<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD Journal Publishing DTD v3.0 20080202//EN" "http://dtd.nlm.nih.gov/publishing/3.0/journalpublishing3.dtd">
<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" article-type="research-article" dtd-version="3.0" xml:lang="en">
<front>
<journal-meta>
<journal-id journal-id-type="publisher">ACP</journal-id>
<journal-title-group>
<journal-title>Atmospheric Chemistry and Physics</journal-title>
<abbrev-journal-title abbrev-type="publisher">ACP</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub">1680-7324</issn>
<publisher><publisher-name>Copernicus GmbH</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/acp-10-5979-2010</article-id>
<title-group>
<article-title>Comparison of UV irradiances from Aura/Ozone Monitoring Instrument (OMI) with Brewer measurements at El Arenosillo (Spain) – Part 1: Analysis of parameter influence</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Antón</surname>
<given-names>M.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff7">
<sup>7</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Cachorro</surname>
<given-names>V. E.</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Vilaplana</surname>
<given-names>J. M.</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Toledano</surname>
<given-names>C.</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Krotkov</surname>
<given-names>N. A.</given-names>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
<xref ref-type="aff" rid="aff6">
<sup>6</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Arola</surname>
<given-names>A.</given-names>
</name>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Serrano</surname>
<given-names>A.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>de la Morena</surname>
<given-names>B.</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Departamento de Física, Universidad de Extremadura, Badajoz, Spain</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Grupo de Óptica Atmosférica, Universidad de Valladolid GOA-UVA, Valladolid, Spain</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>ESAt &quot;El Arenosillo&quot;, INTA, Huelva, Spain</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>GEST Center, University of Maryland, Baltimore County, Maryland, USA</addr-line>
</aff>
<aff id="aff5">
<label>5</label>
<addr-line>Finnish Meteorological Institute (FMI), Kuopio, Finland</addr-line>
</aff>
<aff id="aff6">
<label>6</label>
<addr-line>Laboratory of Atmosphere, NASA/Goddard Space Flight Center, Greenbelt, Maryland, USA</addr-line>
</aff>
<aff id="aff7">
<label>7</label>
<addr-line>now at: Departamento de Física Aplicada, Universidad de Granada, Granada, Spain</addr-line>
</aff>
<pub-date pub-type="epub">
<day>05</day>
<month>07</month>
<year>2010</year>
</pub-date>
<volume>10</volume>
<issue>13</issue>
<fpage>5979</fpage>
<lpage>5989</lpage>
<permissions>
<license xlink:type="simple">
<license-p>This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.</license-p>
</license>
</permissions>
<self-uri xlink:href="http://www.atmos-chem-phys.net/10/5979/2010/acp-10-5979-2010.html">This article is available from http://www.atmos-chem-phys.net/10/5979/2010/acp-10-5979-2010.html</self-uri>
<self-uri xlink:href="http://www.atmos-chem-phys.net/10/5979/2010/acp-10-5979-2010.pdf">The full text article is available as a PDF file from http://www.atmos-chem-phys.net/10/5979/2010/acp-10-5979-2010.pdf</self-uri>
<abstract>
<p>The main objective of this study is to compare the erythemal UV irradiance
(UVER) and spectral UV irradiances (at 305, 310 and 324 nm) from the Ozone
Monitoring Instrument (OMI) onboard NASA EOS/Aura polar sun-synchronous
satellite (launched in July 2004, local equator crossing time 01:45 p.m.) with
ground-based measurements from the Brewer spectrophotometer #150 located
at El Arenosillo (South of Spain). The analyzed period comprises more than
four years, from October 2004 to December 2008. The effects of several
factors (clouds, aerosols and the solar elevation) on OMI-Brewer comparisons
were analyzed. The proxies used for each factor were: OMI Lambertian
Equivalent Reflectivity (LER) at 360 nm (clouds), the aerosol optical depth
(AOD) at 440 nm measured from the ground-based Cimel sun-photometer
(&lt;a href=&quot;http://aeronet.gsfc.nasa.gov&quot;target=&quot;_blank&quot;&gt;http://aeronet.gsfc.nasa.gov&lt;/a&gt;), and solar zenith angle (SZA) at OMI overpass
time.
The comparison for all sky conditions reveals positive biases (OMI higher
than Brewer) 12.3% for UVER, 14.2% for UV irradiance at 305 nm,
10.6% for 310 nm and 8.7% for 324 nm. The OMI-Brewer root mean square
error (RMSE) is reduced when cloudy cases are removed from the analysis,
(e.g., RMSE~20% for all sky conditions and RMSE smaller than 10%
for cloud-free conditions). However, the biases remain and even become more
significant for the cloud-free cases with respect to all sky conditions. The
mentioned overestimation is partially due to aerosol extinction influence.
In addition, the differences OMI-Brewer typically decrease with SZA except
days with high aerosol loading, when the bias is near constant. The seasonal
dependence of the OMI-Brewer difference for cloud-free conditions is driven
by aerosol climatology.
&lt;br&gt;&lt;br&gt;
To account for the aerosol effect, a first evaluation in order to compare
with previous TOMS results (Antón et al., 2007) was performed. This
comparison shows that the OMI bias is between +14% and +19% for UVER
and spectral UV irradiances for moderately-high aerosol load (AOD&gt;0.25).
The OMI bias is decreased by a factor of 2 (the typical bias varies from
+8% to +12%) under cloud-free and low aerosol load conditions
(AOD&lt;0.1). More detailed analysis of absorbing aerosols influence on OMI
bias at our station is presented in a companion paper (Cachorro et al.,
2010).</p>
</abstract>
<counts><page-count count="11"/></counts>
</article-meta>
</front>
<body/>
<back>
<ref-list>
<title>References</title>
<ref id="ref1">
<label>1</label><mixed-citation publication-type="other" xlink:type="simple"> % vor jede Referenz Antón, M., Cachorro, V. E. , Vilaplana, J. M.,. Krotkov, N. A, Serrano, A., Toledano, C., de la Morena, B., and Herman, J. R.: Total ozone mapping spectrometer retrievals of noon erythemal-CIE ultraviolet irradiance compared with Brewer ground-based measurements at El Arenosillo (southwestern Spain), J. Geophys. Res., 112, D11206, doi:10.1029/2006JD007254, 2007. </mixed-citation>
</ref>
<ref id="ref2">
<label>2</label><mixed-citation publication-type="other" xlink:type="simple"> Antón, M., Serrano, A., Cancillo, M. L., Vilaplana, J. M., Cachorro, V. E., and Gröbner, J.: Correction of angular response error in Brewer UV irradiance measurements, J. Atmos. Ocean. Tech., 25, 2018–2017, doi:10.1175/2008JTECHA1040.1, 2008. </mixed-citation>
</ref>
<ref id="ref3">
<label>3</label><mixed-citation publication-type="other" xlink:type="simple"> Antón, M., López, M., Vilaplana, J. M., Kroon, M., McPeters, R., Bañón, M., and Serrano, A. : Validation of OMI-TOMS and OMI-DOAS total ozone column using five Brewer spectroradiometers at the Iberian Peninsula, J. Geophys. Res., 114, D14307, doi:10.1029/2009JD012003, 2009. </mixed-citation>
</ref>
<ref id="ref4">
<label>4</label><mixed-citation publication-type="other" xlink:type="simple"> Arola, A., Kazadzis, S., Krotkov, N., Bais, A., Gröbner, J., and Herman, J. R.: Assessment of TOMS UV bias due to absorbing aerosols, J. Geophys. Res., 110, D23211, doi:10.1029/2005JD005913, 2005. </mixed-citation>
</ref>
<ref id="ref5">
<label>5</label><mixed-citation publication-type="other" xlink:type="simple"> Arola, A., Lindfors, A., Natunen, A., and Lehtinen, K. E. J.: A case study on biomass burning aerosols: effects on aerosol optical properties and surface radiation levels, Atmos. Chem. Phys., 7, 4257–4266, doi:10.5194/acp-7-4257-2007, 2007. </mixed-citation>
</ref>
<ref id="ref6">
<label>6</label><mixed-citation publication-type="other" xlink:type="simple"> Arola, A., Kazadzis, S., Lindfors, A., et al.: A new approach to correct for absorbing aerosols in OMI UV, Geophys. Res. Lett., 36, L22805, doi:10.1029/2009GL041137, 2009. </mixed-citation>
</ref>
<ref id="ref7">
<label>7</label><mixed-citation publication-type="other" xlink:type="simple"> Badarinath, K. V. S., Kharol, S. K., Kaskaoutis, D. G., and Kambezidis, H. D.: Influence of atmospheric aerosols on solar spectral irradiance in an urban area, J. Atmos. Sol.-Terr. Phys., 69, 589–599, 2007. </mixed-citation>
</ref>
<ref id="ref8">
<label>8</label><mixed-citation publication-type="other" xlink:type="simple"> Bhartia, P. K. and Wellemeyer, C. W.: TOMS-V8 total O3 algorithm, in: OMI Algorithm Theoretical Basis Document, vol. II, edited by: Bhartia, P. K., NASA Goddard Space Flight Cent., Greenbelt, Md., 15–32, available online at: http://www.knmi.nl/omi/documents/data/OMI_ATBD_Volume_2_V2.pdf, 2002. </mixed-citation>
</ref>
<ref id="ref9">
<label>9</label><mixed-citation publication-type="other" xlink:type="simple"> Bernard, W. F., Saxena V. K., Wenny B. N., and DeLuisi J. J.: Daily surface UV exposure and its relationship to surface pollutant measurements, J. Air Waste Manage. Assoc., 53, 237–245, 2003. </mixed-citation>
</ref>
<ref id="ref10">
<label>10</label><mixed-citation publication-type="other" xlink:type="simple"> Buchard, V., Brogniez, C., Auriol, F., Bonnel, B., Lenoble, J., Tanskanen, A., Bojkov, B., and Veefkind, P.: Comparison of OMI ozone and UV irradiance data with ground-based measurements at two French sites, Atmos. Chem. Phys., 8, 4517–4528, doi:10.5194/acp-8-4517-2008, 2008. </mixed-citation>
</ref>
<ref id="ref11">
<label>11</label><mixed-citation publication-type="other" xlink:type="simple"> Cachorro, V. E., Vergaz, R., de Frutos, A. M., Vilaplana, J. M., Henriques, D., Laulainen, N., and Toledano, C.: Study of desert dust events over the southwestern Iberian Peninsula in year 2000: two case studies, Ann. Geophys., 24, 1493–1510, doi:10.5194/angeo-24-1493-2006, 2006. </mixed-citation>
</ref>
<ref id="ref12">
<label>12</label><mixed-citation publication-type="other" xlink:type="simple"> Cachorro, V. E., Toledano, C. , Prats, N., Sorribas, M., Mogo, S., Berjón, A., Torres, B.,. Rodrigo, R , de Frutos, A. M., and de la Rosa, J.: The strongest desert dust intrusion mixed with smoke over the Iberian Peninsula registered with sun-photometry, J. Geophys. Res., 113, D14504, doi:10.1029/2007JD009582, 2008. </mixed-citation>
</ref>
<ref id="ref13">
<label>13</label><mixed-citation publication-type="other" xlink:type="simple"> Cachorro, V. E., Toledano, C., Antón, M., Berjón, A., de Frutos, A., Vilaplana, J. M., Arola, A., and Krotkov, N. A.: Comparison of UV irradiances from Aura/Ozone Monitoring Instrument (OMI) with Brewer measurements at El Arenosillo (Spain) – Part 2: Analysis of site aerosol influence, Atmos. Chem. Phys. Discuss., 10, 16385–16423, doi:10.5194/acpd-10-16385-2010, 2010. </mixed-citation>
</ref>
<ref id="ref14">
<label>14</label><mixed-citation publication-type="other" xlink:type="simple"> Cede, A., Luccini, E. , Nuñez, L., Piancetini, R. D., Blumthaler, M., and Herman, J. R.: TOMS-derived erythemal irradiance versus measurements at stations of Argentine UV Monitoring Network, J. Geophys. Res., 109, D08109, doi:10.1029/2004JD004519, 2004. </mixed-citation>
</ref>
<ref id="ref15">
<label>15</label><mixed-citation publication-type="other" xlink:type="simple"> Chubarova, N. Y.,. Yurova, A. Y, Krotkov, N.,. Herman, J. R, and Barthia, P. K: Comparison between ground measurements of broadband ultraviolet irradiance (300 to 380 nm) and total ozone mapping spectrometer ultraviolet estimates at Moscow from 1979 to 2000, Opt. Eng., 41, 3070–3081, 2002. </mixed-citation>
</ref>
<ref id="ref16">
<label>16</label><mixed-citation publication-type="other" xlink:type="simple"> Fioletov, V. E., Kimlin, M. G., Krotkov, N., McArthur, L. J. B., Kerr, J. B., Wardle, D. I., Herman, J. R., Meltzer, R., Mathews, T. W., and Kaurola, J.: UV index climatology over the United States and Canada from groundbased and satellite estimates, J. Geophys. Res., 109, D22308, doi:10.1029/ 2004JD004820, 2004. </mixed-citation>
</ref>
<ref id="ref17">
<label>17</label><mixed-citation publication-type="other" xlink:type="simple"> Gröbner, J., Schreder, J., Kazadzis, S., Bais, A. F., Blumthaler, M., Görts, P., Tax, R., Koskela, T., Seckmeyer, G., Webb, A. R., and Rembges, D.: Traveling reference spectroradiometer for routine quality assurance of spectral solar ultraviolet irradiance measurements, Appl. Opt., 44, 5321–5331, 2005. </mixed-citation>
</ref>
<ref id="ref18">
<label>18</label><mixed-citation publication-type="other" xlink:type="simple"> Holben, B. N., Eck, T. F., Slutsker, I., Tanré, D., Buis, J. P., Setzer., A., Vermote, E. F. Reagan, J. A., Kaufman, I. Y., Nakajima, T., Lavenu, F., Jankowiak, I., and Smirnov, A.: ERONET – A federated instrument network and data archive for aerosol characterization, Remote Sens. Environ., 66, 1–16, 1998. </mixed-citation>
</ref>
<ref id="ref19">
<label>19</label><mixed-citation publication-type="other" xlink:type="simple"> Ialongo, I., Casale, G. R., and Siani, A. M.: Comparison of total ozone and erythemal UV data from OMI with ground-based measurements at Rome station, Atmos. Chem. Phys., 8, 3283–3289, doi:10.5194/acp-8-3283-2008, 2008. </mixed-citation>
</ref>
<ref id="ref20">
<label>20</label><mixed-citation publication-type="other" xlink:type="simple"> Kalliskota, S., Kaurola, J., Taalas P., Herman, J., Celarier, E., and Krotkov, N. : Comparison of daily UV doses estimated from Nimbus 7/TOMS measurements and ground-based spectroradiometer data, J. Geophys. Res., 105, 4273–4277, 2000. </mixed-citation>
</ref>
<ref id="ref21">
<label>21</label><mixed-citation publication-type="other" xlink:type="simple"> Kaskaoutis, D. G., Kambezidis, H. D., Jacovides, C. P., and Steven, M. D: Modification of solar radiation components under different atmospheric conditions in the Greater Athens Area, Greece, J. Atmos. Sol.-Terr. Phys., 68, 1043–1052, 2006. </mixed-citation>
</ref>
<ref id="ref22">
<label>22</label><mixed-citation publication-type="other" xlink:type="simple"> Kazantzidis, A., Bais, A. F., Grobner, J., Herman, J. R., Kazadzis, S., Krotkov, N., Kyrö, E., den Outer, P. N., Garane, K., Görts, P., Lakkala, K., Meleti, C., Slaper, H., Tax, R. B., and Turunen T.: Comparison of satellite-derived UV irradiances with ground-based measurements at four European stations, J. Geophys. Res., 111, D13207, doi:10.1029/2005JD006672, 2006. </mixed-citation>
</ref>
<ref id="ref23">
<label>23</label><mixed-citation publication-type="other" xlink:type="simple"> Kazadzis, S., Bais, A., Arola, A., Krotkov, N., Kouremeti, N., and Meleti, C.: Ozone Monitoring Instrument spectral UV irradiance products: comparison with ground based measurements at an urban environment, Atmos. Chem. Phys., 9, 585–594, doi:10.5194/acp-9-585-2009, 2009. </mixed-citation>
</ref>
<ref id="ref24">
<label>24</label><mixed-citation publication-type="other" xlink:type="simple"> Krotkov, N. A., Barthia, P. K., Herman, J. R., Fioletov, V., and Kerr, J.: Satellite estimation of spectral surface UV irradiance in the presence of tropospheric aerosols, J. Geophys. Res., 103, 8779–8793, 1998. </mixed-citation>
</ref>
<ref id="ref25">
<label>25</label><mixed-citation publication-type="other" xlink:type="simple"> Krotkov, N. A., Herman, J. R., Barthia, P. K., Fioletov, V., and Ahmad, Z.: Satellite estimation of spectral surface UV irradiance 2. Effects of homogeneous clouds and snow, J. Geophys. Res., 106, 11743–11759, 2001. </mixed-citation>
</ref>
<ref id="ref26">
<label>26</label><mixed-citation publication-type="other" xlink:type="simple"> Krotkov, N. A., Herman, J. R., Barthia, P. K., Seftor, C., Arola, A., Kaurola, J., Kalliskota, S., Taalas, P., and Geogdzhaev, I. V.: Version 2 total ozone mapping spectrometer ultraviolet algorithm: Problems and enhancements, Opt. Eng., 41(12), 3028–3039, 2002. </mixed-citation>
</ref>
<ref id="ref27">
<label>27</label><mixed-citation publication-type="other" xlink:type="simple"> Krotkov, N., Herman, J., Fioletov, V., Seftor, C., Larko, D., Vasilkov, A., and Labow, G.: Boundary layer absorbing aerosol correction of an expanded UV irradiance database from satellite Total Ozone Mapping Spectrometer, in Proceedings of the XX Quadrennial Ozone Symposium, June 2004, Kos, Greece, 1159–1160, 2004. </mixed-citation>
</ref>
<ref id="ref28">
<label>28</label><mixed-citation publication-type="other" xlink:type="simple"> Krotkov, N. A., Barthia, P. K., Herman, J. R., Slusser, J., Scott, G., Labow, G., Vasilkov, A. P., Eck, T. F., Dubovik, O., and Holben, B. N.: Aerosol ultraviolet absorption experiment (2000 to 2004), part 2: Absorption optical thickness, refractive index, and single scattering albedo, Opt. Eng., 44(4), 041005, doi:10.1117/1.1886819, 2005. </mixed-citation>
</ref>
<ref id="ref29">
<label>29</label><mixed-citation publication-type="other" xlink:type="simple"> Levelt, P. F., Hilsenrath, E., Leppelmeier, G. W., Van den Oord, G. H. J., Bhartia, P. K., Tamminen, J., De Haan, J. F., and Veefkind, J. P. : The Ozone Monitoring Instrument, IEEE T. Geosci. Remote, 44(5), 1093–1101, 2006. </mixed-citation>
</ref>
<ref id="ref30">
<label>30</label><mixed-citation publication-type="other" xlink:type="simple"> McKenzie, R. L., Seckmeyer, G., Bais, A. F., Kerr, J. B., and Madronich, S.: Satellite retrievals of erythemal UV dose compared with groundbased measurements at northern and southern midlatitudes, J. Geophys. Res., 106, 24051–24062, 2001. </mixed-citation>
</ref>
<ref id="ref31">
<label>31</label><mixed-citation publication-type="other" xlink:type="simple"> McKinlay, A. F. and Diffey, B. L.: A reference spectrum for ultraviolet induced erythema in human skin, CIE-J., 6, 21–27, 1987. </mixed-citation>
</ref>
<ref id="ref32">
<label>32</label><mixed-citation publication-type="other" xlink:type="simple"> Meloni, D., di Sarra A., Herman, J. R., Monteleone, F., and Piacentino, S.: Comparison of ground-based and total ozone mapping spectrometer erythemal UV doses at the Island of Lampedusa in the period 1998–2003: Role of tropospheric aerosols, J. Geophys. Res., 110, D01202, doi:10.1029/2004JD005283, 2005. </mixed-citation>
</ref>
<ref id="ref33">
<label>33</label><mixed-citation publication-type="other" xlink:type="simple"> Sabburg, J., Rives, J. E., Meltzer, R. S., Taylor, T., Schmalzle, G., Zheng, S., Huang, N., Wilson, A., and Udelhofen, P. M.: Comparison of corrected daily integrated erythemal data from the U.S. E.PA/UGA network of Brewer spectroradiometer with model and TOMS-inferred data, J. Geophys. Res., 107(D23), 4676, doi:10.1029/2001JD001565, 2002. </mixed-citation>
</ref>
<ref id="ref34">
<label>34</label><mixed-citation publication-type="other" xlink:type="simple"> Schoeberl, M. R., Douglass, A. R., Hilsenrath, E., Bhartia, P. K., Beer, R., Waters, J. W., Gunson, M. R., Froidevaux, L., Gille, J. C., Barnett, J. J., Levelt, P. E., and DeCola, P.: Overview of the EOS Aura Mission, IEEE T. Geosci. Remote, 4, 1066–1074, 2006. </mixed-citation>
</ref>
<ref id="ref35">
<label>35</label><mixed-citation publication-type="other" xlink:type="simple"> Smirnov, A., Holben, B. N., Eck, T. F., Dubovik, O., and Slutsker, I.: Cloud screening and quality control algorithms for the AERONET database, Remote Sens. Environ., 73, 337–349, 2000. </mixed-citation>
</ref>
<ref id="ref36">
<label>36</label><mixed-citation publication-type="other" xlink:type="simple"> Stanek, M.: Total Ozone and UV Radiation Monitoring Software, available online at: http://www.o3soft.eu/, 2007. </mixed-citation>
</ref>
<ref id="ref37">
<label>37</label><mixed-citation publication-type="other" xlink:type="simple"> Tanskanen, A., Krotkov, N. A. Herman, J. R., and Arola, A.: Surface Ultraviolet Irradiance From OMI, IEEE T. Geosci. Remote, 44, 1267–1271, doi:10.1109/TGRS.2005.862203, 2006. </mixed-citation>
</ref>
<ref id="ref38">
<label>38</label><mixed-citation publication-type="other" xlink:type="simple"> Tanskanen, A., Lindfors, A., Maatta, A., Krotkov, N., Herman, J., Kaurola, J., Koskela, T., Lakkala, K., Fioletov, V., Bernhard, J., McHenzie, R., Kondo, Y., O&apos;Neill, M., Slaper, H., den Outer, P., Bais, A. F., and Tamminen, J.: Validation of daily erythemal doses from OMI with ground-based UV measurement data, J. Geophys. Res., 112, D24S44, doi:10.1029/2007JD008830, 2007. </mixed-citation>
</ref>
<ref id="ref39">
<label>39</label><mixed-citation publication-type="other" xlink:type="simple"> Toledano, C.: Climatología de los aerosoles mediante la caracterización de propiedades ópticas y masas de aire en la estación `El Arenosillo&apos; de la red AERONET, PhD Dissertation, Universidad de Valladolid (Spain), 2005. </mixed-citation>
</ref>
<ref id="ref40">
<label>40</label><mixed-citation publication-type="other" xlink:type="simple"> Toledano, C., Cachorro, V. E., de Frutos, A. M., Sorribas, M., Prats, N., and de la Morena, B.: Inventory of African desert dust events over the southwestern Iberian Peninsula in 2000–2005 with an AERONET Cimel Sun photometer, J. Geophys. Res., 112, D21201, doi:10.1029/2006JD008307, 2007a. </mixed-citation>
</ref>
<ref id="ref41">
<label>41</label><mixed-citation publication-type="other" xlink:type="simple"> Toledano, C., Cachorro, V. E., Sorribas, M., Berjón, A., de la Morena, B. A., de Frutos, A. M., and Gouloub, P.: Aerosol optical depth and Ångström exponent climatology at &quot;El Arenosillo&quot; AERONET site (Huelva, Spain), Q. J. Roy. Meteorol. Soc., 133, 795–807, doi:10.1002/qj.54, 2007b. </mixed-citation>
</ref>
<ref id="ref42">
<label>42</label><mixed-citation publication-type="other" xlink:type="simple"> Torres, O., Tanskanen, A., Veihelmann, B., Ahn, C., Braak, R., Bhartia, P. K., Veefkind, P., and Levelt P.: Aerosols and surface UV products from Ozone Monitoring Instrument observations: An overview, J. Geophys. Res., 112, D24S47, doi:10.1029/2007JD008809, 2007. </mixed-citation>
</ref>
<ref id="ref43">
<label>43</label><mixed-citation publication-type="other" xlink:type="simple"> Vilaplana, J. M: Medida y análisis de ozono y de la radiación solar ultravioleta en El Arenosillo-INTA, Ph.D. dissertation, Universidad de Valladolid, Spain, 2004. </mixed-citation>
</ref>
<ref id="ref44">
<label>44</label><mixed-citation publication-type="other" xlink:type="simple"> Vilaplana, J. M., Cachorro, V. E., Sorbías, M., Luccini, E., de Frutos, A. M., Berjón, A., and de la Morena, B.: Modified calibration procedures for a yankee environmental system UVB-1 biometer based on spectral measurements with a brewer spectrophotometer, Photochem. Photobiol., 82, 508–514, 2006. </mixed-citation>
</ref>
<ref id="ref45">
<label>45</label><mixed-citation publication-type="other" xlink:type="simple"> Weihs, P., Blumthaler, M., Rieder, H. E., Kreuter, A., Simic, S., Laube, W., Schmalwieser, A. W., Wagner, J. E., and Tanskanen, A.: Measurements of UV irradiance within the area of one satellite pixel, Atmos. Chem. Phys., 8, 5615–5626, doi:10.5194/acp-8-5615-2008, 2008. </mixed-citation>
</ref>
<ref id="ref46">
<label>46</label><mixed-citation publication-type="other" xlink:type="simple"> World Meteorological Organization (WMO): Global ozone research and monitoring project, Tech. Rep. 50, Sci. Assess. of Ozone Depletion, Geneva, Switzerland, 2006 </mixed-citation>
</ref>
</ref-list>
</back>
</article>