Adam, Ori and Bischoff, Tobias and Schneider, Tapio (2016) Seasonal and Interannual Variations of the Energy Flux Equator and ITCZ. Part I: Zonally Averaged ITCZ Position. Journal of Climate, 29 (9). pp. 3219-3230. ISSN 0894-8755. http://resolver.caltech.edu/CaltechAUTHORS:20160601-095902123
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In the zonal mean, the ITCZ lies at the foot of the ascending branch of the tropical mean meridional circulation, close to where the near-surface meridional mass flux vanishes. The ITCZ also lies near the energy flux equator (EFE), where the column-integrated meridional energy flux vanishes. This latter observation makes it possible to relate the ITCZ position to the energy balance, specifically the atmospheric net energy input near the equator and the cross-equatorial energy flux. Here the validity of the resulting relations between the ITCZ position and energetic quantities is examined with reanalysis data for the years 1979–2014. In the reanalysis data, the EFE and ITCZ position indeed covary on time scales of seasons and longer. Consistent with theory, the ITCZ position is proportional to the cross-equatorial atmospheric energy flux and inversely proportional to atmospheric net energy input at the equator. Variations of the cross-equatorial energy flux dominate seasonal variations of the ITCZ position. By contrast, variations of the equatorial net energy input, driven by ocean energy uptake variations, dominate interannual variations of the ITCZ position (e.g., those associated with ENSO).
|Additional Information:||© 2016 American Meteorological Society. Manuscript received 23 July 2015, in final form 4 February 2016. We thank Momme Hell for his visualization advice.|
|Subject Keywords:||Circulation/Dynamics; Atmospheric circulation; Physical Meteorology and Climatology; Energy budget/balance; Variability; Climate variability; Interannual variability; Tropical variability|
|Official Citation:||Seasonal and Interannual Variations of the Energy Flux Equator and ITCZ. Part I: Zonally Averaged ITCZ Position Ori Adam, Tobias Bischoff, and Tapio Schneider Journal of Climate 2016 29:9, 3219-3230|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||01 Jun 2016 19:43|
|Last Modified:||01 Jun 2016 19:43|
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