Global and regional trends of atmospheric sulfur

The profound changes in global SO2 emissions over the last decades have affected atmospheric composition on a regional and global scale with large impact on air quality, atmospheric deposition and the radiative forcing of sulfate aerosols. Reproduction of historical atmospheric pollution levels based on global aerosol models and emission changes is crucial to prove that such models are able to predict future scenarios. Here, we analyze consistency of trends in observations of sulfur components in air and precipitation from major regional networks and estimates from six different global aerosol models from 1990 until 2015. There are large interregional differences in the sulfur trends consistently captured by the models and observations, especially for North America and Europe. Europe had the largest reductions in sulfur emissions in the first part of the period while the highest reduction came later in North America and East Asia. The uncertainties in both the emissions and the representativity of the observations are larger in Asia. However, emissions from East Asia clearly increased from 2000 to 2005 followed by a decrease, while in India a steady increase over the whole period has been observed and modelled. The agreement between a bottom-up approach, which uses emissions and process-based chemical transport models, with independent observations gives an improved confidence in the understanding of the atmospheric sulfur budget

Overview of Sun photometer measurements of aerosol properties in Scandinavia and Svalbard

An overview on the data of columnar aerosol properties measured in Northern Europe is provided. Apart from the necessary data gathered in the Arctic, the knowledge of the aerosol loading in nearby areas (e.g. sub-Arctic) is of maximum interest to achieve a correct analysis of the Arctic aerosols and transport patterns. This work evaluates data from operational sites with sun photometer measurements belonging either to national or international networks (AERONET, GAW-PFR) and programs conducted in Scandi- navia and Svalbard. We enumerate a list of sites, measurement type and periods together with observed aerosol properties. An evaluation and analysis of aerosol data was carried out with a review of previous results as well. Aerosol optical depth (AOD) and Ångström exponent (AE) are the current parameters with suf␣cient long-term records for a ␣rst evaluation of aerosol properties. AOD (500 nm) ranges from 0.08 to 0.10 in Arctic and sub-Arctic sites (Ny-Ålesund: 0.09; Andenes: 0.10; Sodankylä: 0.08), and it is somewhat higher in more populated areas in Southern Scandinavia (AOD about 0.10e0.12 at 500 nm). On the Norwegian coast, aerosols show larger mean size (AE � 1.2 at Andenes) than in Finland, with continental climate (AE � 1.5 at Sodankylä). Columnar particle size distributions and related parameters derived from inversion of sun/sky radiances were also investigated. This work makes special emphasis in the joint and collaborative effort of the various groups from different countries involved in this study. Part of the measurements presented here were involved in the IPY projects Polar-AOD and POLARCAT

Towards operational satellite based atmospheric monitoring in Norway SatMoNAir.

The SatMoNAir project [NSC contract nr. JOP.12.12.2] builds on a previous NRS 'følgemiddel'-project, called `Roadmap towards EarthCARE and Sentinel 5 precursor', within which NILU and met.no developed a strategy for how best to prepare themselves for future European satellite missions for measuring atmospheric composition, with respect to their national monitoring, weather predictions and research tasks. Three specific topics were considered particularly relevant: a. Aerosols ¿Climate effects in Scandinavia and polar regions: analysis of episodes with high aerosol loads for Klif reporting, b. the Use of satellite based ozone measurements in national reporting, and c. Satellite based Air Quality monitoring of remote areas for EMEP reporting. Results from the work performed are described in this report. The outcomes of the project have been utilized in support of the National monitoring of greenhouse gases and aerosols (see Myhre et al., 2012), the atmospheric ozone layer (see Svendby et al., 2012), and have been reported to EMEP

Monitoring of the atmospheric ozone layer and natural ultraviolet radiation. Annual report 2012.

This is an annual report describing the activities and main results of the monitoring programme "Monitoring of the atmospheric ozone layer and natural ultraviolet radiation" for 2012. In 2012 the ozone values above Norway were close to the long-term mean, except from the ozone winter values in Oslo which were lower than normal. A clear decrease in the ozone layer above Norway during the period 1979-1997 stopped after 1998 and the ozone layer above Norway now seems to have stabilized

Monitoring of the atmospheric ozone layer and natural ultraviolet radiation. Annual report 2010.

This is an annual report describing the activities and main results of the monitoring programme ¿Monitoring of the atmospheric ozone layer and natural ultraviolet radiation¿ for 2010. 2010 was a year with generally high ozone values above Norway. A clear decrease in the ozone layer above Norway during the period 1979-1997 stopped after 1998 and the ozone layer above Norway seems now to have stabilized

Monitoring of the atmospheric ozone layer and natural ultraviolet radiation. Annual report 2011.

This is an annual report describing the activities and main results of the monitoring programme 'Monitoring of the atmospheric ozone layer and natural ultraviolet radiation' for 2011. 2011 was a year with generally low ozone values above Norway. A clear decrease in the ozone layer above Norway during the period 1979-1997 stopped after 1998 and the ozone layer above Norway seems now to have stabilized