Rain-on-snow (ROS) events on sea ice are becoming increasingly frequent in both polar regions. ROS events modify snow and sea ice geophysical properties, amplifying the thermodynamic coupling at the ocean-sea ice-atmosphere interface. Melt onset timing is an important indicator of the seasonal evolution of the sea ice cover. Moreover, it is not yet clear to what extent ROS events can precondition the snow/sea ice physical system and in turn advance, delay, or alter the timing and progression of seasonal spring melt.

The PhD position’s objective is to investigate this link using observations from multi-frequency satellite SAR (TerraSAR-X, Sentinel-1, RCM, NISAR, ALOS-2/-4) and laser and radar altimetry (ICESat-2, CryoSat-2, SWOT and forthcoming CRISTAL) missions, supported by meteorological data, climate reanalysis and in-situ observations. The project will focus on case studies from Arctic landfast sea ice regions in the Atlantic and Canadian Arctic sectors, examining how ROS events modify snow/sea ice physical properties through the freeze-up and winter period and their consequent influence changes in spring melt onset timing.

The PhD position will have three interconnected objectives: 1) Detect and characterize ROS events and their impact on snow/sea ice physical system using reanalysis, meteorological, satellite data and in situ observations from past field campaigns; 2) Detect ROS-induced melt from
SAR+altimetry observations and investigate and determine whether ROS preconditions and changes the timing of seasonal spring melt onset; and 3) Improve melt onset detection and prediction, using information from previous ROS events, using multi-frequency SAR and altimetry
observations. If time allows, the project intends to also examine if the developed methods can be applied to Antarctic sea ice.