Surface mass balance refers to the balance between the inputs and outputs of ice and snow on the surface of a glacier or ice sheet. These inputs include precipitation in the form of snowfall, while outputs include melting and sublimation of ice. By measuring and analyzing surface mass balance, researchers can better understand how glaciers and ice sheets are responding to climate change, as changes in mass balance can affect sea level rise and other environmental processes. This research area often involves field measurements, remote sensing techniques, and modeling to assess the health and stability of ice masses.