UM_Bristol

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Ozone forcings for HadCM3

Contact Linlin Chen for more information and files (linlin.chen@bristol.ac.uk, linlin.chen128@outlook.com).

Figures could be found from: CMIP7_Ozone.pptx

Processed data and scripts could be found from: Siliruan:/home/bridge/mf22281/CMIP7/CMIP7-Ozone

File list ready for HadCM3BL model running:

• piControl climatology: vmro3*_1-2_185001-185012-clim_73x96x19hybrid_zonmean.nc
• piControl transient: vmro3*_1-2_182901-184912_73x96x19hybrid_zonmean.nc
• piControl and historical transient: vmro3*_2-0_182901-202212_73x96x19hybrid_zonmean.nc

Where to access data

Data description: https://input4mips-cvs.readthedocs.io/en/latest/dataset-overviews/ozone/

Download data from:

• FZJ-CMIP-ozone-1-2: for piControl climatology and transient.
• FZJ-CMIP-ozone-2-0: for historical transient.

The download links would direct you to CMIP7 ozone data version1.2 and version 2.0. But if not, you can search by source_id = FZJ-CMIP-ozone-1-2 and source_id = FZJ-CMIP-ozone-2-0.

Data list:

• v1.2: piControl climatology for 185001-185012.
  • Dataset: input4MIPs.CMIP7.CMIP.FZJ.FZJ-CMIP-ozone-1-2.atmos.monC.vmro3.gn
  • File: vmro3input4MIPs_ozone_CMIP_FZJ-CMIP-ozone-1-2_gn185001-185012-clim.nc
  • Recommendation: This dataset averages over a longer simulation, essentially removing variability like the QBO. If you wish to use this forcing for your piControl, simply apply it on repeat.
  • version: 20251010; replica=false; size=41.81 MB
• v1.2: piControal transient, time range equal to 182901-184912
  • Dataset: input4MIPs.CMIP7.CMIP.FZJ.FZJ-CMIP-ozone-1-2.atmos.mon.vmro3.gn
  • File: vmro3input4MIPs_ozone_CMIP_FZJ-CMIP-ozone-1-2_gn182901-184912.nc
  • Recommendation: The 182901-184912 file should ONLY use for piControl and do NOT include it in historical forcing. This transient piControl forcing includes the QBO signal but uses average solar forcing and repeating 1850 emissions. If you wish to use this forcing for your piControl, simply apply it on repeat.
  • version: 20251025; replica=false; size=541.73 MB
• v2.0: historical forcing for 185001-202212.
  • Dataset: input4MIPs.CMIP7.CMIP.FZJ.FZJ-CMIP-ozone-2-0.atmos.mon.vmro3.gn
  • File1: vmro3input4MIPs_ozone_CMIP_FZJ-CMIP-ozone-2-0_gn185001-189912.nc
  • File2: vmro3input4MIPs_ozone_CMIP_FZJ-CMIP-ozone-2-0_gn190001-194912.nc
  • File3: vmro3input4MIPs_ozone_CMIP_FZJ-CMIP-ozone-2-0_gn195001-199912.nc
  • file4: vmro3input4MIPs_ozone_CMIP_FZJ-CMIP-ozone-2-0_gn200001-202212.nc
  • Comments: CMIP7 historical ozone forcing with nudged QBO signal, historical solar forcing, and historical emissions.
  • version: 20260211; replica=true; size=4.35 GB

How to process data

Step1: regrid to HadCM3BL lon/lat grid

• target: convert to HadCM3BL longitude and latitude resolution (N48)
• input file: vmro3*.nc
• input variable: vmro3(time, plev=66, lat=96, lon=144)
  • time=monthly, plev=hPa, lat=1.875°, long=2.5°
  • variable: vmro3, units = “mole mole-1” ; # volume/mole mixing ratio
  • nominal_resolution = “250 km”
• output file: vmro3*_73x96.nc
• output variable: vmro3(time, plev=66, lat=73, lon=96)
  • time=monthly, plev=hPa, lat=2.5°, long=3.75°
• script: Siliruan:/home/bridge/mf22281/CMIP7/CMIP7-Ozone/regrid.sh

check metadata: ncdump -h input.nc

check lat, lon, plev values: ncks -H -C -v lat,lon,plev input.nc
cdo sinfo input.nc
cdo showlevel input.nc

Step 1.1 define lat, lon

nano grid_73x96.txt

gridtype  = lonlat
xsize     = 96
ysize     = 73
xfirst    = 0
xinc      = 3.75
yfirst    = 90
yinc      = -2.5

Step1.2: regrid

cdo -selname,vmro3 -remapbil,grid_73x96.txt input.nc output_73x96.nc

vmro3 is intensive variable, so choose bilinear method to convert lat and lon.

Step2: interpolate to hybrid levels

Step2.1: prepare surface pressure data

In theory, surface pressure data should be the actual values on a month-by-month basis throughout the period 1850-2013. However, for simplicity, we will use the climatological averages. This is also better as it makes the future scenarios straightforward too.

• target: merge surface pressure data from 12 single-month files to 1 file with 12 months
• input file: Siliruan:swsvalde/ummodel/data/obsel/climate/obsela.pdcljan.nc (and similarly for other months)
• input variable: p_mm_srf(t=1, surface=1, latitude=73, longitude=96) (Pa)
• output file: Siliruan:/home/bridge/mf22281/CMIP7/CMIP7-Ozone/surface_pressure/ps_12mon.nc
• output variable: ps(time=12, lat=73, lon=96) (Pa)
• script: Siliruan:/home/bridge/mf22281/CMIP7/CMIP7-Ozone/merge_files.sh
• main command:

  ncrcat -O input1.nc input2.nc output.nc
  

Step2.2: convert to hybrid levels

• target: Convert ozone vmro3(time,plev,lat,lon) from pressure levels to hybrid levels (19) using NCL pres2hybrid_Wrap function. At each latitude, longitude and level (lev[k]) pressures are computed using: p(k) = A(k)*P0 + B(k)*PS. (See NCL: pres2hybrid for more information.)
• input file: vmro3*_73x96.nc
• input variable: vmro3(time, plev=66, lat=73, lon=96)
• output file: vmro3*_73x96x19hybrid.nc
• output variable: vmro3(time, hybrid_eta_x1000=19, lat=73, lon=96)
• script: Siliruan:/home/bridge/mf22281/CMIP7/CMIP7-Ozone/pres2hybrid_zonmean_vmro3.ncl; Siliruan:/home/bridge/mf22281/CMIP7/CMIP7-Ozone/run_pres2hybrid_zonmean_vmro3_ncl.sh
• main command:

  vmro3_hyb = pres2hybrid_Wrap(plev, ps_full, p0, o3, A, B, intflg)
  ; output dims: (time,hybrid,lat,lon)
  

  where,

• plev: based on vmro3(plev). Convert unit from hPa to Pa (plev=plev*100), then reverse order from bottom->top to top->bottom (plev=plev(::-1).
• ps_full: surface pressure. based on ps(12,lat,lon)(Pa). Expand time dimension from 12 month to targeted 12*years dimension.
• p0=100000.0 Pa
• o3: vmro3
• A: coefficient A=AP/p0. A is model dependent. For HadCM3B,

  AP = (/ \
    0.00000000000000E+00, 0.00000000000000E+00, 0.00000000000000E+00, 0.00000000000000E+00, \
    0.47251826759436E+03, 0.24080372627472E+04, 0.58093227790796E+04, 0.94699333641095E+04, \
    0.12323530274880E+05, 0.14006976046769E+05, 0.14688062426321E+05, 0.14577724933620E+05, \
    0.13660085920729E+05, 0.11801444655940E+05, 0.88617287598797E+04, 0.55294175974212E+04, \
    0.29594332110381E+04, 0.14797166055190E+04, 0.46058805420888E+03 /)
  

  Reverse A to top->bottom order (A=A(::-1)

  • B: coefficient B. Bis model dependent. For HadCM3B,

    B  = (/ \
    0.99699892520659E+00, 0.97495591297058E+00, 0.93041678475353E+00, 0.86983230217049E+00, \
    0.78750330272592E+00, 0.67549398891862E+00, 0.54141001935591E+00, 0.40982251224795E+00, \
    0.29886781207532E+00, 0.21462797853660E+00, 0.15287099931014E+00, 0.10392452480327E+00, \
    0.63025956286467E-01, 0.31486806956303E-01, 0.10629490630593E-01, 0.15600687762778E-02, \
    0.00000000000000E+00, 0.00000000000000E+00, 0.00000000000000E+00 /)
    

    Reverse B to top->bottom order (B=B(::-1)

• intflg=1, values set to nearest valid value

Also set vertical hybrid levels, which could be found in any ozone ancil file, e.g., tdezc1.qrclim.ozone.nc, hybrid_p_x1000(hybrid_p_x1000=19). For HadCM3B,

hybrid_eta_x1000 = (/ \
    996.996, 974.867, 930.25, 869.8323, 792.2285, 699.5743, 599.5032, \
    504.5218, 422.103, 354.6977, 299.7516, 249.7017, 199.6268, \
    149.5012, 99.24676, 56.85421, 29.59433, 14.79717, 4.605881 /)

Reverse hybrid_eta_x1000 to top->bottom order (hybrid_eta_x1000=(::-1))

Step3: calculate zonal average

• input file: vmro3*_73x96x19hybrid.nc
• input variable: vmro3(time, hybrid_eta_x1000=19, lat=73, lon=96)
• output file: vmro3*73x96x19hybrid_zonmean.nc
• output variable: O3(time, hybrid_eta_x1000=19, lat=73)
• script: Siliruan:/home/bridge/mf22281/CMIP7/CMIP7-Ozone/pres2hybrid_zonmean_vmro3.ncl; Siliruan:/home/bridge/mf22281/CMIP7/CMIP7-Ozone/run_pres2hybrid_zonmean_vmro3_ncl.sh
• main command:

  O3 = dim_avg_n_Wrap(vmro3_hyb, 3)      
  ; (time,hybrid_eta_x1000,lat)
  

or use CDO:

cdo -zonmean \
  -selname,vmro3 \
 input.nc output_zonmean.nc

Step4: merge piControl and 4 historical transient files into one

The original file size is too large. So prefer convert before merge them into one single file.

cdo -O mergetime \
  input_182901-184912_72x96x19hybrid_zonmean.nc \
  input_185001-189912_72x96x19hybrid_zonmean.nc \
  input_190001-194912_72x96x19hybrid_zonmean.nc \
  input_195001-199912_72x96x19hybrid_zonmean.nc \
  input_200001-202212_72x96x19hybrid_zonmean.nc \
  output_182901-202212_72x96x19hybrid_zonmean.nc

mergetime concatenates along time and will sort by time if needed. script: Siliruan:/home/bridge/mf22281/CMIP7/CMIP7-Ozone/mergetime.sh; Siliruan:/home/bridge/mf22281/CMIP7/CMIP7-Ozone/run_pres2hybrid_zonmean_vmro3_ncl.sh

How to implement the forcing into HadCM3