Have increased precision of LAT and LON outputs for SMC grids within ww3_ounf by increasing the decimal places in the spaceholder used to calculate the structured grid coordinates and by specifying 'NF90_DOUBLE' when writing these variables to the netcdf file.

Author: ukmo-kitstokes

model/src/ww3_ounf.F90

@@ -2293,10 +2293,10 @@ SUBROUTINE W3EXNC ( NX, NY, IX1, IXN, IY1, IYN, NSEA,             &
 #ifdef W3_SMC
                 ELSE
                   ! CB: Regridded SMC data
-                  SXD=DBLE(0.000001d0*DNINT(1d6*(DBLE(DXO)) ))
-                  SYD=DBLE(0.000001d0*DNINT(1d6*(DBLE(DYO)) ))
-                  X0D=DBLE(0.000001d0*DNINT(1d6*(DBLE(SXO)) ))
-                  Y0D=DBLE(0.000001d0*DNINT(1d6*(DBLE(SYO)) ))
+                  SXD=DBLE(0.00000001d0*DNINT(1d8*(DBLE(DXO)) ))
+                  SYD=DBLE(0.00000001d0*DNINT(1d8*(DBLE(DYO)) ))
+                  X0D=DBLE(0.00000001d0*DNINT(1d8*(DBLE(SXO)) ))
+                  Y0D=DBLE(0.00000001d0*DNINT(1d8*(DBLE(SYO)) ))
                   DO i=1,NXO
                     lon(i)=REAL(X0D+SXD*DBLE(i-1))
 #endif
@@ -3388,9 +3388,9 @@ SUBROUTINE W3CRNC (NCFILE, NCID, DIMID, DIMLN, VARID,  &
 #ifdef W3_SMC
           IF(SMCOTYPE .EQ. 1) THEN
             ! Flat SMC grid - use seapoint dimension:
-            IRET = NF90_DEF_VAR(NCID, 'longitude', NF90_FLOAT, DIMID(2), VARID(1))
+            IRET = NF90_DEF_VAR(NCID, 'longitude', NF90_DOUBLE, DIMID(2), VARID(1))
             CALL CHECK_ERR(IRET)
-            IRET = NF90_DEF_VAR(NCID, 'latitude', NF90_FLOAT, DIMID(2), VARID(2))
+            IRET = NF90_DEF_VAR(NCID, 'latitude', NF90_DOUBLE, DIMID(2), VARID(2))
             CALL CHECK_ERR(IRET)
 
             ! Latitude and longitude are auxililary variables in type 1 sea point
@@ -3412,10 +3412,10 @@ SUBROUTINE W3CRNC (NCFILE, NCID, DIMID, DIMLN, VARID,  &
             IRET = NF90_PUT_ATT(NCID, VARID(6), 'valid_min', 1)
             IRET = NF90_PUT_ATT(NCID, VARID(6), 'valid_max', 256)
           ELSE
-            ! Regirdded regular SMC grid - use lon/lat dimensions:
-            IRET = NF90_DEF_VAR(NCID, 'longitude', NF90_FLOAT, DIMID(2), VARID(1))
+            ! Regridded regular SMC grid - use lon/lat dimensions:
+            IRET = NF90_DEF_VAR(NCID, 'longitude', NF90_DOUBLE, DIMID(2), VARID(1))
             call CHECK_ERR(IRET)
-            IRET = NF90_DEF_VAR(NCID, 'latitude', NF90_FLOAT, DIMID(3), VARID(2))
+            IRET = NF90_DEF_VAR(NCID, 'latitude', NF90_DOUBLE, DIMID(3), VARID(2))
             call CHECK_ERR(IRET)
           ENDIF
 #endif