Sensitivity of Global Modeling Initiative CTM predictions of Antarctic ozone recovery to GCM and DAS generated meteorological fields

• Main Authors: Rotman, D, Bergmann, D
• Language: unknown
• Published: 2021
• Subjects: 54 ENVIRONMENTAL SCIENCES; AIR; BOUNDARY CONDITIONS; CHEMISTRY; FEEDBACK; GENERAL CIRCULATION MODELS; MIXING RATIO; OZONE; SENSITIVITY; SIMULATION; STRATOSPHERE; TRANSPORT; WMO; Antarctic; The Antarctic; Antarc*
• Online Access: http://www.osti.gov/servlets/purl/15013844; https://www.osti.gov/biblio/15013844

We use the Global Modeling Initiative chemistry and transport model to simulate the evolution of stratospheric ozone between 1995 and 2030, using boundary conditions consistent with the recent World Meteorological Organization ozone assessment. We compare the Antarctic ozone recovery predictions of two simulations, one driven by meteorological data from a general circulation model (GCM), the other using the output of a data assimilation system (DAS), to examine the sensitivity of Antarctic ozone recovery predictions to the characteristic dynamical differences between GCM and DAS-generated meteorological data. Although the age of air in the Antarctic lower stratosphere differs by a factor of 2 between the simulations, we find little sensitivity of the 1995-2030 Antarctic ozone recovery between 350 K and 650 K to the differing meteorological fields, particularly when the recovery is specified in mixing ratio units. Relative changes are smaller in the DAS-driven simulation compared to the GCM-driven simulation due to a surplus of Antarctic ozone in the DAS-driven simulation which is not consistent with observations. The peak ozone change between 1995 and 2030 in both simulations is {approx}20% lower than photochemical expectations, indicating that changes in ozone transport at 450 K between 1995 and 2030 constitute a small negative feedback. Total winter/spring ozone loss during the base year (1995) of both simulations and the rate of ozone loss during August and September is somewhat weaker than observed. This appears to be due to underestimates of Antarctic Cl{sub y} at the 450 K potential temperature level.