Sea Ice Prediction and Verification

The YOPP Sea Ice Task Team coordinates and/or supports the following key projects that contribute to the team’s goals. Here, the definition of “project” is very loose and can range from just the formation of interest/discussion groups that keeps each other up to date, to broad and work-intensive projects.

If you are interested in any of these projects, please contact the respective project lead!

Projects associated with the Sea Ice Task Team

A)    Sea Ice Drift Forecast Experiment (SIDFEx)

This YOPP project is a community effort to collect and analyse Arctic sea-ice drift forecasts at lead times from days to a year. The forecasts are made with various methods for drifting sea-ice buoys and, ultimately, the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC), a year-long trans-Arctic drift campaign that has commenced in autumn 2019. A systematic assessment of real drift forecasting capabilities is foreseen to improve our physical understanding of sea ice and to help identify and resolve model shortcomings. More than ten operational forecasting and research groups have already contributed drift forecasts, most groups deriving their 10-days-to-seasonal-range forecasts by means of diagnostic Lagrangian tracking based on prediction drift fields of coupled or uncoupled general circulation models. Some groups submit ensembles of drift trajectories instead of single (deterministic) trajectories, and several groups submit their forecasts in (near-)real-time. Details can be found here.

Lead: Helge Goessling (helge.goessling(at)awi.de)

B)    MOSAiC Near Real-Time Verification Project (MOSAiC-NRV)

The MOSAiC Near Real-Time Verification Project (MOSAiC-NRV) is designed to use observations taken during MOSAiC to improve the simulation of coupled processes unique to the Arctic, such as; The vertical representation of cloud and hydrometeors microphysics, low level (mix-phase) clouds; The representation of the stable boundary layer; Atmosphere-snow interaction and ocean-sea ice-atmosphere coupling. Short-term forecasts are used in this project to identify potential errors in the representation of "fast" processes that cause biases in climate model projections of Arctic climate change. 
The goal of MOSAiC-NRV is to evaluate the skill of fully-coupled short-term forecasts of the MOSAiC campaign at the Polarstern location. Multi-model diagnostics focus on process-based evaluation of the coupled system to identify systematic biases that limit the skill of Arctic forecasts. Observations of snow/sea-ice characteristics (from IMBs), the atmospheric structure (from soundings), cloud characteristics (based on radar/lidar), and surface fluxes (from 3 separate surface flux stations) are used in the evaluation. Initial studies are underway to evaluate the short-term forecast skill of experimental and operational forecast systems during the MOSAiC winter (15 March 2019-15 October 2020), focusing on processes that determine surface temperature, and coupling between the atmosphere and sea ice.

Lead: Amy Solomon (amy.solomon(at)noaa.gov)

The following additional projects are under consideration:

C)    (under consideration) – Sea Ice Reference Forecast Project

The evaluation of sea-ice forecasts and whether or not they can be considered “skillful” depends not only on meaningful verification metrics measuring the “distance” of a forecast from the verifying observation (the error), but also on the benchmark used to put the error into context, turning a “score” into a “skill score”. The SITT is considering promoting and coordinating the development of a common set of (purely observations-based) sea ice reference forecasts (beyond trivial initial-state persistence and climatological benchmarks) to improve the evaluation of sea-ice forecasts, on sub-seasonal and possibly other time scales. This would include facilitating and encouraging the use of these benchmarks among forecasting centres to enable meaningful comparisons of forecast skill between groups.

Lead: TBD

D)    (under consideration) – MOSAiC Drifting Column Project

The SITT is exploring possibilities to help coordinating drifting column simulation experiments that exploit MOSAiC data (associated with YOPPSiteMIP), including ice thickness distribution and deformation data. In this context, promote the storage and exploration of collocated ice-ocean forecasts through the GOV intercomparison.

Lead: TBD

E)    (under consideration) – Next-Level Sea-Ice Verification Project

The SITT would like to expand sea ice verification (1) from the current focus on concentration, edge, and drift, to consider ice thickness, ice pressure, stage of ice development, and Marginal Ice Zone (MIZ), and (2) from large-scale summary metrics to more regional metrics, e.g., in the CAA where complex coastal geometry plays an important role.

Lead: TBD