100 years of atmospheric and marine observations at the Finnish Utö Island in the Baltic Sea

The Utö Atmospheric and Marine Research Station introduced in this paper is located on Utö Island (59°46.84′ N, 21°22.13′ E) at the outer edge of the Archipelago Sea, by the Baltic Sea towards the Baltic Proper. Meteorological observations at the island started in 1881 and vertical profiling of seawater temperature and salinity in 1900. Since 1980, the number of observations at Utö has rapidly increased, with a large number of new meteorological, air quality, aerosol, optical and greenhouse gas parameters, and recently, a variety of marine observations. In this study, we analyze long-term changes of atmospheric temperature, cloudiness, sea salinity, temperature and ice cover. Our main dataset consists of 248 367 atmospheric temperature observations, 1632 quality-assured vertical seawater temperature and salinity profiles and 8565 ice maps, partly digitized for this project. We also use North Atlantic Oscillation (NAO), major Baltic inflow (MBI) and Baltic Sea river runoff data from the literature as reference variables to our data. Our analysis is based on a statistical method utilizing a dynamic linear model. The results show an increase in the atmospheric temperature at Utö, but the increase is significantly smaller than on land areas and has taken place only since the early 1980s, with a rate of 0.4 °C decade−1 during the last 35 years. We also see an increase in seawater temperatures, especially on the surface, with an increase of 0.3 °C decade−1 for the last 100 years. In deeper water layers, the increase is smaller and influenced by vertical mixing, which is modulated by inflow of saline water from the North Sea and freshwater inflow from rivers and by wind-driven processes influenced by the local bathymetry. The date when air temperature in the spring exceeds +5 °C became 5 days earlier from the period 1951–1980 to the period 1981–2010 and the date when sea surface water temperature exceeds +4 °C changed to 9 days earlier. Sea ice cover duration at Utö shows a decrease of approximately 50 % during the last 35 years. Based on the combined results, it is possible that the climate at Utö has changed into a new phase, in which the sea ice no longer reduces the local temperature increase caused by the global warming.</p

Prolonged interglacial warmth during the Last Glacial in northern Europe

Few fossil-based environmental and climate records in northern Europe are dated to Marine Isotope Stage (MIS) 5a around 80 ka BP. We here present multiple environmental and climate proxies obtained from a lake sequence of MIS 5a age in the Sokli basin (northern Finland). Pollen/spores, plant macrofossils, NPPs (e.g. green algae), bryozoa, diatoms and chironomids allowed an exceptionally detailed reconstruction of aquatic and telmatic ecosystem successions related to the development of the Sokli Ice Lake and subsequent infilling of a relatively small and shallow lake confined to the Sokli basin. A regional vegetation development typical for the early half of an interglacial is recorded by the pollen, stomata and plant macrofossil data. Reconstructions of July temperatures based on pollen assemblages suffer from a large contribution of local pollen from the lake's littoral zone. Summer temperatures reaching present-day values, inferred for the upper part of the lake sequence, however, agree with the establishment of pine-dominated boreal forest indicated by the plant fossil data. Habitat preferences also influence the climate record based on chironomids. Nevertheless, the climate optima of the predominant intermediate- to warm-water chironomid taxa suggest July temperatures exceeding present-day values by up to several degrees, in line with climate inferences from a variety of aquatic and wetland plant indicator species. The disequilibrium between regional vegetation development and warm, insolation-forced summers is also reported for Early Holocene records from northern Fennoscandia. The MIS 5a sequence is the last remaining fossil-bearing deposit in the late Quaternary basin infill at Sokli to be studied using multi-proxy evidence. A unique detailed climate record for MIS 5 is now available for formerly glaciated northern Europe. Our studies indicate that interglacial conditions persisted into MIS 5a, in agreement with data for large parts of the European mainland, shortening the Last Glacial by some 50 ka to MIS 4-2.Peer reviewe

Intraregional variability in chironomid-inferred temperature estimates and the influence of river inundations on lacustrine chironomid assemblages.

Floodplain lakes are rarely analysed for fossil chironomids and usually not incorporated in modern chironomid-climate calibration datasets because of the potential complex hydrological processes that could result from flooding of the lakes. In order to investigate this potential influence of river inundations on fossil chironomid assemblages, 13 regularly inundated lakes and 20 lakes isolated from riverine influence were sampled and their surface sediments analysed for subfossil chironomid assemblages. The physical and chemical settings of all lakes were similar, although the variation in the environmental variables was higher in the lakes isolated from riverine influence. Chironomid concentration and taxon richness show significant differences between the two classes of lakes, and the variation in these variables is best explained by loss-on-ignition of the sediments (LOI). Relative chironomid abundances show some differences between the two groups of lakes, with several chironomid taxa occurring preferentially in one of the two lake-types. The variability in chironomid assemblages is also best explained by LOI. Application of a chironomid-temperature inference model shows that both types of lakes reconstruct July air temperatures that are equal to, or slightly underestimating, the measured temperature of the region. We conclude that, although there are some differences between the chironomid assemblages of floodplain lakes and of isolated lakes, these differences do not have a major effect on chironomid-based temperature reconstruction. © 2007 Springer Science+Business Media B.V

Report on climate change and air quality interactions

The main objective of this report is to layout a broad overview of the latest understanding of climate and climate change and its connection with urban air quality. It critically reviews recent research studies that are not yet being used in practical applications and that are critical for later implementation of Passive Control Systems (PCSs) within the iSCAPE project. The Introduction is devoted to review the broad motivation for reducing air pollutant concentration in cities; it also deals with the potential benefits of using climate change information for city planning, a topic that is at the core of the iSCAPE project. The report is organized in two main parts, described as follows. 1. Climate and climate change in European cities 1.1. Description of climate change modelling approach. The study is performed starting from the regional to the urban scale. Issues to be kept in mind when monitoring the impacts of global climate change on urban and smaller scales are data quality and homogeneity; climate conditions in cities may not be captured by weather stations, as these are typically located in open vegetated land (rural or natural landscapes). Moreover, uncertainty is always involved in climates change projections. For simulations of future climate, climate model experiments are run under assumptions about the future evolution of atmospheric composition, land use change and other driving forces of the climate system. Global and regional climate models, typically having a grid size of tens of kilometres or larger, poorly resolve the urban land surface. The geographical pattern of the simulated climate response may be downscaled using various methods. Several physical-based surface models can simulate air-surface interactions at a horizontal scale of about 100 metres. However, many urban parameterizations still follow highly simplified approaches. The Town Energy Balance (TEB) model (Masson, 2000; Lemonsu et al., 2004), included in the surface interaction model SURFEX, is an example of a model capable of clearly separating buildings, air within urban canyons, roads, and, if present, trees, gardens etc. 1.2. Setting of the role of physical variables in current climate and change. The focus is to set the basis for subsequent studies within iSCAPE. The role of the physical variables that can be extracted from future climate change scenarios at urban scale is discussed. These variables are those that are relevant for establishing the link between climate change and air quality i.e. temperature, wind speed, pressure and solar radiation, and these variables have to be used to evaluate the efficacy of PCSs in future scenarios. This is also one of the main aims of iSCAPE. The main results from this sections are: 1.2.1. the observed annual-averaged pan-European temperature trend of 0.179\ub0C per decade since 1960. 1.2.2. the average impact of urbanization on that trend is 0.0026\ub0C per decade since 1960. The effect is strongest in spring and summer. 1.2.3. Among the iSCAPE cities, the projected summertime warming is largest for Bologna and smallest in Dublin. In winter, and also in spring and autumn, the most pronounced increases in temperature are likely to take place in Vantaa. 1.2.4. Precipitation is generally projected to increase in winter and decrease in summer. However, the sign of the change is uncertain in Bologna in winter and in Vantaa in summer. 1.2.5. Incident solar radiation and diurnal temperature range are projected increase in most of Europe in spring, summer and autumn. 1.2.6. The observed reduction in the mean annual solar radiation in southern Finland over the period from 1958 to 1992 was mainly attributed to a pronounced increase in cloudiness, with only a minor contribution from the direct effects of the relatively large aerosol load at that time. 1.2.7. Wintertime sea level air pressure is projected to decrease in Vantaa and increase elsewhere. In Dublin and Guildford, the projected trend is positive in all seasons and in Belgium and Germany in all seasons except for the summer simulations. 2. Air quality and climate change interaction in European cities 2.1. Focus on the mean state of pollutants in the target cities. This part magnifies the focus on the mean state of the main pollutants (NO2, PM10 and PM2.5) as well as O3 that is relevant for climate change for the iSCAPE target cities. Given that, the scope is to identify the preferential conditions for PCSs deployment in each target city and provide state of art knowledge for subsequent work packages (WPs). Specifically, we find that pollutant concentrations have different impacts due to meteorological, geographical and structural features of the single city, but also as a result of local air quality policies. In general traffic-induced emissions (NO2 and PM10) have an influence on total concentration at street level, but not at urban scale. Residential heating systems also contribute again at street level, but its signal is weaker. Two pollutants, NO2 and PM10 have a dependence on emissions at the street scale, while PM2.5 is more homogeneous in the urban environment. Concerning the risks on human heath connected to exposure to high level of PM2.5 has led to a decrease and an adjustment of concentrations at WHO suggested level for human health which is stricter than the European limit. Only Bologna, among the target cities requires to improve its efforts to mitigate the PM2.5 concentrations. Ozone concentrations is quite homogeneous at the city scale. In rural areas ozone concentrations sensibly grow, supported by favourable conditions. 2.2. Assessments on pollutants linkages with climate change. Really few studies have been performed on the relationship between air quality and climate change, especially at small scales. It easier to find studies concerning air quality linked with the urbanization growth (with some problems of inhomogeneity between different nations due to different necessity and city types). At European scale, the climatological variables that mostly affect air quality are: surface temperature, precipitation and sea level pressure. Temperature scenarios, coupled with precipitation pattern projection, facilitate an increase in pollutants such as ozone due to increased biogenic emissions and photochemical rates and reduced wet removal. Changes in meteorological variables can modify global sea level pressure patterns, with consequences on local circulations and distribution of air masses. In the end, climate change induced by enhanced pollutant emissions will in turn increase pollutant concentration. So, a positive feedback is established, leading to an intensification of climate changes in those regions highly affected by pollution. It is important to underline that these connections between climate and pollutants concern the larger scales (global, or at least European). Specific studies at local scale have to be provide to achieve a better understanding on the future livability of our cities

Mechanisms of Ventilation in real Street Canyon: the Bologna iSCAPE case study

Traffic induced emissions have been commonly addressed as major source for air pollution in cities. Gases and particulate matter resulting from the combustion processes are the main components of these emissions, but also pneumatic abrasion, brake discs consumption and road dust resuspension contribute to air quality deterioration. The presence of dense built up areas limits the efficacy of atmospheric winds to disperse pollutants, enhancing near ground concentrations. It is known that tree planting in urban street canyons influences pollutants dispersion and exchange with the free atmosphere by affecting wind ventilation at street and neighborhood levels. Nevertheless, the actual quantification of tree influence depends on different and mutual interacting factors: synoptic meteorological conditions, wind stress at the top of the canyon, geometry of the street canyon and vegetation. Within the recently EU funded project iSCAPE, the role of vegetation in street canyons has being analyzed in real street canyons in the city of Bologna (Italy). Specifically, multi-levels of turbulent fluxes are being measured during summer 2017 in two typical street canyons in combination with ground level concentration measurements. Data interpretation is assisted by Computational Fluid Dynamics (CFD) modelling to extract the key mechanisms of ventilation in typical Italian cities. Results are sought for extension to other European cities that are characterized by low synoptic conditions and similar morphological structures

Report on Footprint of Passive Control Systems

Due to the serious impacts on public health, it is essential to control air pollution, especially in and around cities where a majority of the world\u2019s population lives and pollution concentrations are typically much higher than in rural areas. Passive control systems (PCSs) are interventions for reducing air pollution, which include low boundary walls, green infrastructure (GI), and photocatalytic coating. In this report, we analyse the footprint and the benefits of implementing PCSs as interventions to reduce personal exposure to air pollution in the built environment, with a specific focus on their application in iSCAPE cities. In addition to discussing the available literature, this report provides the methodologies for the assessment and evaluation of PCSs interventions. This report summarises the iSCAPE intervention evaluation methods, sites description, instruments setup and experimental protocols for the potential of using physical passive controls (low boundary walls) and green infrastructure (trees, hedges, green walls and/or roofs), and the utilisation of photo-catalytic coatings (in road tiles or walls). This report considers a SWOT (strengths \u2013 weaknesses \u2013 opportunities \u2013 threats) analysis for each type of PCS intervention

Daily mean sea level pressure reconstructions for the european–north atlantic region for the period 1850–2003

The development of a daily historical European-North Atlantic mean sea level pressure dataset (EMSLP) for 1850-2003 on a 5 latitude by longitude grid is described. This product was produced using 86 continental and island stations distributed over the region 25 degrees-70 degrees N, 70 degrees W-50 degrees E blended with marine data from the International Comprehensive Ocean-Atmosphere Data Set (ICOADS). The EMSLP fields for 1850-80 are based purely on the land station data and ship observations. From 1881, the blended land and marine fields are combined with already available daily Northern Hemisphere fields. Complete coverage is obtained by employing reduced space optimal interpolation. Squared correlations (r(2)) indicate that EMSLP generally captures 80%-90% of daily variability represented in an existing historical mean sea level pressure product and over 90% in modern 40-yr European Centre for Medium-Range Weather Forecasts Re-Analyses (ERA-40) over most of the region. A lack of sufficient observations over Greenland and the Middle East, however, has resulted in poorer reconstructions there. Error estimates, produced as part of the reconstruction technique, flag these as regions of low confidence. It is shown that the EMSLP daily fields and associated error estimates provide a unique opportunity to examine the circulation patterns associated with extreme events across the European-North Atlantic region, such as the 2003 heat wave, in the context of historical events