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Quantifying cloud base updraft speeds of marine stratocumulus from cloud top radiative cooling
Author(s) -
Zheng Youtong,
Rosenfeld Daniel,
Li Zhanqing
Publication year - 2016
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 - 10.1002/2016gl071185
Subject(s) - cloud base , marine stratocumulus , environmental science , atmospheric sciences , radiative transfer , cloud top , cloud condensation nuclei , cloud computing , radiative cooling , cloud cover , meteorology , cloud height , satellite , precipitation , condensation , geology , physics , aerosol , quantum mechanics , computer science , operating system , astronomy
Marine stratocumulus clouds play a significant role in the Earth's radiation budget. The updrafts at cloud base ( W b ) govern the supersaturation and therefore the activation of cloud condensation nuclei, which modifies the cloud and precipitation properties. A statistically significant relationship between W b and cloud top radiative cooling rate (CTRC) is found from the measurements of the Department of Energy's Atmospheric Radiation Measurement Mobile Facility on board a ship sailing between Honolulu and Los Angeles. A similar relation was found on Graciosa Island but with greater scatter and weaker correlation presumably due to the island effect. Based on the relation, we are able to estimate the cloud base updrafts using a simple formula: W b = −0.44 × CTRC + 22.30 ± 13, where the W b and CTRC have units of cm/s and W/m 2 , respectively. This quantification can be utilized in satellite remote sensing and parameterizations of W b in general circulation models.