Long-term solar UV radiation reconstructed by ANN modelling with emphasis on spatial characteristics of input data

Feister, Uwe; Junk, Jürgen; Woldt, Michael; Bais, A. F.; Helbig, Alfred; Janouch, Michal; Josefsson, Weine; Kazantzidis, Andreas; Lindfors, Anders V.; Outer, P. N. den; Slaper, H.

doi:10.5194/acp-8-3107-2008

Cited by 29 publications

(34 citation statements)

References 14 publications

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“…The negative relative changes of irradiance during the 1980s and early 1990s suggest that total ozone, as simulated by the CCMs, had not reached its minimum until early 2000s. These changes in irradiance for the northern middle and high latitudes are generally smaller than ∼5% per decade, and they are in accordance with the changes reported for various locations over Europe from measured or reconstructed irradiance data (e.g., Krzyscin et al, 2004;Lindfors et al, 2007;den Outer et al, 2005;Feister et al, 2008;Rieder et al, 2008;Chubarova, 2008). The magnitude of the calculated changes in erythemal irradiance varies significantly, as a result of the variations in the predicted ozone columns from the CCMs.…”

Section: Methodology and Datasupporting

confidence: 69%

“…The variability of surface UV radiation in the past has been extensively investigated using both measured and reconstructed records (e.g., Lindfors et al, 2007;Lindfors and Vuilleumier, 2005;Feister et al, 2008;den Outer et al, 2005;Krzyscin et al, 2004;Rieder et al, 2008;Chubarova, 2008), showing increasing of UV irradiance in response to the observed ozone reductions in the 1980s and 1990s. Recent observations suggest that the concentration of ozone depleting substances in the atmosphere have started to decrease as a result of the measures taken under the Montreal Protocol and its Amendments and Adjustments (WMO, 2007).…”

Section: Introductionmentioning

confidence: 99%

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Clear sky UV simulations for the 21st century based on ozone and temperature projections from Chemistry-Climate Models

et al. 2009

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Abstract.We have estimated changes in surface solar ultraviolet (UV) radiation under cloud free conditions in the 21st century based on simulations of 11 coupled ChemistryClimate Models (CCMs). The total ozone columns and vertical profiles of ozone and temperature projected from CCMs were used as input to a radiative transfer model in order to calculate the corresponding erythemal irradiance levels. Time series of monthly erythemal irradiance received at the surface during local noon are presented for the period 1960 to 2100. Starting from the first decade of the 21st century, the surface erythemal irradiance decreases globally as a result of the projected stratospheric ozone recovery at rates that are larger in the first half of the 21st century and smaller towards its end. This decreasing tendency varies with latitude, being more pronounced over areas where stratospheric ozone Correspondence to: K. Tourpali (tourpali@auth.gr) has been depleted the most after 1980. Between 2000 and 2100 surface erythemal irradiance is projected to decrease over midlatitudes by 5 to 15%, while at the southern high latitudes the decrease is twice as much. In this study we have not included effects from changes in cloudiness, surface reflectivity and tropospheric aerosol loading, which will likely be affected in the future due to climate change. Consequently, over some areas the actual changes in future UV radiation may be different depending on the evolution of these parameters.

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Section: Methodology and Datasupporting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Clear sky UV simulations for the 21st century based on ozone and temperature projections from Chemistry-Climate Models

et al. 2009

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“…Even though the lowest values of ozone are during 1993, the relative increase in UVB and erythemally weighted UV doses are small in comparison with the range of inter-annual variation. The separation of the mean residuals is estimated at ∼5% which is similar to that seen in the reconstructed values of Feister et al (2008). However, in an earlier paper Feister and Grewe (1995) note a strong seasonal variation in the ozone reduction at Potsdam (52.37°N, 13.08°E) during 1993, so that these effects on the UV annual mean residuals will be somewhat masked.…”

Section: Uv Trendsmentioning

confidence: 57%

Total ozone and surface UV trends in the United Kingdom: 1979–2008

Smedley

Rimmer

Moore

et al. 2011

Intl Journal of Climatology

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ABSTRACT:In this study we present the UK's total ozone and UV data records, their measurement and preliminary processing, and discuss the observed trends. Notably, we combine the records from the Camborne and Reading sites to obtain a single ozone data series for southern England -a total duration of 30 years.Two-section linear trends and cross-over years are determined for Lerwick and southern England, both annually and seasonally. The observed minimum using this technique in the UK ozone record is found to occur during the year 1993. Significant trends of −4.8% per decade for southern England and −5.8% per decade for Lerwick are seen prior to the mid-1990s; the rate of decrease in the UK being at the upper limit of other European stations. No significant ozone trend is seen for the latter period in either location in contrast with Europe as a whole. We, additionally, compare the satellite-derived total ozone trends for both locations.The UV record at Reading showed a significant trend from 1993 to 2008 in the daily maximum UV index record (6.6% per decade), despite no significant recovery in the total ozone data series, suggesting a reduction in cloud cover during the midday period. Filtering data to remove other factors shows the erythemal UV to have an ozone-dependent trend of −0.11% per year, but this is not statistically significant. We find no correlation between anomalies in the surface UV and total ozone records suggesting that the majority of the inter-annual variability is due to changes in cloud cover and other effects.

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“…The ANNs have been employed in diverse applications and fields such as robotics, pattern recognition, forecasting, medicine, power systems, etc. In atmospheric science the use of ANNs is quite recent, for example, ANNs have been successfully used for estimating solar radiation values (Mohandes et al, 1998;Dorvlo et al, 2002;López et al, 2005;Feister and Junk, 2006;Junk et al, 2007;Feister et al, 2008;Paoli et al, 2009;Linares-Rodríguez et al, 2011 or cloud properties (González et al, 2002;Cerdeña et al, 2006). However, their use for AOD estimations is quite recent and limited to short periods.…”

Section: Introductionmentioning

confidence: 99%

Aerosol optical depth retrievals at the Izaña Atmospheric Observatory from 1941 to 2013 by using artificial neural networks

García

Cuevas

et al. 2016

Atmos. Meas. Tech.

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Abstract. This paper presents the reconstruction of a 73-year time series of the aerosol optical depth (AOD) at 500 nm at the subtropical high-mountain Izaña Atmospheric Observatory (IZO) located in Tenerife (Canary Islands, Spain). For this purpose, we have combined AOD estimates from artificial neural networks (ANNs) from 1941 to 2001 and AOD measurements directly obtained with a Precision Filter Radiometer (PFR) between 2003 and 2013. The analysis is limited to summer months (July-August-September), when the largest aerosol load is observed at IZO (Saharan mineral dust particles). The ANN AOD time series has been comprehensively validated against coincident AOD measurements performed with a solar spectrometer Mark-I (1984Mark-I ( -2009 and AERONET (AErosol RObotic NETwork) CIMEL photometers (2004)(2005)(2006)(2007)(2008)(2009) at IZO, obtaining a rather good agreement on a daily basis: Pearson coefficient, R, of 0.97 between AERONET and ANN AOD, and 0.93 between Mark-I and ANN AOD estimates. In addition, we have analysed the long-term consistency between ANN AOD time series and long-term meteorological records identifying Saharan mineral dust events at IZO (synoptical observations and local wind records). Both analyses provide consistent results, with correlations > 85 %. Therefore, we can conclude that the reconstructed AOD time series captures well the AOD variations and dust-laden Saharan air mass outbreaks on shortterm and long-term timescales and, thus, it is suitable to be used in climate analysis.

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Long-term solar UV radiation reconstructed by ANN modelling with emphasis on spatial characteristics of input data

Cited by 29 publications

References 14 publications

Clear sky UV simulations for the 21st century based on ozone and temperature projections from Chemistry-Climate Models

Clear sky UV simulations for the 21st century based on ozone and temperature projections from Chemistry-Climate Models

Total ozone and surface UV trends in the United Kingdom: 1979–2008

Aerosol optical depth retrievals at the Izaña Atmospheric Observatory from 1941 to 2013 by using artificial neural networks

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