Basics

Downloading the Data

The data is available from our ftp server using the credentials:

username: osirislevel2user
password: hugin

The level 2 profile data is distributed in monthly netcdf files with the naming convention:

PRODUCT-L2-LP-OSIRIS_ODIN-SASK_v7_2-YYYYMM.nc

where PRODUCT is one of ‘AEROSOL’, ‘OZONE’, or ‘NITROGEN’. The approximate sizes of the datasets are 0.8GB for aerosol, 1.2GB for ozone, and 1.8GB for nitrogen.

The data conforms to CF-conventions 1.7 so should be readable by most NetCDF software. However, some simple python examples are included to help users get started, see Example Usage.

Changes from 7.1 to 7.2

Changes to the retrieval algorithm:

  • Implemented a point spread function correction, which reduces the effects of temperature-dependent blurring in the spectrograph optics

  • Updated O3 cross sections to the Daumont, Brion, and Malicet [1] dataset

  • Adjusted Tikhonov scale factor in the NO2 retrieval for a less strict regularization

Changes to the format of the data files:

  • In the aerosol data files, changed the units of pressure from Pa to hPa to be consistent with the ozone and nitrogen products

  • Added a vertical resolution data field to the aerosol files, computed as the FWHM of the averaging kernel. This field was already included in version 7.1 of the ozone and nitrogen files

  • For profiles where the tropopause altitude could not be determined, changed the fill value from 99 km to NaN

1

Daumont, D., et al. “Ozone UV spectroscopy I: Absorption cross-sections at room temperature.” Journal of Atmospheric Chemistry 15.2 (1992): 145-155.

See Changelog for the full history of OSIRIS version 7.

Processing Status

March 2022

Data files for January 2022 are now available. Additionally, a small number of orbits that were missing due to a computing error have been reprocessed and added to the data. The result is an additional 38 orbits from 2002 to 2013 and 13 orbits from Dec. 27-29, 2021.

February 2022

Release of v7.2 ozone, aerosol, and nitrogen products. Processing is complete to the end of 2021. Version 5.10 of the ozone product will no longer be produced and is now fully replaced by version 7.2.

June 2021

Release of v7.1 of the aerosol extinction product. Monthly files are processed up to March 2021.