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35 years of global watch of our changing atmosphere
Long-term measurements of the atmospheric composition at key locations on Earth are essential to monitoring the chemical and physical state of our changing atmosphere and climate, to understanding the causes and consequences of the profound and complex transformations that take place in the Earth system, and to advance the modelling and prediction capabilities necessary to elaborate informed environmental policies and monitor their effects.
Concepts for formally organised global networks of ground-based observations already existed in the middle of twentieth century for weather watch parameters and for atmospheric ozone, however, the discovery of the Antarctic ozone hole and if the long-term ozone depletion at our latitudes in the mid-1980s triggered the inception in 1991 of the Network for the Detection of Stratospheric Change (NDSC).
The NDSC was a global network of remote sounding stations measuring not only the stratospheric ozone layer but also both natural and human-induced constituents controlling ozone abundance in the middle atmosphere.
Since, NDSC data have been critical in understanding the causes of ozone decline, in supporting the Montreal Protocol and its successive amendments and adjustments, and in monitoring its impact. Thanks to the efforts by the global ozone research community and managers, stratospheric ozone is no longer declining.
Over the years, NDSC has remained committed to the long-term monitoring of ozone; however, it has also broadened substantially its measurement capabilities to a wider portfolio of atmospheric species and research themes, justifying its renaming in 2005 as Network for the Detection of Atmospheric Composition Change (NDACC).
A few recent NDACC achievements
Since the ramp-up of the network in 1991 BIRA-IASB has been member of its Steering Committee and has provided to its central database high-quality ground-based measurements of ozone, climate variables and other trace gases.
In recent years the institute has led international initiatives to develop central processing facilities for UV-visible (FRM4DOAS) and FTIR (CDPS) instruments to harmonize data quality and uncertainty reporting across the network and beyond. Advances have been made with new, more portable instrumentation to foster network evolution and easier deployment in field campaigns.
In support to the EU Copernicus programme and to its own satellite missions like ALTIUS, the institute has participated in the development of the CEOS-FRM Maturity Assessment Framework and promoted its implementation in NDACC to better tailor ground-based measurements to the evolving validation needs and new challenges of the satellites and of the operational services like:
Establishing the NDACC strategy for the next decade
After 35 years of continuous operation and permanent development, and together with international partners, BIRA-IASB has reflected on the needed evolution of NDACC strategies for the next decade.
While the primary goal of the network remains to establish long-term datasets for detecting changes and trends in the chemical and physical state of the atmosphere (mesosphere, stratosphere, and troposphere), it also puts emphasis on cutting-edge scientific questions like the coupling of atmospheric composition changes with climate and air quality, and on technical advances needed to meet the needs of the stakeholders and operational services.
Recognizing the need for an integrated approach to atmospheric composition monitoring, and to assure appropriate response to ever-evolving scientific and societal needs, BIRA-IASB is active in integrating the European NDACC component in the European Research Infrastructure ACTRIS (Aerosol, Clouds and Trace Gas Research Infrastructure) and in strengthening NDACC engagement with cooperating networks measuring complementary data.
It also contributes actively to engagement with institutional stakeholders like:
- space agencies
- WMO’s Global Atmosphere Watch (GAW) and Global Greenhouse Gas Watch (G3W) programmes,
- the aforementioned Copernicus operational services.
The revised strategic orientation of NDACC for the next decade is the subject of a scientific article that will be presented at the NDACC 35th Anniversary Scientific Symposium in October 2025.
