The NDACC UV-VIS Working Group

The NDACC UV-VIS Working Group (UVVIS-WG) consists of about 15 research institutes and University labs specialized in UV-Visible spectroscopy and atmospheric gas retrieval. They operate more than 30 UV-visible spectrometers deployed around the world, from pole to pole. Launched in the early 90s to study the long-term evolution of the ozone layer, NDACC's UV-VIS zenith-sky monitoring has produced long series of measurements of O₃ and NO₂ columns, sometimes spanning more than three decades, supplemented in the polar regions by observations of OClO and BrO. More recently the focus of the UVVIS-WG has been enlarged to also encompass the monitoring of several key tropospheric gases by means of the Multi-AXis DOAS (MAX-DOAS) technique. This technique, which utilizes different viewing directions in addition to zenith, has been developed for detecting absorbers in the lowest few kilometers of the atmosphere. Based on multiple-scattering radiative transfer modelling the inversion of MAX-DOAS measurements allows retrieving the vertical distribution of several tropospheric species like NO₂, HCHO, BrO, CHOCHO, as well as aerosols. The number of NDACC stations equipped with MAX-DOAS instruments has increased in recent years. To ensure that consistent, traceable and quality controlled data products are generated from these instruments, a centralised data processing system has been developed as part of the ESA FRM₄DOAS project. This service feeds the NDACC RD repository with total ozone and tropospheric NO₂ products with a latency of one day. It also assists PIs in generating consolidated MAX-DOAS data sets.

Data evaluation and quality assessment procedures are under the responsibility of the NDACC UVVIS-WG. These are essential for ensuring the long-term quality and consistency of the data sets. Within this objective, field instruments and algorithms intercomparison campaigns are organized on a regular basis since 1992. The NDACC UVVIS-WG also provides recommendations and data analysis tools to foster the harmonization of the network data series.

Representatives of the UV/VIS Working Group in the NDACC Steering Committee :

Dr Michel Van Roozendael
Royal Belgian Institute for Space Aeronomy (BIRA-IASB)
3, Avenue Circulaire
B-1180 Brussels
Belgium
Phone: +32 2 373 04 16
Fax : +32 2 374 84 23
E-mail : michelv@aeronomie.be

Dr Karin Kreher
Bodeker Scientific
42 Young Lane RD1
Alexandra 9391
Central Otago
New Zealand
Phone: +64-3-4492206
Fax : +64-3-4492206
E-mail : karin@bodekerscientific.com