7.2.4 SalinityThe measurement of salinity from remotely sensed data is not operational at the present time. Research, however, indicates the possibility of determining salinity with the use of microwave sensors to an accuracy of one part per thousand. The microwave properties of the sea surface are a function of its physical and chemical state. The emissivity of sea water is related to salinity. Changes in salinity cause significant changes in the emissive brightness temperature of water for frequencies less than 5 GHz. Hence the salinity of sea water can be determined remotely by measuring accurately the emissive brightness temperature. The precision afforded by this technique may be adequate for mapping the spread of fresh water at a river mouth or for studying estuaries and near shore waters.
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