High Cloud Influence on Atmospheric Energy Budget and Cross-Equatorial Heat Transport
Abstract
Many studies have shown strong linkages between hemispheric asymmetries in atmospheric and oceanic energy budgets, tropical precipitation and the mean position of the ITCZ. The contrast in net top-of-atmosphere (TOA) radiation implies a combined atmospheric and oceanic cross-equatorial heat transport (XHT) from the southern hemisphere (SH) to the northern hemisphere (NH). This is mainly driven by the hemispheric contrast in net downward energy at the surface, which exceeds that at TOA by a factor of two. The implied atmospheric XHT in a cloudless atmosphere is also from the SH to the NH, but the opposite is the case when clouds are considered because of how clouds are distributed vertically in the two hemispheres and how cloud altitude influences atmospheric radiative heating. Low clouds are more prevalent in the SH than the NH while the opposite is true for high clouds. In general, low clouds radiatively cool the atmospheric column and high clouds radiatively warm it. It thus follows that atmospheric XHT is from NH to SH. In this study, we examine the role of high clouds on the atmospheric energy budget in the context of large-scale atmospheric XHT. Our analysis combines radiation and cloud data from CERES, MODIS, CALIPSO and Cloudsat together with mass corrected divergence in atmospheric total energy transport from reanalysis.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A24G..01L
- Keywords:
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- 0320 Cloud physics and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 3311 Clouds and aerosols;
- ATMOSPHERIC PROCESSESDE: 3360 Remote sensing;
- ATMOSPHERIC PROCESSESDE: 1626 Global climate models;
- GLOBAL CHANGE