AT National Report for the Ozone Research Managers …



AUSTRIA

National Report for the 10th WMO/UNEP Ozone Research Managers Meeting

1. OBSERVATION ACTIVITIES

Long-term monitoring activities with respect to ozone column and UV are performed in Austria by Universities, especially by the Institute of Meteorology at the University of Natural Resources and Life Sciences Vienna (BOKU-Met) and by the Division of Biomedical Physics at the Medical University of Innsbruck (iMED-Phys). Activities have been financed since the early 1990ies by the Federal Ministry responsible for the environment – currently the Federal Ministry for Agriculture, Forestry, Environment and Water Management.

1.1 Column measurements of ozone and other gases/variables relevant to ozone loss

1.1.1 Brewer Spectrophotometer

Measurement of total ozone by the Brewer MkIV #93 Spectrophotometer at the high altitude station Hoher Sonnblick by BOKU-Met has been initiated in 1993. A time series of daily observations of total ozone is available from 1994 onwards.

The observatory at Hoher Sonnblick provides meteorological data from uninterrupted observations starting in 1886. Due to its remote location, largely uninfluenced by tropospheric confounding factors and human activity, it has grown to an environmental monitoring and research station in the 80ies of the last century. It hosts a. o. various measurements of radiation and atmospheric components. Having been a regional GAW station for a long time, it has become a global station in 2016.

|Location |Lat/Lon |Altitude |Instrument |Start |

|Hoher Sonnblick |47.05°N, 12.95°E |3106 m asl |Brewer Mk IV No. 093 |1994 |

1.2 Profile measurements of ozone and other gases/variables relevant to ozone loss

Apart from measurements of total ozone, measurements of the vertical distribution of ozone have been carried out with the Brewer spectrophotometer by applying the Umkehr retrieval algorithm UMK04 (Petropavlovskikh et al., 2005). The comparison between Brewer observations and the space-borne EOS MLS (NASA Earth Observing System Microwave Limb Sounder onboard the Aura satellite) data showed good agreement with low bias.

Figure 1 shows the climatological seasonal Umkehr profiles for the period from 1994 to 2011. The seasonal changes in the topmost layers’ contributions are generally smaller, not exceeding −0.8% in spring and summer and +0.6% during fall. These numbers underpin the importance of (mainly dynamically induced) changes in ozone concentrations in the lower layers, as opposed to the upper layers, which contribute considerably less to total ozone column.

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Fig. 1: Climatological Umkehr profiles, seasonal means (black line) and mean over the

whole year (dashed line, grey) for spring, summer, fall and winter.

1.3 UV measurements

1.3.1 Broadband measurements

A network for the monitoring of erythemal UV radiation in Austria has been established in the 1990ies by iMED-Phys. Currently the network consists of 13 UV biometers distributed all over Austria, at altitudes between 150 and 3100 m asl. Continuous time series are available starting with 1997. The monitoring is performed in co-operation with the Department for Biomedical Sciences of the University of Veterinary Medicine Vienna, the Institute of Physics of the University of Graz, BOKU-Met, the Austrian Met Office (ZAMG) and the Federal Environment Agency (Umweltbundesamt).

In addition, monitoring of UV-A (310–400 nm, global radiation and diffuse radiation) has started in 2012 at three stations.

|Location |Lat/Lon |Altitude |Instrument |Start (–End) |

|Wien |48.26°N, 16.43°E |153 m asl |Solar Light Mod. 501 |1999 |

|Wien |-“- |-“- |CMS Schreder J1034 |2012 |

|Grossenzersdorf |48.20°N, 16.57°E |156 m asl |Solar Light Mod. 501 |2009 |

|Bad Vöslau |47.97°N, 16.20°E |286 m asl |Solar Light Mod. 501 |1997 |

|Steyregg |48.29°N, 14.35°E |335 m asl |Solar Light Mod. 501 |1997 |

|Graz |47.10°N, 15.42°E |348 m asl |Solar Light Mod. 501 |1997 |

|Dornbirn |47.43°N, 9.73°E |410 m asl |Solar Light Mod. 501 |1997 |

|Klagenfurt |46.65°N, 14.32°E |448 m asl |Solar Light Mod. 501 |1997 |

|Kirchbichl |47.49°N, 12.09°E |526 m asl |Solar Light Mod. 501 |2016 |

|Kirchbichl |-“- |-“- |GigaHertz Optik UVA |2016 |

|Innsbruck |47.26°N, 11.38°E |577 m asl |Solar Light Mod. 501 |1998 |

|Innsbruck |-“- |-“- |GigaHertz Optik UVA |2012–16 |

|Mariapfarr |47.15°N, 13.75°E |1153 m asl |Solar Light Mod. 501 |1998 |

|Gerlitzen |46.68°N, 13.91°E |1526 m asl |Solar Light Mod. 501 |2005 |

|Gerlitzen |-“- |-“- |CMS Schreder J1034 |2012 |

|Hafelekar |47.32°N, 11.39°E |2275 m asl |Solar Light Mod. 501 |2009 |

|Hoher Sonnblick |47.05°N, 12.95°E |3106 m asl |Solar Light Mod. 501 |1998 |

1.3.2 Spectroradiometers

Monitoring of spectral UV irradiance by BOKU-Met with Bentham instruments has been initiated in the second half of the 1990ies. Measurements are performed at two quite different stations in Austria: At Hoher Sonnblick (see above) and at a station in the east of Austria in the vicinity of an urban agglomeration (Grossenzersdorf). The stations are part of the NDACC.

|Location |Lat/Lon |Altitude |Instrument |Start |

|Grossenzersdorf |48.20°N, 16.57°E |156 m asl |Bentham DM 150 |1998 |

|Hoher Sonnblick |47.05°N, 12.95°E |3106 m asl |Bentham DM 150 |1997 |

1.4 Calibration activities

Calibration of the Bentham instruments with a self-built secondary 1000 W FEL lamp assembly is performed every one to two months over the whole measurement range of 290-500 nm. The secondary lamp itself is regularly calibrated to a NIST (National Institute of Standards and Technology, United States) and a PTB (Physikalisch-Technische Bundesanstalt, Germany) calibrated 1000 W lamp at the optical laboratory of BOKU-Met and in the laboratory facility in Großenzersdorf.

Calibration of the Brewer instrument with a 50 W standard lamp is performed periodically by BOKU-Met. Calibration against the standard instrument #017 is performed by the International Ozone Service Ltd. every three years. Since 2009 both Bentham UV spectrophotometers are part of NDACC, fulfilling the network’s tight requirements in quality control and assurance. Intercomparison campaigns for the portable Bentham instrument are performed on a regular basis and were last conducted 2014 in Hannover, Germany. The results of the intercomparison show that the spectral irradiance measured by the BOKU-Met instrument deviates less than 3% from the reference instrument for a large variety of measuring conditions, which is well within the NDACC specifications and is very satisfactory

Annual calibration of the UV broadband sensors is performed by CMS Schreder () in the laboratory and by comparison with a national standard spectroradiometer. Intercomparison of the national standard with the travelling standard QASUME from PMOD/WRC has been done in 2010 and 2015.

2. RESULTS FROM OBSERVATIONS AND ANALYSIS

The UV-Index data since 1998 together with measurements of global radiation and ozone levels from OMI are used to study long term trends for the stations of the monitoring network. Besides a strong variability from year to year, no statistically significant trend is found for the UV-Index and for ozone neither for all weather conditions nor for clear sky conditions (cf. Fig. 2).

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Fig. 2: Annual mean values (dots) of UV-Index, ozone and global radiation (G) for all weather conditions (left) and for days with clear sky conditions (right) at 19° solar elevation in Innsbruck, normalized to the respective mean value over 18 years. Straight lines show the linear fit.

The relation between UV-Index and ozone level can be expressed with the radiation amplification factor RAF in the power law formulation UVI ( O3-RAF. For Innsbruck at 19° solar elevation a value of 0.91+0.05 was found for low ground albedo and 1.03+0.08 for days with high ground albedo due to snow cover.

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Fig. 3: Relation between UV-Index and ozone column

Continuous long-term measurements of ozone and spectral UV radiation have been investigated for estimates of trends and long-term changes. Trend estimates for total ozone measured by the Brewer spectrophotometer were realized with monthly mean anomalies of detrended total ozone data. With +0.3±1.0 %/dec the year round trend of total ozone in Fig. 4 shows little increase and no significance (≤ 95 %).

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Fig. 4: Left: total ozone measured with the Brewer MkIV #93 spectro-photometer between 1994 and 2016 and monthly means; Right: year round trend estimates of monthly mean anomalies of total ozone

Figure 5 shows the complete series of measurements of erythemal radiation at Hoher Sonnblick from 1994 to 2016. The diurnal variation with maxima during summer and minima during winter is clearly visible.

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Fig. 5: Daily erythemal dosis from Brewer MkIV #093 spectrophotometer between 1994 and 2016

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Fig. 6: Year-round trend estimates in monthly mean anomalies at Hoher Sonnblick

at three selected wavelengths and ERY; solid red lines indicate trend,

significance is given for 95 % (*), 99 % (**), and 99.9 % (***)

Long-term records of spectral UV irradiance from Bentham spectroradiometer measured at the high-altitude mountain site Hoher Sonnblick from the period 1997–2016 have been investigated for potential trends. Linear trend estimates were established using Sen’s Q method while the nonparametric Mann-Kendall trend test was used to assess the linear changes’ significance levels. The trend estimates were calculated for wavelengths between 305 nm (strong ozone absorption) and 325 nm (weak ozone absorption) and erythemally weighted irradiance (ERY) according to McKinlay and Diffey (1987). Fig. 6 shows the trend estimates of spectral UV irradiance on a basis of monthly mean anomalies, measured by the Bentham spectroradiometer for the period 1997–2016.

Significant upward trends are found at wavelengths of 315 and 325 nm and for erythemally weighted irradiance (ERY) with +9.8±2.1%/dec, +10.3±1.9%/dec and +9.7±2.3%/dec, respectively, and overall high significance (99.9%), while the trend at 305 nm is considerably smaller (+5.4±2.1%/dec) with less significance (95%).

Consequently, it is believed that the increases in UV irradiance are mainly caused by changes in cloudiness and aerosol optical depth (AOD) along with potential contributions to effective surface albedo through clouds below the observatory. It has also been found that the selection of the investigation period has a substantial influence on trend results and assessment. It can therefore be stated that prolonged, continuous high-quality measurement series still play a crucial role for the unambiguous assessment of ozone recovery and trends of surface UV radiation.

3. THEORY, MODELLING, AND OTHER OZONE RELATED RESEARCH

A new method was developed to combine the ground-based UV measurements with regional data about cloudiness from Meteosat and with radiative transfer modeling in order to calculate a map of the regional distribution of the UV-Index over Austria in near real time every 15 minutes.

Due to the impact of UV radiation on human health, an attempt was made to combine both meteorological and medical aspects of this subject (e.g. Haluza et al., 2014). As part of the project UVSkinRisk, studies of UV variability in the past, future estimations, influence of climate change and expected impacts on skin health risks, like skin cancer in Austria, have been carried out (Simic et. al, 2015). UV radiation from the past and the future has been modeled using meteorological standard observations and regional climate scenarios. A new approach has been chosen to estimate the UV exposure of humans by using a 3-dimensional model of a human body, considering the complex geometry of the radiation field (Schrempf et. al., 2016).

4. DISSEMINATION OF RESULTS

4.1 Data reporting

Data from the Austrian broadband measurements (erythemal radiation) are step by step reported to WOUDC. Data from the spectroradiometers are reported to the NDACC.

4.2 Information to the public

Daily total ozone values are published by BOKU-Met via teletext (television text service) and in the internet (). Near real-time UV-index data from the Austrian stations (and also from neighbouring countries) is made available in the internet by iMED-Phys, as well as an area-wide UV-Index map based on measurement, Meteosat cloud data and modelling ().

4.3 Relevant scientific papers

Blumthaler, M. (2004): Quality assurance and quality control methodologies within the Austrian UV monitoring network. Rad. Prot. Dos. 111, 359-362.

Blumthaler, M., Klotz, B., Schwarzmann, M. and Schreder, J. (2017): The Austrian UV monitoring network. AIP Conference Proceedings, International Radiation Symposium 2016, Auckland, New Zealand. In press.

Fitzka, M., Hadzimustafic, J. and Simic, S. (2014). Total ozone and Umkehr observations at Hoher Sonnblick 1994–2011: Climatology and extreme events. J. Geophys. Res.-Atmos. 119.2, 739-752.

Fitzka, M., Simic, S. and Hadzimustafic, J. (2012): Trends in spectral UV radiation from long-term measurements at Hoher Sonnblick, Austria. Theor. Appl. Climatol. 110.4, 585-593.

Haluza, D., Simic, S. and Moshammer, H. (2014): Temporal and spatial melanoma trends in Austria: an ecological study. Int. J. Environ. Res. Public Health. 11(1), 734-748.

Schallhart, B., Blumthaler, M., Schreder, J. and Verdebout, J. (2008): A method to generate near real time UV-Index maps of Austria. Atmos. Chem. Phys. 8, 7483-7491.

Schrempf, M., Haluza, D., Simic, S., Riechelmann, S., Graw, K. and Seckmeyer, G. (2016): Is Multidirectional UV Exposure Responsible for Increasing Melanoma Prevalence with Altitude? A Hypothesis Based on Calculations with a 3D-Human Exposure Model. Int. J. Environ. Res. Public Health, 13(10), 961.

Simic, S. (2015): UVSkinRisk- Health at risk through UV induced Skin Cancer in the Context of a Changing Climate. AUSTRIAN CLIMATE RESEARCH PROGRAMME in ESSENCE, 20-25.

Simic, S., Fitzka, M., Schmalwieser, A. , Weihs, P. and Hadzimustafic, J. (2011): Factors affecting UV irradiance at selected wavelengths at Hoher Sonnblick. Atmos. Res., 101(4), 869-878.

5. PROJECTS, COLLABORATION, TWINNING AND CAPACITY BUILDING

National Projects:

• Long-term measurements of total ozone and high-resolution spectral UV radiation at Hoher Sonnblick and Groß-Enzersdorf (STRATO-UV).

• Health at risk through UV induced Skin Cancer in the Context of a Changing Climate (UVSkinRisk).

• Analysis of total ozone and UV-radiation in Austria (UVKlim).

• Collaboration for the operation of measurement sites for the Austrian UV-B Network.

International Collaboration:

• The international Network for the Detection of Atmospheric Composition Change (NDACC).

• Global Atmosphere Watch (GAW).

• Close cooperation is established with PMOD/WRC in order to assure high quality of the calibration of the broadband UV detectors.

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Sonnblick observatory

© Michael Staudinger (ZAMG)

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