Interannual fluctuations of the relationship between winter precipitation and air temperature in the heavy-snowfall zone of Japan
Interannual fluctuations of the relationship between winter precipitation and air temperature in the heavy-snowfall zone of Japan
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DOI：
10.3189/2013aog62a302
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发表时间：
2013
影响因子：
2.9
通讯作者：
S. Yamaguchi;K. Iwamoto;Sento Nakai
中科院分区：
文献类型：
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作者：
S. Yamaguchi;K. Iwamoto;Sento Nakai
面对日本海的日本地区拥有世界上最深的季节性积雪，尽管在这个中等海拔地区（35-40˚N），冬季最冷的月份（1 - 2月）的平均气温超过0°C。因此，即使是轻微的温度升高，也可能通过将降水形式从雪转变为雨而急剧减少该地区的雪深。在这项研究中，为了加强对冬季降水条件的理解，我们引入了冬季降水曲线（WPC），该曲线利用逐时数据绘制了冬季降水（12月至2月）与相应气温的分布。然后，我们研究了WPC与区域气候条件之间的关系。本研究将WPC分为两种类型：单峰型（SP），在0°C附近有一个尖峰；多峰型（MP），有几个小峰。这里的“峰”表示降水在一定温度下频繁发生。MP型峰的位置随冬季平均气温的波动而变化，SP型峰的位置随冬季平均气温的年波动而变化不大。MP型的多个峰中的一个出现在~ 0°C，该峰随着冬季平均温度的波动也几乎保持平稳。SP型和MP型的WPC峰值都出现在0℃附近，这可能是由于积雪融化的冷却作用导致0℃等温层的发展。
Abstract Regions of Japan facing the Sea of Japan have some of the world’s deepest seasonal snowpack, although air temperatures averaged over the coldest winter months (January-February) are above 0°C in this mid-altitude zone (35–40˚ N). Therefore, even a slight temperature increase is likely to drastically decrease the snow depth in this area by changing the precipitation form from snow to rain. In this study, to enhance understanding of winter precipitation conditions, we introduce the winter precipitation curve (WPC), which plots the distribution of winter precipitation (December-February) against the corresponding air temperature using hourly data. We then examine the relationship between the WPC and regional climate conditions. The WPC was classified into two types in the study: the single-peak (SP) type, having one sharp peak near 0°C, and the multiple-peaks (MP) type, having several small peaks. Here ‘peak’ indicates that precipitation frequently occurs at a certain temperature. Peaks of the MP type changed position with fluctuations in mean winter temperature, but the peak of the SP type moved only slightly despite annual fluctuations in winter mean temperature. One of the multiple peaks of the MP type appeared at ∼0°C and this peak also remained nearly stationary with fluctuations in winter mean temperature. The peak of the WPC appearing near 0°C in both the SP and MP types likely resulted from the development of the 0°C isothermal layer due to the cooling effect of melting snow particles.