<snippage>
ice seriously impedes heat flow.
I am sure you are right, but my question is what impedes the heat flow, as the thermal conductivity of ice (and any snow on top) is greater than that of water. Is it because of wind and waves and turbulence assisting the process?
Water is dynamic and while the "r" value of water may be less than ice, water can transfer heat via convection, which ice cannot.
Water will also loose heat via evaporation, which ice will not, so you have a loss from phase change in addition to straight-up thermal transfer.
Not to mention that liquid water is at least -2 C, whereas ice can be cold. Ice presents the atmosphere with a surface about the same temperature as the air (-40 for example), and has linear increase in temperature as you go down. Water shows the air -2C.
Ice though isn’t actually an unbroken slab. There’s holes all over the place where heat (and mammals) can poke through the ice. In open water I assume the effect on temperature flux is slight, but near shore we see in Iqaluit the steam come out through tidal cracks. I’d expect the narrow passages through the archipelago would also provide a fair bit of creasing and cracking.
I think this is very important point. Especially when you have a situation like north of Svalbard last week with large long swell penetrating deeply into fragile pack with deep heterogeneous layered water with much heat below.
Its worth downloading the data
http://imb-crrel-dartmouth.org/imb.crrel/irid_data/2017B_clean.csv from imb 2017B which finally took the fram exit ramp along with co-locate itp95 late December. The charts show the picture in brief:
, but looking closely at the in depth thermistor data is far richer.
spreadsheet column format:
1Date 2Latitude (degrees) 3Longitude (degrees) 4Quality (+/- km) 5Air Temp (C) 6Air Pressure (mb) 7Snow Surface Position (m) 8Ice Thickness (m) 9Ice Surface Position (m) 10Ice Bottom Position(m) 11T1 (C) 12T2 (C) 13T3 (C) (....further thermistors at 10cm intervals)
and final data point on 12/12/2017:
12/12/2017 12:00 83.30389 2.17579 GPS -6.09 1003.13 0.39 0.74 0 -0.74 -6.42 -5.6 -4.85 -4.1 -3.72 -3.34 -2.84 -2.4 -1.96 -1.77 -1.83 -1.83 -1.83
basically what happened with these buoys is they melted out in September and then the pack consolidated and froze them back in a few weeks later. However the ice never achieved any free-board and up to mid December when they stopped reporting no bottom growth or thickening was achieved. However the snow load had built to 40cm from sea level to above. It is possible that more than 40cm of snow actually built up, the portion of this weighted to below waterline, or wicking up water, scavenging a little inter-grain ice crystal growth from the seawater. And a little bottom melt continued at least up to end of data. whatever, the ice never got above 0.75m thick.
Anyway IMO any of this ice or snow would be ridiculous to portray as anything but fragile, porous, soggy with seawater and brine inclusions.
You get big long swell propagating hundreds of km into stuff like this like last week, then unlikely its anything but a soggy slushy, wetted with seawater to the snow surface by swells 4-6 times a minute . It wouldn't surprise me if heat transfer seawater to atmosphere can far exceed open water in situations like this. The surface area of water exposed to the air would be far greater, and phase change when air temps are below zero probably allows latent heat to transfer to atmosphere too.
its an ongoing source of extreme frustration that imb's 2017C,D are still being data censored in the Beaufort, where the have been colocates with itp's 101 and 108 for six months.
IMHO a coordinated pester campaign to the following email addresses would be appropriate:
"To obtain information on the datafiles contact Don Perovich at Donald.K.Perovich@Dartmouth.edu"
"Please address any questions regarding the data to Bruce Elder ( Bruce.C.Elder@usace.army.mil )"
These have always previously been available from prior missions. Be nice to have an explanation at least, better still the valuable picture of whats going on that tax dollars have paid for.