Arctic Sea Ice

2016 SIPN Sea Ice Outlook: August report

The third and last Sea Ice Outlook of this year has been published. The SIO is organized by the Sea Ice Prediction Network (as part of the Arctic research program 'Study of Environmental Arctic Change', or SEARCH), and is a compilation of projections for the September 2016 Arctic sea ice extent, based on NSIDC monthly extent values. These projections are submitted by professionals as well as amateurs (public outlooks).

Here's the summary for the August report:

This month the median pan-Arctic extent Outlook for September 2016 sea ice extent is 4.4 million square kilometers (km²) with quartiles of 4.2 and 4.7 million km², which is slightly higher than July's value (4.3 million km²) (See Figure 1 in the full report, below). If the median Outlook should agree with the observed estimate come September, this year would be the third lowest September in the satellite record. The spread in the Outlook contributions narrowed slightly from July to August, with an overall range this month of 3.7 to 5.2 million km².

The full range of Outlooks submitted this month lies within the range of the ten lowest years of sea ice extent in the observational record. As in July, no Outlook is predicting a new record this year, despite the warm winter, record low extents for every month in 2016 except March and July, and evidence of thin ice in spring. Current sea ice extent and meteorological conditions suggest a record low is unlikely, as surface temperature over the central Arctic has been near normal in the last two months and forecasts of atmospheric temperatures for the next few weeks indicate average surface temperatures. However, a major storm in the central Arctic during mid- to late August will support continued breakup of the central ice pack. The higher end of the predictions is also unlikely given that the current extent as of 16 August is 5.3 million km².

And here's the figure showing all the projections (click for a larger version):

The September minimums for the last 11 years (in million km2, found here):

The September minimums for the last 11 years (in million km2, found here):

2016 SIPN Sea Ice Outlook: July report

The second Sea Ice Outlook of this year has been published. The SIO is organized by the Sea Ice Prediction Network (as part of the Arctic research program 'Study of Environmental Arctic Change', or SEARCH), and is a compilation of projections for the September 2016 Arctic sea ice extent, based on NSIDC monthly extent values. These projections are submitted by professionals as well as amateurs (public outlooks).

Here's the summary for the July report:

This month the median pan-Arctic extent Outlook for September 2016 sea ice extent is 4.3 million square kilometers (essentially unchanged from June) with quartiles of 4.1 and 4.6 million square kilometers (See Figure 1 in the full report, below). If the median Outlook should agree with the observed estimate come September, this year would be the third lowest September in the satellite record. The spread in the Outlook contributions narrowed slightly from June to July, with an overall range this month of 3.6 to 5.2 million square kilometers.

The full range of Outlooks submitted this month lies within the range of the 10 lowest years of sea ice extent in the observational record. No Outlook is predicting a new record this year, despite the warm winter, record low extents for every month in 2016 except March, and evidence of thin ice in spring. Does this mean it won't be a record? Meteorological conditions suggest not, as surface temperature over the central Arctic has been near normal in the last month and forecasts of atmospheric circulation for the next few weeks suggest near normal surface temperature in the near future. At the same time, the subpolar seas are warmer than average and the land surrounding the Arctic Ocean has been warm and both are projected to continue to be warm in August and September. Finally, we note that no Outlook predicted a record low in 2012 either, and as a whole, the Outlooks tend to be miss the extreme low and high years compared to the long-term trend.

And here's the figure showing all the projections (click for a larger version):

 

 The September minimums for the last 11 years (in million km2, found here):

2016 SIPN Sea Ice Outlook: June report

The first Sea Ice Outlook of this year has been published. The SIO is organized by the Sea Ice Prediction Network (as part of the Arctic research program 'Study of Environmental Arctic Change', or SEARCH), and is a compilation of projections for the September 2016 Arctic sea ice extent, based on NSIDC monthly extent values. These projections are submitted by professionals as well as amateurs (public outlooks).

Here's the summary for the June report:

The distribution of Outlooks for statistical and dynamical models have a median extent that is 0.15 million square kilometers different from each other, with a slightly larger spread for the statistical models than the dynamical models. The same sort of spread difference was seen in 2015. Separating out fully-coupled dynamical models from ice-ocean models shows that fully coupled models give a slightly lower forecast with a median of 4.57 versus 4.62, yet have a larger spread (Figure 2). The median forecast of heuristic forecasts is 4.0 million square kilometers and the spread is small. However, actual contributions to the two polls show a diverse range from 2.9 to 5.3 million square kilometers.

The overall width of the distribution of Outlooks has narrowed compared to last year: the interquartile spread across all types of contributions is 0.53 million square kilometers, which is a decrease of 0.27 million square kilometers since last year. The overall range is also reduced to 3.4 to 5.23 million square kilometers.

And here's the figure showing all the projections (click for a larger version):

2016 melting momentum, part 1

Melting momentum, it's what I call the absorption of heat and solar radiation during May and June that does not directly lead to melt and a reduction in ice cover, but rather comes into play during July and August (I had a more wordy explanation last year).

As important as it seems to be for the final outcome of the melting season, it is one of those aspects of Arctic sea ice that has proven to be really difficult to measure. Observations based on satellite images have been developed in the recent past, but for some strange reason, this research didn't receive further funding.

I will discuss some indirect and experimental measurements further below, but start off with the best tool we have by far to get a feel for how much melting momentum is being built up during this crucial period in the melting season: the melt pond fraction simulation model developed by CPOM researchers at the University of Reading (more info).

Again this year, Dr David Schröder has been so kind as to send me the May melt pond fraction maps he uses for his SIPN 2016 Sea Ice Outlook prediction, showing melt pond anomalies for the years 2012, 2014, 2015 and 2016 compared to the average for the last 10 years:

Caveat: This is a model result, and so the distribution of melt ponds doesn't necessarily reflect reality.

This past May has been similar to last year's, but nowhere near May 2012. Here are two more maps that show the difference in melt pond fraction with May 2012 and 2015 (red = more melt ponds now, blue = less melt ponds now):

2015 SIPN Sea Ice Outlook: August report

The third and last Sea Ice Outlook of this year has been published. The SIO is organized by the Sea Ice Prediction Network (as part of the Arctic research program 'Study of Environmental Arctic Change', or SEARCH), and is a compilation of projections for the September 2015 Arctic sea ice extent, based on NSIDC monthly extent values. These projections are submitted by professionals as well as amateurs (public outlooks).

Scroll down to the bottom to see the results from this year's Arctic Sea Ice Forum polls that were held at the same time as the periods preceding the SIO monthly submission deadlines.

Here's the summary for the August report:

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.

Read the entire report here.

And here's the figure showing all the projections (click for a larger version):

2015 SIPN Sea Ice Outlook: July report

The second Sea Ice Outlook of this year has been published. The SIO is organized by the Sea Ice Prediction Network (as part of the Arctic research program 'Study of Environmental Arctic Change', or SEARCH), and is a compilation of projections for the September 2015 Arctic sea ice extent, based on NSIDC monthly extent values. These projections are submitted by professionals as well as amateurs (public outlooks).

Here's the summary for the July report:

The median Outlook for September 2015 Arctic sea ice extent is 5.0 million square kilometers (km²), which is the same as the June Outlook median. The quartile range is 4.4 to 5.2 km² (see Figure 1 in the Overview section, below). Contributions are based on a range of methods: statistical, numerical models, estimates based on trends, and subjective information. The overall range (excluding an extreme outlier) is 3.3 to 5.7 million km². The median Outlook value is up from the July 2014 median value of 4.8 million km². These values compare to observed values of 4.3 million km² in 2007, 4.6 million km² in 2011, 3.6 million km² in 2012, and 5.3 million km² in 2014. In general, the heuristic approaches forecast a mean September extent around 4.1 million km², whereas the statistical and dynamical modeling approaches both suggest mean September extent near 5.1 million km², with the dynamical modeling contributions showing a narrower range.

The lack of significant change between this month and last is largely related to the fact that most contributors did not change their forecast for July. Another factor could be the lack of significant atmospheric or oceanic forcing that would result in a large change from the June forecasts. A discussion of 11 dynamical model contributions shows no major differences compared to last month's report. This month's report also includes results from three regional predictions and a discussion of current ice and atmospheric conditions.

Read the entire report here.

And here's the figure showing all the projections (click for a larger version):

The September minimums for the last 10 years (in millions km2, found here):

Junction June 2015

Melt pond May alliterates well and the name conveys what it's about: the time when melt ponds first start to form. Luckily, a couple of weeks ago, someone on the forum (forgot who, but thanks!) helped me find a perfect alliteration for June: Junction June. This name refers to the month's importance for the rest of the melting season.

The idea is simple: the fraction of the ice pack's area that is covered by melt ponds during May and June, preconditions the ice for the rest of the melting season, because melt ponds lower the pack's albedo and thus soak up more solar radiation. This in turn increases melting momentum, which can sustain a high decrease during the second half of the melting season, even if weather conditions aren't perfect for melting, compaction and transport. Conversely, if melting momentum is low, chances of new September records are minimal, unless weather conditions during July and August favour huge losses. Hence the word 'junction'. The trajectory for the melting season is largely determined during May and June.

Just like last month, I'll analyse the melt pond situation by comparing this year's weather conditions with those of previous years that generated records (2007, 2011 and 2012) as well as rebounds (2013 and 2014). But first I want to look at the melt pond distribution maps that were sent to me by David Schröder from the University of Reading and are based on his research published last year. A model,  using NCEP reanalysis data for atmospheric forcing, simulates the melt pond distribution across the Arctic, and although pond area in May is only around 1% of the total melting season area, this melt pond cover fraction according to Schröder et al seems to have the strongest impact on the sea-ice state in September.

This correlation has been contested in a recent study by Jiping Liu et al, published in Environmental Research Letters back in May. The paper states that "a significantly strong relationship (high predictability) first emerges as the melt pond fraction is integrated from early May to late June, with a persistent strong relationship only occurring after late July." Either way, late June is now well behind us, so here are the melt pond distribution maps for 2012, 2014 and this year (click for a larger version):

Mind you, these maps are model results and don't display the exact locations of melt ponds.

Eyeballing the maps it's clear that 2015 has more melt ponds than 2014, but doesn't come even close to 2012. Dr. Schröder writes:

2015 SIPN Sea Ice Outlook: June report

The first Sea Ice Outlook of this year has been published. The SIO is organized by the Sea Ice Prediction Network (as part of the Arctic research program 'Study of Environmental Arctic Change', or SEARCH), and is a compilation of projections for the September 2015 Arctic sea ice extent, based on NSIDC monthly extent values. These projections are submitted by professionals as well as amateurs (public outlooks).

Here's the summary for the June report:

The median Outlook value for September 2015 sea ice extent is 5.0 million square kilometers with quartiles of 4.4 and 5.2 million square kilometers (See Figure 1 in the full report, below). Contributions are based on a range of methods: statistical, numerical models, estimates based on trends, and subjective information. We have a large spread in the Outlook contributions, which is not surprising given the wide-ranging observed values for the September extent in the past few years. The overall range (excluding an extreme outlier) is 3.3 to 5.7 million square kilometers. The median Outlook value is up from 4.7 million square kilometers in 2014. These values compare to observed values of 4.3 million square kilometers in 2007, 4.6 million square kilometers in 2011, 3.6 million square kilometers in 2012 and 5.3 million square kilometers in 2014.

Read the entire report here.

And here's the figure showing all the projections (click for a larger version):

The September minimums for the last 10 years (in millions km2, found here):

    2005: 5.57
    2006: 5.92
    2007: 4.30
    2008: 4.73
    2009: 5.39
    2010: 4.93
    2011: 4.63
    2012: 3.63
    2013: 5.35
    2014: 5.28

Again, it's nice to see some people who comment here and /or on the Forum to have again submitted contributions, like Rennie, Cole, Hamilton, Dekker and of course Chris Reynolds. Chris' projection of 5.15 million km2 for the September average is right between that of Schröder's 5.1 million km2 - whose projection I discussed in this recent blog post concerning melt ponds during May- and that of Zhang's 5.2 million km2, based on the PIOMAS model. These are among the best sources of projections (melt ponds and ice thickness) in my opinion, and so Chris' projection looks well-based and solid for the time being.

SIPN Call for Contributions to 2015 Sea Ice Outlook

Most of you interested in this and thinking about contributing a prediction, probably know about it already, but for those of you who don't: you can send in your prediction to the Sea Ice Outlook as organised by the Sea Ice Prediction Network under the umbrella of the Arctic Research Consortium of the United States (ARCUS).

Details are below:

The Sea Ice Prediction Network (SIPN) announces a call for Sea Ice
Outlook (SIO) contributions to the June report (based on May data):

- The firm submission deadline is 6:00 p.m. (AKDT) on Friday, 12 June 2015.
- Guidelines for contributors can be found at:
http://www.arcus.org/sipn/sea-ice-outlook/2015/june/call
- All submissions should be sent to: [email protected]

The Sea Ice Outlook (SIO) provides an open process for those interested in Arctic sea ice to share predictions and ideas about the monthly September minimum sea ice extent. The monthly reports contain a variety of perspectives from advanced numerical models to qualitative perspectives from citizen scientists. All past contributors as well as new participants are encouraged to submit Outlooks this year. A post-season report will provide an in-depth analysis of factors driving sea ice extent this summer as well as explore the scientific methods for predicting seasonal ice extent.

For the June Outlook report, pan-Arctic and regional outlooks will be accepted and spatial forecasts and maps are particularly encouraged. A short executive summary and summary of methods are required this year.

Contributors should review the submission guidelines for detailed instructions and templates including:

- Core requirements for pan-Arctic contributions,
- Additional (optional) items for pan-Arctic contributions,
- Regional Outlooks, and
- Figures and data.

Detailed submission guidelines for contributions are available at:
http://www.arcus.org/sipn/sea-ice-outlook/2015/june/call.

For questions, contact Betsy Turner-Bogren, ARCUS
Email: [email protected]

Naturally, I'll be reporting on the SIO every month (as I do every year). After all, predicting the annual outcome of the melting season is one of the most exciting scientific challenges in cryospheric sciences.