source: TOOLS/CMIP6_FORCING/AER_STRAT/README @ 4036

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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 to v4 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
30cdo divc,9810. geop_LR.nc geop_LR_l79.nc
31cdo zonmean geop_LR_l79.nc geop_zonmean_LR_l79.nc
32ferret'ize file to make it readable by ferret
33We have files for LR, MR, HR model versions.
34
35The data are fed on ciclad (currently in /data/$USER/CMIP6/VOLC/)
36
37Annual files: taulwstrat.2D.$year.nc and taulwstrat.2D.$year.nc
38to be used for historical simulations
39
40Average 1850-2014 conditions (no seasonal cycle): taulwstrat.2D.ave.nc and tauswstrat.2D.ave.nc
41to be used for piControl, pdControl and for scenario runs (past a 10 year transition from 2014 conditions)
42subject to changes in the protocol
43
44Following the CMIP6 protocol, a linear transition between 2014 and average conditions is
45performed and should be used for the period 2015-2023. Average conditions should then be used for
462024 onwards.
47
48CMIP6 stratospheric aerosols are activated in LMDz with flag_aerosol_strat=2
49
50Files to be renamed as taulwstrat.2D.nc and tauswstrat.2D.nc for use by LMDz
51No additional interpolation between months is done.
52
53Olivier Boucher
5427/07/2016
55Revised 10/09/2017
56Revised 04/10/2017
57Revised 15/04/2018
58Revised 18/09/2018
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