Open AccessChanges in the structure and propagation of the M JO with increasing C O 2
Author(s) -
Adames Ángel F.,
Kim Daehyun,
Sobel Adam H.,
Del Genio Anthony,
Wu Jingbo
Publication year - 2017
Publication title -
journal of advances in modeling earth systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.03
H-Index - 58
ISSN - 1942-2466
DOI - 10.1002/2017ms000913
Subject(s) - madden–julian oscillation , climatology , atmospheric sciences , moisture , environmental science , relative humidity , precipitation , gcm transcription factors , water vapor , climate change , general circulation model , geology , meteorology , convection , physics , oceanography
Abstract Changes in the Madden‐Julian Oscillation (MJO) with increasing CO 2 concentrations are examined using the Goddard Institute for Space Studies Global Climate Model (GCM). Four simulations performed with fixed CO 2 concentrations of 0.5, 1, 2, and 4 times preindustrial levels using the GCM coupled with a mixed layer ocean model are analyzed in terms of the basic state, rainfall, moisture and zonal wind variability, and the structure and propagation of the MJO. The GCM simulates basic state changes associated with increasing CO 2 that are consistent with results from earlier studies: column water vapor increases at ∼7.1% K −1 , precipitation also increases but at a lower rate (∼3% K −1 ), and column relative humidity shows little change. Moisture and rainfall variability intensify with warming while zonal wind variability shows little change. Total moisture and rainfall variability increases at a rate this is similar to that of the mean state change. The intensification is faster in the MJO‐related anomalies than in the total anomalies, though the ratio of the MJO band variability to its westward counterpart increases at a much slower rate. On the basis of linear regression analysis and space‐time spectral analysis, it is found that the MJO exhibits faster eastward propagation, faster westward energy dispersion, a larger zonal scale, and deeper vertical structure in warmer climates.