Projected Changes in Extreme Precipitation in a 60‐km AGCM Large Ensemble and Their Dependence on Return Periods. Issue 13 (28th June 2020)

• Record Type: Journal Article
• Authors: Mizuta, Ryo; Endo, Hirokazu
• Is Part Of: Geophysical research letters. Volume 47:Issue 13(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-06-28
• Subjects: extreme events -- precipitation -- climate change -- large ensemble simulations; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2019GL086855
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: The dependence of projected changes in extreme precipitation on the return period, as well as on the temporal and spatial scales, is investigated using a large ensemble climate simulation with a 60‐km resolution global atmospheric model. The rate of increase in extreme precipitation is noticeably larger for longer return values in most parts of the world. While thermodynamic contribution to this increase generally follows the Clausius‐Clapeyron relationship for all return periods, dynamic contribution determines the dependence on the return periods. While the dependence on the temporal scales of precipitation has similar characteristics, that on spatial scales is not large. Composites for days with the 100‐year return value show that upward motion is enhanced in the middle and upper troposphere, accompanied by the enhanced horizontal water vapor convergence below. It suggests that an increase in latent heat release due to the water vapor increase plays a significant role in the dynamic contribution. Plain Language Summary: Over 5, 000 years of high‐resolution atmospheric, climate simulations are used to assess future changes in heavy rainfall events. In most parts of the world, the rate of increase in precipitation is noticeably larger for events occurring once in 100 years than those occurring once every year. The increase can be decomposed into two contributions. One is that from water vapor in the atmosphere that increases ~7% per 1‐K temperature rise. The other is that from upward motion that lifts up near‐surface water vapor to condensate into rainfall. The simulation results show that the upward motion in the middle and upper troposphere conspicuously increases for the events occurring once in 100 years. Key Points: High‐resolution large ensemble simulations are used to assess changes in extreme precipitation under +4‐K surface warming The rate of increase in precipitation is noticeably larger for longer return period events on most parts of the world Dynamic contribution from the vertical wind change in the middle and upper troposphere determines the dependence on return period