Diurnal variability of outgoing longwave radiation
- Columbia Univ., New York, NY (United States)
This study investigates diurnal variations in outgoing longwave radiation (OLR) in view of its importance in the Earth`s radiation budget. A comparison is made of two data sets: (1) the Earth Radiation Budget Experiment measurements of broadband radiances, and (2) the International Satellite Cloud Climatology Project (ISCPP) calculated fluxes. The ERBE OLR and the ISCPP calculated OLR agree reasonably well in terms of the amplitude of the diurnal cycle, but show large differences in phase. The diurnal cycle of ISCCP calculated OLR appears more realistic and is in better agreement with previous studies, which are similarly based on narrowband observations. The ERBE OLR, however, was found to contain severe biases. Over land, the use of the half-sine model with a maximum at noon is primarily responsible for the bias. Over the ocean, the ERBE OLR is found to be biased by both the intersatellite calibration errors and spectral correction errors, which result in a larger daytime bias. Since the satellite combinations used in the ERBE processing change with time, intersatellite calibration/spectral correction errors produce spurious interannual variations. Moreover, the predominance of the ocean data suggests that care should be taken when using the ERBE data to study climate variabilities. 16 refs., 3 figs.
- OSTI ID:
- 535161
- Report Number(s):
- CONF-960146--
- Country of Publication:
- United States
- Language:
- English
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