PIOMAS April 2017
Another month has passed and so here is the updated Arctic sea ice volume graph as calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center:
Just like last month, there haven't been any major changes, and that's good, because it means things haven't gotten worse (according to PIOMAS). But things haven't improved either. After a month of below average volume growth, the difference with number 2 in the rankings (2011), has decreased slightly from 1851 to 1731 km3. On the other hand the difference with 2012, the year when the lowest minimum on record was hit, has increased from 2099 to 2491 km3.
Here's how the differences with previous years have evolved from last month:
Here's Wipneus' version, showing the gap is still more than intact:
And commenter Oren posted this graph over on the Arctic Sea Ice Forum showing the modelled trend for end of March since 1979:
Of course, this means that the trend line on the PIOMAS sea ice volume anomaly graph is still in two standard deviation territory, which is exceptional for this time of year:
As for average sea ice thickness (a crude calculation of PIOMAS volume numbers divided by total JAXA sea ice extent, hence the name PIJAMAS), 2017 is still lowest here as well:
Likewise on the Polar Science Center thickness plot:
The volume maximum is going to be reached this month (a bit later than extent because ice is still thickening at more northern latitudes). Below is a table that shows the maximums for the past 10 years, and next to that the potential 2017 maximum if it gains as much volume as those years did between end of March and their respective maximums:
The average of all those potential maximums for 2017 is 20795 km3. Now, the average of total melt for the past 10 years is 18269 km3, which means that at the end of this year's melting season the minimum could be only 2526 km3 (the lowest minimum on record reached in 2012 was 3673 km3). If we take the lowest amount of volume growth since the end of March (2007), and subtract the highest total melt (19693 km3 in 2010) from that potential maximum, the minimum could even go lower than 1 million km3!
But that's just numbers. Even though it shows the theoretically possible, we'll have to wait and see what the weather brings this melting season. Suffice to say that it would take some crazy circumstances for this theoretical extreme to become practice.
And we also mustn't forget that PIOMAS and CryoSat-2 currently aren't in agreement on how much volume the Arctic sea ice pack represents (see the final part of last month's PIOMAS update). If you want to know how this discrepancy between model data and observations is evolving, keep an eye on the dedicated thread on the Arctic Sea Ice Forum. CryoSat-2 data is about to be updated as well.
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