Open AccessThe accuracy of downward short‐ and long‐wave radiation at the earth's surface calculated using simple models
Author(s) -
Finch J. W.,
Best M. J.
Publication year - 2004
Publication title -
meteorological applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 59
eISSN - 1469-8080
pISSN - 1350-4827
DOI - 10.1017/s1350482703001154
Subject(s) - sky , downwelling , cloud fraction , mean squared error , radiative transfer , environmental science , meteorology , root mean square , radiation , cloud cover , atmospheric sciences , physics , mathematics , statistics , cloud computing , geology , optics , computer science , oceanography , quantum mechanics , upwelling , operating system
Estimates of the downward global solar and long‐wave radiations are commonly made using simple models. We have tested the estimates produced by a number of these simple models against the values predicted by the radiative transfer model used in a climate model in order to determine their suitability for global applications. For clear sky, two simple models were comparable, but under cloudy conditions a combination of a clear‐sky model based on the Angstrom‐Prescott equation (which deals with the downwelling solar radiation) with a cloud transmissivity utilising total cloud fraction proved best. The lowest root mean square errors were 27 W m −2 for clear‐sky global solar radiation and 90 W m −2 for cloudy conditions. For downward long‐wave radiation in clear‐sky conditions, the model of Garratt (1992) performed best with a root mean square error of 24 W m −2 . However, in cloudy conditions the model of Idso & Jackson (1969) performed best with a root mean square error of 22 W m −2 , and, as it performs nearly as well as that of Garratt (1992) in clear‐sky conditions, it is probably the best choice. Copyright © 2004 Royal Meteorological Society.