I think I am going to move this to a separate thread, but it is interesting to consider how much extra energy is required to bottom-melt MYI in the Arctic Ocean because it has strong implications in this melting season:
- Out of spring, water right underneath the ice is at -1.8C in thermodynamic equilibrium with the freezing bottom.
- Let's say bottom melting starts in June/July depending on the location (year/round near Atlantic currents).
- For MYI, after a while of bottom-melting the half a meter or so of last season bottom-freezing, the temperature of the water has to raise from -1.8C to 0C in order to continue melting. In contrast, for the more saline FYI, melting proceeds at or slightly above -1.8C.
- This raise of temperature to continue bottom-melting MYI must happen for the whole water column of the mixed layer. In other words, the mixing that happens in this layer will take care of keeping its temperature homogeneous, with a turnover time of the order of the day or a few days.
- Assume the mixing layer is 20 to 40 m depending on location. Let's take 30 m in average.
- The energy for raising 1.8 degrees 30 m of water is equivalent to that needed for bottom-melting approximately 0.75 m of ice!!!! (since raising 1C of a 80m-deep extent of water requires the same energy to melt 1m of the same extent of ice)
So what happens this summer? In parts of the pacific half of the Arctic, and, especially, along Eurasia, we find typically 25-100 cm thinner ice than any previous year.
https://forum.arctic-sea-ice.net/index.php/topic,119.msg112166.html#msg112166 On top of that, most of it is FYI, which will require "75 cm-equivalent less energy" to start bottom-melting than MYI. The MYI is mostly accumulated in a region that is gradually melting out no matter what due to its proximity with Atlantic water.
So as in 2013 (or even more than 2013), we will have to ask ourselves, in case it is an uneventful season, why there was no record or even <1m km2 ice in September. Something must happen in the melting season to prevent so (negative feedback due to snow cover, a cold PAC to prevent insolation and WAAs,...). Otherwise I have little doubt we can get a record low in September.