From 80a486763c4267c7419b2273649e622cc5750c11 Mon Sep 17 00:00:00 2001
From: XL-OU <Xu.Lu@noaa.gov>
Date: Wed, 8 Nov 2023 09:03:49 -0600
Subject: [PATCH] Change orientation check for ensemble. Force ensemble has the
 same orientation as the control.     -- Xu Lu & Xuguang Wang from OU. POC:
 xuguang.wang@ou.edu

---
 src/gsi/gsi_rfv3io_mod.f90 | 36 +++++++++++-------------------------
 1 file changed, 11 insertions(+), 25 deletions(-)

diff --git a/src/gsi/gsi_rfv3io_mod.f90 b/src/gsi/gsi_rfv3io_mod.f90
index 43fb40e8ad..cad61959ba 100644
--- a/src/gsi/gsi_rfv3io_mod.f90
+++ b/src/gsi/gsi_rfv3io_mod.f90
@@ -559,7 +559,7 @@ subroutine gsi_rfv3io_get_ens_grid_specs(grid_spec,ierr)
   integer(i_kind) :: nio,nylen
   integer(i_kind),allocatable :: gfile_loc_layout(:)
   character(len=180)  :: filename_layout
-  integer(i_kind) imiddle,jmiddle
+  integer(i_kind) imiddle,jmiddle,grid_ens_type_fv3_regional
 
 
     iret=nf90_open(trim(grid_spec),nf90_nowrite,gfile_grid_spec)
@@ -635,33 +635,19 @@ subroutine gsi_rfv3io_get_ens_grid_specs(grid_spec,ierr)
     if(mype==0)write(6,*),'ny_layout_bens=',ny_layout_bens
     if(mype==0)write(6,*),'ny_layout_eens=',ny_layout_eens
 
-!
-!  need to decide the grid orientation of the FV regional model   
-!
-!   grid_type_fv3_regional = 0 : decide grid orientation based on
-!                                grid_lat/grid_lon
-!                            1 : input is E-W N-S grid
-!                            2 : input is W-E S-N grid
-!
-    if(grid_type_fv3_regional == 0) then
-        imiddle=nxens/2
-        jmiddle=nyens/2
-        if( (grid_latt(imiddle,1) < grid_latt(imiddle,nyens)) .and. &
-            (grid_lont(1,jmiddle) < grid_lont(nxens,jmiddle)) ) then
-            grid_type_fv3_regional = 2
-        else
-            grid_type_fv3_regional = 1
-        endif
+    imiddle=nxens/2
+    jmiddle=nyens/2
+    if( (grid_latt(imiddle,1) < grid_latt(imiddle,nyens)) .and. &
+        (grid_lont(1,jmiddle) < grid_lont(nxens,jmiddle)) ) then
+        grid_ens_type_fv3_regional = 2
+    else
+        grid_ens_type_fv3_regional = 1
     endif
 ! check the grid type
-    if( grid_type_fv3_regional == 1 ) then
-       if(mype==0) write(6,*) 'FV3 regional input grid is  E-W N-S grid'
-       grid_reverse_flag=.true.    ! grid is revered comparing to usual map view
-    else if(grid_type_fv3_regional == 2) then
-       if(mype==0) write(6,*) 'FV3 regional input grid is  W-E S-N grid'
-       grid_reverse_flag=.false.   ! grid orientated just like we see on map view
+    if( grid_type_fv3_regional == grid_ens_type_fv3_regional ) then
+       if(mype==0) write(6,*) 'Ensemble has the same orientation as the control, Cool!'
     else
-       write(6,*) 'Error: FV3 regional input grid is unknown grid'
+       write(6,*) 'Error! Ensemble has a different orientation as the control, Abort!'
        call stop2(678)
     endif
 !