A proposed remote sensing technique for monitoring the large scale distribution of surface salinity. It depends on the influence of salinity on microwave emissions, strongest at 1.4 GHz. Since temperature has a larger effect, high accuracy temperature measurements must also be made using another band at either 2.65 or 5.0 GHz. This yields a salinity accuracy of 0.05 parts per thousand, although this can be achieved only via long time (30 days) and space (100 km) averaging. A resolution of 10 km would degrade salinity measurement accuracy to 2 parts per thousand.