Suchergebnisse

Final Publishable JRP Report. Issued: November 2017. Version V1.0 ; Ozone in the earth's upper atmosphere absorbs ultraviolet radiation, preventing most of it reaching the ground.This is important because ultraviolet radiation can harm life on earth, and for example lead to skin cancer.Since the 1980s, it has been known that human-produced chlorofluorocarbons (CFCs) have led to recurring losses of total ozone in the Antarctic (the ozone hole), and these have also been recently observed in the Arctic, while in middle-latitudes, moderate ozone depletion has been observed. The Montreal Protocol on Substances that Deplete the Ozone Layer is an international treaty signed in 1994 designed to protect the ozone layer by phasing out the production of substances that are responsible for ozone depletion, and it has been successful in reducing the emission of ozone-depleting substances. However, monitoring of the recovery of the ozone layer requires accurate long-term observations with reliable and well understood instruments and the development of future instrumentation. This project characterised key reference and network instruments for the traceability of ozone retrievals (or measurements), developed new instruments and devices for in-field characterisation of the existing network instruments and new ozone monitoring instruments, and generated new datasets for ozone absorption crosssections and extra-terrestrial solar reference spectrum. ; The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.

A Microtops II "ozone monitor" with UV channels centered at 305.5, 312.5, and 320 nm has been used routinely in six experimental campaigns carried out in several geographic locations and seasons, covering latitudes from 35 to 68° N during the last ten years (2001–2011). The total ozone content is retrieved by Microtops II by using different combinations (Channel I, 305.5/312.5 nm; Channel II, 312.5/320 nm; and Channel III, 305.5/312.5/320 nm) of the signals at the three ultraviolet wavelengths. The long-term performance of the total ozone content determination has been studied taking into account the sensitivities to the calibration, airmass, temperature and aerosols. When a calibration was used and the airmass limit was fixed to 3, the root mean square deviations of the relative differences produced by Microtops II with respect to several Brewers are 0.9, 2, and 2% respectively for the Channel I, Channel II, and Channel III retrieval. The performance of the Microtops retrieval has been stable during the last ten years. Channel I represents the best option to determine the instantaneous total ozone content. Channels II and III values appear weakly sensitive to temperature, ozone content, and aerosols. Channel II is more stable than Channel I for airmasses larger than 2.6. The conclusions do not show any dependence on latitude and season. ; This study was possible thanks to a postdoctoral fellowship funded by the Generalitat Valenciana in the case of J. L. G´omez Amo (in the framework of "Estancies postdoctorals en centres de Excellencia de la Comunitat Valenciana" programme) and a Juan de la Cierva research contract (JCI-2009-04455) in the case of V. Estell´es, funded by the Spanish Ministry of Science and Innovation (MICINN). This work was also supported by the MICINN projects CGL2007-60648 and CGL2009-07790, and by the Valencian Autonomous Government through the Project PROMETEO/2010/064.

A Microtops II "ozone monitor" with UV channels centered at 305.5, 312.5, and 320 nm has been used routinely in six experimental campaigns carried out in several geographic locations and seasons, covering latitudes from 35 to 68◦ N during the last ten years (2001–2011). The total ozone content is retrieved by Microtops II by using different combinations (Channel I, 305.5/312.5 nm; Channel II, 312.5/320 nm; and Channel III, 305.5/312.5/320 nm) of the signals at the three ultraviolet wavelengths. When a calibration was used and the airmass limit was fixed to 3, Microtops II produce mean relative deviations with respect to the Brewer of 0.1, −11, and 8 % respectively for the Channel I, Channel II, and Channel III retrieval. The performance of the Microtops retrieval has been stable during the last ten years. Channel I represents the best option to determine the instantaneous total ozone content. Channel II and III values appear weakly sensitive to temperature, ozone content, and aerosols. Channel II is more stable than Channel I for airmasses larger than 2.6. The conclusions do not show any dependence on latitude and season. ; This study was possible thanks to a postdoctoral fellowship funded by the Generalitat Valenciana in the case of J. L. Gomez Amo (in the framework of "Estancies post- doctorals en centres de Excellencia de la Comunitat Valenciana" programme) and a Juan de la Cierva research contract (JCI-2009-04455) in the case of V. Estellés, funded by the Spanish Ministry of Science and Innovation (MICINN). This work was also supported by the MICINN projects CGL2007-60648 and CGL2009-07790, and by the Valencian Autonomous Government through the Project PROMETEO/2010/064.

From 25 May to 5 June 2015, the 10th regional intercomparison campaign of the Regional Brewer Calibration Center – Europe (RBCC-E) was held at El Arenosillo atmospheric sounding station of the Instituto Nacional de Técnica Aeroespacial (INTA). This campaign was jointly conducted by COST Action ES1207 EUBREWNET and the Area of Instrumentation and Atmospheric Research of INTA. A total of 21 Brewers, 11 single- and 10 double-monochromator instruments from 11 countries participated and were calibrated for total column ozone (TOC) and solar UV irradiance. In this 2015 campaign we have introduced a formal approach to the characterisation of the internal instrumental stray light, the filter non-linearity and the algorithm for correcting for its effects on the TOC calculations. This work shows a general overview of the ozone comparison and the evaluation of the correction of the spectral stray light effect for the single-monochromator Brewer spectrophotometer, derived from the comparison with a reference double-monochromator Brewer instrument. At the beginning of the campaign, 16 out of the 21 participating Brewer instruments agreed within better than ±1%, and 10 instruments agreed within better than ±0.5% considering data with ozone slant column between 100 and 900DU, which does not require instrumental stray light correction. ; This article is based upon work from COST Action 1207 EUBREWNET. This work has been supported by the European Metrology Research Programme within the joint research project ENV59 "Traceability for atmospheric total column ozone" (ATMOZ). The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union. We also gratefully acknowledge further support by the Fundación General de la Universidad de La Laguna. This study and the campaigns were supported at large part by ESA project CEOS Intercalibration of ground-pectrometers and lidars (ESRIN contract 22202/09/I-EC).

Póster elaborado para el Quadrennial Ozone Symposium celebrado en Edimburgo del 4 al 9 de septiembre de 2016. ; This work has been supported by the European Metrology Research Programme (EMRP) within the joint research project ENV59 "Traceability for atmospheric total column ozone" (ATMOZ). The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.

Cover -- Half Title Page -- Title Page -- Copyright Page -- Contents -- List of Figures -- List of Tables -- Abbreviations -- Preface -- 1 Introduction -- 2 The Atmosphere and Climate -- 3 Ozone Circulation and Chemistry -- 4 The Study of Earth's Atmosphere from Space -- 5 Study Area -- 6 Introduction to SCIAMACHY -- 7 Methodology -- 7.1 Remotely sensed data -- 7.2 The SCIAMACHY standard data -- 7.3 Data sources -- 7.4 Backward trajectory analysis -- 7.5 Methodology and the hybrid approach -- 7.6 Model evaluation -- 8 Results -- 8.1 Multiple regression analysis of ozone -- 8.2 Multiple regression and principal component regression analyses -- 9 Evaluation of Total Column Ozone Value from SCIAMACHY Observation Data -- 10 Comparison and Validation of The Regression Models -- 10.1 Comparison of predicted ozone value by multiple regression analysis and the combined multiple regression analysis and principal component analysis -- 10.2 Validation of the predicted ozone values with the observed airs ozone values -- 10.3 Validation of the multiple regression analysis method -- 10.4 Validation of the combined multiple regression analysis and principal component analysis method -- 11 Backward Trajectory Analysis -- 12 Framework for Long-Range Transport -- 13 Conclusion -- References -- The Authors -- Index -- Back Cover.

Presentación realizada en: ATMOZ workshop at 11th RBCC-E, celebrado en El Arenosillo, Huelva, el 1 de junio de 2017. ; This work has been supported by the European Metrology Research Programme (EMRP) within the joint research project ENV59 "Traceability for atmospheric total column ozone" (ATMOZ). The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.

The Universities of Malta and Valladolid (Spain) developed a measurement campaign, which took place in the Institute for Energy Technology in Marsaxlokk (Southern Malta) between May and October 2012, and it was supported by the Spanish government through the Project titled "Measurement campaign about Solar Radiation, Ozone, and Aerosol in the Mediterranean area" (with reference CGL2010-12140-E). This campaign provided the first ground-based measurements in Malta of erythemal radiation and UV index, which indicate the effectiveness of the sun exposure to produce sunburn on human skin. A wide variety of instruments was involved in the campaign, providing a complete atmospheric characterization. Data of erythemal radiation and UV index (from UVB-1 pyranometer), total shortwave radiaton (global and diffuse components from CM-6B pyranometers), and total ozone column, aerosol optical thickness, and precitable water column (from a Microtops-II sunphotometer) were available in the campaign. Ground-based and satellite instruments were used in the analysis, and several intercomparisons were carried out to validate remote sensing data. OMI, GOME, GOME-2, and MODIS instru- ments, which provide data of ozone, aerosol load and optical properties, were used to this end. The effects on solar radiation, ultraviolet and total shortwave ranges, of total ozone column, aerosol optical thickness and precipitable water column were obtained using radiation measurements at different fixed solar zenith angles. The empirical results shown a determinant role of the solar position, a negligible effect of ozone on total shortwave radiation, and a stronger attenuation provided by aerosol particles in the erythemal radiation. A variety of aerosol types from different sources (desert dust, biomass burning, continental, and maritime) reach Malta, in this campaign several dust events from the Sahara desert occurred and were analyzed establishing the air mass back-trajectories ending at Malta at several heights calculated by means of the HYSPLIT model. Hence, changes in the UV index due to atmospheric aerosol were characterized. ; N/A

Laboratory investigations of optical characteristics of three standard Dobsons provide real wavelength settings and slit functions. These parameters were compared with the original values given in the manuals. The differences between real and nominal values are not too large, but their application will in any case improve the quality of the total ozone column measurements in the global network. This improvement was the main objective of the ATMOZ project funding these activities. ; This work has been supported by the European Metrology Research Programme (EMRP) within the joint research project EMRP ENV59 ATMOZ "Traceability for atmospheric total column ozone". The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.

This paper presents an extensive intercomparison and validation for the ozone (O3) product measured by the two Infrared Atmospheric Sounding Interferometers (IASIs) launched on board the MetOp-A and MetOp-B satellites in 2006 and in 2012 respectively. IASI O3 total columns and vertical profiles obtained from Fast Optimal Retrievals on Layers for IASI (FORLI) v20140922 software (running up until recently) are validated against independent observations during the period 2008-2014 on a global scale. On average for the period 2013-2014, IASI-A and IASI-B total ozone columns (TOCs) retrieved using FORLI are consistent, with IASI-B providing slightly lower values with a global difference of only 0.2±0.8%. The comparison between IASI-A and IASI-B O3 vertical profiles shows differences within ±2% over the entire altitude range. Global validation results for 7 years of IASI TOCs from FORLI against the Global Ozone Monitoring Experiment-2 (GOME-2) launched on board MetOp-A and Brewer-Dobson data show that, on average, IASI overestimates the ultraviolet (UV) data by 5-6% with the largest differences found in the southern high latitudes. The comparison with UV-visible SAOZ (Système d'Analyse par Observation Zénithale) measurements shows a mean bias between IASI and SAOZ TOCs of 2-4% in the midlatitudes and tropics and 7% at the polar circle. Part of the discrepancies found at high latitudes can be attributed to the limited information content in the observations due to low brightness temperatures. The comparison with ozonesonde vertical profiles (limited to 30km) shows that on average IASI with FORLI processing underestimates O3 by ∼ 5-15% in the troposphere while it overestimates O3 by ∼ 10-40% in the stratosphere, depending on the latitude. The largest relative differences are found in the tropical tropopause region; this can be explained by the low O3 amounts leading to large relative errors. In this study, we also evaluate an updated version of FORLI-O3 retrieval software (v20151001), using look-up tables recalculated ...

Ground-based Fourier transform infrared (FTIR) measurements of solar absorption spectra can provide ozone total columns with a precision of 2% but also independent partial column amounts in about four vertical layers, one in the troposphere and three in the stratosphere up to about 45km, with a precision of 5–6%. We use eight of the Network for the Detection of Atmospheric Composition Change (NDACC) stations having a long-term time series of FTIR ozone measurements to study the total and vertical ozone trends and variability, namely, Ny-Ålesund (79° N), Thule (77° N), Kiruna (68° N), Harestua (60° N), Jungfraujoch (47° N), Izaña (28° N), Wollongong (34° S) and Lauder (45° S). ; This study has been supported by the EU FP7 project NORS, the ESA PRODEX project A3C, as well as the AGACC-II project within the Science for a Sustainable Development research program funded by the Belgian Science Policy Office.

In this contribution we present the wavelength calibration of the travelling reference Brewer spectrometer of the Regional Brewer Calibration Center for Europe (RBCCE) at PTB in Braunschweig, Germany. The wavelength calibration is needed for the calculation of the ozone absorption coefficients used by the Brewer ozone algorithm. In order to validate the standard procedure for determining Brewer's wavelength scale, a calibration has been performed by using a tunable laser source at PTB in the framework of the EMRP project ENV59 ATMOZ "Traceability for the total column ozone". Here we compare these results to those of the standard procedure for the wavelength calibration of the Brewer instrument. Such a comparison allows validating the standard methodology used for measuring the ozone absorption coefficient with respect to several assumptions. The results of the laser-based calibrations reproduces those obtained by the standard operational methodology and shows that there is an underestimation of 0.8 % of the ozone absorption coefficients due to the use of the parametrized slit functions. ; This work has been supported by the European Metrology Research Programme (EMRP) within the joint research project ENV59 "Traceability for atmospheric total column ozone" (ATMOZ). The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.