Ice sheets and Surface mass balance - what does this mean? Scientific explanation

What is surface mass balance, how do we calculate it and why is it important? This is a video that has come out of a collaboration between two Horizon Europe (EU science programme) funded projects PolarRES and OCEAN:ICE. The video series: “Explain it in Two Ways” In the first episode Ruth Mottram, project coordinator, explains what surface mass balance means, and its importance in Polar research. This is the technical version, have a look at the easier version and see which makes most sense to you!