Surficial and Groundwater Exchanges by Means of Landsat Thermal Data: The Eastern Laizhou Bay (China)

In this study, we observed Sea Surface Temperature (SST) anomalies in the Southern and Eastern Laizhou Bay, China, during summer and winter, by means of Landsat thermal data. The interpretation of these features, also considering the morpho-hydrogeologic setting of the areas, showed that SST anomalies are not related to long-shore circulation or river discharge and therefore may be associated to local potential submarine groundwater discharge (SGD). Moreover, in situ measurements of salinity and temperature in surficial waters support this hypothesis of SGD in the eastern Laizhou Bay. Our results suggest that the analysis of satellite thermal images can conveniently address hydrogeological field investigations permitting to map features, both localized and diffuse, such as gradients and anomalies associated to submarine groundwater seepage. Although the use of remote sensing cannot replace direct investigations, it proves to be an efficient tool for driving field activities, like samplings and geophysical surveys for detailed SGD investigations.