The "September Sea Ice Outlook: August Report" has just been released by ARCUS.
Summary
Thank you to the groups that contributed to the 2015 August Report. We have 38 (including one regional only) contributions, which again sets a new record for the total number of submissions.
The median August Outlook for September 2015 Arctic sea ice extent is 4.8 million square kilometers (km2), 200,000 km2 lower than the June and July medians. The quartile range is 4.2 to 5.2 million km2 (see Figure 1 in the Overview section, below). Contributions are based on a range of methods: statistical, dynamical models, estimates based on trends, and subjective information. The overall range (excluding an extreme outlier) is 2.7 to 5.6 million km2. The low end of the range dropped substantially from July (3.3 million km2), due to one new contribution, while the high end changed only slightly from July (5.7 million km2).
The median's decrease from the June and July values reflects rather rapid ice loss during July. The drop is mostly due to lower statistical and mixed statistical/heuristic contributions (Figure 2), because these methods are generally at least partially based on extrapolation from current/previous conditions whereas modeling contributions are generally not.
The August Outlook was developed by lead author Walt Meier (NASA Goddard Space Flight Center) with contributions from the rest of the SIPN leadership team. This month's report includes a compilation of ship-based observations from the Geographic Information Network of Alaska IceWatch program, a discussion of the August modeling contributions and how they compare to June and July, a look at the predictions in specific regions, and a discussion of current ice and weather conditions.