Lower number-density termination threshold

Merge branch 'lower_termination_threshold'

Fixes to termination logic to allow demotion to occur successfully

reduces termination threshold due to small number density and also
deletes calls to terminate_cohorts in CanopyStructureMod except for
those that are after a call to fuse_cohorts.

Fixes: #187

User interface changes?: No

Code review: changes done in consultation with @rgknox and @rosiealice

Testing:

  ckoven

    Test suite: ed tests on lawrencium
    Test baseline: a5dc8da
    Test namelist changes:
    Test answer changes: climate changing

    Test summary: [Remove 'PASS' fields]

        [cdkoven@n0002 ed.lawrencium-lr3.intel.37ba5ce]$ ./cimeteststatus | grep FAIL
        FAIL SMS_D_Lm6.f45_f45.ICLM45ED.lawrencium-lr3_intel.clm-edTest.clm2.h0.nc : baseline compare clm2.h0 (baseline: compare .base file with ed.lawrencium-lr3.intel.a5dc8da file)
        FAIL SMS_D_Lm6.f45_f45.ICLM45ED.lawrencium-lr3_intel.clm-edTest.cpl.hi.nc : baseline compare cpl.hi (baseline: compare .base file with ed.lawrencium-lr3.intel.a5dc8da file)
        FAIL SMS_D_Lm6.f45_f45.ICLM45ED.lawrencium-lr3_intel.clm-edTest.rtm.h0.nc : baseline compare rtm.h0 (baseline: compare .base file with ed.lawrencium-lr3.intel.a5dc8da file)
        FAIL SMS_D_Lm6.f45_f45.ICLM45ED.lawrencium-lr3_intel.clm-edTest : baseline compare summary (baseline: compare .base file with ed.lawrencium-lr3.intel.a5dc8da file)

  andre:

    Test suite: ed - yellowstone gnu, intel, pgi
                     hobart nag
    Test baseline: 4ccb9ef
    Test namelist changes: none
    Test answer changes: climate changing, only expected to show up on longer tests
    Test status:
        PASS - all functionality tests.
        Expected baseline failures for all SMS_D_Lm6.f45_f45.ICLM45ED.yellowstone_{gnu,intel,pgi}.clm-edTest.
        PASS - all other tests are bit for bit with baseline.

    Test suite: clm_short - yellowstone gnu, intel, pgi
    Test baseline: clm4_5_12_r195
    Test namelist changes: none
    Test answer changes: bit for bit
    Test status: all tests pass

components/clm/src/ED/biogeochem/EDCanopyStructureMod.F90

@@ -298,7 +298,6 @@ subroutine canopy_structure( currentSite )
                               !currentCohort%canopy_layer,currentCohort%dbh
 
                       endif
-                     ! call terminate_cohorts(currentPatch) 
 
                       !----------- End of cohort splitting ------------------------------!             
                    endif !canopy layer = i
@@ -307,7 +306,6 @@ subroutine canopy_structure( currentSite )
 
                 enddo !currentCohort 
 
-                call terminate_cohorts(currentSite, currentPatch)
                 arealayer(i) = arealayer(i) - sumloss
                 !Update arealayer for diff calculations of layer below. 
                 arealayer(i + 1) = arealayer(i + 1) + sumloss 
@@ -343,7 +341,6 @@ subroutine canopy_structure( currentSite )
 
        enddo !is there still excess area in any layer?      
 
-       call terminate_cohorts(currentSite, currentPatch)
        call fuse_cohorts(currentPatch)
        call terminate_cohorts(currentSite, currentPatch)
 
@@ -503,7 +500,6 @@ subroutine canopy_structure( currentSite )
                               !currentCohort%pft,currentPatch%patchno
 
                       endif
-                      !call terminate_cohorts(currentPatch) 
                       if(promswitch == 1)then
                         ! write(fates_log(),*) 'cohort loop',currentCohort%pft,currentPatch%patchno
                       endif
@@ -565,7 +561,6 @@ subroutine canopy_structure( currentSite )
           endif
        enddo !is there still not enough canopy area in any layer?         
 
-       call terminate_cohorts(currentSite, currentPatch)
        call fuse_cohorts(currentPatch)
        call terminate_cohorts(currentSite, currentPatch)
 

components/clm/src/ED/main/EDTypesMod.F90

@@ -67,15 +67,12 @@ module EDTypesMod
   integer , parameter :: N_DBH_BINS           = 5          ! no. of dbh bins used when comparing patches
 
 
-  real(r8), parameter :: min_npm2       = 1.0d-5   ! minimum cohort number density per m2 before termination
-  real(r8), parameter :: min_patch_area = 0.001_r8 ! smallest allowable patch area before termination
-  real(r8), parameter :: min_nppatch    = 1.0d-8   ! minimum number of cohorts per patch (min_npm2*min_patch_area)
-
-  ! in some cases, we want to immediately remove super small
-  ! number densities of cohorts to prevent FPEs, this is usually
-  ! just relevant in the first day after recruitment
-  real(r8), parameter :: min_n_safemath = 1.0E-15_r8  
-
+  real(r8), parameter :: min_npm2       = 1.0E-8_r8  ! minimum cohort number density per m2 before termination
+  real(r8), parameter :: min_patch_area = 0.001_r8   ! smallest allowable patch area before termination
+  real(r8), parameter :: min_nppatch    = 1.0E-11_r8 ! minimum number of cohorts per patch (min_npm2*min_patch_area)
+  real(r8), parameter :: min_n_safemath = 1.0E-15_r8 ! in some cases, we want to immediately remove super small
+                                                     ! number densities of cohorts to prevent FPEs, this is usually
+                                                     ! just relevant in the first day after recruitment
   character*4 yearchar                    
 
   ! special mode to cause PFTs to create seed mass of all currently-existing PFTs