6533b835fe1ef96bd129ec60

RESEARCH PRODUCT

Analysis of the atmospheric and emissivity influence on the splitwindow equation for sea surface temperature

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Abstract In this paper we have analysed the effects of the different atmospheric species (water vapour, fixed gases and aerosols) and the surface emissivity on the split-window method for determining the sea surface temperature. The widely used split-window method is based on the differential absorption of water vapour in the atmospheric window 10.5ndash;12.5 μm. Other atmospheric species with absorption coefficients different to that of water vapour can then have a large influence on the split-window. The effect of gases, such as C02, N20, CH4, CO and 03, and maritime aerosols is evaluated by comparing the effect of the water vapour alone. To do this we simulated AVHRR measurements in channels 4 and 5 for a set of mid-latitude atmospheres using LOWTRAN 7 code. Our results indicated that the fixed gases have a negative effect on the split-window specially for dry atmospheres; in this case the error in retrieved temperatures was shown to increase by about 70 per cent with respect to that obtained consideri...