Finland ground based observations

In Finland, ozone column monitoring has been carried out by the Finnish Meteorological Institute (FMI) at Sodankylä (67.4°N, 26.6°E) since 1988, at Jokioinen (60.5°N, 23.3°E) during 1994—2015 and at Helsinki since 2016. At the stations an automated system based on Brewer spectrophotometer is continuously operated. Since November 2012 this monitoring programme has taken place in close cooperation with the COST Action ES1207: A EUropean BREWer NETwork – EUBREWNET. At Sodankylä Arctic research centre (FMI-ARC) wintertime ozone columns are also monitored with a SAOZ spectrophotometer which is operated in cooperation with CNRS-Paris already since 1990. The SAOZ measurements also provide NO₂ and OClO column amounts.

Ozone soundings have been carried out since 1989 at Sodankylä on regular basis throughout the year, while in Jokioinen these measurements have been conducted during winter and spring when chemical ozone depletion is expected. Both sites have participated in the ozonesonde Match project, which is a coordinated effort to measure ozone loss in the Arctic vortex. Measurements of polar stratospheric cloud (PSC) properties have been carried out at Sodankylä since 1991/1992 by lidar and since 1994 by aerosol backscatter sondes. Stratospheric water vapor is measured at Sodankylä during all seasons using Cryogenically cooled Frost point Hygrometer (CFH). Sodankylä site is participating in GCOS Reference Upper-Air Network (GRUAN). The national meteorological institutes in Finland (FMI) and Argentina (SMN) jointly carry out regular ozonesonde measurements at Marambio (64.1°S, 56.4°W), Antarctica, since 1988.

FMI operates SL501 broadband instruments at seven sites in Finland. These instruments provide on-line information on the erythemal irradiance that is published through the internet along with the UV-Index forecast (http://en.ilmatieteenlaitos.fi/uv-index). To complete the network, new broadband measurements were started in November 2014 in Kuopio. FMI measures incoming and outgoing broadband SL501 UV radiation (UV albedo) in the GAW stations of Sodankylä (2008-) and Marambio (2013-).

FMI has three narrowband NILU-UV filter instruments, from which two measures at the roof of the sounding station in Sodankylä and one is located in Helsinki and used for campaigns. In 2016, FMI invested in two GUV multifilter radiometers, which will be used for continuous UV measurements in the Antarctic in the research station of Marambio. They will rotate so that one is always measuring in Marambio, and the second one is recalibrated in Finland. The first one has been sent to Marambio in December 2016 and will be set up in February 2017. The GUV measurements will be made within the existing Antarctic research cooperation between FMI and SMN.

FMI has monitored the spectral UV irradiance with Brewer instruments in Jokioinen (Mark III during 1995-2015), Helsinki (Mark III since 2016) and Sodankylä (Mark II since 1990, Mark III since 2013). The monitoring program conducted with the FMI Brewer spectroradiometers is described in Mäkelä et al. (2016). In addition, a Bentham DM150 spectroradiometer is maintained and used for campaigns. Furthermore, two CCD spectrometers (Flame, from Ocean Optics Inc.) with wavelength range 348–1024 nm are employed, one in Mukteshwar, India, since 2015, and another in Kumpula, Finland, since 2016.

FMI is operating dark room UV calibration facilities both in Helsinki and Sodankylä (Lakkala et al. 2016). FMI has participated in several UV measurement comparison campaigns, where it has been established that the quality of Finnish Brewer measurements is high and steady. The maintenance of the irradiance scale and the procedures ensuring the traceability of the scale is described by Heikkilä et al. (2016). The Brewer instrument of Helsinki serves as one of the core instruments of the QUASUME project (Quality Assurance of Spectral Ultraviolet Measurements in Europe). The European reference spectroradiometer developed in the project and now hosted by the WMO World Calibration Center for UV radiation in Davos is invited for auditing visits to both observatories on a regular basis. FMI is also responsible for the calibration of the Antarctic/Marambio GUV-multifilter radiometer and for its data quality assurance. Brewer total ozone measurements in Helsinki and Sodankylä are calibrated by annual visits of a travelling Brewer standard instrument or by visiting the Regional Brewer Calibration Center for Europe (RBCC-E) at Tenerife/Spain.

FMI stations at Sodankylä and Jokioinen have participated in ozonesonde Match campaigns during each Arctic winter, including winter 2015/2016.

Validation and intercomparison of satellite ozone profiles studies have been performed (Rahpoe et al., 2015; Kauppi et al, 2016). The methods for validation of uncertainty estimates are presented in (Sofieva et al., 2014b). The influence of orbital sampling on averaged ozone distributions from satellite measurements is discussed in (Sofieva et al., 2014c)

FMI has a strong participation in several satellite instruments that are targeted for monitoring ozone in the atmosphere (GOMOS/Envisat, OSIRIS/Odin, OMI/EOS-Aura, GOME-2/METOP-A, METOP-B, Sentinel). FMI participates in ensuring the GOMOS data quality and in improving the data processing as a member of the ESA’s GOMOS quality working group. In several international projects (Ozone-CCI, ALGOM, MesosphEO, SPARC DI) new GOMOS data sets have created and made available:

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  GOMOS user friendly products: All Level 2 products. Vertically gridded nighttime products. Available from: https://earth.esa.int/web/sppa/activities/instrument-characterization-studies/algom and http://mesospheo.fmi.fi/index.html.
  
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  GOMOS O₃, NO₂, NO₃ nighttime climatologies: http://mesospheo.fmi.fi/index.html
  
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  GOMOS O₃, NO₂, aerosols nightime climatologies: http://www.sparc-climate.org/data-center/data-access/sparc-data-initiative/
  
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  GOMOS daytime ozone: ftp.fmi.fi
  
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  GOMOS UTLS-corrected ozone: https://earth.esa.int/web/sppa/activities/instrument-characterization-studies/algom
  

FMI is hosting the OMI UV surface irradiance processing and archiving facility which includes level 2 data, gridded level 2 data and level 3 data. The improvement and validation of the UV products are continued. In addition, local maps of total ozone columns and UV irradiance together with other atmospheric constituents covering Central and Northern Europe are processed at FMI. These Very Fast Delivery (VFD) products exploit the Direct Broadcast antenna at the Satellite Data Centre of FMI-ARC in Sodankylä, Northern Finland. These products are available in the Internet (http://sampo.fmi.fi/) within 15 min after the overpass of the satellite. Presently similar real time ozone products are being developed for OMPS instrument on-board NASA/NOAA Suomi NPP satellite.

FMI has developed quality control (QC) and quality assurance (QA) practices that are suitable for many kinds of UV instruments. At FMI, at the moment, only Brewer UV measurements are considered to have a sufficient quality for assessment of long-term changes (e.g., Heikkilä et al. 2017b). The Sodankylä spectral time series is among the longest in the Arctic. No statistically significant spectral UV changes were found for the SZA interval 63°-65° at Sodankylä during 1990-2014. The effect of snow, enhancing the measured UVR due to high albedo, was important during late spring. Short-term variations were mostly due to changes in cloudiness, which was the dominant factor during summertime.

FMI's ground based and satellite UV and ozone measurements have been used to prepare the yearly published Ozone and UV chapter of the State of the Climate in the Bull. Amer. Meteor. Soc. (e.g. Bernhard et al. 2016). The UV and ozone time series of FMI have been used to assess the future UV levels (Eleftheratos et al. 2014). Recently, columnar amounts of atmospheric SO₂ measured by the FMI spectroradiometers was used in a study detecting volcanic SO₂ plumes (Zerefos et al. 2017).
FMI has participated in multidisciplinary research projects that aim at better understanding of the effects of increased UV exposures on human health, terrestrial and aquatic ecosystems, and materials. Research on the effects of UV radiation on materials has yielded new methods for the research on the effects of UV radiation on materials (Heikkilä 2014), new knowledge on the wavelength sensitivity of photo-degradation, especially photo-yellowing (Heikkilä & Kärhä 2014, Heikkilä et al. 2015) and novel instrumentation for the research thereon (Vaskuri et al. 2015, 2017).
4. THEORY, MODELLING, AND OTHER RESEARCH

The modelling activities related to middle atmospheric ozone includes the use of a global 3D chemistry transport model of the stratosphere and mesosphere (FinROSE-ctm), two climate models covering the middle atmosphere (MAECHAM, CESM/WACCM) and a model of the ionosphere (Sodankylä Ion and neutral Chemistry model). A model study using the FinROSE-ctm was made to evaluate the stratospheric water vapour distribution and variability in the Arctic. The calculations suggested that the variability in water vapour could mostly be explained by transport-related processes. An increase in water vapour in the presence of the low winter temperatures led to a more frequent occurrence of ice polar stratospheric clouds in the Arctic vortex. A study using MAECHAM model investigated possible impacts of Arctic ozone depletion 2011 on tropospheric circulation. It was found that both ozone depletion of observed magnitude and observed anomalies of sea surface temperature were needed to induce significant impacts on the troposphere.

FMI has participated in the Global Atmospheric Watch (GAW) programme since 1994. Within the program, FMI maintains the Pallas-Sodankylä GAW station and conducts an extensive research programme related to atmospheric aerosols. Within this twin GAW station surface and boundary layer measurements are done in FMI clean air site of Pallas while upper air measurements, UV and Ozone monitoring takes place at Sodankylä (fmiarc.fmi.fi). In upper air research Sodankylä functions as an auxiliary station in the global Network of Detection of Atmospheric Composition Change (NDACC). The total ozone values are reported to the WOUDC.

FMI maintains the European UV Database (EUVDB) with a coherent QA system (Heikkilä et al. 2016). EUVDB is a database containing currently over 3.4 million UV spectra (uvdb.fmi.fi/uvdb/) from 49 measurement sites. For five stations, the stored data sets cover over 20 years of measurements. (uvdb.fmi.fi/uvdb/). The UV spectra of two Finnish Brewer instruments are submitted to EUVDB. The UV time series of FMI are used to yearly update the Ozone and UV chapter of the BAMS State of the Climate https://www.ncdc.noaa.gov/bams.

Figure 1. Ozone sounding at Sodankylä in January 2017. The ozone soundings have been made on regular basis in an effort to study Arctic stratospheric and tropospheric ozone changes. Results of the ozone soundings have been made publicly available through the FMI web site.
Regular ozone soundings have been performed at Marambio since 1988, the ozone data is sent to two international databases at the World Ozone and Ultraviolet Data Centre (WOUDC, Toronto, www.woudc.org) and the Norsk institutt for luftforskning (NILU, Oslo, www.nilu.no/nadir/). The ozone measurements are used in scientific publications, and form a significant contribution to the WMO ozone bulletins (www.wmo.ch).
5.2 Information to the public

FMI provides a 3-day global forecast of the UV Index (http://en.ilmatieteenlaitos.fi/uv-index). The forecast, which is published on the internet, includes contour maps of the local solar noon maximum clear sky maximum UV Index. Additionally, local clear sky UVI forecasts are provided for several sites in Finland and globally. The Finnish broadband UVI measurements are also incorporated in near-real-time on the web page. Several newspapers, radio channels and TV publish the forecasted or measured values during April to August. Warnings of high UV index are included in the general warning maps, and the global forecasted UV index is made available through a mobile phone application. FMI has actively participated in increasing the awareness of general public on the health effects of UV radiation, e.g. each year an UV info day is organized for the journalists as collaboration between FMI and other Finnish research institutes. Ozone depletion has a large public interest due to related health (UV) and environmental issues. Popularized information is distributed through press releases and interviews. Information about research activities, remote sensing projects as well as measurements and analysis results are available through FMI web pages, http://en.ilmatieteenlaitos.fi. FMI-ARC observations and analyses are available at http://fmiarc.fmi.fi.

3. 
   Recent relevant scientific papers (2014–2017)
   

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  Andersson, M.E., P.T. Verronen, D.R. Marsh, S.-M. Päivärinta and J.M.C. Plane, WACCM-D - Improved modeling of nitric acid and active chlorine during energetic particle precipitation, J. Geophys. Res. Atmos., 121, 10328-10341, http://dx.doi.org/10.1002/2015JD024173, 2016.
  
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  Andersson, M.E., Verronen, P.T., Rodger, C.J., Clilverd, M.A. and Seppälä, A., Missing driver in the Sun-Earth connection from energetic electron precipitation impacts mesospheric ozone, Nature Commun., 5:5197, http://dx.doi.org/10.1038/ncomms6197, 2014.
  
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  Andrady A., et al.. 2017. Environmental effects of ozone depletion and its interactions with climate change: progress report, Accepted for publication in Photochem. Photobiol. Sci. DOI: 10.1039/c7pp90001e
  
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  Arola A, Lindfors AV, Pitkänen M, Lakkala K, Koskela T, Hovila J, Kalakoski N, Tamminen J, The OMUVB satellite UV product, OMI Science Team Meeting nr. 19, KNMI, August 2015, 2015
  
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  Bernhard G, Fioletov V, Heikkilä A, Johnsen B, Koskela T, Lakkala K, Svendby T, Dahlbäck A, [The Arctic] UV Radiation [in State of the Climate in 2013]. Bull. Amer. Meteor. Soc., 95(7), S121-S123, 2014
  
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  Bernhard G, Ialongo I, Groos J.-U., Hakkarainen J, Johnson B, Manney G.-L., Fioletov V, Heikkilä A, Lakkala K., Ozone and UV radiation. (2015). In: State of the Climate in 2015. J. Blunden and D. S. Arndt, Eds., Bull. Amer. Meteor. Soc., 97(8), S152-S153, 2016
  
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  Bernhard G, Ialongo I, Grooß J.-U, Hakkarainen J, Johnsen B, Manney G.L, Fioletov V, Heikkilä A, Lakkala K, The Arctic - Ozone and UV radiation [in 'State of the Climate in 2015']. Bull. Amer. Meteor. Soc., 97 (8), S192-S193. 2016
  
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  Bernhard G., Arola A., Dahlback A., Fioletov V., Heikkilä A., Johnsen B., Koskela T., Lakkala K., Svendby T., Tamminen J., Comparison of OMI UV observations with ground-based measurements at high northern latitudes.,Atmos. Chem. Phys., 15, 7391-7412, doi:10.5194/acp-15-7391-2015, 2015.
  
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  Bourassa, E., D. A. Degenstein, W. J. Randel, J. M. Zawodny, E. Kyrölä, C. A. McLinden, C. E. Sioris, and C. Z. Roth. Trends in stratospheric ozone derived from merged SAGE II and Odin-OSIRIS satellite observations. Atmospheric Chemistry & Physics, 14:6983– 6994, July 2014. 

  
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  Deshler, T., Stübi, R., Schmidlin, F. J., Mercer, J. L., Smit, H. G. J., Johnson, B. J., Kivi, R., and Nardi, B.: Methods to homogenize ECC ozonesonde measurements across changes in sensing solution concentration or ozonesonde manufacturer, Atmos. Meas. Tech. Disc., doi:10.5194/amt-2016-415, in review
  
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  Dirksen,R.J., Sommer, M., Immler, F. J., Hurst, D. F., Kivi, R., and Vömel, H.: Reference quality upper-air measurements: GRUAN data processing for the Vaisala RS92 radiosonde, Atmos. Meas. Tech.,7,4463-4490,2014.
  
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  Eleftheratos K., et al. Ozone and Spectroradiometric UV Changes in the Past 20 Years over High Latitudes, Atmosphere-Ocean, doi:10.1080/07055900.2014.919897, 2014
  
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  Engel, I., Luo, B. P., Khaykin, S. M., Wienhold, F. G., Vömel, H., Kivi, R., Hoyle, C. R., Grooß, J.-U., Pitts, M. C., and Peter, T.: Arctic stratospheric dehydration – Part 2: Microphysical modeling, Atmos. Chem. Phys., 14, 3231-3246, doi:10.5194/acp-14-3231-2014, 2014.
  
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  Grooß, J.-U., et al.: Nitric acid trihydrate nucleation and denitrification in the Arctic stratosphere, Atmos. Chem. Phys., 14, 1055-1073, doi:10.5194/acp-14-1055-2014, 2014.
  
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  Harris, N.R.P., et al., Past changes in the vertical distribution of ozone – Part 3: Analysis and interpretation of trends Atmospheric Chemistry and Physics, Volume 15, Issue 17, 2015, pp.9965-9982
  
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  Hassinen, S., et al., Overview of the O3M SAF GOME-2 operational atmospheric composition and UV radiation data products and data availability, Atmos. Meas. Tech., 9, 383-407, doi:10.5194/amt-9-383-2016, 2016.
  
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  Hassler, B., I. et al. Past changes in the vertical distribution of ozone - Part 1: Measurement techniques, uncertainties and availability. Atmospheric Measurement Techniques, 7:1395–1427, 2014.
  
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  Heikkilä A, et al., European UV DataBase (EUVDB) as a repository and quality analyser for solar spectral UV irradiance monitored in Sodankylä, Geosci. Instrum. Method. Data Syst., 5, 333-345, doi:10.5194/gi-5-333-2016, 2016.
  
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  Heikkilä A, Mäkelä JS, Lakkala K, Meinander O, Kaurola J, Koskela T, Karhu J, Karppinen T, Kyrö E, De Leeuw G.,In search of traceability: two decades of calibrated Brewer UV measurements in Sodankylä and Jokioinen, Geosci. Instrum. Method. Data Syst., 5, 531-540, doi:10.5194/gi-5-531-2016, 2016.
  
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  Heikkilä A., Kazadzis S., Meinander O., Vaskuri A., Kärhä P., Mylläri V., Syrjälä S., and Koskela T., 2017. UV exposure in artificial and natural weathering: A comparative study, 2017. In: R. Davies, L. Egli & W. Schmutz (eds.), Proceedings of the International Radiation Symposium 2016 16-22 April, 2016, Auckland, New Zealand. AIP Publishing. Accepted for publication.
  
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  Heikkilä A., Uusitalo K., Kärhä P,, Vaskuri A., Lakkala K., and Koskela T., 2017. Variability of daily UV index in Jokioinen, Finland, over the years 1995-2015, 2017. In: R. Davies, L. Egli & W. Schmutz (eds.), Proceedings of the International Radiation Symposium 2016 16-22 April, 2016, Auckland, New Zealand. AIP Publishing. Accepted for publication.
  
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  Heikkilä, A. & Kärhä, P. 2014, "Photoyellowing revisited: Determination of an action spectrum of newspaper", Polymer Degradation and Stability, vol. 99, pp. 190-195.
  
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  Heikkilä, A. 2014, Methods for assessing degrading effects of UV radiation on materials, Finnish Meteorological Institute Contributions No. 111, ISBN 978-951-697-843-0, Helsingin yliopisto, Unigrafia Oy, Helsinki.
  
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  Heikkilä, A., Vaskuri, A. & Kärhä, P. 2015, Photoyellowing of transparent materials as quantified with a setup of lasers, Natural and Artificial Ageing of Polymers, 7th European Weathering Symposium 16-18 September 2015, Naples, Italy, ed. T. Reichert, Gesellshaft für Umweltsimulation e.V. GUS, Karlsruhe, Germany, 16-18 Sep 2015, pp. 209.
  
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  Hubert, D., et al. Ground-based assessment of the bias and long-term stability of 14 limb and occulta- tion ozone profile data records. Atmospheric Measurement Techniques, 9:2497–2534, June 2016.
  
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  Karpechko, A. Yu., J. Perlwitz, and E. Manzini (2014), A model study of tropospheric impacts of the Arctic ozone depletion 2011, J. Geophys. Res. Atmos., 119, 7999–8014
  
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  Karppinen T, Ala-Houhala M, Ylianttila L, Kautiainen H, Lakkala K, Hannula H, Turunen E, Viljakainen H, Reunala T, Snellman E, The effect of vernal solar UV radiation on serum 25-hydroxyvitamin D concentration depends on the baseline level: observations from a high latitude in Finland, Accepted to International Journal of Circumpolar Health, 2016
  
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  Karppinen T, Lakkala K, Karhu J.M., Heikkinen P, Kivi R, Kyrö E., Brewer spectrometer total ozone column measurements in Sodankylä., Geosci. Instrum. Method. Data Syst., 5, 229-239, doi:10.5194/gi-5-229-2016, 2016
  
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  Karppinen T, Redondas A, Garcia R.D., Lakkala K, McElroy C.T., Kyrö E., Compensating for the Effects of Stray Light in Single-Monochromator Brewer Spectrophotometer Ozone Retrieval, ATMOSPHERE-OCEAN Volume: 53 Issue: 1 Pages: 66-73, 2015, DOI: 10.1080/07055900.2013.871499
  
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  Kauppi, A., Tuinder, O. N. E., Tukiainen, S., Sofieva, V., and Tamminen, J.: Comparison of GOME-2/Metop-A ozone profiles with GOMOS, OSIRIS and MLS measurements, Atmos. Meas. Tech., 9, 249-261, doi:10.5194/amt-9-249-2016, 2016
  
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  Keppens, A., et al., Round-robin evaluation of nadir ozone profile retrievals: Methodology and application to MetOp-A GOME-2, Atmos. Meas. Tech., 8, 2093-2120, 2015
  
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  Kujanpää, J. and Kalakoski, N.: Operational surface UV radiation product from GOME-2 and AVHRR/3 data, Atmos. Meas. Tech., 8, 4399-4414, doi:10.5194/amt-8-4399-2015, 2015.
  
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  Kyrö E, et al., Bipolar Finnish research activities in Marambio and Sodankylä since the first Marambio ozone-soundings in 1988, abstract in SCAR open science conference, Auckland, New Zealand 25.-28.8.2014, 2014
  
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  Laine, M., N. Latva-Pukkila, and E. Kyrölä. Analyzing time varying trends in stratospheric ozone time series using state space approach. Atmospheric Chemistry & Physics, 14(18):9707–9725, 2014
  
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  Lakkala K, Asmi E, Meinander O, Hamari B, Redondas A, Almansa F, Carreno V, Ochoa H, Deferrari G Observations from the NILU-UV Antarctic network since 2000 abstract in SCAR open science conference, Auckland, New Zealand 25.-28.8.2014, 2014
  
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  Lakkala K, Heikkilä A, Kärhä P, Ialongo I, Karppinen T, Karhu J, Lindfors A, Meinander O.,25 Years of Spectral UV Measurements at Sodankylä, Accepted to be published in the Proceedings of the International Radiation Symposium 2016 held in Auckland, New Zealand, 16-22 April, 2016, 2016
  
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  Lakkala K, Jaros A, Aurela M, Tuovinen J-P, Kivi R, Suokanerva H, Karhu J, Laurila T, Radiation measurements at the Pallas-Sodankylä Global Atmosphere Watch station - diurnal and seasonal cycles of ultraviolet, global and photosynthetically-active radiation, Boreal Env. Res. 21: 427-444. ISSN 1797-2469, 2016
  
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  Lakkala K, Meinander O, Redondas A, Cuevas E, Torres C, Deferrari G, Ochoa H. UV measurements in the Antarctic, In: FINNARP. Science and Support in Antarctica. Finnish Antarctic Research Program (FINNARP), ISBN 978-951-697-841-6, 2014
  
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  Lakkala K, Suokanerva H, Karhu J, Aarva A, Poikonen A, Karppinen T, Ahponen M, Hannula H, Kontu A, Kyrö E., Optical laboratory facilities at the Finnish Meteorological Institute ? Arctic Research Centre, Geosci. Instrum. Method. Data Syst., 5, 315?320, 2016, doi:10.5194/gi-5-315-2016, 2016
  
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  Lakkala K., Koskela T., Kärhä P. Irradiance scale of long term UV measurements at Sodankylä and Jokioinen, Finland. Abstract EAO_PO_003 to NEWRAD 2014 Conference 24 - 27 June, Aalto Universit95(7), S121-S123, 2014, Espoo, 2014
  
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  Madonna, F., Rosoldi, M., Güldner, J., Haefele, A., Kivi, R., Cadeddu, M. P., Sisterson, D., and Pappalardo, G.: Quantifying the value of redundant measurements at GRUAN sites, Atmos. Meas. Tech., 7, 3813-3823, 2014.
  
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  Meinander O. Effects of black carbon and Icelandic dust on snow albedo, melt and density. PhD thesis. Finnish Meteorological Institute Contributions 125, 122 p., 978-951-697-895-9 (paperback), 78-951-697-896-6 (pdf), Erweko, Helsinki, 2016.
  
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  Mäkelä J.S., et al., Data flow of spectral UV measurements at Sodankylä and Jokioinen, Geosci. Instrum. Method. Data Syst., 5, 193-203, doi:10.5194/gi-5-193-2016, 2016., 2016
  
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  Orphal, J., et al.. Absorption cross-sections of ozone in the ultraviolet and visible spectral regions: Status report 2015. Journal of Molecular Spectroscopy, 327:105– 121, September 2016.
  
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  Päivärinta, S.-M., Verronen, P.T., Funke, B., Gardini, A., Seppälä, A. and Andersson, M.E., Transport vs. energetic particle precipitation: Northern polar stratospheric NOx and ozone in January-March 2012, J. Geophys. Res. Atmos., 121, 6085-6100, http://dx.doi.org/10.1002/2015JD024217, 2016.
  
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  Pulli T, Kärhä P, Karppinen T, Karhu J, Lakkala K, Vaskuri A, Shpak M, Mes J., Out-of-range stray light characterization of single-monochromator Brewer spectrophotometer, UVNews, The official newsletter of the Thematic Network for Ultraviolet Measurement, Issue 11 / March 2016, p. 20-23, 2016
  
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  Rahpoe, N., et al.: Relative drifts and biases between six ozone limb satellite measurements from the last decade, Atmos. Meas. Tech., 8, 4369-4381, doi:10.5194/amt-8-4369-2015, 2015.
  
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  Ryan N.J, Walker K.A, Raffalski U, Kivi R, Gross J, Manney G.L, Ozone profiles above Kiruna from two ground-based radiometers, Atmos. Measur. Techniq. v9 p4503-4519. doi: 10.5194/amt-9-4503-2016, 2016
  
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  Seppälä, A., M.A. Clilverd, M.J. Beharrell, C.J. Rodger, P.T. Verronen, M.E. Andersson and D.A. Newnham, Substorm-induced energetic electron precipitation: Impact on atmospheric chemistry, Geophys. Res. Lett., 42, 8172-8176, http://dx.doi.org/10.1002/2015GL065523, 2015.
  
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  Sofieva, V. F. et al.: Improved GOMOS/Envisat ozone retrievals in the upper troposphere and the lower stratosphere, Atmos. Meas. Tech., 10, 231-246, doi:10.5194/amt-10-231-2017, 2017
  
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  Sofieva, V. F., J. Tamminen, E. Kyrölä, T. Mielonen, P. Veefkind, B. Hassler, and G. E. Bodeker. A novel tropopause-related climatology of ozone profiles. Atmospheric Chemistry & Physics, 14:283–299, 2014a.
  
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  Sofieva, V.F., et al. Validation of GOMOS ozone precision estimates in the stratosphere. Atmospheric Measurement Techniques, 7:2147–2158, 2014b.
  
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  Sofieva, V. F., Kalakoski, N., Päivärinta, S.-M., Tamminen, J., Kyrölä, E., Laine, M., and Froidevaux, L.(2014c): On sampling uncertainty of satellite ozone profile measurements, Atmos. Meas. Tech., 7, 1891-1900, doi:10.5194/amt-7-1891-2014, 2014c,
  
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  Thölix, L., Backman, L., Kivi, R., and Karpechko, A. Yu.: Variability of water vapour in the Arctic stratosphere, Atmos. Chem. Phys., 16, 4307-4321, doi:10.5194/acp-16-4307-2016, 2016.
  
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  Tukiainen, S. On the retrieval of atmospheric profiles, PhD thesis, University of Helsinki, 2016, https://helda.helsinki.fi/handle/10138/166538
  
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  Tukiainen, S., E. Kyrölä, J. Tamminen, J. Kujanpaa, and L. Blanot. Gomos bright limb ozone data set. Atmospheric 
Measurement Techniques, 8(8): 3107–3115, 2015.
  
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  Tummon, F., et al. Intercomparison of vertically resolved merged satellite ozone data sets: interannual variability and long-term trends. Atmospheric Chemistry & Physics, 15:3021– 3043, March 2015.
  
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  Turunen, E., Kero, A., Verronen, P.T., Miyoshi, Y., Oyama, S. and Saito, S., Mesospheric ozone destruction by high-energy electron precipitation associated with pulsating aurora, J. Geophys. Res. Atmos., 121, 11852-11861, http://dx.doi.org/10.1002/2016JD025015, 2016.
  
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  Vanhellemont, F. et al.: Aergom, an improved algorithm for stratospheric aerosol extinction retrieval from GOMOS observations – part 1: Algorithm description. Atmos. Measur. Techniques, 9(9):4687–4700, 2016.
  
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  Vaskuri A., Kärhä P., Heikkilä A., and Ikonen E., 2017. Facility for Determining Action Spectra of UV Photodegradation. In: R. Davies, L. Egli & W. Schmutz (eds.), Proceedings of the International Radiation Symposium 2016 16-22 April, 2016, Auckland, New Zealand. AIP Publishing. Accepted for publication.
  
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  Vaskuri, A., Kärhä, P., Heikkilä, A. & Ikonen, E. 2015, High-resolution setup for measuring wavelength sensitivity of photoyellowing of translucent materials, Review of Scientific Instruments, v86, N10, pp. 103103.
  
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  Verronen, P.T. and Lehmann, R., Enhancement of odd nitrogen modifies mesospheric ozone chemistry during polar winter, Geophys. Res. Lett., 42, 10445-10452, http://dx.doi.org/10.1002/2015GL066703, 2015.
  
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  Zerefos C.S., et al. 2017. Detecting volcanic sulfur dioxide plumes in the Northern Hemisphere using the Brewer spectrophotometers, other networks, and satellite observations. Atmos. Chem. Phys. 17, 551-574.
  
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  Zhang, Y., Y. Liu, C. Liu, and V. F. Sofieva (2015), Satellite measurements of the Madden–Julian oscillation in wintertime stratospheric ozone over the Tibetan Plateau and East Asia, Adv. Atmos. Sci., 32(11), 1481–1492, doi:10.1007/s00376-015-5005-y [online]
  

The major national funding organisations are the Academy of Finland and Tekes, the Finnish Funding Agency for Innovation. Both of them have partially funded the ozone research in Finland in addition to FMI. FMI collaborates with Finnish universities and Research Institutes on atmospheric modelling and developing data retrieval methods, assimilation techniques for the satellite instruments and UV effect research. FMI has worked to enhance multidisciplinary UV research in Finland by organizing a national seminar on UV effects. The idea is to organize the seminar every second year in the future. FMI representative (Anu Heikkilä) has been nominated as a member in the UV-SAG (Scientific Advisory Group for Solar UV Radiation) of WMO (World Meteorological Organization). FMI representative (Anu Heikkilä) has been also invited as a full panel member in the UNEP-EEAP (United Nations Environmental Program – Environmental Effects Assessment Panel).FMI is chairing the Nordic Ozone and UV WG of the NORDMET since 2015.

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  ASTREX (Advanced Analyses of Stratosphere- Troposphere Exchange) (ended)
  
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  A4 - Arctic Absorbing Aerosols and Albedo of Snow, 2012-2016, http://en.ilmatieteenlaitos.fi/a4-project
  
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  UTLS WaVa (Arctic upper troposphere lower stratosphere water vapour) (ended)
  
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  COOL (Aerosol intervention technologies to cool the climate: costs, benefits, side effects, and governance) (ended)
  
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  Match: an international project, coordinated by AWI, to measure stratospheric ozone loss
  
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  GRUAN (GCOS Reference Upper-Air Network)
  
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  EMRP project ATMOZ - Traceability for atmospheric total column ozone
  
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  ICASIF (Influence of Clouds and atmospheric Aerosols on Solar energy in India and Finland) – principal financier: Academy of Finland
  
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  UVEMA (Effects of UV radiation on Materials, uvema.fmi.fi/)
  
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  MACC-II (EU project, FMI participating in task related to UV-radiation)
  
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  NABCEA - Novel Assessment of Black Carbon in the Eurasian Arctic: From Historical Concentrations and Sources to Future Climate Impacts, 2016-2020
  
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  O3M-SAF (EUMETSAT’s Satellite application facility on ozone and atmospheric chemistry): (http://o3msaf.fmi.fi)
  
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  IGACO-O3/UV secretariat (WMO and GAW-ozone): IGACO (International Global Atmospheric Chemistry Observations) is a strategy which aims for bringing together ground-based, aircraft and satellite observations of 13 chemical species in the atmosphere. The implementation of IGACO-O3/UV has been organized through the Global Atmospheric Watch (GAW) programme of WMO. Everyday work during 2005 - 2015 has been coordinated by WMO jointly with a secretariat hosted by FMI with a Memorandum of Understanding with the WMO. The implementation plan of IGACO-O3/UV was published in 2008 (http://www.igaco-o3.fi/linked/en/IGACO-O3_UV_Implementation_Plan.pdf). During the last years IGACO-O3/UV has concentrated on two activities: ACSO (Absorption Cross Sections of Ozone, http://igaco-o3.fmi.fi/ACSO) and SI2N (SPARC-IO3C-IGACO-O3-NDACC initiative on Past Changes on Vertical Distribution of Ozone, http://igaco-o3.fmi.fi/VDO/).
  
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  ACSO (Absorption cross sections of ozone, IGACO-O3/UV activity): Review the presently available ozone absorption cross sections. Determine the impact of changing the reference ozone absorption cross sections for all of the commonly used (both ground-based and satellite) atmospheric ozone monitoring instruments. Recommend whether a change needs to bemade to the presently used WMO/IO₃C standard ozone absorption cross section data
  
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  Ozone_cci (ESA Climate Change Initiative) aimed at the creation of homogenized and merged ozone profile datasets based on limb or occultation measurements from ESA and ESA Third Party Mission instruments. Six instruments that provide long-term measurements are involved in this project. Three of them are on board Envisat: GOMOS, MIPAS and SCIAMACHY; two of them are on board Odin: OSIRIS and SMR, and one is on board the SCISAT-1 satellite: ACE-FTS. FMI is responsible for creating Level 3 datasets.
  
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  EUBREWNET (EUropean BREWer NETwork, COST Action ES1207 for the years 2012-2017 whose main objective is to establish a coherent network of European Brewer Spectrophotometer stations to harmonise and develop approaches, practices and protocols to achieve consistency in quality control, quality assurance and coordinated operations.)
  
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  SI2N (Past changes in vertical distribution of ozone, SPARC, IO3C, IGACO-O3, NDACC initiative) (ended)
  
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  PP-TROPOMI (Processor prototype studies for TROPOMI, Tekes funded)
  
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  SPIN (ESA funded project, GOMOS ozone data and time series) (ended)
  
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  MesosphEO (http://mesospheo.fmi.fi/index.html) is a project of European Space Agency (ESA) The aim is to provide the atmospheric science community a comprehensive data set of Level 2-4 mesospheric data products covering a time period of at least 10 years from the satellite instruments on ENVISAT (GOMOS, MIPAS, SCIAMACHY), on Odin (OSIRIS, SMR), and on SCISAT (ACE-FTS).
  
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  The ESA ALGOM project (https://earth.esa.int/web/sppa/activities/instrument-characterization-studies/algom) consists of different Level 2 studies aimed at the improvement of the quality of the GOMOS products: Improvement of the algorithm for O₃ retrievals in the UTLS, improvements of the algorithms for H₂O and O₂ retrievals, design a new algorithm for minor species using averaged transmissions, user friendly GOMOS Level 2 data.
  
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  SPARC Data Initiative (http://www.sparc-climate.org/data-center/data-access/sparc-data-initiative/) The goal of the SPARC Data Initiative is to improve our knowledge and understanding of the overall uncertainty in chemical trace gas and aerosol observations from limb-viewing satellite instruments. The SPARC Data Initiative Team, which consists of representatives from each instrument team and data analysts, has compiled zonal mean monthly mean time series of all available chemical trace gas and aerosol data in a common format (NetCDF). FMI has participated providing GOMOS data sets.
  
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  ESA Climate Change Initiative project (Ozone_cci, http://www.esa-ozone-cci.org) aimed at the creation of homogenized and merged ozone profile datasets based on limb or occultation measurements from ESA and ESA Third Party Mission instruments. FMI is responsible for creating Level 3 datasets.
  

FMI aims to maintain its ongoing measurement programs and research activities in the Arctic and the Antarctic through nationally and internationally funded projects. The new GUV measurements in Marambio will continue the long-term UV time series. The continuation of the time series deals with two important topics: 1) long term stratospheric changes and 2) the atmospheric radiation budget in Polar Regions, specifically UV radiation. The work is in part dealing with the collection of key environmental datasets at Antarctica (ozone profiles, UV radiation), but emphasis is also put on the data analysis and utilization of data in modelling studies. The long-term observational data sets of ozone and UV are important for monitoring purposes supporting the Montreal Protocol. Our research also fits the scientific topics given by the international Scientific Committee on Antarctic Research (SCAR) on Antarctica and Climate. The future work on Snow UV albedo can offer a new potentially significant application of UV radiation measurements to reveal UV-absorbing impurities in snow, including the climatically significant soot (Black Carbon, BC) particles.

Although the basic processes related to stratospheric ozone are now believed to be fairly well understood, there remain important research topics related to ozone and UV, such as the interaction between ozone depletion/recovery and climate change and the effects of UV-irradiance on nature, human health, agriculture, and on materials. Also, future ozone recovery scenarios contain many uncertainties. Therefore it is important to ensure the continuity of long-term observational data sets of ozone and UV.