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Cirrus detrainment‐temperature feedback
Author(s) -
Chou Chia,
Neelin J. David
Publication year - 1999
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl900219
Subject(s) - cirrus , atmospheric sciences , environmental science , albedo (alchemy) , climatology , cloud fraction , cloud physics , cloud forcing , cloud cover , climate change , climate model , physics , cloud computing , geology , computer science , art , oceanography , performance art , art history , operating system
In considering the role of cirriform clouds in climate change, it is important to distinguish among the relationships of different high cloud types to large‐scale atmospheric dynamics. While cirrostratus and cirrocumulus (CsCc) have a clear relation to deep convective sources, the ensemble behavior of cirrus is more subtle. An empirical relation is found between cirrus fraction and deep cloud top temperature that points to detrainment temperature as a dominant factor governing tropical and subtropical cirrus. This cirrus‐detrainment‐temperature (CDT) relation provides a target for modelers, and suggests an additional cloud‐climate feedback. As surface temperatures warm, detrainment temperatures cool as deep cloud top height increases. The CDT relation implies that cirrus fraction increases. Because cirrus are optically thinner than CsCc, the competition between longwave feedbacks and cloud albedo feedbacks leads to a hypothesized positive climate feedback by cirrus fraction.