Opened 2 years ago

Last modified 19 months ago

#1894 assigned Enhancement

mass and heat budgets in NEMO

Reported by: clem Owned by: clem
Priority: low Milestone:
Component: OCE Version: trunk
Severity: minor Keywords:
Cc:

Description (last modified by nicolasmartin)

Context

Mass and heat fluxes in NEMO are a bit messy and should be cleaned at some point. Therefore this ticket is a reminder for what should be done (or discussed) for the next NEMO release

As far as I understand, the mass budget of the ocean+ice/snow is written:

$Doce + Dice + Dsnow = - emp_oce - emp_ice + rnf - fwfisf$

  • emp_ice is E-P over sea ice
  • emp_oce includes calving ("calving_cea") in addition to E-P over ocean
  • runoffs include icerbergs ("iceberg_cea") in addition to river runoff
  • fwfisf is the ice-shelf melting (<0 = melting)

This interleaving of variables makes things complicated when it comes to define a heat budget.

  • calving ⇒ we suppose Tcal = 0degC (i.e. no sensible flux) and latent heat is removed from qns to take into account the ocean heat uptake to melt the ice (in sbccpl.F90)
  • river runoff ⇒ we suppose Trnf = SST (in sbcrnf.F90)
  • iceberg ⇒ latent heat is removed from qns (in sbccpl.F90) but since we treat iceberg as a runoff, its temperature is also at the SST (in sbcrnf.F90)
  • ice-shelf ⇒ latent heat is removed from the ocean directly as a temperature change and the sensible flux is taken into account with a melting temperature fixed at -1.9 degC (in sbcisf.F90)

Note that in coupled mode you generally have:

  • iceberg = half of the Antarctic fresh water flux is distributed in the ocean according to a climatology of icebergs distribution
  • iceshelf = half of the Antarctic fresh water flux is distributed along the coast where there is iceshelf
  • calving = Greenland fresh water is uniformly distributed

Fix

  • separate calving from emp_oce?
  • separate river runoff from icerbegs?
  • change temperature of the ice-shelf when melting?
  • change temperature for calving?
  • fwfisf does not follow the convention for runoff (>0 = input for the ocean)
  • other things?

Commit History (0)

(No commits)

Change History (4)

comment:1 Changed 2 years ago by clevy

  • Type changed from Enhancement to Task

comment:2 Changed 2 years ago by nicolasmartin

  • Description modified (diff)
  • Owner nemo deleted
  • Status changed from new to assigned

comment:3 Changed 22 months ago by nicolasmartin

  • Severity set to minor
  • Type changed from Task to Enhancement

comment:4 Changed 19 months ago by nicolasmartin

  • Owner set to clem
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