The effect of the quasi-biennial oscillation on the Madden-Julian oscillation in the Met Office Unified Model Global Ocean Mixed Layer configuration

Lee, J. C. K. and Klingaman, N. P. (2018) The effect of the quasi-biennial oscillation on the Madden-Julian oscillation in the Met Office Unified Model Global Ocean Mixed Layer configuration. Atmospheric Science Letters, 19 (5). e816. ISSN 1530-261X doi: 10.1002/asl.816

Abstract/Summary

Using multi-decadal simulations, we investigate the relationship between the Quasi-Biennial Oscillation (QBO) and the Madden–Julian Oscillation (MJO) in the Global Ocean Mixed Layer Configuration of the Met Office Unified Model (MetUM-GOML1) at two horizontal resolutions (approximately 200 km and 90 km at the equator). MetUM-GOML1 produces a weak and insignificant correlation between QBO winds and mean MJO amplitude in boreal winter, in contrast to the significant anti-correlation in reanalysis. While reanalysis shows the easterly QBO favors stronger Maritime Continent MJO activity, MetUM-GOML1 displays stronger West Pacific MJO activity. The biased QBO-MJO relationship in MetUM-GOML1 may be due to weak QBO-induced temperature anomalies in the tropical tropopause layer, or to errors in MJO vertical structure.