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A New Mechanism for the Dependence of Tropical Convection on Free‐Tropospheric Humidity
Author(s) -
Virman M.,
Bister M.,
Sinclair V. A.,
Järvinen H.,
Räisänen J.
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 - 10.1002/2018gl077032
Subject(s) - troposphere , convection , precipitation , climatology , environmental science , subsidence , atmospheric sciences , anomaly (physics) , water vapor , entrainment (biomusicology) , moisture , evaporation , atmospheric convection , geology , meteorology , physics , paleontology , condensed matter physics , structural basin , rhythm , acoustics
Atmospheric deep convection is responsible for transport of the most important greenhouse gas, water vapor, to the free‐troposphere and for most of the precipitation on Earth. Observations show that deep convection is strongly sensitive to the amount of moisture in the low‐to‐midtroposphere. The current understanding is that this sensitivity is due to entrainment. In this study, it is found that over tropical oceans shallow warm anomalies, likely strong enough to hinder subsequent convection, are observed just above the boundary layer after precipitation, but only where the low‐to‐midtroposphere is dry. The results, showing a cold anomaly above the warm anomaly, suggest that evaporation of stratiform precipitation and subsidence warming below likely cause these temperature anomalies. Evaporation of stratiform precipitation should therefore be a topic of high priority for developing more realistic theories of convective weather phenomena and for improving climate and weather forecast models.