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Retrievals of sea surface temperature from infrared imagery: origin and form of systematic errors
Author(s) -
Merchant C. J.,
Horrocks L. A.,
Eyre J. R.,
O'carroll A. G.
Publication year - 2006
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1256/qj.05.143
Subject(s) - depth sounding , radiative transfer , sky , nonlinear system , satellite , surface (topology) , quadratic equation , remote sensing , brightness , sea surface temperature , infrared , systematic error , meteorology , environmental science , mathematics , geology , physics , statistics , optics , geometry , oceanography , quantum mechanics , astronomy
We show that retrievals of sea surface temperature from satellite infrared imagery are prone to two forms of systematic error: prior error (familiar from the theory of atmospheric sounding) and error arising from nonlinearity. These errors have different complex geographical variations, related to the differing geographical distributions of the main geophysical variables that determine clear‐sky brightness‐temperatures over the oceans. We show that such errors arise as an intrinsic consequence of the form of the retrieval (rather than as a consequence of sub‐optimally specified retrieval coefficients, as is often assumed) and that the pattern of observed errors can be simulated in detail using radiative‐transfer modelling. The prior error has the linear form familiar from atmospheric sounding. A quadratic equation for nonlinearity error is derived, and it is verified that the nonlinearity error exhibits predominantly quadratic behaviour in this case. Copyright © 2006 Royal Meteorological Society.