A Stochastic Model for Diagnosing Subtropical Humidity Dynamics with Stable Isotopologues of Water Vapor
A Stochastic Model for Diagnosing Subtropical Humidity Dynamics with Stable Isotopologues of Water Vapor
复制标题
水蒸气稳定同位素体诊断亚热带湿度动态的随机模型
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
D. Rabanus
中科院分区：
文献类型：
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作者：
J. Galewsky;D. Rabanus
摘要自由对流层的湿度可以用冷点脱水来模拟，然后通过与边界层空气混合而变湿。这些过程之间的相对平衡对于理解湿度的年际变化和理解水汽反馈具有重要意义。水蒸气同位素组成的测量可以对这些过程提供定量的限制。作者开发了一个随机模型，根据这些过程参数化水蒸气同位素组成，并将模型参数拟合到智利Chajnantor高原（23°S）的数据中。2012年8 - 11月平均混合比为1680 ppmv，平均水汽δD为- 234‰，平均氘过量21‰。非对称的末饱和混合比rs为391(+45,−75)ppmv，中位数rs为368(+45,−75)ppmv，冻干空气与湿空气的平均混合分数为368(+45,−75)ppmv。
AbstractThe humidity of the free troposphere can be modeled, to first order, in terms of cold-point dehydration, followed by moistening via mixing with boundary layer air. The relative balance between these processes is of prime interest for understanding interannual variability of humidity and for understanding the water vapor feedback. Measurements of water vapor isotopic composition can provide quantitative constraints on these processes. The authors developed a stochastic model that parameterizes water vapor isotopic composition in terms of these processes and fit the model parameters to data from the Chajnantor Plateau, Chile (23°S). For August–November 2012, the average mixing ratio was 1680 ppmv, with mean water vapor δD of −234‰ and mean deuterium excess of 21‰. The data were best fit by an asymmetric last-saturation distribution with mean last-saturation mixing ratio rs of 391 (+45, −75) ppmv, a median rs of 368 (+45, −75) ppmv, and a mean mixing fraction between the freeze-dried air and moist bo...