| 1 | Stratospheric aerosol files for LMDz can be created by running on ciclad the script |
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| 2 | ./volc.sh |
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| 3 | which itself prepares two more files and submit a job on ciclad which may take a couple of days to run. |
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| 4 | |
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| 5 | The stratospheric AOD data originates from data prepared by Beiping Luo ETZH for CMIP6. |
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| 6 | See http://www.wcrp-climate.org/wgcm-cmip/wgcm-cmip6 |
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| 7 | and ftp://iacftp.ethz.ch/pub_read/luo/CMIP6/ |
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| 8 | The data were provided in June 2016 and were not versioned (but were later referred as v2). |
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| 9 | A new version (v3) was made available on 15 September 2017 due to a glitch in the 1970s data. |
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| 10 | The new version also modified the trend in the background aerosol. |
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| 11 | |
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| 12 | Beiping calculated for the solar radiation 8 bands (bands 1-6 for the SW 6 bands |
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| 13 | model and 7-8 for the SW 2 bands model) and likewise for the 16 bands of the RRTM LW model. |
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| 14 | |
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| 15 | The data are processed in IDL on ciclad for different resolutions |
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| 16 | of the IPSL model and aerosol optical properties are generated for AOD, |
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| 17 | omega and g per model layer (SW), and absorption AOD per model layer (LW). |
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| 18 | |
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| 19 | The stratospheric aerosol data extends into the troposphere but a mask is applied |
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| 20 | in the LMDz model to remove tropospheric data. The data are interpolated on the vertical |
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| 21 | from the CMIP6 altitude coordinate (z, resolution 0.5 km) to the model coordinate (sigma). |
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| 22 | This is done using a monthly (10-year mean) climatology of the geopotential height. |
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| 23 | zalt_LR_l79.nc = 10 yr climatology from a coupled IPSL-CM6.0.12 simulation |
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| 24 | zalt_zonmean_LR_l79.nc = zonal mean of the above file (cdo zonmean zalt.nc zalt_zonmean.nc) |
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| 25 | zalt_zonmean_LR_l79_rev.nc = same as above but ferret'ized so that can be read in idl |
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| 26 | |
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| 27 | In September 2017 the processing idl routine was to v4 changed to rely on climatological LMDz altitudes |
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| 28 | that vary monthly and with latitude (based on GEOP variable Z=GEOP/RG/1000 [in km]). |
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| 29 | Start from a file geop.nc with monthly GEOP variable |
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| 30 | cdo divc,9810. geop_LR.nc zalt_LR_l79.nc |
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| 31 | cdo zonmean zalt_LR_l79.nc zalt_zonmean_LR_l79.nc |
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| 32 | ferret'ize file to make it readable by ferret : zalt_zonmean_LR_l79_rev.nc |
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| 33 | We have files for LR, MR, HR model versions. |
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| 34 | The variable is called GEOP but is now the altitude in km as required by the interpolation scheme. |
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| 35 | |
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| 36 | The data are fed on ciclad (currently in /data/$USER/CMIP6/VOLC/) |
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| 37 | |
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| 38 | Annual files: taulwstrat.2D.$year.nc and taulwstrat.2D.$year.nc |
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| 39 | to be used for historical simulations |
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| 40 | |
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| 41 | Average 1850-2014 conditions (no seasonal cycle): taulwstrat.2D.ave.nc and tauswstrat.2D.ave.nc |
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| 42 | to be used for piControl, pdControl and for scenario runs (past a 10 year transition from 2014 conditions) |
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| 43 | subject to changes in the protocol |
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| 44 | |
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| 45 | Following the CMIP6 protocol, a linear transition between 2014 and average conditions is |
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| 46 | performed and should be used for the period 2015-2023. Average conditions should then be used for |
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| 47 | 2024 onwards. |
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| 48 | |
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| 49 | CMIP6 stratospheric aerosols are activated in LMDz with flag_aerosol_strat=2 |
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| 50 | |
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| 51 | Files to be renamed as taulwstrat.2D.nc and tauswstrat.2D.nc for use by LMDz |
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| 52 | No additional interpolation between months is done. |
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| 53 | |
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| 54 | Olivier Boucher |
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| 55 | 27/07/2016 |
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| 56 | Revised 10/09/2017 |
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| 57 | Revised 04/10/2017 |
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| 58 | Revised 15/04/2018 |
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| 59 | Revised 18/09/2018 |
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| 60 | Revised 11/12/2018 |
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