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Dynamic amplification of extreme precipitation sensitivity [Earth, Atmospheric, and Planetary Sciences]
Proceedings of the National Academy of Sciences of the United States of America ( IF 11.1 ) Pub Date : 2018-09-18 , DOI: 10.1073/pnas.1800357115
Ji Nie 1 , Adam H. Sobel 2, 3 , Daniel A. Shaevitz 3 , Shuguang Wang 3
Affiliation  

A useful starting hypothesis for predictions of changes in precipitation extremes with climate is that those extremes increase at the same rate as atmospheric moisture does, which is 7%K1 following the Clausius–Clapeyron (CC) relation. This hypothesis, however, neglects potential changes in the strengths of atmospheric circulations associated with precipitation extremes. As increased moisture leads to increased precipitation, the increased latent heating may lead to stronger large-scale ascent and thus, additional increase in precipitation, leading to a super-CC scaling. This study investigates this possibility in the context of the 2015 Texas extreme precipitation event using the Column Quasi-Geostrophic (CQG) method. Analogs to this event are simulated in different climatic conditions with varying surface temperature (Ts) given the same adiabatic quasigeostrophic forcing. Precipitation in these events exhibits super-CC scaling due to the dynamic contribution associated with increasing ascent due to increased latent heating, an increase with importance that increases with Ts. The thermodynamic contribution (attributable to increasing water vapor; assuming no change in vertical motion) approximately follows CC as expected, while vertical structure changes of moisture and diabatic heating lead to negative but secondary contributions to the sensitivity, reducing the rate of increase.



中文翻译:

极端降水敏感性的动态放大[地球,大气和行星科学]

预测极端降水随气候变化的一个有用的起始假设是,这些极端增长的速率与大气湿度的增长速率相同,即 7ķ-1个遵循克劳修斯(Clausius)-克拉珀龙(Clapeyron)(CC)关系。但是,这一假设忽略了与极端降水有关的大气环流强度的潜在变化。随着增加的水分导致增加的降水,增加的潜热可能导致更大规模的上升,因此,降水进一步增加,从而导致超CC结垢。本研究使用列拟地转(CQG)方法在2015年德克萨斯州极端降水事件的背景下调查了这种可能性。在不同的气候条件下,随着表面温度的变化,模拟该事件的类似物(Ťs)给予相同的绝热拟营养作用力。这些事件中的降水表现出超级CC缩放,这归因于动态潜能的增加,而动态潜能的增加是由于潜热增加而引起的上升,重要性的增加随Ťs。如预期的那样,热力学贡献(归因于水蒸气的增加;假设垂直运动没有变化)大致遵循CC,而水分和非绝热加热的垂直结构变化导致灵敏度产生负面但次要的贡献,从而降低了增长率。

更新日期:2018-09-19
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