This will be my last forum post unless something decisive is done about the trolling, stupidity, chat, and trash that are overwhelming the main melt season forum. Page after page after page of complete crap, eg 32 moronic posts in a single day by one completely clueless phony.
I do not want my posts flanked on all sides by this type of degrading material, who does? A lot of very knowledgable people here and many excellent posts but the ratio has dropped to 1:20 on the main forum. Too much to wade through.
And that is by design: a dire melt season --> extra trolls are hired to keep the swamp filled.
We need to do something
very differently to get the main forum to work. For instance, allow the crap to continue unabated on side forums but promote worthwhile posts to a restricted-access forum. The worst jerks need to be put on ice until after melt season, minimally.
/=/=/=/=/===
At any rate, the expandable thumbnail below tests whether Arctic Basin bathymetry lines (0, 30, 100, 300, 1000 meters) vis-a-vis salinity have any explanatory power for melt season. Mercator Ocean unfortunately does not provide the key 150 m contour often taken as the continental shelf break in the Arctic.
The bathymetric contours show the extreme asymmetry of shallow water distribution (ie Beringia) favoring the Siberian side. The CAA and AK coasts have very narrow shelves and so little explanatory power for the June 30th ice data columns (AMSR2 concentration, Osisaf sea ice motion, Ascat ice age).
While warming waters there have potentially catastrophic implications for the frozen lid capping already-released methane underground, early melt there probably has more to do with advection of Siberian land heat, clear skies (resp. favorable cloud cover) and horrifically encroaching atlantification than with depth per se.
We've been wondering for months when the Svalbard-FJL is going to open up. It's late because ice motion this year has brought ice in at a sharper meridional angle than in past (ie traditional zonal TransPolar Drift.
V Ivanov 2019 provides an excellent distillation of recent decades of oceanographic research north and east of Svalbard, ie the Nansen Basin (as the bathymetric shelf is minimal offshore as shown).
A great deal of sincere but erroneous and dated information is being posted on the forums so it is worthwhile quoting the highlights here:
https://iopscience.iop.org/article/10.1088/1755-1315/231/1/012024/pdf free full text, no excuses
Atlantic Water (AW) is the major advective heat source which substantially makes up the Arctic Ocean heat budget. The temperature increase in the AW branch entering the Arctic Ocean through the Fram Strait has been observed since in 1990s. The first warming pulse with a temperature peak about 1°C above the climate norm of 1950-1990 was documented in mid-1990s. After a short term cooling, a stronger pulse (up to 1.75°C above climate norm) occurred in the mid-2000s.
Later on, the AW temperature permanently remained within the range of .5 – 1.5°C above the climate norm.
A steady shift to the warmer state of the AW inflow disturbed the existing balance at the lower ice surface due to the increased heat flux from below . According to estimations by,an increase in the average vertical heat flux from the AW from conventional 2 W/m2 to 4 W/m2 would be enough to provide the observed thinning of the Arctic sea ice in the 2000s.
However, it is important to underline that the higher temperature of the AW layer does not guarantee increased heat impact on the sea ice, because almost everywhere in the Arctic Ocean the AW is isolated from the ocean surface and sea ice by high gradient transition layers. In this sense, the western nansen basin (WNB) is a very specific region, because at its western margin the AW
reaches the ocean surface.
In ice covered seas, ocean-air heat loss is predominantly compensated by ice growth, release of brine into the water, and subsequent density increase. However, over most of the Arctic Ocean, the depth of haline convection is limited to a few tens of meters since the amount of brine released from the growing ice is
insufficient to make the water dense enough for mixing up the underlying pycnocline. With the increasing seasonality of Arctic sea ice cover, this steady regime is changing and the most noticeable change occurs along the AW flow in the Nansen Basin.
The reduction of pan Arctic sea ice cover initiated a positive feedback loop connecting the change of vertical thermohaline structure with regional ice decay in the Western Nansen Basin, where eastward-moving warm Atlantic Water collides with sea ice drifting out from the central basin.
This collision results in AW cooling and freshening in its surfaced upper part due to ice melt. Under these conditions, a compact region north of Svalbard (the so-called Whalers Bay) remained permanently ice free in winter because of steady sensible heat polynya, maintained by the AW heat.
In the changing climate, the Arctic sea ice cover shrinks down and the share of seasonal ice increases while the ice itself becomes more thin, mobile and fragile. These changes on the pan-Arctic scale invoked regional response, namely reduced ice import to the marginal transition zones (seas) from the central basin.
In case of the WNB, breaking of earlier existed steady-state heat and salt balances in the upper mixed layer (UML), together with an increased heat and salt import with the AW inflow, reduced vertical density stratification, thus facilitating development of winter thermohaline convection along the AW pathway.
Enhanced convection delivers additional heat and salt to the UML contributing to accelerated sea ice melt and/or impeding local ice formation. The strong seasonal cycle of temperature in the AW layer with the culmination at the mid-WNB meridian in early winter additionally facilitates convection development above the AW warm core. Satellite detectable outcome of this chain of events is an anomalously long duration of low ice concentration zone in the WNB in mid-winter, which is observed after 2012.
The currently observed decrease of ice area in the Barents Sea was preconditioned by the reduction of ice import from the central basin in the 1990-2000s. Consequent weakening of density stratification enhanced vertical mixing down to intermediate Atlantic origin water (AW). Excessive heat input from the AW to the upper mixed layer (UML) led to further reduction of sea ice, thus closing the positive feedback loop.