New advances in remote sensing of Arctic sea ice thickness from Operation IceBridge and beyond

Since 2009, NASA's Operation IceBridge mission has undertaken an annual campaign of measuring sea ice thickness in the western Arctic. The combined suite of laser, radar, visible, and infrared instruments provides an incredibly rich set of data for accurately measuring sea ice thickness at a variety of scales, and has broad implications for extension beyond the IceBridge mission. The traditional approach to measuring sea ice thickness is taken from hydrostatic balance assumptions and measurements of the sea ice freeboard and snow thickness. In going beyond the traditional methods previously employed, this work will present new techniques for the remote sensing of sea ice thickness, which will allow for a more accurate record focusing on retrieval of the full thickness distribution of sea ice. The retrieval of thin sea ice thickness is shown through the use of a simple thermodynamic calculation and surface temperature retrievals from a new high resolution thermal infrared camera installed on the IceBridge mission in 2015. The retrieval of sea ice thickness from ridged and deformed sea ice is shown through use of the high resolution of the IceBridge ATM laser altimeter. Together with surface topography measurements, the high spatial resolution ultra-wideband radar suite on the IceBridge mission is currently being used to provide information on the thickness of snow on sea ice. We will discuss how the extension of the IceBridge radar and topography results has wide applicability to improving the retrieval of sea ice freeboard and thickness from CryoSat-2 since the physical mechanisms governing the scattering of radar returns are very similar. Lastly, we will demonstrate a new approach which synthesizes the combined knowledge generated by the IceBridge airborne data set along with satellite and model data sources to produce a record of sea ice thickness change in the Arctic.