MJO simulation in CMIP5 climate models: MJO skill metrics and process-oriented diagnosis

By M. Ahn, Daehyun Kim, K. Sperber, I. Kang, E. Maloney, Duane Waliser, H. Hendon. Climate Dynamics, 2017

158 citations recorded by the source corpus.

The Madden-Julian Oscillation (MJO) simulation diagnostics developed by MJO Working Group and the process-oriented MJO simulation diagnostics developed by MJO Task Force are applied to 37 Coupled Model Intercomparison Project phase 5 (CMIP5) models in order to assess model skill in representing amplitude, period, and coherent eastward propagation of the MJO, and to establish a link between MJO simulation skill and parameterized physical processes. Process-oriented diagnostics include the Relative Humidity Composite based on Precipitation (RHCP), Normalized Gross Moist Stability (NGMS), and the Greenhouse Enhancement Factor (GEF). Numerous scalar metrics are developed to quantify the results. Most CMIP5 models underestimate MJO amplitude, especially when outgoing longwave radiation (OLR) is used in the evaluation, and exhibit too fast phase speed while lacking coherence between eastward propagation of precipitation/convection and the wind field. The RHCP-metric, indicative of the sensitivity of simulated convection to low-level environmental moisture, and the NGMS-metric, indicative of the efficiency of a convective atmosphere for exporting moist static energy out of the column, show robust correlations with a large number of MJO skill metrics. The GEF-metric, indicative of the strength of the column-integrated longwave radiative heating due to cloud-radiation interaction, is also correlated with the MJO skill metrics, but shows relatively lower correlations compared to the RHCP- and NGMS-metrics. Our results suggest that modifications to processes associated with moisture-convection coupling and the gross moist stability might be the most fruitful for improving simulations of the MJO. Though the GEF-metric exhibits lower correlations with the MJO skill metrics, the longwave radiation feedback is highly relevant for simulating the weak precipitation anomaly regime that may be important for the establishment of shallow convection and the transition to deep convection.

Subfields: Atmospheric Science, Global and Planetary Change

View Paper: https://www.semanticscholar.org/paper/1bfc2fa9c02ffeb1439cb6ca1335c61d419326a3

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atmospheric Science

1. Duane Waliser
2. F. Vitart
3. Hye-Mi Kim
4. Chidong Zhang
5. E. Maloney
6. C. DeMott
7. N. Klingaman
8. Hai Lin

In Global and Planetary Change

1. Duane Waliser
2. F. Vitart
3. Hye-Mi Kim
4. Chidong Zhang
5. E. Maloney
6. C. DeMott
7. N. Klingaman
8. Hai Lin

Citations in the corpus

• The Flexible Global Ocean‐Atmosphere‐Land System Model Grid‐Point Version 3 (FGOALS‐g3): Description and Evaluation (2020, methodology): “These two metrics reflect the robustness of the eastward propagating feature of the simulated MJO, and have been frequently used in model evaluation studies (e.g., Ahn et al., 2017; Lin et al., 2006).”
• Overview of the Norwegian Earth System Model (NorESM2) and key climate response of CMIP6 DECK, historical, and scenario simulations (2020, methodology): “This diagnostic was developed by the USCLIVAR MJO working group and plotted using a script from the NCAR Command Language (NCL) examples that perform the US-CLIVAR diagnostics (https://www.ncl.ucar.edu/Applications/mjoclivar.shtml; Waliser et al., 2009; Ahn et al., 2017).”
• Fifty Years of Research on the Madden‐Julian Oscillation: Recent Progress, Challenges, and Perspectives (2020, methodology): “The new modeling tools—superparameterized GCMs and GCRMs—and regional CRMs were actively used to study the initiation and subsequent eastward propagation of the DYNAMO MJO events in the form of hindcast experiments.”
• Prediction of the Madden–Julian Oscillation: A Review (2018, methodology): “…the Maritime Continent9 (YMC) international project. b. Process-based hindcast evaluation Many GCMs still exhibit shortcomings in simulating realistic MJO characteristics, including its amplitude, propagation, and horizontal and vertical structures (e.g., Jiang et al. 2015, 2018; Ahn et al. 2017).”