Estimation of the isotopic composition and origins of winter precipitation over Japan using a regional isotope circulation model
Estimation of the isotopic composition and origins of winter precipitation over Japan using a regional isotope circulation model
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使用区域同位素环流模型估算日本冬季降水的同位素组成和来源
DOI：
10.1002/2017jd026751
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
and Y. Hirabayashi
中科院分区：
文献类型：
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作者：
Tanoue;M.;K. Ichiyanagi;K. Yoshimura;J. Shimada;and Y. Hirabayashi
降水的氘过量（d-过量）有助于识别蒸汽源区，因为它反映了这些地区的湿度条件。对于日本来说，研究假设当冬季的d-过剩值大于20‰或高于夏季的平均值时，日本海是冬季降水的主要来源。由于这一假设是基于这样一种解释，即高d-过量值是由于大陆冬季风（WM）和温暖的日本海之间的相互作用，因此它可能不适合于由热带气旋（EC）引起的冬季降水。在这里，我们澄清当地模式的同位素组成和降水的起源在WM和EC类型在日本使用区域同位素循环模型。结果表明，在WM型中，日本海对日本海一侧的降水贡献最大，而在EC型中，太平洋是日本降水的主要来源。由于WM型的d-excess值比EC型高，因此可以认为，当d-excess值高时，日本海一侧的降水主要来自日本海。相比之下，我们无法仅从太平洋沿岸的本州岛的d-过量值确定源区，因为WM和EC类型之间的d-过量值的差异尚不清楚。此外，WM变异性可以从观察到的d-过量值估计，因为它们具有明显的正相关性。
The deuterium excess (d‐excess) of precipitation aids in identifying vapor source regions because it reflects humidity conditions in those regions. For Japan, studies have assumed that the Sea of Japan was the dominant source of winter precipitation when the d‐excess value in winter is >20‰ or higher than the average value in summer. Because this assumption is based on an interpretation that the high d‐excess value is due to an interaction between the continental winter monsoon (WM) and warm Sea of Japan, it may not be appropriate for winter precipitation due to extratropical cyclones (ECs). Here we clarify local patterns of isotopic composition and the origins of precipitation in WM and EC types over Japan using a regional isotope circulation model. The results indicate that the Sea of Japan made the highest contribution to precipitation on the Sea of Japan side in the WM type, whereas the Pacific Ocean is the dominant source of precipitation over Japan in the EC type. Because d‐excess values are higher in the WM type than the EC type, we can assume that the Sea of Japan is the dominant source of precipitation on the Sea of Japan side when the d‐excess value is high. In comparison, we cannot identify the source regions from d‐excess values alone for Honshu Island bordering the Pacific Ocean, because the difference in the d‐excess value between the WM and EC types is unclear. Moreover, WM variability can be estimated from observed d‐excess values due to their clear positive correlation.