[MITgcm-support] the calculation of the MXLDEPTH

[Menemenlis, Dimitris (329D)]

look at MITgcm/model/src/calc_oce_mxlayer.F for available mixed layer definitions:

C--   Select which "method" to use:
       method = 0
       IF ( hMixCriteria.LT.0. ) method = 1
       IF ( hMixCriteria.GT.1. ) method = 2

       IF ( method.EQ.1 ) THEN

C--   First method :
C     where the potential density (ref.lev=surface) is larger than
C       surface density plus Delta_Rho = hMixCriteria * Alpha(surf)
C     = density of water which is -hMixCriteria colder than surface water
C     (see Kara, Rochford, and Hurlburt JGR 2000 for default criterion)

c       hMixCriteria  = -0.8 _d 0
c       dRhoSmall = 1. _d -6

…

       ELSEIF ( method.EQ.2 ) THEN

C--   Second method :
C     where the local stratification exceed the mean stratification above
C     (from surface down to here) by factor hMixCriteria

c       hMixCriteria  = 1.5 _d 0
c       dRhoSmall = 1. _d -2



If you use pkg/kpp, there is also output for “mixing” layer depth: KPPHBL


On Jul 26, 2015, at 4:34 AM, 刘成彦 <killy at nuist.edu.cn<mailto:killy at nuist.edu.cn>> wrote:

Dear all,
Recently, I have focused on the output of the MXLDEPTH in data.diagnostics. In my understanding, the "MXLDEPTH" means the depth of the mixed layer or the thickness of the mixed layer in the upper ocean. However, I can not make sure how is the "MXLDEPTH" calculated in the MITGCM. I have checked the meaning in the manual. It was described as "Mixed layer depth, dT=.8degC density criterion" in Page320 in section of 6.4.2.6 KPP diagnostics. So, I want to ask does it means that the MXLDEPTH is defined as that the bottom of the mixed layer is at where the temperature is lower 0.8 degC than that at the sea surface in MITGCM. Does the MITGCM still use this method to calculated the MXLDEPTH now? Or it was just used in former versions and it has new method to calculate it now.
Cheers
Liu

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mitgcm.org/pipermail/mitgcm-support/attachments/20150726/de7f241e/attachment-0001.htm>