The project intends to make an advanced exploitation of
past and current ground-based remote-sensing measurements for the study of a selection of atmospheric species that play an important role in the chemistry of the atmosphere and that have a direct or indirect impact on climate or air quality. It will contribute to the solution of actual related questions, like: Can one observe a change in the distribution of the atmospheric water vapour? What determines the evolution of methane in the atmosphere? What about the aerosol load above Ukkel and its impact on the surface radiation?
The new and improved data products that will derive from this study will be carefully characterised, thereby exploiting possible synergies and complementarities between different instruments operated at the same site.
The target geophysical parameters are:
- lower tropospheric aerosols, water vapour (H2O) and its HDO isotopologue in the troposphere and lower stratosphere;
- methane (CH4) and HCFCs that have a direct impact on climate;
- carbon monoxide (CO), non-methane hydrocarbons, hydrogen cyanide (HCN), formaldehyde (H2CO), which are source gases that influence the oxidizing capacity of the atmosphere, and therefore indirectly also climate.
- Some feasibility studies are planned for the detection of the carbon isotopic partitioning in CH4 and CO, as well as for the retrieval of OH, C2H4 and some HFC/HCFCs.
The instrumentation includes:
- 3 types of spectrometers:
- Fourier transform infrared (FTIR);
- UV-Visible Multi-Axis Differential Optical Absorption Spectroscopy (MAXDOAS);
- 1 CIMEL sun photometer.
Most of the instruments are affiliated with the Network for the Detection of Atmospheric Composition Change, NDACC (formerly known as the Network for the Detection of Stratospheric Change, NDSC), thus meeting its high-quality standard requirements. Quality controls defined in NDACC and AERONET protocols to maintain maximum instrumental stabilities will be pursued on a regular basis.
The observational data acquired with these instruments are of primary importance for the long-term monitoring of the atmosphere. But, the data have never before been exploited for the detection of the project target species, or we know that improved and better characterized data products can be derived from them - which is the goal of this project.
For all target products, data retrievals will be optimized to maximize the information content, and error budget evaluations will be carried out. Possible synergies and complementarities between instruments will be exploited, including exchange of data with other research teams at the specified locations.
Dedicated laboratory data will support the investigations. New or improved spectroscopic line parameters produced in the project will be submitted to relevant databases like HITRAN, as was already done regularly in the past.
For further details, please consult the methodology section.
The measurement stations involved are:
- Uccle/Ukkel (complementary NDACC station, 50.5°N, 4°E);
- Jungfraujoch (primary Alpine station of the NDACC, 46.5°N, 8°E);
- Ile de La Réunion (complementary NDACC station, 21°S, 55°E), where it is planned to have access to an NDACC infrastructure at the Maido site, at about 2200 m asl, from 2009 onwards. Up to that time, only campaign data will be available.
The project will also care for a proper interpretation and dissemination of the research results, in order to maximize their use for atmospheric chemistry and climate applications and in environmental assessments, in support of policy makers and for enhancing the awareness of the public.