Mechanisms of Arctic Surface Air Temperature Change in Response to the Madden–Julian Oscillation

Using lagged composites and projections with the thermodynamic energy equation, in this study the mechanisms that drive the boreal winter Arctic surface air temperature (SAT) change associated with the Madden–Julian oscillation (MJO) are investigated. The Wheeler and Hendon MJO index, which divides...

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Bibliographic Details
Published in:Journal of climate 2012-09, Vol.25 (17), p.5777-5790
Main Authors: Yoo, Changhyun, Lee, Sukyoung, Feldstein, Steven B.
Format: Article
Language:English
Subjects:
Adiabatic
Adiabatic flow
Advection
Air temperature
Atmosphere
Climate change
Convection
Convective heating
Cooling
Datasets
Earth, ocean, space
Eddy heat flux
Energy equation
Exact sciences and technology
External geophysics
Fluctuations
Heat
Heat flux
Heat transfer
Humidity
I.R. radiation
Infrared radiation
Latent heat
Madden-Julian oscillation
Marine
Meteorology
Planetary waves
Precipitation
Radiation
Rossby waves
Sensible and latent heat
Standardized tests
Studies
Surface temperature
Surface-air temperature relationships
Temperature changes
Wave propagation
Weather forecasting
Winter
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Summary:Using lagged composites and projections with the thermodynamic energy equation, in this study the mechanisms that drive the boreal winter Arctic surface air temperature (SAT) change associated with the Madden–Julian oscillation (MJO) are investigated. The Wheeler and Hendon MJO index, which divides the MJO into 8 phases, where phase 1 (phase 5) corresponds to reduced (enhanced) convection over the Maritime Continent and western Pacific Ocean, is used. It is shown that the more zonally localized (uniform) tropical convective heating associated with MJO phase 5 (phase 1) leads to enhanced (reduced) excitation of poleward-propagating Rossby waves, which contribute to Arctic warming (cooling). Adiabatic warming/cooling, eddy heat flux, and the subsequent change in downward infrared radiation (IR) flux are found to be important for the Arctic SAT change. The adiabatic warming/cooling initiates the Arctic SAT change, however, subsequent eddy heat fluxmakes a greater contribution. The resulting SAT change is further amplified by alteration in downward IR. It is shown that changes in surface sensible and latent heat fluxes oppose the contribution by the above processes.
ISSN:0894-8755
1520-0442
DOI:10.1175/jcli-d-11-00566.1