The Post 2007 Arctic Ocean September Extent

I've been very busy at work, it's audit season, so no spare time. But this weekend is down-time to rest. So I've just had a look at the Arctic Ocean sea ice data for September 2007 to 2022.

The Fast Transition

In May 2015 I concluded a series of posts with The Slow Transition. It was a risky prognostication but an additional 7 years of data has supported what I said back then: That the transition to a seasonally sea ice free state would be slow, not fast, as some argued. This post is about the period preceding that, and with the further 7 years of data something substantive can be said about that.

The Arctic Ocean's sea-ice has undergone a fast transition from one stable mode to another equally stable mode. Between those modes there was a bifurcation driven by the power of an increase of Open Water Formation Efficiency and Ice Albedo Feedback. That bifurcation happened between 2002 and 2006, with the 2007 stochastic event delivering the coup-de-grace that finalised the bifurcation event.

Open Water Formation Efficiency Part 4

Open Water Formation Efficiency (OWFE) is a measure of the ease with which melt season thinning of sea-ice reveals open water. In March I published a post looking at how this operates from a theoretical perspective. In this post I look at how it operates in practice in various regions of the Arctic Ocean.

A Picture is Worth a Thousand Words.

 

The BCE Region Killzone

The BCE region is comprised of the Beaufort, Chukchi, East Siberian Seas. Due to the Beaufort Gyre it has a special role in the dynamics of Arctic sea ice.

Open Water Formation Efficiency - Part 3

Previously, 9 years ago, I produced two posts on Open Water Formation Efficiency, here and here. Now, as a bed rock to a series of posts I am going to revisit that issue. First, in this post, I outline a theoretical model to demonstrate the process involved.

Arctic Ocean: A New Ice Pack

Just a quick first review of PIOMAS data from 1978 to 2021. The results of this preliminary data-dive are what I had expected, which is not good.

May 2015 Status: Four Dipoles

Not all of the NCEP/NCAR data is available, and PIOMAS is yet to be released, but with the data available there is still a lot to cover about sea ice state in May 2015.

The Slow Transition

Ten months ago I posted about my change of mind, from thinking that a fast crash was a very real possibility to expecting a slow transition of the Arctic sea ice to a seasonally ice free state. I have now finished the series of posts detailing my argument. I should start by clarifying; by a slow transition I do not expect the summer sea ice to last into the 2050s, I suspect that around 2030 we will see the first summer with an extent of less than 1 million km^2.

The Slow Transition: Arctic Ocean Energy Gain.

The decline in sea ice volume can reasonably be viewed as a process of net energy gain in the Arctic Ocean's ice/ocean system. How can it be possible for the rate of volume loss to reduce, against the trend of past energy gain?

The Fast Transition

The peripheral seas of the Arctic Ocean are now virtually ice free in September, they are seasonal sea ice seas.

Need I say more?



It seems I do...

In comments Oale wanted to see this in terms of area, which is fair enough. I've done two graphs, one for area one for extent, both with a plot as percentage of April area and extent.

The August Extent Loss Oscillation

In my July Status blog post I rounded up by mentioning a possible oscillation in August NSIDC Extent losses. Using the Wipneus extent calculation based on NSIDC concentration, and with the benefit of 2014's August figures, I think it is worth looking at the again.

However I don't have a convincing explanation, and at this stage I am not convinced it needs one.

June Sea Ice Area and Melt Ponding

I've previously blogged about the anomaly cliff in CT Area during June and its relationship with melt ponding. This anomaly drop is also seen in Wipneus's area and extent calculations based on gridded NSIDC data, it is not peculiar to Cryosphere Today Area.

However are the recent June anomaly cliffs simply due to spread of melt ponding, or is there something else going on?

The Slow Transition

I've been busy with the day job, which has given me time to ponder something I've hinted at before but am now firmly behind. This year isn't a major factor, due to my increased workload in the day job I've had time away from this subject doing something else (often repetitive and boring admin) that has let my subconscious work on the issue - the issue being the long term outlook for Arctic sea ice. Here is what I am now 90% convinced of, having entertained the scenario as a possibility over the last year or so.

What is the future of Arctic Sea Ice? Part 2.

In my previous post I discussed the results of model forecasts for Arctic sea ice, and have outlined why I am not convinced by GCM results suggesting long term survival of perennial ice well into this century. What happens if the current trend of sea ice losses continues and will the trend of volume loss continue?

What is the future of Arctic Sea Ice? Part 1.

Recently I blogged about a paper showing the cause of the post 1995 volume decline in PIOMAS, this being the period of greatest and most persistent volume loss. The cause turned out to be self-acceleration of volume loss caused by the ice albedo feedback, as this is such a fundamental process and as the later version of the PIOMAS has proven to be so successful, I am in little doubt that Lindsay & Zhang's hypothesis is correct and that in the 1990s atmospheric impacts on the ice ushered in a period of decline largely driven by the ice albedo feedback.

There is really only one issue I can move on to address now, and that is the future of the sea ice.

PIOMAS March 2014

PIOMAS volume data is now out for March. The PIOMAS model uses NCEP/NCAR reanalysis data to drive the ice and ocean components of the model, so the monthly data is for the month up to the final day of the month. Some thickening is due to occur over April in the Arctic Ocean, but this is typically small. So this data can be taken as indicative of conditions as the melt season starts.

2014: Large MYI Export into Beaufort & Chukchi

Last year weather led to a pulse of increased volume being fed into the sea ice system, since then we have seen this pulse being severely reduced. Now much of the increased extent of older ice (multi-year ice or MYI) in the Central Arctic has been transported out into Beaufort and is currently making its way into Chukchi. What does this mean for the coming melt season?

What caused the volume loss in PIOMAS?

Behind all of my blogging on sea ice is the volume loss, which is driving the changes. The volume loss is shown by other data (e.g. Submarine upward looking sonar, ICESat, IceBridge, Cryosat 2), but the most detailed picture is that provided by PIOMAS. What is driving the volume loss in PIOMAS and is this process at work in reality?

Sea Ice Thinning, Open Water Formation, and Ice Albedo Feedback

What is the link between the thinning of Arctic Sea ice and the increased open water seen in recent years?