Opened 8 weeks ago

Last modified 8 weeks ago

#2582 new Defect

Error in the diagnostic bottom pressure

Reported by: Robin_Waldman Owned by: systeam
Priority: low Milestone:
Component: DIA Version: trunk
Severity: minor Keywords: Bottom, pressure, diagnostics,
Cc: Branch review: failed
MP ready?: no Task progress: Unspecified

Description (last modified by nemo)


Within DIA/diaar5.F90, the routine dia_ar5 computes wrongly the bottom pressure (variable zbotpres)


The bottom pressure formulation in L.185 of diaar5.F90 has a dimensional error. Indeed, the hydrostatic part is multiplied twice by density, once in the zbotpres computation of L.164-179, and a second time within the constant coefficient zztmp computed in L.184.


  1. For already existing model outputs with the variable zbotpres (pbo in the CMIP nomenclature): the bottom pressure can be retrieved offline by combining zbtotpres and sshn as follows:
    true_zbotpres(:,:) = zbotpres(:,:)/rau0 + (sshn(:,:) + thick0(:,:)) * g * (rau0 - 1)
  2. The correction to diaar5.F90 to retrieve the true bottom pressure is:
    184            zztmp = grav * 1.e-4_wp               ! recover pressure from pressure anomaly and cover to dbar = 1.e4 Pa
    185            zbotpres(:,:) = zztmp * ( zbotpres(:,:) + rho0 * (ssh(:,:,Kmm) + thick0(:,:)) )

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Change History (2)

comment:1 Changed 8 weeks ago by Robin_Waldman

rau0 instead of rho0 in L.185.

comment:2 Changed 8 weeks ago by nemo

  • Description modified (diff)
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