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POP Exiting in deep glaciation simulations

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jyangdas@...
POP Exiting in deep glaciation simulations

Using CCSM4 (B_1850), I simulate the initiation of Snowball Earth under an abrupt decrease in solar radiation and/or CO2 concentration, such as 12% less solar radiation than the present level. The model blows up just prior to the completely ice-covered state. The error message follows:
==============================
58:POP Exiting...
58:POP_SolversChronGear: solver not converged
58:POP_SolverRun: error in ChronGear
58:POP_BarotropicDriver: error in solver
58:Step: error in barotropic
==============================
When I do the similar simulations using CCSM3, the error message did not arise.
Look forward to any suggestions. Thanks.

jun yang

Jun Yang

University of Chicago

njn01

jyangdas wrote:

Using CCSM4 (B_1850), I simulate the initiation of Snowball Earth under an abrupt decrease in solar radiation and/or CO2 concentration, such as 12% less solar radiation than the present level. The model blows up just prior to the completely ice-covered state. The error message follows:
==============================
58:POP Exiting...
58:POP_SolversChronGear: solver not converged
58:POP_SolverRun: error in ChronGear
58:POP_BarotropicDriver: error in solver
58:Step: error in barotropic
==============================
When I do the similar simulations using CCSM3, the error message did not arise.
Look forward to any suggestions. Thanks.

jun yang

If your case has been running successfully for a period of time and then the ocean model fails to converge, you might need to decrease the ocean timestep and restart your case. I would recommend backing up at least one month prior to the time of nonconvergence, decreasing the ocean timestep by roughly 20%, and restarting your case.

To decrease the ocean timestep, you need to increase the pop2 namelist variable DT_COUNT. If, for example, DT_COUNT=23 in your case, then you could try setting DT_COUNT=26 or 27. To do this, change the present value of DT_COUNT in the $CASE/Buildconf/pop2.buildnml.csh script. You do not need to rebuild the executable.

Information on restarting a CESM case can be found in the CESM User's Guide (http://www.cesm.ucar.edu/models/cesm1.0/cesm/cesm_doc/x2006.html#running_ccsm_restarts)

jyangdas@...

Thanks very much. I will try this way you suggested. ---jun

Jun Yang

University of Chicago

gaoyanqiujuly11...

Did you solve the problem? I encounter the the same problem as what you described above.

And I modified 'DT_COUNT' to 26, the same problem is still exist.

Could you tell me the anwser of this problem?

Thank you very much!

 

Yanqiu

janezhang8587@...

This error also occured during my simulation for deep time climate: 

 728 CalcWorkPerBlock: Total blocks:   128 Ice blocks:    75 IceFree blocks:    45 Land blocks:     8

 729 MCT::m_Router::initp_: GSMap indices not increasing...Will correct

 730 MCT::m_Router::initp_: RGSMap indices not increasing...Will correct

 731 MCT::m_Router::initp_: RGSMap indices not increasing...Will correct

 732 MCT::m_Router::initp_: GSMap indices not increasing...Will correct

 733  Opened file rec20.cam.h1.0001-01-01-00000.nc to write      458752

 734   filew failed, worst i, j, qtmp, q =            1          59

 735   filew failed, worst i, j, qtmp, q =            1           5

 736  -4.227765476901517E-052  1.079281150309118E-072

 737   filew failed, worst i, j, qtmp, q =            1           4

 738  -7.330778636034141E-031  2.868021791171315E-063

 739  -1.055701244605496E-046  4.948054005673251E-060

 740   filew failed, worst i, j, qtmp, q =            1           5

 741  -2.838134069305025E-073  1.608453567997771E-085

 742   filew failed, worst i, j, qtmp, q =            1           6

 743  -4.665050768520916E-069  1.124663740597901E-108

 744   filew failed, worst i, j, qtmp, q =            1           5

 745  -3.344304678849421E-070 -3.030527799319106E-070

 746   filew failed, worst i, j, qtmp, q =            1           6

 747  -8.695927076093604E-069 -4.249473172465746E-069

 748 POP_SolversChronGear: solver not converged

 749 POP_SolverRun: error in ChronGear

 750 POP_BarotropicDriver: error in solver

 751 Step: error in barotropic

 752 ------------------------------------------------------------------------

 753 

 754 POP aborting...

 755  ERROR in step

-------------------------------------------- Can anyone help me ? Thanks! Jian
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