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Evidence for Radiative‐Convective Bistability in Tropical Atmospheres
Author(s) -
Dewey M.,
Goldblatt C.
Publication year - 2018
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 - 10.1029/2018gl078903
Subject(s) - convection , atmospheric sciences , outgoing longwave radiation , longwave , environmental science , atmosphere (unit) , radiative transfer , radiant energy , greenhouse effect , radiative cooling , troposphere , climate model , climatology , physics , climate change , meteorology , global warming , radiation , geology , oceanography , quantum mechanics
Earth's energy balance requires that energy absorbed and emitted at the top of the atmosphere be equal; to first order this balance is maintained via the Planck feedback: outgoing longwave radiation increases as surface temperature increases. Failure of the Planck feedback to stabilize the climate is described by three generally independent phenomena: the super‐greenhouse effect, the runaway greenhouse, and multiple equilibria of radiative‐convective atmospheres. Here we use satellite observations and models to show that the existence of the super‐greenhouse gives rise to a radiative‐convective instability which is relevant to Earth's tropics. The super‐greenhouse is caused by the low troposphere becoming optically thick, causing a positive feedback on near surface temperature and moisture, driving deep convection, column moistening, and reduced outgoing longwave radiation. Aspects of the runaway greenhouse physics are implicated, but a local runaway greenhouse is avoided. These results have implications for understanding the response of the tropics to a warming world.