Premium
Observations of the diurnal cycle of outgoing longwave radiation from the Geostationary Earth Radiation Budget instrument
Author(s) -
Comer Ruth E.,
Slingo Anthony,
Allan Richard P.
Publication year - 2007
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 - 10.1029/2006gl028229
Subject(s) - outgoing longwave radiation , environmental science , diurnal cycle , geostationary orbit , longwave , atmospheric sciences , climatology , cloud cover , convection , meteorology , radiation , geology , physics , satellite , cloud computing , astronomy , computer science , operating system , quantum mechanics
The Geostationary Earth Radiation Budget instrument on Meteosat‐8, located over Africa, provides unprecedented temporal sampling (∼17 minutes) of the broadband emitted thermal and reflected solar radiances. We analyse the diurnal cycle of the outgoing longwave radiation (OLR) fluxes derived from the thermal radiances for July 2006. Principal component (PC) analysis separates the signals of the surface temperature response to solar heating and of the development of convective clouds. The first two PCs explain most of the OLR variations: PC1 (surface heating) explains 82.3% of the total variance and PC2 (cloud development) explains 12.8% of the variance. Convection is initiated preferentially over mountainous regions and the cloud then advects downstream in the ambient flow. Diurnal variations are much weaker over the oceans, but a coherent signal over the Gulf of Guinea suggests that the cloudiness is modulated by the diurnally varying contrast between the Gulf and the adjacent land mass.