The main objective of this project is to derive a reconciled estimate of Arctic sea ice mass balance using data from the most advanced, recent EO missions, namely ESA’s ERS, Envisat, CryoSat and SMOS missions and NASA’s ICESat mission, and state-of-the-art numerical models. Numerous processing methods have been developed and estimates of seasonal and interannual ice volume changes have been published. We will collect these different data sets and apply unified methods when converting freeboard to thickness and then mass over consistent regions and time periods. This will strongly take advantage of improved snow thickness products once produced by a parallel Arctic+ Theme 1 project carried out by the same PIs. Satellite products and models will be validated by means of airborne laser altimetry and electromagnetic data from ESA’s CryoVEx campaigns and NASA’s Operation IceBridge, as well as by in-situ ice mass balance buoys (IMBs) and upward looking sonar (ULS). The validation will focus on key regions of multiyear and first-year ice coverage, in the spring of 2011 and 2014, where the most extensive validation data are available. Longer time series of reconciled ice mass estimates will then be compared with results from previous studies. Satellite products and models will be used mutually to evaluate uncertainties in both approaches. We will show the impact of reconciled sea ice mass estimates on predictions of seasonal and longer-term ice mass changes, sea ice dynamics and deformation, and freshwater fluxes through Fram Strait. The latter interfaces with a potential Arctic+ Theme 3 project. Results lead to a scientific roadmap for the time frame 2017-2021 suggesting further improved processing methods, reconciled estimates, and the development of assimilation systems and optimized EO missions.

This study is carried out by Alfred Wegener Institute (AWI), the Finish Meteorological Institute (FMI), isardSAT Poland , University College London (UCL), and York University (YU), in response to Theme 2. The planned work will fulfill the aim of exploring, developing and validating different approaches to improve sea ice mass estimates and their application; to develop a new prototype processor; and to produce and validate an experimental dataset of improved, multi-product Arctic ice thickness, volume and mass.