[MITgcm-support] "too much qnet and qsw into the ocean cause theta higher than in the real ocean ?? "

李志远 oceanlizy at 163.com
Tue May 6 00:20:15 EDT 2014


From: LIZHI  <oceanlizy at 163.com>
To: MITgcm Support <mitgcm-support at mitgcm.org>
Subject: "too much qnet and qsw into the ocean cause theta higher than in the real ocean ?? "


HI, everyone;
     First,I would thank all the mitgcm user groups help me solve my problems in running the model. At present ,the model runs normally .
In my case, my study is to simulate a semi-enclosed shelf sea wind-driven circulation ,forced by wind, heat flux and salt flux ,with three open boundarys .
All the forces used are monthly averaged, the model run one year (31104000s) ,then run 8 years repeat  use the former 12 months force input files.
After the model run 6 months (about 16000000s),I check the dynstat in STDOUT  file  as below:
(PID.TID 0009.0001) %MON dynstat_theta_max            =   4.4231392467937E+01
(PID.TID 0009.0001) %MON dynstat_theta_min            =   2.4523931205110E-02
(PID.TID 0009.0001) %MON dynstat_theta_mean           =   7.7194987621196E+00
(PID.TID 0009.0001) %MON dynstat_theta_sd             =   8.0850682681407E+00
(PID.TID 0009.0001) %MON dynstat_theta_del2           =   1.0822950836111E-03
(PID.TID 0009.0001) %MON dynstat_salt_max             =   3.4933326465688E+01
(PID.TID 0009.0001) %MON dynstat_salt_min             =   2.3054378969265E+01
(PID.TID 0009.0001) %MON dynstat_salt_mean            =   3.4371271436462E+01
(PID.TID 0009.0001) %MON dynstat_salt_sd              =   4.9827239874762E-01
(PID.TID 0009.0001) %MON dynstat_salt_del2            =   9.1914069314048E-04
(PID.TID 0009.0001) %MON dynstat_sst_max              =   4.4231392467937E+01
(PID.TID 0009.0001) %MON dynstat_sst_min              =   1.4408592842513E+01
(PID.TID 0009.0001) %MON dynstat_sst_mean             =   2.8036902458641E+01
(PID.TID 0009.0001) %MON dynstat_sst_sd               =   3.4186199069183E+00
(PID.TID 0009.0001) %MON dynstat_sst_del2             =   4.7653010800736E-03
(PID.TID 0009.0001) %MON dynstat_sss_max              =   3.4533567131686E+01
(PID.TID 0009.0001) %MON dynstat_sss_min              =   2.3054378969265E+01
(PID.TID 0009.0001) %MON dynstat_sss_mean             =   3.2506716075619E+01
(PID.TID 0009.0001) %MON dynstat_sss_sd               =   1.3256646018218E+00
(PID.TID 0009.0001) %MON dynstat_sss_del2             =   7.1735891243063E-04
(PID.TID 0009.0001) %MON forcing_qnet_max             =   0.0000000000000E+00
(PID.TID 0009.0001) %MON forcing_qnet_min             =  -2.2799058703469E+02
(PID.TID 0009.0001) %MON forcing_qnet_mean            =  -1.8055982707359E+02
(PID.TID 0009.0001) %MON forcing_qnet_sd              =   2.0513172000761E+01
(PID.TID 0009.0001) %MON forcing_qnet_del2            =   1.5242962055729E-02
(PID.TID 0009.0001) %MON forcing_qsw_max              =   0.0000000000000E+00
(PID.TID 0009.0001) %MON forcing_qsw_min              =  -2.8755120472859E+02
(PID.TID 0009.0001) %MON forcing_qsw_mean             =  -2.6151417171239E+02
(PID.TID 0009.0001) %MON forcing_qsw_sd               =   1.4810230980981E+01
(PID.TID 0009.0001) %MON forcing_qsw_del2             =   1.9161474907293E-02


 from the dynstat ,the theta max up to 44 , it is so much higher !!  Then ,I check the dynstat  theta  from running one month  to six months . at the starting run ,theta is 25, 
after three months run ,it up to 27 ,four months ,29 , six months, it up to 44 !!   I think this is related to  the heat flux  I put into the model . I define short wave heating in 
CPP_OPTIONS.h , and in the data.exf , hflux=longwave + latent +sensible (upward) ,swflux=shortwave (upward)  . I see from the dynstat qnet=hflux , qsw =swflux ,after run one
month :
MON forcing_qnet_max             =   3.9943856171090E+02
MON forcing_qnet_min             =   0.0000000000000E+00
MON forcing_qnet_mean            =   2.3198055124623E+02
MON forcing_qnet_sd              =   8.7156610180731E+01
MON forcing_qnet_del2            =   1.1373761926168E-02
MON forcing_qsw_max              =   0.0000000000000E+00
MON forcing_qsw_min              =  -1.3211841646767E+02
 after run three months:
MON dynstat_theta_max            =   2.5327612035139E+01
MON dynstat_theta_min            =   3.5184123692558E-02
MON dynstat_theta_mean           =   7.5122741860641E+00
 MON forcing_qnet_max             =   4.9928777577151E+01
MON forcing_qnet_min             =  -1.7492545823003E+02
MON forcing_qnet_mean            =  -6.4452481550955E+01
MON forcing_qnet_sd              =   6.4712970366950E+01
MON forcing_qnet_del2            =   9.7404863498980E-03
MON forcing_qsw_max              =   0.0000000000000E+00
MON forcing_qsw_min              =  -2.4983138268434E+02
MON forcing_qsw_mean             =  -2.1085011096057E+02
MON forcing_qsw_sd               =   1.0793094916623E+01
after run six months:
MON dynstat_theta_max            =   4.4900585496648E+01
MON dynstat_theta_min            =   1.8188185685620E-02
MON dynstat_theta_mean           =   7.7407523304911E+00
MON forcing_qnet_max             =   0.0000000000000E+00
MON forcing_qnet_min             =  -2.2144150892065E+02
MON forcing_qnet_mean            =  -1.6959988101404E+02
MON forcing_qnet_sd              =   1.9948965716262E+01
MON forcing_qnet_del2            =   1.4611895368271E-02
MON forcing_qsw_max              =   0.0000000000000E+00
MON forcing_qsw_min              =  -2.8140803701641E+02
MON forcing_qsw_mean             =  -2.5862899621063E+02


I see that from the first month to sixth month ,the qnet and qsw into the ocean become much larger ,  so this causes the theta change from 25 to 44 ??
I am puzzled that , in the next few months run  ,the theta will decrease with less qnet and qsw into ocean ??
Because the model will run about 8 years , so ,when the model get the "steady state" ,will the theta get a reasonable value range ?
or ,should I adjust the hflux and swflux input file ,so as to decrease the net heat flux into ocean ?


Any one could give me some advice ?
your quick reply will be great appreciated !


YOURS LIZHI
THANKS !




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