Future Changes of Extreme Precipitation and Related Atmospheric Conditions in East Asia under Global Warming Projected in Large Ensemble Climate Prediction Data

Extreme precipitation is expected to pose a more severe threat to human society in the future. This work assessed the historical performance and future changes in extreme precipitation and related atmospheric conditions in a large ensemble climate prediction dataset, the database for Policy Decision-making for Future climate change (d4PDF), over East Asia. Compared with the Tropical Rainfall Measuring Mission (TRMM) and fifth major global reanalysis produced by ECMWF (ERA5) datasets, the historical climate in d4PDF represents favorably the precipitation characteristics and the atmospheric conditions, although some differences are notable in the moisture, vertical motion, and cloud water fields. The future climate projection indicates that both the frequency and intensity of heavy precipitation events over East Asia increase compared with those in the present climate. However, when comparing the atmospheric conditions in the historical and future climates for the same precipitation intensity range, the future climate indicates smaller relative humidity, weaker ascent, less cloud water content, and smaller temperature lapse rate, which negatively affect generating extreme precipitation events. The comparison of the precipitation intensity at the same amount of precipitable water between the historical and future climates indicates that extreme precipitation is weaker in the future because of the more stabilized troposphere in the future. The general increase in extreme precipitation under future climate is primarily due to the enhanced increase in precipitable water in the higher temperature ranges, which counteracts the negative conditions of the stabilized troposphere. Significance Statement Extreme precipitation can have disastrous effects on human lives, economy, and ecosystems and is anticipated to significantly increase in both intensity and frequency under future climate. The purpose of this study is to investigate the mechanism for the future change of extreme precipitation. We examined the relationship between future changes in extreme precipitation and changes in the related atmospheric conditions. It is important for reducing uncertainties in future projections of extreme precipitation. Our results highlight that the future atmospheric condition is unfavorable for generating future extreme precipitation events in terms of stability and humidity changes. The increase in the column moisture content is the primary factor for the increase of extreme precipitation, which counteracts the negative conditions.