Total columns of the trace gases nitric acid (HNO3) and hydrogen chloride (HCl) are sensitive to variations in the lower stratospheric age of air (AoA), a quantity that describes transport timescales in the stratosphere. We analyzed HNO3 and HCl columns from 9 NDACC FTIR sites spanning 77oS to 79oN and detected changes in the extratropical stratospheric transport circulation from 1994 to 2018.
There have been a number of changes to the NDACC Steering Committee, based on actions taken during the October 2019 NDACC Steering Committee meeting, as well as recent events. Those changes are detailed below. We welcome the newest members of the Steering Committee; we congratulate the recently re-elected members, and we thank the departing members for their years of service and contributions to NDACC!
The Cooperating Network Agreement between NDACC and the Pandonia Global Network (PGN) was finalized on 24 June 2020.
As a result of this agreement, Barry Lefer (NASA Headquarters) and Angelika Dehn (also the ESA-ESRIN Representative) have been named PGN Co-Representatives to the NDACC Steering Committee.
The third SPARC/WMO Long-term Ozone Trends and Uncertainties in the Stratosphere (LOTUS) workshop originally planned for Helsinki was held virtually May 28-29, 2020.
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.