#291 closed Bug (fixed)
Question about the surface boundary condition for the mixing length
| Reported by: | greffray | Owned by: | ctlod |
|---|---|---|---|
| Priority: | low | Milestone: | |
| Component: | OCE | Version: | v3.0 |
| Severity: | Keywords: | OPA SBC mixing turbulent v3.0 | |
| Cc: |
Description
Near the surface, l = Kz0 with K = 0.41 (Von Kalman's constant) and z0 the surface roughness parameter. Mellor and Blumberg 2004 propose to calculate z0 in this way :
z0 = beta * tau / (rho * g) with beta = 2.e5.
This surface boundary condition is implemented in NEMO_3.0 (routine zdftke.F90) but where is K ?
Guillaume.
IF( ln_mxl0 ) THEN ! surface mixing length = F(stress) : l=2.e5*sqrt(utau2 + vtau2)/(rau0*g)
!!gm this should be useless
zmxlm(:,:,1) = 0.e0
!!gm end
zraug = 0.5 * 2.e5 / ( rau0 * grav )
DO jj = 2, jpjm1
!CDIR NOVERRCHK
DO ji = fs_2, fs_jpim1 ! vector opt.
ztx2 = utau(ji-1,jj ) + utau(ji,jj)
zty2 = vtau(ji ,jj-1) + vtau(ji,jj)
zmxlm(ji,jj,1) = MAX( rn_lmin0, zraug * SQRT( ztx2 * ztx2 + zty2 * zty2 ) )
END DO
END DO
ELSE ! surface set to the minimum value
zmxlm(:,:,1) = rn_lmin0
ENDIF
Commit History (1)
| Changeset | Author | Time | ChangeLog |
|---|---|---|---|
| 1268 | ctlod | 2009-01-14T15:08:06+01:00 | include the missing Von Karman constant in surface mixing length computation and set to 0.1 the default value for the rn_lmin parameter, see ticket: #291 |
Change History (14)
comment:1 Changed 15 years ago by ctlod
- Owner changed from NEMO team to gm
comment:2 Changed 15 years ago by ctlod
- Owner changed from gm to ctlod
- Status changed from new to assigned
comment:3 in reply to: ↑ description Changed 15 years ago by ctlod
comment:4 Changed 15 years ago by ctlod
- Resolution set to fixed
- Status changed from assigned to closed
comment:5 Changed 8 years ago by nicolasmartin
- Keywords conditions added; condition removed
comment:6 Changed 8 years ago by nicolasmartin
- Keywords boundaries added; boundary removed
comment:7 Changed 8 years ago by nicolasmartin
- Keywords nemo_v3* added
comment:8 Changed 8 years ago by nicolasmartin
- Milestone NEMO improvements deleted
Milestone NEMO improvements deleted
comment:9 Changed 8 years ago by nicolasmartin
- Keywords SBC added; boundaries conditions surface removed
comment:10 Changed 8 years ago by nicolasmartin
- Keywords mixing_length added; length mixing removed
comment:11 Changed 7 years ago by nemo
- Keywords mixing added; mixing_length removed
comment:12 Changed 6 years ago by nemo
- Keywords release-3.0 added; nemo_v3* removed
comment:13 Changed 2 years ago by nemo
- Keywords OPA r3.0 added; release-3.0 removed
comment:14 Changed 2 years ago by nemo
- Keywords v3.0 added; r3.0 removed
Replying to greffray@mercator-ocean.fr:
Thank you for submitting this ticket.
Right, the Von Karman is clearly missing, it must appear in the computation above, using
the vkarmn constant defined in the phycst.F90 module and which is equal to 0.4.
Claude