Transition to fv3atm write grid component restart capability for single domain

[junwang-noaa]

Description

This work is to update the regression test to use the write grid component restart capability developed un issue #1587. In issue #1587, the initial code updates were developed to allow the write grid component to write out single domain fv3atm restart files, the same as those written out by the FMS. The restart reproducibility is also maintained. Three sample test case for cpld_control_p8, control_p8 and regional_control are added to regression test suite for testing and transition purpose. This issue is intended to resolve possible issues raising at the experiment testing time after the initial code is committed to the develop branch and to transition the current regression restart tests for those applications that use fms restart to write grid component restart. A separate issue will cover the future work for multiple domain restart files for HAFS and regional apps.

Solution

This new feature needs to be verified in global and regional workflow, and in the parallel (or parallel like) testing before we completely switch to write grid component restart capability.

Alternatives

Related to

[junwang-noaa]

One issue was find when running high resolution coupled test (c768 with 32BIT turned on) with the write grid component writing restart files. The total writing time is about 140s, while the fms writing restart files takes ~20s.

o.32x32x.64x8.wrt.480.960.0.32.4..32: RESTART/20200602.000000.fv_core.res.nc Write Time is 31.78815 at Fcst 24:00
o.32x32x.64x8.wrt.480.960.0.32.4..32: RESTART/20200602.000000.fv_srf_wnd.res.nc Write Time is 0.40996 at Fcst 24:00
o.32x32x.64x8.wrt.480.960.0.32.4..32: RESTART/20200602.000000.fv_tracer.res.nc Write Time is 33.91616 at Fcst 24:00
o.32x32x.64x8.wrt.480.960.0.32.4..32: RESTART/20200602.000000.phy_data.nc Write Time is 25.47137 at Fcst 24:00
o.32x32x.64x8.wrt.480.960.0.32.4..32: RESTART/20200602.000000.sfc_data.nc Write Time is 54.93180 at Fcst 24:00

Dusan looked at the case and made changes in write grid comp to use sequential writing for restart on write grid comp, now the total time of writing restart files is reduced to:

      RESTART/20200602.000000.fv_core.res.nc Write Time is    4.05802 at Fcst   24:00
   RESTART/20200602.000000.fv_srf_wnd.res.nc Write Time is    0.01971 at Fcst   24:00
    RESTART/20200602.000000.fv_tracer.res.nc Write Time is    5.14343 at Fcst   24:00
         RESTART/20200602.000000.phy_data.nc Write Time is    4.46039 at Fcst   24:00
         RESTART/20200602.000000.sfc_data.nc Write Time is    2.88944 at Fcst   24:00

[junwang-noaa]

The issue of long writing time with parallel netcdf will be checked.

[junwang-noaa]

@DusanJovic-NOAA This is the issue on transition to fv3atm write grid comp writing restart. As we discussed, the atmosphere only global and regional RT test will be transition to use the write restart on write grid component.