Abstract
Rapid dynamic changes at the margins of the Greenland Ice Sheet,
synchronous with ocean warming, have raised concern that tidewater
glaciers can respond sensitively to ocean forcing. Understanding of the
processes encompassing ocean forcing nevertheless remains embryonic. The
authors use buoyant plume theory to study the dynamics of proglacial
discharge plumes arising from the emergence of subglacial discharge into
a fjord at the grounding line of a tidewater glacier, deriving scalings
for the induced submarine melting. Focusing on the parameter space
relevant for high discharge tidewater glaciers, the authors suggest that
in an unstratified fjord the often-quoted relationship between total
submarine melt volume and subglacial discharge raised to the ⅓ power is
appropriate regardless of plume geometry, provided discharge lies below a
critical value. In these cases it is then possible to formulate a
simple equation estimating total submarine melt volume as a function of
discharge, fjord temperature, and calving front height. However, once
linear stratification is introduced—as may be more relevant for fjords
in Greenland—the total melt rate discharge exponent may be as large as ¾
(⅔) for a point (line) source plume and display more complexity. The
scalings provide a guide for more advanced numerical models, inform
understanding of the processes encompassing ocean forcing, and
facilitate assessment of the variability in submarine melting both in
recent decades and under projected atmospheric and oceanic warming.
Original language | English |
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Pages (from-to) | 1839-1855 |
Number of pages | 17 |
Journal | Journal of Physical Oceanography |
Volume | 46 |
Issue number | 6 |
DOIs | |
Publication status | Published - 2 Jun 2016 |
Keywords
- Geographic location/entity
- Glaciers
- Ice sheets
- North Atlantic Ocean
- Circulation/dynamics
- Convection
- Atm/Ocean structure/phenomena
- Runoff
- Mathematical and statistical techniques
- Differential equations