Add subgrid hillslope hydrology (NGEE Arctic IM2) #6718
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Add namelist variable use_IM2_hillslope_hydrology, which implements a transfer from higher elevation topounits to lower elevation topunits within the same gridcell. Based on design document from NGEE Arctic Phase 3 project (IM2) [NML]
Should be BFB when use_IM2_hillslope_hydrology namelist flag is off
thorntonpe
added
Land
Stealth
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Have there been any long-ish runs with this feature on? |
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The development was done on site-level simulations. Once the site-level evaluation was complete, I added a test that implemented this new development at the global scale, on top of the existing test SMS.r05_r05.IELM.pm-cpu_gnu.elm-topounit. That is a very strong test since it exercises this new capability on the full range of actual topounit, landunit, and column arrangements. That is only a five day test, so the answer to @rljacob question is "no". |
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@rljacob I can start a longer test - how long do you suggest? |
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I'd suggest a 1-year smoke test. Is this going to be used by E3SM in some future version? |
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Thanks, I'll set that up. Next phase for this work is to evaluate multiple Arctic code changes operating together at the pan-Arctic scale (under ecosystem project NGEE Arctic). The plan would be to have this as a candidate capability in whatever version is current about three years from now. |
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@rljacob I ran a one-year test of this new capability on the global r05 land domain, based on the existing r05 topounit-enabled surface dataset. That run completed successfully. |
| do fc = 1, num_hydrologyc | ||
| c = filter_hydrologyc(fc) | ||
| t = col_pp%topounit(c) | ||
| ! add flood water flux to qflx_top_soil | ||
| qflx_top_soil(c) = qflx_top_soil(c) + qflx_snow_h2osfc(c) + qflx_floodc(c) | ||
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| ! flow from uphill topounit goes to top of soil for soil, crop, and pervious road columns | ||
| if (use_IM2_hillslope_hydrology) then | ||
| qflx_from_uphill(c) = (col_pp%wttopounit(c)/top_pp%uphill_wt(t)) * (frac_from_uphill * top_ws%from_uphill(t)) / dtime | ||
| qflx_top_soil(c) = qflx_top_soil(c) + qflx_from_uphill(c) | ||
| endif | ||
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| end do |
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How about avoiding the if (use_IM2_hillslope_hydrology) within the do-loop by leaving the original code as is and then adding a separate if-loop like
do fc = 1, num_hydrologyc
... original code
enddo
if (use_IM2_hillslope_hydrology) then
.... new code
do fc = 1, ...
enddo
endif
| call hist_addfld1d (fname='QFROM_UPHILL', units='mm/s', & | ||
| avgflag='A', long_name='input to top layer soil from uphill topounit(s)', & | ||
| ptr_col=this%qflx_from_uphill, c2l_scale_type='urbanf') | ||
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| call hist_addfld1d (fname='QTO_DOWNHILL', units='mm/s', & | ||
| avgflag='A', long_name='output from column to downhill topounit', & | ||
| ptr_col=this%qflx_to_downhill, c2l_scale_type='urbanf') | ||
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If these fields are added by default, let's only add them if the new physics is turned on.
| !----------------------------------------------------------------------- | ||
| ! initialize history fields for members of top_ws | ||
| !----------------------------------------------------------------------- | ||
| call hist_addfld1d (fname='FROM_UPHILL', units='mm', & |
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How about renaming FROM_UPHILL to WATER_FROM_UPHILL?
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These fields should be only read/written out if the new physics is turned on.
| ! Close file | ||
| ! call ncd_pio_closefile(ncid) | ||
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Please delete these lines.
| do fc = 1, num_hydrologyc | ||
| c = filter_hydrologyc(fc) | ||
| t = col_pp%topounit(c) | ||
| top_pp%uphill_wt(t) = 0._r8 | ||
| end do | ||
| ! Next sum the weights | ||
| do fc = 1, num_hydrologyc | ||
| c = filter_hydrologyc(fc) | ||
| t = col_pp%topounit(c) | ||
| top_pp%uphill_wt(t) = top_pp%uphill_wt(t) + col_pp%wttopounit(c) | ||
| end do |
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Couldn't these weights be computed during initialization?
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@thorntonpe please respond to comments. |
This new capability builds on the existing topographic unit (topounit) subgrid scheme by implementing transport of water within a gridcell from higher to lower elevation topounits. Assuming that the topounit information on an existing surface dataset includes mean elevation for each topounit on a gridcell, the code will calculate topounit connectivity (topology) at run time during model initialization. On each time step a user-specified fraction of the surface runoff, ponded water runoff, and perched water table drainage terms are shifted to the next-lower topounit, where that water is distributed to the columns on the topounit with a user-defined decay term.
[BFB]
[FCC]
[NML]