netcdf I4MC6LJCCOQAMgwnldngn180525_1_226925924906878778 { dimensions: bnds = 2 ; lon = 144 ; lat = 96 ; plev = 66 ; time = UNLIMITED ; // (600 currently) variables: double lon(lon) ; lon:bounds = "lon_bnds" ; lon:units = "degrees_east" ; lon:axis = "X" ; lon:long_name = "longitude" ; lon:standard_name = "longitude" ; lon:realtopology = "linear" ; double lon_bnds(lon, bnds) ; double lat(lat) ; lat:bounds = "lat_bnds" ; lat:units = "degrees_north" ; lat:axis = "Y" ; lat:long_name = "latitude" ; lat:standard_name = "latitude" ; lat:realtopology = "linear" ; double lat_bnds(lat, bnds) ; double plev(plev) ; plev:bounds = "plev_bnds" ; plev:units = "hPa" ; plev:axis = "Z" ; plev:long_name = "pressure" ; plev:standard_name = "air_pressure" ; plev:realtopology = "linear" ; double plev_bnds(plev, bnds) ; double time(time) ; time:bounds = "time_bnds" ; time:units = "days since 1850-01-01 00:00" ; time:calendar = "365_day" ; time:axis = "T" ; time:long_name = "time" ; time:standard_name = "time" ; time:realtopology = "linear" ; double time_bnds(time, bnds) ; float vmro3(time, plev, lat, lon) ; vmro3:units = "mole mole-1" ; vmro3:long_name = "ozone volume mixing ratio" ; vmro3:standard_name = "mole_fraction_of_ozone_in_air" ; vmro3:cell_methods = "time: mean" ; vmro3:_FillValue = 1.e+20f ; vmro3:missing_value = 1.e+20f ; // global attributes: :Conventions = "CF-1.6" ; :comment = "Merged data product using WACCM (WACCM1-CESM CCMI tag34) and CMAM (CMAM simulation 964c) ozone fields. This variant is for use with the historical stratospheric aerosol forcing only experiment, hist-volc, of the Detection and Attribution MIP (DAMIP). The ozone field has been constructed from the 12 month pre-industrial control ozone, with the addition of the volcanic signal. The signal was derived from multiple linear regression of the original WACCM and CMAM ozone fields (before they were merged) over 1850 - 1909, including terms for a linear trend, solar cycle, volcanic and (for WACCM) QBO effects. The regression was done using the zonal average ozone, deseasonalized by fitting four sine and cosine terms. The monthly anomalies for WACCM and CMAM were then fit to the solar cycle using the monthly 120 - 130 nm solar flux from the CMIP6 database, smoothed with a 1-2-1 filter applied 10 times, as the solar cycle proxy. Although both models did not use the same Ex-T solar flux, the timeseries were highly corrlated and the use of individual solar cycle proxies had little impact on the regression. The volcanic proxy was calculated as the average stratospheric surface area density over 30S to 30N and 16 - 28 km and was calculated separately for both WACCM and CMAM as both models did not use the same SSAD fields. WACCM also included a QBO and the QBO signal was derived by regression against the 10S - 10N average zonal winds from the WACCM simulation, with separate terms for winds at 50 and 30 hPa. A linear trend term was also included for the 1850 - 1909 fitting. All regression terms included a sine and cosine term with a period of one year to represent the seasonal dependence of the effects. See Vyushin et al., JGR, 115, doi:10.1029/2009JD013105, 2010 for a full description of the regression terms. Due to difficulties fitting both the Krakatoa (1883) and Santa Maria (1902) eruptions, the volcanic proxy was split into two separate regression terms, one for values of SSAD less than 4 um^2/cm^3 and one for values greater than 4 that was set to zero when SSAD was less than the cutoff. The signals for each model derived from the regression over 1850 - 1909 were then extrapolated for the full 1850 - 2014 period using the full timeseries of each proxy. The zonal average anomalies due to the volcanic term from each model were merged following the same approach as used for the default CCMI CMIP6 ozone database and then added on to a repeating annual cycle of 3-D ozone fields from the CMIP6 pre-industrial control." ; :license = "The CCMI data produced by CCCma is licensed under a Commons Attribution-ShareAlike 4.0 International License (http://creativecommons.org/licenses/by-sa/4.0/). The data producers and data providers make no warranty, either express or implied, including but not limited to, warranties of merchantability and fitness for a particular purpose. In no event will Environment Canada be liable for any indirect, special, consequential or other damages attributed to the use of the data product." ; :activity_id = "input4MIPs" ; :variable_id = "vmro3" ; :variant_info = "Time-evolving stratospheric ozone with volcanic terms added on to the annual cycle of ozone from the CCMI CMIP6 pre-industrial control. The source of the model outputs used in the regression analysis were the original WACCM and CMAM ozone fields that were combined to produce v1.0 of the CCMI CMIP6 specified ozone dataset." ; :realm = "atmos" ; :mip_era = "CMIP6" ; :institution_id = "CCCma" ; :institution = "Canadian Centre for Climate Modelling and Analysis, Victoria, BC V8P 5C2, Canada" ; :title = "CCMI v1.1 dataset with the volcanic signal derived from regression added to the repeating annual cycle of pre-industrial values" ; :nominal_resolution = "250 km" ; :frequency = "mon" ; :creation_date = "2018-05-24T21:14:13Z" ; :source = "The original WACCM and CMAM ozone fields used to produce the CCMI V1.0 ozone dataset" ; :contact = "David Plummer (