From MSS to OLI: a retrospective on Landsat. Contribution to groundwater science

This article examines the fifty-year contribution of the Landsat programme to groundwater science, analysing the evolution of its sensors from the Multispectral Scanner (MSS) to the Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS). It illustrates how improvements in spectral, spatial, and radiometric resolution have enhanced groundwater monitoring through surface indicators such as vegetation stress, thermal anomalies, and subsidence. The article discusses key applications, highlighting methodological advancements and inherent limitations. It underscores the importance of integrating with other technologies (e.g., InSAR, GRACE) and using machine learning to overcome data gaps. Finally, it explores future missions, such as Landsat Next, which promise to further revolutionise the sustainable management of global groundwater resources.