Monthly Antarctic-wide surface meltwater evolution between 2006 and 2021, and its links to climate

Understanding the distribution and evolution of surface meltwater on the Antarctic Ice Sheets is vital in enabling us to predict how the ice sheet will respond to a warming climate. The majority of Antarctic surface meltwater studies have typically been limited by either spatial or temporal scale. We have overcome these limitations by using a fully automated method to map surface meltwater across the entire Antarctic continent between 2006 and 2021 at a monthly temporal resolution. Furthermore, by accounting for variability in both cloud cover and satellite image coverage, we have generated the first consistent and continuous multi-year time series of Antarctic-wide surface meltwater to date. Here, we present results from analysis of this dataset, including long-term trends in surface meltwater extent, comparison between surface meltwater area and modelled melt, and associations between surface meltwater area and climatic factors. Regression analysis shows strong correlations between surface meltwater area and modelled snowmelt around the ice sheet margin, increasing our confidence in regional climate models to predict future melt conditions. Synoptic scale climate regimes, such as the Southern Annular Mode, exert a strong controlling factor on surface meltwater area totals on an annual basis. However, regional climatic processes and melt-albedo feedbacks can have strong second-order influences on localised melt rates, resulting in high variability in meltwater coverage, especially in parts of East Antarctica. This multi-year dataset offers the opportunity to explore surface meltwater evolution at local, catchment and continental scales, and will be of widespread use in understanding the operation of surface hydrological systems.