Predicted Ice Images PRIIMA: Methodology and System Evaluation

Today's ice information is already outdated the moment it is available, due to sea-ice drift. All Arctic stakeholders are in an urgent need for ice forecasts. Presently there is no high-resolution ice forecast product available on the market. PRIIMA is going to tackle this problem. PRIIMA is being developed in a 6 months kick-start project funded by the European Space Agency (ESA). It started on March 1, 2018. PRIIMA combines the lower resolution forecast information from operational sea-ice and weather models with an actual satellite image of the ice cover. It performs an image transformation from the recorded satellite image to a predicted image how it might look in 1-3 days. The process involves translation and rotation of ice features as well as scaling of the ice area. The concept is pragmatic in the sense that it establishes a helpful product developed in close collaboration with our test users from the field of cargo shipping, research ice breakers and expedition cruises. The prediction of sea-ice situations by image warping of near-real time radar images can be differentiated into scenarios with increasing complexity: Free drifting ice away from the coast with a relatively homogenous wind field can be addressed with a single global transformation operator (G1-method) or determined on the bases of the four corner coordinates of the image (L4C-method).Ice drift close to the coast or in presence of heterogeneous wind fields requires local transformation of subsets of the SAR image. A possible solution is to define a dense grid of control points which will constrain the movement of the inland pixels(LMP method). The quality of PRIIMA primarily depends on the accuracy of the available wind forecasts. In free drifting sea-ice a 24-hours forecast of the position of individual ice features was within 1 km to the true position. PRIIMA delivers ice forecasts with the resolution of a satellite radar image. It enables the operating ice manager a quick assessment of the upcoming ice situation.