Saturday, February 2, 2019

The Ghost Photons - 3

Thwaites Glacier
I am in the process of finishing the big chunks of the latest ghost series.

The ghost photons are the tiniest ghosts, compared to ghost water (The Ghost-Water Constant, 2, 3, 4, 5, 6, 7, 8, 9; The Gravity of Sea Level Change, 2, 3, 4NASA Busts The Ghost), and ghost plumes (The Ghost Plumes, 2, 3, 4, 5, 6, 7; The Ghost Photons, 2).

So, today's post begins an attempt to complete the plumes and photon hypotheses and to calculate the photon flow "where the rubber meets the road", that is, where the tidewater meets the tidewater glacier's ice face (graphs in a few days).

A recent paper elaborates on why this is important (P. Milillo, E. Rignot, P. Rizzoli, B. Scheuchl, J. Mouginot, J. Bueso-Bello, P. Prats-Iraola, Heterogeneous retreat and ice melt of Thwaites Glacier, West Antarctica., Sci. Adv. 5, eaau3433 (2019)).

That paper is in agreement with McDougall 2003 in pointing out that models don't do well when it comes to elaborating on ocean heat content (and the induced melting of tidewater glaciers by infrared heat):
"Such complexities in ice-ocean interaction are not currently represented in coupled ice sheet/ocean models"

"Ice shelf melt at A exceeds values used in numerical ice sheet/ocean models by factors of 2 to 3"

"preferential melt channels 1 to 2 km wide and newly formed cavities less than 100 m in height would require ocean models to operate at the subkilometer horizontal scale and sub–100 m vertical scale to replicate the melt processes that form the cavities, which is a challenge"

"the fact that peak melt rates in the main trunk are two to three times higher than those in models limits the ability of models to reproduce ice retreat at those locations"

"ocean-induced ice melt occurs over a 2.5-km-wide grounding zone, whereas numerical ice sheet models use fixed grounding lines, i.e., not affected by tidal mixing (3, 5, 10–12), with zero melt applied at the grounding line"

"ice shelf melt rates may be lower along retrograde slopes than those along prograde slopes, another observation to explore in detail with ice-ocean models"

"We conclude that the cavity shape, including bed slope, bumps, and hollows in the bed, influences the access of ocean heat to the glacier and ocean-induced melt rates"
(P. Milillo et al. 2019).  McDougall 2003 may have explained some of the thermodynamic reasons for that, which entails replacing "potential temperature" with "Conservative Temperature" (and using TEOS-10).

I have shown that McDougall was spot on in his assertion that the new variable for ocean heat content and flux is "Potential Enthalpy" (In Search Of Ocean Heat - 4).

The previous post in this series is here.

1 comment:

  1. Even some AGW deniers get it ... "Radiating the Ocean" (link)