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International audience ; National and European legislation over the past 20 yr, and the modernisation or removal of industrial sources, have significantly reduced European ozone precursor emissions. This study quantifies observed and modelled European ozone annual and seasonal linear trends from 158 harmonised rural background monitoring stations over a constant time period of a decade (1996-2005). Mean ozone concentrations are investigated, in addition to the ozone 5th percentiles as a measure of the baseline or background conditions, and the 95th percentiles that are representative of the peak concentration levels. This study aims to characterise and quantify surface European ozone concentrations and trends and assess the impact of the changing anthropogenic emission tracers on the observed and modelled trends. Significant (p<0.1) positive annual trends in ozone mean, 5th and 95th percentiles are observed at 54%, 52% and 45% of sites respectively (85 sites, 82 sites and 71 sites). Spatially, sites in central and north-western Europe tend to display positive annual ozone trends in mean, 5th and 95th percentiles. Significant negative annual trends in ozone mean 5th and 95th percentiles are observed at 11%, 12% and 12% of sites respectively (18 sites, 19 sites and 19 sites) which tend to be located in the eastern and southwestern extremities of Europe. European-averaged annual trends have been calculated from the 158 sites in this study. Overall there is a net positive annual trend in ob-served ozone mean (0.16 +/- 0.02 ppbv yr(-1) (2 sigma error)), 5th (0.13 +/- 0.02 ppbv yr(-1)) and 95th (0.16 +/- 0.03 ppbv yr(-1)) percentiles, representative of positive trends in mean, baseline and peak ozone. Assessing the sensitivity of the derived overall trends to the constituent years shows that the European heatwave year of 2003 has significant positive influence and 1998 the converse effect; demonstrating the masking effect of inter-annual variability on decadal based ozone trends. The European scale 3-D CTM CHIMERE ...

International audience ; National and European legislation over the past 20 yr, and the modernisation or removal of industrial sources, have significantly reduced European ozone precursor emissions. This study quantifies observed and modelled European ozone annual and seasonal linear trends from 158 harmonised rural background monitoring stations over a constant time period of a decade (1996-2005). Mean ozone concentrations are investigated, in addition to the ozone 5th percentiles as a measure of the baseline or background conditions, and the 95th percentiles that are representative of the peak concentration levels. This study aims to characterise and quantify surface European ozone concentrations and trends and assess the impact of the changing anthropogenic emission tracers on the observed and modelled trends. Significant (p<0.1) positive annual trends in ozone mean, 5th and 95th percentiles are observed at 54%, 52% and 45% of sites respectively (85 sites, 82 sites and 71 sites). Spatially, sites in central and north-western Europe tend to display positive annual ozone trends in mean, 5th and 95th percentiles. Significant negative annual trends in ozone mean 5th and 95th percentiles are observed at 11%, 12% and 12% of sites respectively (18 sites, 19 sites and 19 sites) which tend to be located in the eastern and southwestern extremities of Europe. European-averaged annual trends have been calculated from the 158 sites in this study. Overall there is a net positive annual trend in ob-served ozone mean (0.16 +/- 0.02 ppbv yr(-1) (2 sigma error)), 5th (0.13 +/- 0.02 ppbv yr(-1)) and 95th (0.16 +/- 0.03 ppbv yr(-1)) percentiles, representative of positive trends in mean, baseline and peak ozone. Assessing the sensitivity of the derived overall trends to the constituent years shows that the European heatwave year of 2003 has significant positive influence and 1998 the converse effect; demonstrating the masking effect of inter-annual variability on decadal based ozone trends. The European scale 3-D CTM CHIMERE was used to simulate hourly O-3 concentrations for the period 1996-2005. Comparisons between the 158 observed ozone trends to those equivalent sites extracted from regional simulations by CHIMERE better match the observed increasing annual ozone (predominantly in central and north-western Europe) for 5th percentiles, than for mean or 95th ozone percentiles. The European-averaged annual ozone trend in CHIMERE 5th percentiles (0.13 +/- 0.01 ppbv yr(-1)) matches the corresponding observed trend extremely well, but displays a negative trend for the 95th percentile (-0.03 +/- 0.02 ppbv yr(-1)) where a positive ozone trend is observed. Inspection of the EU-averaged monthly means of ozone shows that the CHIMERE model is overestimating the summer month O-3 levels. In comparison to trends in EMEP emissions inventories, with the exception of Austria-Hungary, we do not find that anthropogenic NOx and VOC reductions have a substantial effect on observed annual mean O-3 trends in the rest of Europe. On a ten year time-scale presented in this study, O-3 trends related to anthropogenic NOx and VOC reductions are being masked as a result of a number of factors including meteorological variability, changes in background ozone and shifts in source patterns.

International audience ; National and European legislation over the past 20 yr, and the modernisation or removal of industrial sources, have significantly reduced European ozone precursor emissions. This study quantifies observed and modelled European ozone annual and seasonal linear trends from 158 harmonised rural background monitoring stations over a constant time period of a decade (1996-2005). Mean ozone concentrations are investigated, in addition to the ozone 5th percentiles as a measure of the baseline or background conditions, and the 95th percentiles that are representative of the peak concentration levels. This study aims to characterise and quantify surface European ozone concentrations and trends and assess the impact of the changing anthropogenic emission tracers on the observed and modelled trends. Significant (p<0.1) positive annual trends in ozone mean, 5th and 95th percentiles are observed at 54%, 52% and 45% of sites respectively (85 sites, 82 sites and 71 sites). Spatially, sites in central and north-western Europe tend to display positive annual ozone trends in mean, 5th and 95th percentiles. Significant negative annual trends in ozone mean 5th and 95th percentiles are observed at 11%, 12% and 12% of sites respectively (18 sites, 19 sites and 19 sites) which tend to be located in the eastern and southwestern extremities of Europe. European-averaged annual trends have been calculated from the 158 sites in this study. Overall there is a net positive annual trend in ob-served ozone mean (0.16 +/- 0.02 ppbv yr(-1) (2 sigma error)), 5th (0.13 +/- 0.02 ppbv yr(-1)) and 95th (0.16 +/- 0.03 ppbv yr(-1)) percentiles, representative of positive trends in mean, baseline and peak ozone. Assessing the sensitivity of the derived overall trends to the constituent years shows that the European heatwave year of 2003 has significant positive influence and 1998 the converse effect; demonstrating the masking effect of inter-annual variability on decadal based ozone trends. The European scale 3-D CTM CHIMERE was used to simulate hourly O-3 concentrations for the period 1996-2005. Comparisons between the 158 observed ozone trends to those equivalent sites extracted from regional simulations by CHIMERE better match the observed increasing annual ozone (predominantly in central and north-western Europe) for 5th percentiles, than for mean or 95th ozone percentiles. The European-averaged annual ozone trend in CHIMERE 5th percentiles (0.13 +/- 0.01 ppbv yr(-1)) matches the corresponding observed trend extremely well, but displays a negative trend for the 95th percentile (-0.03 +/- 0.02 ppbv yr(-1)) where a positive ozone trend is observed. Inspection of the EU-averaged monthly means of ozone shows that the CHIMERE model is overestimating the summer month O-3 levels. In comparison to trends in EMEP emissions inventories, with the exception of Austria-Hungary, we do not find that anthropogenic NOx and VOC reductions have a substantial effect on observed annual mean O-3 trends in the rest of Europe. On a ten year time-scale presented in this study, O-3 trends related to anthropogenic NOx and VOC reductions are being masked as a result of a number of factors including meteorological variability, changes in background ozone and shifts in source patterns.

International audience ; National and European legislation over the past 20 yr, and the modernisation or removal of industrial sources, have significantly reduced European ozone precursor emissions. This study quantifies observed and modelled European ozone annual and seasonal linear trends from 158 harmonised rural background monitoring stations over a constant time period of a decade (1996-2005). Mean ozone concentrations are investigated, in addition to the ozone 5th percentiles as a measure of the baseline or background conditions, and the 95th percentiles that are representative of the peak concentration levels. This study aims to characterise and quantify surface European ozone concentrations and trends and assess the impact of the changing anthropogenic emission tracers on the observed and modelled trends. Significant (p<0.1) positive annual trends in ozone mean, 5th and 95th percentiles are observed at 54%, 52% and 45% of sites respectively (85 sites, 82 sites and 71 sites). Spatially, sites in central and north-western Europe tend to display positive annual ozone trends in mean, 5th and 95th percentiles. Significant negative annual trends in ozone mean 5th and 95th percentiles are observed at 11%, 12% and 12% of sites respectively (18 sites, 19 sites and 19 sites) which tend to be located in the eastern and southwestern extremities of Europe. European-averaged annual trends have been calculated from the 158 sites in this study. Overall there is a net positive annual trend in ob-served ozone mean (0.16 +/- 0.02 ppbv yr(-1) (2 sigma error)), 5th (0.13 +/- 0.02 ppbv yr(-1)) and 95th (0.16 +/- 0.03 ppbv yr(-1)) percentiles, representative of positive trends in mean, baseline and peak ozone. Assessing the sensitivity of the derived overall trends to the constituent years shows that the European heatwave year of 2003 has significant positive influence and 1998 the converse effect; demonstrating the masking effect of inter-annual variability on decadal based ozone trends. The European scale 3-D CTM CHIMERE was used to simulate hourly O-3 concentrations for the period 1996-2005. Comparisons between the 158 observed ozone trends to those equivalent sites extracted from regional simulations by CHIMERE better match the observed increasing annual ozone (predominantly in central and north-western Europe) for 5th percentiles, than for mean or 95th ozone percentiles. The European-averaged annual ozone trend in CHIMERE 5th percentiles (0.13 +/- 0.01 ppbv yr(-1)) matches the corresponding observed trend extremely well, but displays a negative trend for the 95th percentile (-0.03 +/- 0.02 ppbv yr(-1)) where a positive ozone trend is observed. Inspection of the EU-averaged monthly means of ozone shows that the CHIMERE model is overestimating the summer month O-3 levels. In comparison to trends in EMEP emissions inventories, with the exception of Austria-Hungary, we do not find that anthropogenic NOx and VOC reductions have a substantial effect on observed annual mean O-3 trends in the rest of Europe. On a ten year time-scale presented in this study, O-3 trends related to anthropogenic NOx and VOC reductions are being masked as a result of a number of factors including meteorological variability, changes in background ozone and shifts in source patterns.

International audience ; National and European legislation over the past 20 yr, and the modernisation or removal of industrial sources, have significantly reduced European ozone precursor emissions. This study quantifies observed and modelled European ozone annual and seasonal linear trends from 158 harmonised rural background monitoring stations over a constant time period of a decade (1996-2005). Mean ozone concentrations are investigated, in addition to the ozone 5th percentiles as a measure of the baseline or background conditions, and the 95th percentiles that are representative of the peak concentration levels. This study aims to characterise and quantify surface European ozone concentrations and trends and assess the impact of the changing anthropogenic emission tracers on the observed and modelled trends. Significant (p<0.1) positive annual trends in ozone mean, 5th and 95th percentiles are observed at 54%, 52% and 45% of sites respectively (85 sites, 82 sites and 71 sites). Spatially, sites in central and north-western Europe tend to display positive annual ozone trends in mean, 5th and 95th percentiles. Significant negative annual trends in ozone mean 5th and 95th percentiles are observed at 11%, 12% and 12% of sites respectively (18 sites, 19 sites and 19 sites) which tend to be located in the eastern and southwestern extremities of Europe. European-averaged annual trends have been calculated from the 158 sites in this study. Overall there is a net positive annual trend in ob-served ozone mean (0.16 +/- 0.02 ppbv yr(-1) (2 sigma error)), 5th (0.13 +/- 0.02 ppbv yr(-1)) and 95th (0.16 +/- 0.03 ppbv yr(-1)) percentiles, representative of positive trends in mean, baseline and peak ozone. Assessing the sensitivity of the derived overall trends to the constituent years shows that the European heatwave year of 2003 has significant positive influence and 1998 the converse effect; demonstrating the masking effect of inter-annual variability on decadal based ozone trends. The European scale 3-D CTM CHIMERE was used to simulate hourly O-3 concentrations for the period 1996-2005. Comparisons between the 158 observed ozone trends to those equivalent sites extracted from regional simulations by CHIMERE better match the observed increasing annual ozone (predominantly in central and north-western Europe) for 5th percentiles, than for mean or 95th ozone percentiles. The European-averaged annual ozone trend in CHIMERE 5th percentiles (0.13 +/- 0.01 ppbv yr(-1)) matches the corresponding observed trend extremely well, but displays a negative trend for the 95th percentile (-0.03 +/- 0.02 ppbv yr(-1)) where a positive ozone trend is observed. Inspection of the EU-averaged monthly means of ozone shows that the CHIMERE model is overestimating the summer month O-3 levels. In comparison to trends in EMEP emissions inventories, with the exception of Austria-Hungary, we do not find that anthropogenic NOx and VOC reductions have a substantial effect on observed annual mean O-3 trends in the rest of Europe. On a ten year time-scale presented in this study, O-3 trends related to anthropogenic NOx and VOC reductions are being masked as a result of a number of factors including meteorological variability, changes in background ozone and shifts in source patterns.

International audience ; National and European legislation over the past 20 yr, and the modernisation or removal of industrial sources, have significantly reduced European ozone precursor emissions. This study quantifies observed and modelled European ozone annual and seasonal linear trends from 158 harmonised rural background monitoring stations over a constant time period of a decade (1996-2005). Mean ozone concentrations are investigated, in addition to the ozone 5th percentiles as a measure of the baseline or background conditions, and the 95th percentiles that are representative of the peak concentration levels. This study aims to characterise and quantify surface European ozone concentrations and trends and assess the impact of the changing anthropogenic emission tracers on the observed and modelled trends. Significant (p<0.1) positive annual trends in ozone mean, 5th and 95th percentiles are observed at 54%, 52% and 45% of sites respectively (85 sites, 82 sites and 71 sites). Spatially, sites in central and north-western Europe tend to display positive annual ozone trends in mean, 5th and 95th percentiles. Significant negative annual trends in ozone mean 5th and 95th percentiles are observed at 11%, 12% and 12% of sites respectively (18 sites, 19 sites and 19 sites) which tend to be located in the eastern and southwestern extremities of Europe. European-averaged annual trends have been calculated from the 158 sites in this study. Overall there is a net positive annual trend in ob-served ozone mean (0.16 +/- 0.02 ppbv yr(-1) (2 sigma error)), 5th (0.13 +/- 0.02 ppbv yr(-1)) and 95th (0.16 +/- 0.03 ppbv yr(-1)) percentiles, representative of positive trends in mean, baseline and peak ozone. Assessing the sensitivity of the derived overall trends to the constituent years shows that the European heatwave year of 2003 has significant positive influence and 1998 the converse effect; demonstrating the masking effect of inter-annual variability on decadal based ozone trends. The European scale 3-D CTM CHIMERE was used to simulate hourly O-3 concentrations for the period 1996-2005. Comparisons between the 158 observed ozone trends to those equivalent sites extracted from regional simulations by CHIMERE better match the observed increasing annual ozone (predominantly in central and north-western Europe) for 5th percentiles, than for mean or 95th ozone percentiles. The European-averaged annual ozone trend in CHIMERE 5th percentiles (0.13 +/- 0.01 ppbv yr(-1)) matches the corresponding observed trend extremely well, but displays a negative trend for the 95th percentile (-0.03 +/- 0.02 ppbv yr(-1)) where a positive ozone trend is observed. Inspection of the EU-averaged monthly means of ozone shows that the CHIMERE model is overestimating the summer month O-3 levels. In comparison to trends in EMEP emissions inventories, with the exception of Austria-Hungary, we do not find that anthropogenic NOx and VOC reductions have a substantial effect on observed annual mean O-3 trends in the rest of Europe. On a ten year time-scale presented in this study, O-3 trends related to anthropogenic NOx and VOC reductions are being masked as a result of a number of factors including meteorological variability, changes in background ozone and shifts in source patterns.

International audience ; National and European legislation over the past 20 yr, and the modernisation or removal of industrial sources, have significantly reduced European ozone precursor emissions. This study quantifies observed and modelled European ozone annual and seasonal linear trends from 158 harmonised rural background monitoring stations over a constant time period of a decade (1996-2005). Mean ozone concentrations are investigated, in addition to the ozone 5th percentiles as a measure of the baseline or background conditions, and the 95th percentiles that are representative of the peak concentration levels. This study aims to characterise and quantify surface European ozone concentrations and trends and assess the impact of the changing anthropogenic emission tracers on the observed and modelled trends. Significant (p<0.1) positive annual trends in ozone mean, 5th and 95th percentiles are observed at 54%, 52% and 45% of sites respectively (85 sites, 82 sites and 71 sites). Spatially, sites in central and north-western Europe tend to display positive annual ozone trends in mean, 5th and 95th percentiles. Significant negative annual trends in ozone mean 5th and 95th percentiles are observed at 11%, 12% and 12% of sites respectively (18 sites, 19 sites and 19 sites) which tend to be located in the eastern and southwestern extremities of Europe. European-averaged annual trends have been calculated from the 158 sites in this study. Overall there is a net positive annual trend in ob-served ozone mean (0.16 +/- 0.02 ppbv yr(-1) (2 sigma error)), 5th (0.13 +/- 0.02 ppbv yr(-1)) and 95th (0.16 +/- 0.03 ppbv yr(-1)) percentiles, representative of positive trends in mean, baseline and peak ozone. Assessing the sensitivity of the derived overall trends to the constituent years shows that the European heatwave year of 2003 has significant positive influence and 1998 the converse effect; demonstrating the masking effect of inter-annual variability on decadal based ozone trends. The European scale 3-D CTM CHIMERE was used to simulate hourly O-3 concentrations for the period 1996-2005. Comparisons between the 158 observed ozone trends to those equivalent sites extracted from regional simulations by CHIMERE better match the observed increasing annual ozone (predominantly in central and north-western Europe) for 5th percentiles, than for mean or 95th ozone percentiles. The European-averaged annual ozone trend in CHIMERE 5th percentiles (0.13 +/- 0.01 ppbv yr(-1)) matches the corresponding observed trend extremely well, but displays a negative trend for the 95th percentile (-0.03 +/- 0.02 ppbv yr(-1)) where a positive ozone trend is observed. Inspection of the EU-averaged monthly means of ozone shows that the CHIMERE model is overestimating the summer month O-3 levels. In comparison to trends in EMEP emissions inventories, with the exception of Austria-Hungary, we do not find that anthropogenic NOx and VOC reductions have a substantial effect on observed annual mean O-3 trends in the rest of Europe. On a ten year time-scale presented in this study, O-3 trends related to anthropogenic NOx and VOC reductions are being masked as a result of a number of factors including meteorological variability, changes in background ozone and shifts in source patterns.

International audience ; National and European legislation over the past 20 yr, and the modernisation or removal of industrial sources, have significantly reduced European ozone precursor emissions. This study quantifies observed and modelled European ozone annual and seasonal linear trends from 158 harmonised rural background monitoring stations over a constant time period of a decade (1996-2005). Mean ozone concentrations are investigated, in addition to the ozone 5th percentiles as a measure of the baseline or background conditions, and the 95th percentiles that are representative of the peak concentration levels. This study aims to characterise and quantify surface European ozone concentrations and trends and assess the impact of the changing anthropogenic emission tracers on the observed and modelled trends. Significant (p<0.1) positive annual trends in ozone mean, 5th and 95th percentiles are observed at 54%, 52% and 45% of sites respectively (85 sites, 82 sites and 71 sites). Spatially, sites in central and north-western Europe tend to display positive annual ozone trends in mean, 5th and 95th percentiles. Significant negative annual trends in ozone mean 5th and 95th percentiles are observed at 11%, 12% and 12% of sites respectively (18 sites, 19 sites and 19 sites) which tend to be located in the eastern and southwestern extremities of Europe. European-averaged annual trends have been calculated from the 158 sites in this study. Overall there is a net positive annual trend in ob-served ozone mean (0.16 +/- 0.02 ppbv yr(-1) (2 sigma error)), 5th (0.13 +/- 0.02 ppbv yr(-1)) and 95th (0.16 +/- 0.03 ppbv yr(-1)) percentiles, representative of positive trends in mean, baseline and peak ozone. Assessing the sensitivity of the derived overall trends to the constituent years shows that the European heatwave year of 2003 has significant positive influence and 1998 the converse effect; demonstrating the masking effect of inter-annual variability on decadal based ozone trends. The European scale 3-D CTM CHIMERE was used to simulate hourly O-3 concentrations for the period 1996-2005. Comparisons between the 158 observed ozone trends to those equivalent sites extracted from regional simulations by CHIMERE better match the observed increasing annual ozone (predominantly in central and north-western Europe) for 5th percentiles, than for mean or 95th ozone percentiles. The European-averaged annual ozone trend in CHIMERE 5th percentiles (0.13 +/- 0.01 ppbv yr(-1)) matches the corresponding observed trend extremely well, but displays a negative trend for the 95th percentile (-0.03 +/- 0.02 ppbv yr(-1)) where a positive ozone trend is observed. Inspection of the EU-averaged monthly means of ozone shows that the CHIMERE model is overestimating the summer month O-3 levels. In comparison to trends in EMEP emissions inventories, with the exception of Austria-Hungary, we do not find that anthropogenic NOx and VOC reductions have a substantial effect on observed annual mean O-3 trends in the rest of Europe. On a ten year time-scale presented in this study, O-3 trends related to anthropogenic NOx and VOC reductions are being masked as a result of a number of factors including meteorological variability, changes in background ozone and shifts in source patterns.

International audience ; National and European legislation over the past 20 yr, and the modernisation or removal of industrial sources, have significantly reduced European ozone precursor emissions. This study quantifies observed and modelled European ozone annual and seasonal linear trends from 158 harmonised rural background monitoring stations over a constant time period of a decade (1996-2005). Mean ozone concentrations are investigated, in addition to the ozone 5th percentiles as a measure of the baseline or background conditions, and the 95th percentiles that are representative of the peak concentration levels. This study aims to characterise and quantify surface European ozone concentrations and trends and assess the impact of the changing anthropogenic emission tracers on the observed and modelled trends. Significant (p<0.1) positive annual trends in ozone mean, 5th and 95th percentiles are observed at 54%, 52% and 45% of sites respectively (85 sites, 82 sites and 71 sites). Spatially, sites in central and north-western Europe tend to display positive annual ozone trends in mean, 5th and 95th percentiles. Significant negative annual trends in ozone mean 5th and 95th percentiles are observed at 11%, 12% and 12% of sites respectively (18 sites, 19 sites and 19 sites) which tend to be located in the eastern and southwestern extremities of Europe. European-averaged annual trends have been calculated from the 158 sites in this study. Overall there is a net positive annual trend in ob-served ozone mean (0.16 +/- 0.02 ppbv yr(-1) (2 sigma error)), 5th (0.13 +/- 0.02 ppbv yr(-1)) and 95th (0.16 +/- 0.03 ppbv yr(-1)) percentiles, representative of positive trends in mean, baseline and peak ozone. Assessing the sensitivity of the derived overall trends to the constituent years shows that the European heatwave year of 2003 has significant positive influence and 1998 the converse effect; demonstrating the masking effect of inter-annual variability on decadal based ozone trends. The European scale 3-D CTM CHIMERE was used to simulate hourly O-3 concentrations for the period 1996-2005. Comparisons between the 158 observed ozone trends to those equivalent sites extracted from regional simulations by CHIMERE better match the observed increasing annual ozone (predominantly in central and north-western Europe) for 5th percentiles, than for mean or 95th ozone percentiles. The European-averaged annual ozone trend in CHIMERE 5th percentiles (0.13 +/- 0.01 ppbv yr(-1)) matches the corresponding observed trend extremely well, but displays a negative trend for the 95th percentile (-0.03 +/- 0.02 ppbv yr(-1)) where a positive ozone trend is observed. Inspection of the EU-averaged monthly means of ozone shows that the CHIMERE model is overestimating the summer month O-3 levels. In comparison to trends in EMEP emissions inventories, with the exception of Austria-Hungary, we do not find that anthropogenic NOx and VOC reductions have a substantial effect on observed annual mean O-3 trends in the rest of Europe. On a ten year time-scale presented in this study, O-3 trends related to anthropogenic NOx and VOC reductions are being masked as a result of a number of factors including meteorological variability, changes in background ozone and shifts in source patterns.

International audience ; Meteorological data measured by ground stations are often a key element in the development and validation of methods exploiting satellite images. These data are considered as a reference against which satellite-derived estimates are compared. Long-term radiation and meteorological measurements are available from a large number of measuring sta- tions. However, close examination of the data often reveals a lack of quality, often for extended periods of time. This lack of quality has been the reason, in many cases, of the rejection of large amount of available data. The quality data must be checked before their use in order to guarantee the inputs for the methods used in modelling, monitoring, forecast, etc. To control their quality, data should be submitted to several conditions or tests. After this checking, data that are not flagged by any of the test is released as a plausible data. In this work, it has been performed a bibliographical research of quality control tests for the common meteoro- logical variables (ambient temperature, relative humidity and wind speed) and for the usual solar radiometrical variables (horizontal global and diffuse components of the solar radiation and the beam normal component). The different tests have been grouped according to the variable and the average time period (sub-hourly, hourly, daily and monthly averages). The quality test may be classified as follows: * Range checks: test that verify values are within a specific range. There are two types of range checks, those based on extrema and those based on rare observations. * Step check: test aimed at detecting unrealistic jumps or stagnation in the time series. * Consistency checks: test that verify the relationship between two or more time series. The gathered quality tests are applicable for all latitudes as they have not been optimized regionally nor seasonably with the aim of being generic. They have been applied to ground measurements in several geographic locations, what result in the detection of some control tests that are no longer adequate, due to different reasons. After the modification of some test, based in our experience, a set of quality control tests is now presented, updated according to technology advances and classified. The presented set of quality tests allows radiation and meteorological data to be tested in order to know their plausibility to be used as inputs in theoretical or empirical methods for scientific research. The research leading to those results has partly receive funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under Grant Agreement no. 262892 (ENDORSE project

International audience ; To face the consequences of climate change and unsustainable urbanization, green roofs are currently widely implemented in urban environments. Despite their benefits to restore ecosystem services are quite well established at the roof scale, green roofs need to be widely and appropriately distributed to perform efficiently at larger scales. However for now, this scale-factor is not considered to guide and conduct green roof implementation policies. Here we show that a multi-scale analysis based on fractal theory is helpful in providing information for green roof implementation and in assessing the relevance of these policies. We found the fractal dimensions computed for green roofs are sparse, ranging from 0.49 to 1.35 for the nine studied cities, and illustrate some different degrees of progress in urban greening. Our results demonstrate some significant inconsistencies between political ambition and their in situ realization, and the necessity to better take into account the spatial distribution of green roof implementations in order to optimize their performances.

International audience ; To face the consequences of climate change and unsustainable urbanization, green roofs are currently widely implemented in urban environments. Despite their benefits to restore ecosystem services are quite well established at the roof scale, green roofs need to be widely and appropriately distributed to perform efficiently at larger scales. However for now, this scale-factor is not considered to guide and conduct green roof implementation policies. Here we show that a multi-scale analysis based on fractal theory is helpful in providing information for green roof implementation and in assessing the relevance of these policies. We found the fractal dimensions computed for green roofs are sparse, ranging from 0.49 to 1.35 for the nine studied cities, and illustrate some different degrees of progress in urban greening. Our results demonstrate some significant inconsistencies between political ambition and their in situ realization, and the necessity to better take into account the spatial distribution of green roof implementations in order to optimize their performances.

This thesis is devoted to an analysis of the lightning activity of storm systems in Equatorial Africa (10°E-35°E; 15°S-10°N) over the period 2005-2013. Firstly, data from the World Wide Lightning Location Network (WWLLN) were compared with those from the Lightning Imaging Sensor (LIS) to estimate the relative detection efficiency of the WWLLN. Then, they established a high-resolution regional climatology of lightning activity. Finally, they were combined with data on cloud and meteorological characteristics to carry out thunderstorm case studies in different situations in order to examine the correlations between lightning activity, storm activity, cloud characteristics and meteorological conditions. The appropriate method introduced for estimating the WWLLN detection efficiency in the study area provides values ??consistent with those found in other regions of the world. Its spatial and temporal variability helps to interpret changes affecting several parameters of lightning activity. The climatology realized reveals original characteristics of the temporal evolution and the spatial distribution of the lightning activity, in particular those of a very sharp maximum in the Eastern Democratic Republic of Congo. Thus, the location, the dimensions, the shape, the seasonal persistence and the environment of this maximum have been specified. The zonal distribution of lightning shows a high proportion in the southern tropical band, linked to the principal maximum but also to a high activity spread out longitudinally and constituting a large secondary maximum where the storm activity is more spatially variable from one year to another, temporally from one season to another, and where the diurnal cycle is less marked. [.] ; Cette thèse est consacrée à une analyse de l'activité d'éclairs des systèmes orageux en Afrique équatoriale (10°E - 35°E ; 15°S - 10°N) sur la période de temps 2005-2013. Tout d'abord, les données fournies par le réseau global de détection d'éclairs WWLLN (World Wide Lightning Location Network) ont ...

This thesis is devoted to an analysis of the lightning activity of storm systems in Equatorial Africa (10°E-35°E; 15°S-10°N) over the period 2005-2013. Firstly, data from the World Wide Lightning Location Network (WWLLN) were compared with those from the Lightning Imaging Sensor (LIS) to estimate the relative detection efficiency of the WWLLN. Then, they established a high-resolution regional climatology of lightning activity. Finally, they were combined with data on cloud and meteorological characteristics to carry out thunderstorm case studies in different situations in order to examine the correlations between lightning activity, storm activity, cloud characteristics and meteorological conditions. The appropriate method introduced for estimating the WWLLN detection efficiency in the study area provides values ??consistent with those found in other regions of the world. Its spatial and temporal variability helps to interpret changes affecting several parameters of lightning activity. The climatology realized reveals original characteristics of the temporal evolution and the spatial distribution of the lightning activity, in particular those of a very sharp maximum in the Eastern Democratic Republic of Congo. Thus, the location, the dimensions, the shape, the seasonal persistence and the environment of this maximum have been specified. The zonal distribution of lightning shows a high proportion in the southern tropical band, linked to the principal maximum but also to a high activity spread out longitudinally and constituting a large secondary maximum where the storm activity is more spatially variable from one year to another, temporally from one season to another, and where the diurnal cycle is less marked. [.] ; Cette thèse est consacrée à une analyse de l'activité d'éclairs des systèmes orageux en Afrique équatoriale (10°E - 35°E ; 15°S - 10°N) sur la période de temps 2005-2013. Tout d'abord, les données fournies par le réseau global de détection d'éclairs WWLLN (World Wide Lightning Location Network) ont ...

This thesis is devoted to an analysis of the lightning activity of storm systems in Equatorial Africa (10°E-35°E; 15°S-10°N) over the period 2005-2013. Firstly, data from the World Wide Lightning Location Network (WWLLN) were compared with those from the Lightning Imaging Sensor (LIS) to estimate the relative detection efficiency of the WWLLN. Then, they established a high-resolution regional climatology of lightning activity. Finally, they were combined with data on cloud and meteorological characteristics to carry out thunderstorm case studies in different situations in order to examine the correlations between lightning activity, storm activity, cloud characteristics and meteorological conditions. The appropriate method introduced for estimating the WWLLN detection efficiency in the study area provides values ??consistent with those found in other regions of the world. Its spatial and temporal variability helps to interpret changes affecting several parameters of lightning activity. The climatology realized reveals original characteristics of the temporal evolution and the spatial distribution of the lightning activity, in particular those of a very sharp maximum in the Eastern Democratic Republic of Congo. Thus, the location, the dimensions, the shape, the seasonal persistence and the environment of this maximum have been specified. The zonal distribution of lightning shows a high proportion in the southern tropical band, linked to the principal maximum but also to a high activity spread out longitudinally and constituting a large secondary maximum where the storm activity is more spatially variable from one year to another, temporally from one season to another, and where the diurnal cycle is less marked. [.] ; Cette thèse est consacrée à une analyse de l'activité d'éclairs des systèmes orageux en Afrique équatoriale (10°E - 35°E ; 15°S - 10°N) sur la période de temps 2005-2013. Tout d'abord, les données fournies par le réseau global de détection d'éclairs WWLLN (World Wide Lightning Location Network) ont ...