source: TOOLS/CMIP6_FORCING/AER_STRAT/README

Last change on this file was 4605, checked in by oboucher, 3 years ago

netcdf files are now on /bdd/input4MIPs/ZALT
volc.sh is modified accordingly
zalt files are now compulsory

File size: 3.3 KB
Line 
1Stratospheric aerosol files for LMDz can be created by running on ciclad the script
2./volc.sh
3which itself prepares two more files and submit a job on ciclad which may take a couple of days to run.
4
5The stratospheric AOD data originates from data prepared by Beiping Luo ETZH for CMIP6.
6See http://www.wcrp-climate.org/wgcm-cmip/wgcm-cmip6
7and ftp://iacftp.ethz.ch/pub_read/luo/CMIP6/
8The data were provided in June 2016 and were not versioned (but were later referred as v2).
9A new version (v3) was made available on 15 September 2017 due to a glitch in the 1970s data.
10The new version also modified the trend in the background aerosol.
11
12Beiping calculated for the solar radiation 8 bands (bands 1-6 for the SW 6 bands
13model and 7-8 for the SW 2 bands model) and likewise for the 16 bands of the RRTM LW model.
14
15The data are processed in IDL on ciclad for different resolutions
16of the IPSL model and aerosol optical properties are generated for AOD,
17omega and g per model layer (SW), and absorption AOD per model layer (LW).
18
19The stratospheric aerosol data extends into the troposphere but a mask is applied
20in the LMDz model to remove tropospheric data. The data are interpolated on the vertical
21from the CMIP6 altitude coordinate (z, resolution 0.5 km) to the model coordinate (sigma).
22This is done using a monthly (10-year mean) climatology of the geopotential height.
23zalt_LR_l79.nc = 10 yr climatology from a coupled IPSL-CM6.0.12 simulation
24zalt_zonmean_LR_l79.nc = zonal mean of the above file  (cdo zonmean zalt.nc zalt_zonmean.nc)
25zalt_zonmean_LR_l79_rev.nc = same as above but ferret'ized so that can be read in idl
26
27In September 2017 the processing idl routine was changed to rely on climatological LMDz altitudes
28that vary monthly and with latitude (based on GEOP variable Z=GEOP/RG/1000 [in km]).
29Start from a file geop.nc with monthly GEOP variable (ideally from a 10-yr run)
30cdo ymonmean geop.nc geop_LR.nc
31cdo divc,9810. geop_LR.nc zalt_LR_l79.nc
32cdo zonmean zalt_LR_l79.nc zalt_zonmean_LR_l79.nc
33ferret'ize file to make it readable by ferret : zalt_zonmean_LR_l79_rev.nc
34for this an example is provided in example_convert.jnl
35We have files for VLR, LR, MR, HR model versions.
36The variable is called GEOP but is now the altitude in km as required by the interpolation scheme.
37
38The data are fed on ciclad (currently in /data/$USER/CMIP6/VOLC/)
39
40Annual files: taulwstrat.2D.$year.nc and taulwstrat.2D.$year.nc
41to be used for historical simulations
42
43Average 1850-2014 conditions (no seasonal cycle): taulwstrat.2D.ave.nc and tauswstrat.2D.ave.nc
44to be used for piControl, pdControl and for scenario runs (past a 10 year transition from 2014 conditions)
45subject to changes in the protocol
46
47Following the CMIP6 protocol, a linear transition between 2014 and average conditions is
48performed and should be used for the period 2015-2023. Average conditions should then be used for
492024 onwards.
50
51CMIP6 stratospheric aerosols are activated in LMDz with flag_aerosol_strat=2
52
53Files to be renamed as taulwstrat.2D.nc and tauswstrat.2D.nc for use by LMDz
54No additional interpolation between months is done.
55
56v3 : original CMIP6 files
57v4 : corrected CMIP6 files (Pinatubo) and extended in time beyond 2014
58
59Olivier Boucher
6027/07/2016
61Revised 10/09/2017
62Revised 04/10/2017
63Revised 15/04/2018
64Revised 18/09/2018
65Revised 11/12/2018
66Revised 06/2019 by Th. Lurton to add support for VLR-L39.
67Revised 03/07/2019
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