Hysteresis of European summer precipitation under a symmetric CO 2 ramp-up and ramp-down pathway

• Published in: Environmental Research Letters
• Main Authors: Im, Nari, Kim, Daehyun, An, Soon-Il, Paik, Seungmok, Kim, Soong-Ki, Shin, Jongsoo, Min, Seung-Ki, Kug, Jong-Seong, Oh, Hyoeun
• Other Authors: Korea Research Environment Open NETwork, the National Center for Meteorological Supercomputer of the Korea Meteorological Administration (KMA), the National Supercomputing Center, Korean Government, National Research Foundation of Korea, Seoul National University
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: IOP Publishing 2024
• Subjects: The Ramp; North Atlantic
• Online Access: http://dx.doi.org/10.1088/1748-9326/ad52ad; https://iopscience.iop.org/article/10.1088/1748-9326/ad52ad; https://iopscience.iop.org/article/10.1088/1748-9326/ad52ad/pdf

Abstract This study investigates the mechanism of the hysteresis of European summer mean precipitation in a CO 2 removal (CDR) simulation. The European summer mean precipitation exhibits robust hysteresis in response to the CO 2 forcing; after decreasing substantially (∼40%) during the ramp-up period, it shows delayed recovery during the ramp-down period. We found that the precipitation hysteresis over Europe is tied to the hysteresis in the Atlantic Meridional Overturning Circulation (AMOC). During the ramp-down period, an anomalous high surface pressure circulation prevails over Europe. The anomalous high pressure system is a baroclinic response of the atmosphere to strong North Atlantic cooling associated with a weakened AMOC. This anomalous circulation suppresses summertime convective activity over the entire Europe by decreasing near-surface moist enthalpy in Central and Northern Europe while increasing lower free-tropospheric temperature in Southern Europe. Our findings underscore the need to understand complex interactions in the Earth system for reliable future projections of regional precipitation change under CDR scenarios.