The dehydration carousel of stratospheric water vapor inthe Asian summer monsoon anticyclone

Year: 2023

Authors: Paul Konopka; Christian Rolf; Marc von Hobe; Sergey M. Khaykin; Benjamin Clouser; Elisabeth Moyer; Fabrizio Ravegnani; Francesco D’Amato; Silvia Viciani; Nicole Spelten; Armin Afchine; Martina Krdmer; Fred Stroh; and Felix Ploeger

Autors Affiliation: Forschungszentrum Julich, IEK 7, Julich, Germany; Univ Wuppertal, Inst Atmospher & Environm Res, Wuppertal, Germany; Sorbonne Univ, Lab Atmospheres, Observat Spatiales LATMOS, CNRS INSU, Guyancourt, France; Univ Chicago, Dept Geophys Sci, Chicago, IL USA; CNR, ISAC, Bologna, Italy; CNR, INO, Via Madonna del Piano 10, Florence, Italy.

Abstract: During the StratoClim Geophysica campaign, air with total water mixing ratios up to 200 ppmv and ozone up to 250 ppbv was observed within the Asian summer monsoon anticyclone up to 1.7 km above the local cold-point tropopause (CPT). To investigate the temporal evolution of enhanced water vapor being transported into the stratosphere, we conduct forward trajectory simulations using both a microphysical and an idealized freeze-drying model. The models are initialized at the measurement locations and the evolution of water vapor and ice is compared with satellite observations of MLS and CALIPSO. Our results show that these extremely high water vapor values observed above the CPT are very likely to undergo significant further freeze-drying due to experiencing extremely cold temperatures while circulating in the anticyclonic “dehydration carousel”. We also use the Lagrangian dry point (LDP) of the merged back-and-forward trajectories to reconstruct the water vapor fields. The results show that the extremely high water vapor mixed with the stratospheric air has a negligible impact on the overall water vapor budget. The LDP mixing ratios are a better proxy for the large-scale water vapor distributions in the stratosphere during this period.

Journal/Review: ATMOSPHERIC CHEMISTRY AND PHYSICS

Volume: 23      Pages from: 12935  to: 12947

More Information: This research has been supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation; TRR 301, project ID 428312742). Campaign planning and logistics were largely covered by the StratoClim project, funded by the European Commission´s Seventh Framework Programme(FP7/2007-2013) under grant agreement no. 603557
KeyWords: Asian summer monsoon anticyclone, STRATOCLIM, dehydration, stratospheric water vapor
DOI: 10.5194/acp-23-12935-2023

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