UC San Diego

Surface melting is an important mass loss process from ice sheets. In West Antarctica, the lack of direct surface observations poses difficulties in studying surface melt and loss of ice mass. This thesis presents seven contrasting cases in which surface melt was detected by satellite passive microwave sensors and analyzed using both reanalysis data and satellite data. During these melt events meteorological conditions caused the total melt energy to elevate for anywhere between 3 – 8 days, compared with the rest of the month. This elevated melt energy can be induced by four main mechanisms typical of the austral summer climate described in this study. These mechanisms are thermal blanketing from optically thick clouds; thin clouds enhancing all-wave radiation at the surface; sensible heat flux preconditioning the surface to melt; and föhn wind presence on the lee side of mountains. The study locations are Siple Dome, Pine Island and Thwaites Glaciers, the southern portion of the Ross Ice Shelf, and the Larsen C Ice Shelf. Through assessing the surface energy budget, total melt energy, temperature and wind components, and cloud microphysics with regards to both 25-km resolution and small-scale spatial variability, the importance of using the highest resolution data available is demonstrated. This study not only defines drivers of West Antarctic melt, but identifies improvements that could be made to the methods and data sets used to quantify the climatology of surface melt.