News Item
2023 Sea Ice Outlook Season Overview
For questions, please contact
Betsy Turner-Bogren, ARCUS
Email: betsy [at] arcus.org
Sea Ice Prediction Network (SIPN) team members are organizing the 2023 Sea Ice Outlook (SIO), pending funding. For information about the 2023 SIO season, please see the tentative season overview and report schedule below.
The SIO provides an open process for those interested in Arctic sea-ice to share ideas. Four monthly reports during the sea-ice retreat season will include a variety of contributions—from advanced numerical models to qualitative perspectives from citizen scientists—as well as brief related discussions. Plans for a brief Post-Season Report, with focus on performance of Outlooks as compared to the observed sea ice minimum, will be developed at the end of the retreat season.
As always, we encourage all past contributors to submit Outlooks this year and we also hope to see new participants. Please feel free to distribute this overview to others who might be interested in participating in the SIO.
TENTATIVE OVERVIEW OF THE 2023 SIO SEASON
The 2023 SIO solicitation and submission process is the same as 2022. Again this year contributors will need to re-submit outlooks for each report—no contributions will be automatically carried forward from one month to subsequent monthly reports.
2023 SIO Submission Form and Process:
- Outlooks for pan-Arctic, pan-Antarctic, and Alaskan regional September monthly mean sea-ice extent, related uncertainty/probability estimates, and the optional submissions of sea-ice extent anomaly forecasts will be collected via a Google-based form. A link to the form will be provided in each of the monthly calls for contributions. (See the tentative schedule below.)
- For August and September only: Forecasts for sea-ice advance dates (IAD) will be calculated from the full spatial fields of sea ice concentration that extend through the ice-advance seasons as submitted via the SIPN Data Portal (password is require and instructions will be provided in the monthly calls for contributions).
- Contributors who do not have access to the Google-based form or a Google account will have access to an alternative form and/or a PDF of the submission form, to be submitted via email to sio2023 [at] mail.arcus.org.
- Supplemental materials, including PDFs of any additional figures and/or text files, will be accepted via email to sio2023 [at] mail.arcus.org.
Further details will be included in the Call for Contributions to the 2023 SIO June Report that will be sent to the community in late May 2023.
Note: All participants whose methods provide information at the regional scale are again encouraged to provide full spatial fields via the SIPN Data Portal (password is required—instructions will be provided in the monthly calls for contributions). These submissions will allow organizers to compute metrics such as sea ice probability and first ice-free day for contributors, as well as additional regional analysis for the Sea Ice Outlook.
Solicitation of Pan-Arctic Sea-Ice Extent Anomalies
Organizers again invite pan-Arctic sea-ice extent anomaly forecasts for the 2023 SIO. This is an optional submission and it is recognized that not all SIO contributors will be able to provide anomaly forecasts. The request is motivated by the large spread in SIO predictions of mean September sea-ice extent. Some of this spread likely reflects inter-model biases, i.e., some models consistently overestimate ice extent while others underestimate it (relative to observations). The goal of this activity is to eliminate this source of inter-model prediction spread. The long-term mean is not a well-defined concept in a rapidly changing Arctic. The pan-Arctic sea-ice extent anomaly is the departure of the contributors’ September extent Outlook relative to the contributors’ baseline trend, e.g., the trend in historical observations, model hindcasts, etc.
To calculate a pan-Arctic sea-ice extent anomaly:
1. Calculate the multi-year linear trend (slope) of September-mean extent from your baseline period. The linear trend will be different for each contributor due to inter-method/model biases.
2. Extrapolate the linear trend to calculate an extrapolated September 2023 extent value.
3. Calculate the extent anomaly value by subtracting the September 2023 Outlook extent from the extrapolated trend September 2023 value.
2023 SIO TENTATIVE REPORT SCHEDULE
JUNE REPORT: (Based on May data)
- 23 May 2023 (Tuesday): Call for Contributions to June Report
- 12 June 2023 (Monday): Deadline for June Contributions
- 23 June 2023 (Friday): June Report Released
JULY REPORT: (Based on May and June data)
- 26 June 2023 (Monday): Call for Contributions to July Report
- 12 July 2023 (Wednesday): Deadline for July Contributions
- 24 July 2023 (Monday): July Report Released
AUGUST REPORT: (Based on May, June, and July data)
- 28 July 2023 (Friday): Call for Contributions to August Report
- 14 August 2023 (Monday): Deadline for August Contributions
- 25 August 2023 (Friday): August Report Released
SEPTEMBER REPORT: (Based on May, June, July, and August data)
- 28 August 2023 (Monday): Call for Contributions to September Report
- 13 September 2023 (Wednesday): Deadline for September Contributions
- 20 September 2023 (Wednesday): September Report Released
Note: The September report will be an abbreviated report to include summary figures, PDFs of contributed outlooks, and limited discussion.
BRIEF POST-SEASON REPORT
- Developed following the conclusion of the retreat season.
- Focus will be on the performance of Outlooks as compared to sea-ice minimum.
- Additional discussion and analysis of factors driving sea-ice extent during the 2023 melt season.
For questions, please contact
Betsy Turner-Bogren, ARCUS
Email: betsy [at] arcus.org