we expect 300*0.9=270 m^3/s of glacier meltwater to enter Petermann Fjord as freshwater. This is about half a Delaware River or a Thames River.
That is absolutely amazing to have a river of this magnitude flowing out from under a frozen glacier whose surface features have stable for decades, giving no indication of the melt turmoil underneath. And where is all this fresh water going (to the south) and to what effect?
I would guess there is only minor seasonality to the flow since circulating ocean water deep below has vast thermal inertia and lacks effective contact with the freezing winter or warmer summer air above.
However within ocean circulation per se, in addition to tides, there could be both seasonal effects associated with Nares Strait as well as longer term trends attributable to climate change induced rearrangements in large scale circulation. It is great to have some actual data to put bounds on speculation and put model theory to the experimental test.
Down the road, after total disappearance of the ice shelf, the melt would come from the newly exposed vertical face as the bottom sits on bedrock and is not exposed to sea water. This presents far less surface area (12 km2
than the horizontal under-shelf (~800 km2
). It's not clear to me how much of the current oceanic circulatory pattern would carry over to the shelf-free situation, perhaps quite a bit.
Petermann might retreat fairly slowly under oceanic facial melt up its prograde slope until a broad sill is reached several dozen km upglacier so is not a proxy in this sense for the more worrisome retrograde West Antarctic ice shelves.
In terms of temperature-with-depth of ice within the floating ice shelf, this situation presents interesting but manageable boundary conditions for Fourier's heat equation which would have an exact solution here (after certain idealizations) on a trapezoidal slab. Still, it's good to have the thermister strings.
It might be feasible to get at the temperature profile a ways upglacier from the grounding line, though it is problematic that this would shed light on the basal upheaval anomalies which barely extend to Schoubye. Logistically, it would make far more sense to drill basal features at Eqip than here.