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Investigating Recent Changes in MJO Precipitation and Circulation in Multiple Reanalyses
Author(s) -
Hsiao WeiTing,
Maloney Eric D.,
Barnes Elizabeth A.
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl090139
Subject(s) - madden–julian oscillation , climatology , precipitation , anomaly (physics) , environmental science , amplitude , oscillation (cell signaling) , atmospheric sciences , general circulation model , circulation (fluid dynamics) , coupled model intercomparison project , geology , meteorology , climate change , convection , physics , chemistry , thermodynamics , biochemistry , oceanography , quantum mechanics , condensed matter physics
Recent work using CMIP5 models under RCP8.5 suggests that individual multimodel mean changes in precipitation and wind variability associated with the Madden‐Julian oscillation (MJO) are not detectable until the end of the 21st century. However, a decrease in the ratio of MJO circulation to precipitation anomaly amplitude is detectable as early as 2021–2040, consistent with an increase in dry static stability as predicted by weak temperature gradient balance. Here, we examine MJO activity in multiple reanalyses (ERA5, MERRA‐2, and ERA‐20C) and find that MJO wind and precipitation anomaly amplitudes have a complicated time evolution over the record. However, a decrease in the ratio of MJO circulation to precipitation anomaly amplitude is detected over the observational period, consistent with the change in dry static stability. These results suggest that weak temperature gradient theory may be able to help explain changes in MJO activity in recent decades.