Climate change and future ozone concentrations in high resolution over Europe

In this study a methodology is developed that applies the ozone concentration change signal from a global climate-chemical modeling system with a coarse horizontal resolution to a finer resolution. To this aim simulations with two different configurations of the GEOS-CHEM chemical transport model are conducted a) driven from the GISS III general circulation model (4ox 5o) for a present (1999–2001) and a future (2049–2051) period and b) driven by assimilated meteorological data (GEOS, 0.5o x 0.667o) for the year 2005. Results indicate highest increases between the future and the reference period in the north west and the south west Europe for both the average mean (~ 5 ppb) and average daily maximum ozone concentrations (~ 10 ppb) whereas the highest decreases (~ 4-6 ppb) are shown in the south East Europe for the same statistical targets. Moreover, these results are of the same sign to the results of the global climate-chemical modelling system in the North-west and the South-east Europe. Nevertheless changes in the GISS/GEOS-CHEM between the future and the present climate are in the range of ± 2 ppb and ± 3 ppb for the average mean and the average daily maximum ozone concentrations respectively

Monitoring climate related risk and opportunities for the wine sector: The MED-GOLD pilot service

MED-GOLD was a 54-months research and innovation project, whose main aim was to co-develop climate services for three staples of the Mediterranean food system, namely grapes, olives and durum wheat. This paper describes the methodology adopted for the co-development of the pilot climate service for the wine sector, focusing on the Douro Wine Region in northern Portugal. In the first step, the MED-GOLD industrial partner SOGRAPE identified key decisions and users’ needs for the wine sector in the Douro region by involving managers from their own vineyards in that region. From this information, the relevant bioclimatic indicators (and associated essential climate variables) were selected. Afterwards, two compound risk indices, the Sanitary and Heat Risk indices, were introduced as a combination of some of the aforementioned bioclimatic indicators. This methodological work was validated against the empirical climate characterization for the region of interest, of several ‘bad’ and ‘good’ years chosen by users according to their recollections of grape and wine production outcomes, namely quality and yields. In this paper, the overall strategy for selection of these years is presented. The components of the service based on historical climate, seasonal predictions and longer-term climate projections are described along with the visual interface developed: the MED-GOLD Dashboard, an interactive tool that displays detailed historical climate data, seasonal predictions and climate projections. The Dashboard consists of an ICT platform with a map-based user-focused front end to aid easy access to and manipulation of the data. The Dashboard was iteratively co-designed with the users to ensure their needs were met

Ozone-temperature relationship during the 2003 and 2014 heatwaves in Europe

High values of temperature and ozone (O3) concentrations often coexist revealing the strong relationship between them. In this study, we examine the O3-temperature slopes for two heatwave episodes during the summers of 2003 and 2014 in Europe. In both heatwave episodes, similar slopes of about 3.1 ppb/°C are found, about 1 ppb/°C higher when compared with summers with near normal temperatures. The lowest correlation coefficient calculated for the two variables in the 2003 heatwave is attributed to the break of the O3-temperature relationship in the higher percentiles of both variables, while for the 2014 heatwave the highest correlation coefficient is attributed to the increased isoprene emission fluxes. However, the clear response of O3 to temperature perturbations in 2003 was better manifested when the mean anomalies of the two variables between the heatwave and the normal period were examined, with the calculated slope of about 4.75 ppb/°C. In addition, the slope of about 1.5 days of O3 exceedances/day with Tmax > 90th percentile indicates the role of extreme temperatures to the extension of the O3 exceedance period. This indicates that when future O3 levels are estimated based on the relationship of O3 with meteorological variables (such as temperature), extreme periods (such as heatwaves) should be taken into account in their training periods in order to obtain more realistic results. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature

Statistical estimations of the number of future ozone exceedances due to climate change in Europe

A statistical model to examine the potential impact of increasing future temperatures due to climate change on ozone exceedances (days with daily maximum 8 h average ≥ 60 ppb) is developed for Europe. We employ gridded observed daily maximum temperatures and hourly ozone observations from nonurban stations across Europe, together with daily maximum temperatures for 2021-2050 and 2071-2100 from three regional climate models, based on the Intergovernmental Panel on Climate Change Special Reports on Emissions Scenarios A1B scenario. A rotated principal components analysis is applied to the ozone stations yielding five principal components, which divide the study domain in five subregions. The historical ozone-temperature relationship is examined and then used to provide estimates of future ozone exceedance days under current emissions and under the assumption that this relationship will retain its main characteristics. Results suggest that increases in the upper temperature percentiles lead to statistically significant increases (95% statistical significance level) of the ozone exceedances for both future periods. The greatest average increases depending on the particular regional climate model range from 5 to 12 extra ozone days/yr for 2021-2050 and from 16 to 25 for 2071-2100, in southeast Europe. The lowest average increases range from 0 to 2 extra ozone days/yr for 2021-2050 and from 2 to 4 for 2071-2100 and are seen in northwest Europe. The simulations with the dynamical Goddard Institute of Space Studies/GEOS-CHEM climate chemistry modeling system shows decreases instead of increases in eastern Europe, higher increases in northwest Europe, whereas for the other subregions similar results to the statistical model are obtained. Key Points Statistical models can complement the dynamical ones Statistical models could provide useful tools for policymakers Greatest increases of climate change impact on ozone are seen in Southern Europe © 2013. American Geophysical Union. All Rights Reserved

The role of planetary boundary-layer parameterizations in the air quality of an urban area with complex topography

The effect of different planetary boundary-layer (PBL) parameterization schemes on the spatial distribution of atmospheric pollution over the complex topography of the greater Athens area is investigated. Four PBL schemes originally implemented in a numerical meteorological model and a fifth one simulating the urban effect are examined. Two different atmospheric conditions are analyzed; a typical summer and a typical winter pollution episode. The relative importance of chemical and physical processes of the pollution predictions is discussed using process analysis. It is revealed that, for primary pollutants, a local scheme seems more adequate to represent the maximum observed concentrations while, completely different in structure, a non-local scheme reproduces the mean observed values in the basin. Concerning secondary pollutants, peak concentration differences, due to the different PBL schemes, are smoothed out. Nevertheless, the PBL scheme selection shapes the horizontal and the vertical extension of maximum values. The non-local and semi non-local schemes are superior to the others, favouring strong vertical mixing and transport towards the surface. The stronger turbulence accommodated effectively by the semi non-local urban scheme enhances ozone production along the sea-breeze axis and preserves the high ozone concentrations during the nighttime hours in the urban core. © Springer Science+Business Media B.V. 2009

Issues related to aircraft take-off plumes in a mesoscale photochemical model

The physical and chemical characteristics of aircraft plumes at the take-off phase are simulated with the mesoscale CAMx model using the individual plume segment approach, in a highly resolved domain, covering the Athens International Airport. Emission indices during take-off measured at the Athens International Airport are incorporated. Model predictions are compared with in situ point and path-averaged observations (NO, NO2) downwind of the runway at the ground. The influence of modeling process, dispersion properties and background air composition on the chemical evolution of the aircraft plumes is examined. It is proven that the mixing properties mainly determine the plume dispersion. The initial plume properties become significant for the selection of the appropriate vertical resolution. Besides these factors, the background NOx and O3 concentration levels control NOx distribution and their conversion to nitrogen reservoir species. © 2013 Elsevier B.V

Urban thermal risk reduction: Developing and implementing spatially explicit services for resilient cities

Elevated urban temperatures and heatwaves are a serious threat to the health and wellbeing of the continuously growing urban population and are projected to worsen under climate change. For this reason well-informed disaster risk reduction (DRR) actions, where science and technology play a key role, are required. However insufficient communication between scientific and policy-making communities (known as the science-policy gap) hampers the use of science in DRR. Hence there is a strong need to interpret existing scientific knowledge into actionable knowledge, i.e. science that is useful, usable and used. This article presents a series of services and tools that build-upon existing scientific knowledge and aim to provide actionable knowledge to authorities and citizens for reducing the risks of elevated urban temperatures. The above were implemented in the context of the European Commission's Thermal Risk rEduction Actions and tools for secURE cities (TREASURE) project, and address many of the goals and priorities for action set in the Sendai framework for disaster risk reduction (SFDRR) of the United Nations. A key policy-making user of the implemented services and tools is the City of Athens in Greece, which is one of the largest metropolitan areas in Europe. © 2017 Elsevier Lt

Is the ozone climate penalty robust in Europe?

Ozone air pollution is identified as one of the main threats bearing upon human health and ecosystems, with 25 000 deaths in 2005 attributed to surface ozone in Europe (IIASA 2013 TSAP Report #10). In addition, there is a concern that climate change could negate ozone pollution mitigation strategies, making them insufficient over the long run and jeopardising chances to meet the long term objective set by the European Union Directive of 2008 (Directive 2008/50/EC of the European Parliament and of the Council of 21 May 2008) (60 ppbv, daily maximum). This effect has been termed the ozone climate penalty. One way of assessing this climate penalty is by driving chemistry-transport models with future climate projections while holding the ozone precursor emissions constant (although the climate penalty may also be influenced by changes in emission of precursors). Here we present an analysis of the robustness of the climate penalty in Europe across time periods and scenarios by analysing the databases underlying 11 articles published on the topic since 2007, i.e. a total of 25 model projections. This substantial body of literature has never been explored to assess the uncertainty and robustness of the climate ozone penalty because of the use of different scenarios, time periods and ozone metrics. Despite the variability of model design and setup in this database of 25 model projection, the present meta-analysis demonstrates the significance and robustness of the impact of climate change on European surface ozone with a latitudinal gradient from a penalty bearing upon large parts of continental Europe and a benefit over the North Atlantic region of the domain. Future climate scenarios present a penalty for summertime (JJA) surface ozone by the end of the century (2071-2100) of at most 5 ppbv. Over European land surfaces, the 95% confidence interval of JJA ozone change is [0.44; 0.64] and [0.99; 1.50] ppbv for the 2041-2070 and 2071-2100 time windows, respectively. © 2015 IOP Publishing Ltd

Geophysical validation of MIPAS-ENVISAT operational ozone data

The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), on-board the European ENVIronmental SATellite (ENVISAT) launched on 1 March 2002, is a middle infrared Fourier Transform spectrometer measuring the atmospheric emission spectrum in limb sounding geometry. The instrument is capable to retrieve the vertical distribution of temperature and trace gases, aiming at the study of climate and atmospheric chemistry and dynamics, and at applications to data assimilation and weather forecasting. MIPAS operated in its standard observation mode for approximately two years, from July 2002 to March 2004, with scans performed at nominal spectral resolution of 0.025 cm -1 and covering the altitude range from the mesosphere to the upper troposphere with relatively high vertical resolution (about 3 km in the stratosphere). Only reduced spectral resolution measurements have been performed subsequently. MIPAS data were re-processed by ESA using updated versions of the Instrument Processing Facility (IPF v4.61 and v4.62) and provided a complete set of level-2 operational products (geolocated vertical profiles of temperature and volume mixing ratio of H2O, O3, HNO3, CH4, N2O and NO2) with quasi continuous and global coverage in the period of MIPAS full spectral resolution mission. In this paper, we report a detailed description of the validation of MIPAS-ENVISAT operational ozone data, that was based on the comparison between MIPAS v4.61 (and, to a lesser extent, v4.62) O3 VMR profiles and a comprehensive set of correlative data, including observations from ozone sondes, ground-based lidar, FTIR and microwave radiometers, remote-sensing and in situ instruments on-board stratospheric aircraft and balloons, concurrent satellite sensors and ozone fields assimilated by the European Center for Medium-range Weather Forecasting. A coordinated effort was carried out, using common criteria for the selection of individual validation data sets, and similar methods for the comparisons. This enabled merging the individual results from a variety of independent reference measurements of proven quality (i.e. well characterized error budget) into an overall evaluation of MIPAS O3 data quality, having both statistical strength and the widest spatial and temporal coverage. Collocated measurements from ozone sondes and ground-based lidar and microwave radiometers of the Network for the Detection Atmospheric Composition Change (NDACC) were selected to carry out comparisons with time series of MIPAS O 3 partial columns and to identify groups of stations and time periods with a uniform pattern of ozone differences, that were subsequently used for a vertically resolved statistical analysis. The results of the comparison are classified according to synoptic and regional systems and to altitude intervals, showing a generally good agreement within the comparison error bars in the upper and middle stratosphere. Significant differences emerge in the lower stratosphere and are only partly explained by the larger contributions of horizontal and vertical smoothing differences and of collocation errors to the total uncertainty. Further results obtained from a purely statistical analysis of the same data set from NDACC ground-based lidar stations, as well as from additional ozone soundings at middle latitudes and from NDACC ground-based FTIR measurements, confirm the validity of MIPAS O3 profiles down to the lower stratosphere, with evidence of larger discrepancies at the lowest altitudes. The validation against O3 VMR profiles using collocated observations performed by other satellite sensors (SAGE II, POAM III, ODIN-SMR, ACE-FTS, HALOE, GOME) and ECMWF assimilated ozone fields leads to consistent results, that are to a great extent compatible with those obtained from the comparison with ground-based measurements. Excellent agreement in the full vertical range of the comparison is shown with respect to collocated ozone data from stratospheric aircraft and balloon instruments, that was mostly obtained in very good spatial and temporal coincidence with MIPAS scans. This might suggest that the larger differences observed in the upper troposphere and lowermost stratosphere with respect to collocated ground-based and satellite O3 data are only partly due to a degradation of MIPAS data quality. They should be rather largely ascribed to the natural variability of these altitude regions and to other components of the comparison errors. By combining the results of this large number of validation data sets we derived a general assessment of MIPAS v4.61 and v4.62 ozone data quality. A clear indication of the validity of MIPAS O3 vertical profiles is obtained for most of the stratosphere, where the mean relative difference with the individual correlative data sets is always lower than ±10%. Furthermore, these differences always fall within the combined systematic error (from 1 hPa to 5OhPa) and the standard deviation is fully consistent with the random error of the comparison (from 1 hPa to ∼~30-40hPa). A degradation in the quality of the agreement is generally observed in the lower stratosphere and upper troposphere, with biases up to 25% at 100 hPa and standard deviation of the global mean differences up to three times larger than the combined random error in the range 50-100 hPa. The larger differences observed at the bottom end of MIPAS retrieved profiles can be associated, as already noticed, to the effects of stronger atmospheric gradients in the UTLS that are perceived differently by the various measurement techniques. However, further components that may degrade the results of the comparison at lower altitudes can be identified as potentially including cloud contamination, which is likely not to have been fully filtered using the current settings of the MIPAS cloud detection algorithm, and in the linear approximation of the forward model that was used for the a priori estimate of systematic error components. The latter, when affecting systematic contributions with a random variability over the spatial and temporal scales of global averages, might result in an underestimation of the random error of the comparison and add up to other error sources, such as the possible underestimates of the p and T error propagation based on the assumption of a 1K and 2% uncertainties, respectively, on MIPAS temperature and pressure retrievals. At pressure lower than 1 hPa, only a small fraction of the selected validation data set provides correlative ozone data of adequate quality and it is difficult to derive quantitative conclusions about the performance of MIPAS O2 retrieval for the topmost layers