A U.S.‐based analysis of the ability of the Clausius‐Clapeyron relationship to explain changes in extreme rainfall with changing temperature. Issue 7 (4th April 2016)

• Record Type: Journal Article
• Authors: Ivancic, Timothy J; Shaw, Stephen B
• Is Part Of: Journal of geophysical research. Volume 121:Issue 7(2016)
• Page Start: 3066
• Page End: 3078
• Publication Date: 2016-04-04
• Subjects: Clausius‐Clapeyron -- extreme precipitation; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1002/2015JD024288
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Numerous papers have shown links between >99th percentile hourly precipitation and daily temperature ( P extreme versus T ), often explained using the Clausius‐Clapeyron (CC) relationship. The CC relationship predicts an approximately 7% increase in precipitation intensity per degree celsius. However, recent analyses indicate that the P extreme versus T rate can be larger than the CC prediction. In this work, we analyze the P extreme versus T rate with an automated method across the contiguous U.S. using station data aggregated on a 161 km grid. To evaluate controls on P extreme versus T, we isolate convective storms to evaluate whether greater than CC rates are due to the transition between storm types or are a feature of convective storms at high T . We repeat the analysis using dew point to assess whether T control on extreme P is indeed a matter of moisture availability. When evaluated using both T and dew point, the northeastern U.S. is most likely to exhibit a greater than predicted P extreme versus T rate (57% of the region when using T ). At 56% of these points, the > CC rates appeared to occur entirely because of a transition between frontal and convective storms. At 30% of these sites, a greater than CC relationship appeared to occur entirely because of greater than CC scaling in convective intensity. At 11% of sites neither was found to be significant, and at 3% both were found to contribute significantly. This analysis suggests that > CC scaling is not prevalent everywhere in the contiguous U.S., and in regions where it does occur, it can be due to multiple causes. Key Points: Extreme precipitation scaling with temperature exceeds the Clausius‐Clapeyron rate in the NE U.S. Extreme precipitation scaling is often forced by a transition from frontal to convective rain At high temperatures ≳20 degrees celsius, limited moisture may suppress extreme precipitation intensity