On the Accuracy of Satellite-Observed Sea Surface Temperatures
A comparison between shipborne observations and sea surface temperatures measured by the satellites (NOAA-3, NOAA-4, NOAA-5, NOAA-6 and TIROS-N) off the Pacific coast of Canada indicates that in each case a linear regression is sufficient to relate the two sets of data. The standard error of estimate for the temperatures observed by the above satellites were: ±0.5°C, ±0.6°C, ±0.3 – ±0.4°C, ±0.6°C and ±0.5°C, respectively. When reliable ground truth data is available, sea surface temperatures in a limited region and time can be measured by the satellites to the above accuracy using this “field-calibration” method. Estimates of errors as large as ±2°C reported in literature are suspected to be mainly due to errors in shipborne measurements, failure to correct adequately for atmospheric effects, and uncertainty in the radiometer calibration. Eventually, these errors are likely to be reduced considerably but there still remains a problem of the proper interpretation of satellite-determined sea surface temperatures in the presence of marine haze, thin clouds and light mist. Until these problems are resolved the method of applying field-calibrations appears to be the only practical way of obtaining reliable estimates of sea surface temperatures in a given region.
KeywordsSatellite Data Advanced Very High Resolution Radiometer Advanced Very High Resolution Radiometer Radiometer Calibration Metre Depth
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