snowfall explain the majority of the observed snowfall increase across the region. Variations in the synoptic types associated with cyclonically induced snowfall are shown to be unimportant to snowfall changes across the eastern Great Lakes area. Possible reasons for increases in the frequency and the intensity of the lake-effect synoptic types are discussed.