New output for 2019 is available for all stations. The files are generated from a GMI chemistry transport model (CTM) simulation integrated with MERRA2 reanalysis meteorology – the same version as used for 1985-2018 files. All files can be downloaded via anonymous ftp from ftp://ftp.cpc.ncep.noaa.gov/ndacc/gmi_model_data.
There is no change to file format or composition. Files for all lidar, sonde, and Dobson stations contain hourly vertical profiles of O3, NO2, H2O, temperature, pressure, and potential vorticity at 0.75 km resolution from the surface to 60 or 0-75 km, depending on the variable. Model files for FTIR stations have temperature, pressure, and tropopause pressures reported at both the 1-2 pm local time and 12z. The simulated species reported at 1-2 pm are O3, CO, CH2O, NO, and NO2; all other daily species are still reported at 12z. BrO profiles and columns are reported as monthly averages.
Simulated station data are useful for understanding the variability and representativeness of NDACC measurements, thus building a bridge between individual station measurements and the global perspective. The figure shows how the simulation is used to understand why profile differences are found between 2 nearby stations, Hohenpeissenburg and Haute Provence. A brief description of the GMI CTM and its uses can be found at http://www.ndacc-theory.org/24.php. Detailed information on the GMI CTM and this simulation (‘Hindcast-MERRA2’) can be found at https://gmi.gsfc.nasa.gov.
Do you need day/night or hourly values for a particular species? Just ask! We can rerun the model to save the special output you need. We know this matters for diurnally-varying species such as ClO and BrO. Additional fields may be available - contact Susan Strahan (email@example.com).