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Reference atmospheric models: Corsika input

We have to create reference atmospheric models for DPPS release 0. Those models will be used as input for the Corsika simulations that will create the pre-calculated IRF grid.

5 seasonal models are required: summer, winter and intermediate for North, summer and winter for South. Those models should have altitude profiles, from sea level up to 120km a.s.l. of the following parameters:

  • density
  • atmospheric thickness
  • refractive index (-1)
  • partial water pressure
  • temperature
  • pressure

For the purposes of release 0 we will create the so called "mock-up" profiles, i.e. quite reasonable and elaborate profiles but with 5 years worth of data and without the most refined selection.

For the altitude range between sea level and 45km a.s.l. we will use the ECMWF ERA-5 dataset "reanalysis-era5-pressure-levels-monthly-means", available through Copernicus, which features atmospheric parameters in pressure levels, for each hour of a day but averaged over the full month.

The definition of the season is:

  • north summer [June, July, August]
  • north winter [December, January, February]
  • north intermediate [March, April, May, September, October, November]
  • south summer [October, November, December, January, February, March]
  • south winter [April, May, June, July, August, September]

Each season features a single dark time definition, calculated with Astral package.

The area of selection for La Palma is latitude 28N-29N, longitude 17W-18W. For Atacama is latitude 24N-25S, longitude 70W-71W. Therefore more than one ECMWF grid point will be used. This is something to be agreed upon in the future.

For mock-up profiles only 5 years worth of data will be used (2018-2022) The climate normal is 30 years, but probably we will not use so many years of data for CTA (given that climate changes rapidly...)

For the altitude range between 45km a.s.l and 120km a.s.l. we will use data from the COSPAR International Atmospheres (CIRA). The data have a resolution of 10deg in latitude, thus 30N for La Palma and 20S for Atacama, and are averaged over a month. Obviously we should use the same definition of seasons.

The current 12MACOBAC value shall be used. Currently it is 419.3125 ppm.

The MolecularProfiles functionality will be used for the creation of the models.