Hi,
I’m trying to use CMAQ 5.3.1 over Bogotá, Colombia, and I used Equatorial Mercator as projection in WRF domains, and I created MCIP files with EM projection, but when I ran ICON I get this error
“LAT/LON calculations for GDTYP3D 7 not supported”
Could you suggest me any solution for my problem? There’s a way to fix it without changing Projection system? if not, What do you consider the best projection to work in equatorial zones?
When we ran Bogota, we used an alternative ICON/BCON processor. The most recent incarnation is at https://github.com/barronh/aqmbc.
Using the standard tools is always nice. It looks like it would be a relatively easy fix to ICON/BCON. In the common/lat_lon.F, each grid has an initialization and than a conversion. You’d need to add the same thing for EQM. Below is a quick attempt to copy the Polar Stereographic
ELSE IF ( GDTYP .EQ. EQMGRD3) THEN ! Equatorial Mercator
IF ( .NOT. SETEQM( SNGL( P_ALP ), ! first, initialize
& SNGL( P_BET ), ! for EQM2LL()
& SNGL( P_GAM ),
& SNGL( XCENT ),
& SNGL( YCENT ) ) ) THEN
MSG='Equatorial mercator projection setup error for CTM CONC file'
CALL M3EXIT ( PNAME, 0, 0, MSG, 2 )
END IF
X = X0 + FLOAT( COL ) * SNGL( XCELL )
Y = Y0 + FLOAT( ROW ) * SNGL( YCELL )
IF ( .NOT. EQM2LL( X, Y, LON, LAT ) ) THEN
MSG = 'Equatorial mercator conversion error for CTM CONC file'
CALL M3EXIT ( PNAME, 0, 0, MSG, 2 )
END IF
You would insert this before the unsupported coordinates section. Then, you’d need to recompile icon and test it.
When you get to BCON, you’ll have to do the same thing there.
[1] https://github.com/USEPA/CMAQ/blob/master/PREP/icon/src/common/lat_lon.F
[2] https://github.com/USEPA/CMAQ/blob/master/PREP/bcon/src/common/lat_lon.F
Thank You Barron, I’m going to try aqmbc option
The edits posted by Barron to modify lat_lon.F in the icon and bcon src/common directories should do the trick.
Dear @fliu,
I have created IC conditions based on the github tutorial. Although the simulation was successful I have doubts about the created netcdf file since I see a very large resolution. I attached an image of my obtained result. Could you tell me if you got a similar result?
I have used CCTM_CONC_v53beta2_intel17.0_HEMIS_cb6r3m_ae7_kmtbr_m3dry_2016_quarterly_av.nc and for meteorology files the files given in the CCTM tutorial CMAQ/CMAQ_UG_tutorial_benchmark.md at master · USEPA/CMAQ · GitHub
The hemispheric simulation from which the quarterly average concentrations were derived was performed on a polar stereographic grid with a horizontal grid spacing of 108 km. When ICON generates initial conditions in regridding mode, the regridding is performed by determining the closest grid cell of the coarse domain (in this case hemispheric) for each grid cell in the fine grid (target domain). Therefore, the spatial patterns of the initial conditions generated by ICON retain the resolution of the coarse grid from which they are derived.