Are the Pyrenees a barrier for the transport of birch (Betula) pollen from Central Europe to the Iberian Peninsula?

This work provides a first assessment of the possible barrier effect of the Pyrenees on the atmospheric transport of airborne pollen from Europe to the North of the Iberian Peninsula. Aerobiological data recorded in three Spanish stations located at the eastern, central and western base of the Pyrenees in the period 2004–2014 have been used to identify the possible long range transport episodes of Betula pollen. The atmospheric transport routes and the origin regions have been established by means of trajectory analysis and a source receptor model. Betula pollen outbreaks were associated with the meteorological scenario characterized by the presence of a high-pressure system overm over Morocco and Southern Iberian Peninsula. France and Central Europe have been identified as the probable source areas of Betula pollen that arrives to Northern Spain. However, the specific source areas are mainly determined by the particular prevailing atmospheric circulation of each location. Finally, the Weather Research and Forecasting model highlighted the effect of the orography on the atmospheric transport patterns, showing paths through the western and easternmost lowlands for Vitoria-Gasteiz and Bellaterra respectively, and the direct impact of air flows over Vielha through the Garona valley.Peer ReviewedPreprin

Atmospheric dispersion of airborne pollen evidenced by near-surface and columnar measurements in Barcelona, Spain

Hourly measurements of pollen near-surface concentration and lidar-derived profiles of particle backscatter coefficients and of volume and particle depolarization ratios during a 5-day pollination event observed in Barcelona, Spain, between 27 – 31 March, 2015, are presented. Maximum hourly pollen concentrations of 4700 and 1200 m-3 h-1 were found for Platanus and Pinus, respectively, which represented together more than 80 % of the total pollen. Everyday a clear diurnal cycle caused by the vertical transport of the airborne pollen was visible on the lidar-derived profiles of the backscatter coefficient with maxima usually reached between 12 and 15 UT. A method based on the lidar polarization capabilities was used to retrieve the contribution of the pollen to the total signal. On average the diurnal (9 – 17 UT) pollen aerosol optical depth (AOD) was 0.05 which represented 29 % of the total AOD, the volume and particle depolarization ratios in the pollen plume were 0.08 and 0.14, respectively, and the diurnal mean of the height of the pollen plume was found at 1.24 km. The dispersion of the Platanus and Pinus in the atmosphere was simulated with the Nonhydrostatic Multiscale Meteorological Model on the B grid at the Barcelona Supercomputing Center with a newly developed Chemical Transport Model (NMMB/BSC-CTM). Model near-surface daily concentrations were compared to our observations at two sites: in Barcelona and Bellaterra (12 km NE of Barcelona). Model hourly concentrations were compared to our observations in Barcelona.Peer ReviewedPostprint (author's final draft

Modelling of pollen dispersion in the atmosphere: evaluation with a continuous 1ß+1d lidar

Pollen allergenicity plays an important role on human health and wellness. It is thus of large public interest to increase our knowledge of pollen grain behavior in the atmosphere (source, emission, processes involved during their transport, etc.) at fine temporal and spatial scales. First simulations with the Barcelona Supercomputing Center NMMB/BSC-CTM model of Platanus and Pinus dispersion in the atmosphere were performed during a 5-day pollination event observed in Barcelona, Spain, between 27 – 31 March, 2015. The simulations are compared to vertical profiles measured with the continuous Barcelona Micro Pulse Lidar system. First results show that the vertical distribution is well reproduced by the model in shape, but not in intensity, the model largely underestimating in the afternoon. Guidelines are proposed to improve the dispersion of airborne pollen by numerical prediction models.Peer ReviewedPostprint (published version

Itineraris de natura a la UAB

El campus de la UAB, ha esdevingut amb el temps l'element més valuós del nostre patrimoni. El patrimoni natural on som inserits és ric i variat. Aquest llibret -que actualitza el fulletó que es va editar l'any 1998 amb motiu de la inauguració dels itineraris de natura de la universitat- vol contribuir a fer-nos-en més conscients de l'entorn, tot proposant-nos dos passejos per zones poc conegudes

Potential contribution of distant sources to airborne Betula pollen levels in Northeastern Iberian Peninsula

Betula (birch) pollen is one of the most important causes of respiratory allergy in Northern and Central Europe. While birch trees are abundant inCentral, Northern, and Eastern Europe,theyare scarce inthe Mediterranean territories, especially in the Iberian Peninsula (IP), where they grow only in the northern regions and as ornamental trees in urban areas. However, the airborne birch pollen patterns in Catalonia (Northeastern IP) show abrupt high concentrations in areas withusually low local influence.The intensity of the derived health problemscan beincreasedbyoutbreaksdue to long-range pollen transport. The present work evaluates the different potential contributions to Catalonia from the main source regions: Pyrenees, Cantabria, and the forests of France and Central Europe. To this end, we computed the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) back trajectories of air masses associated with the main Betula pollen peaks occurring simultaneously over different Catalan monitoring stations, and we studied their provenance over a 15-year period. The Vielha aerobiological station on the northern slopes of the Central Pyrenees was used to identify the dates of the pollen season in the Pyrenean region. In order to better understand the role of the Pyrenees, whichis thenearest of thefourbirch forested regions, weclassifiedthepollenpeaksinthe other Catalan stations into three groups based onthe relationship between the peak andthe pollenseason in thePyrenees. Our analysis of back-trajectory residence time, combined with the associated pollen concentration, reveals that two principal routes other than the Pyrenean forest sustain the northerly fluxes that enter Catalonia and carry significant concentrations of Betula pollen. This study has also allowed quantifying the differentiated contributions of the potential sourcePeer ReviewedObjectius de Desenvolupament Sostenible::3 - Salut i BenestarObjectius de Desenvolupament Sostenible::15 - Vida d'Ecosistemes TerrestresPostprint (published version

Real time secure communications using chaotic encryption systems

Available from British Library Document Supply Centre- DSC:DXN065315 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Is long range transport of pollen in the NW Mediterranean basin influenced by Northern Hemisphere teleconnection patterns?

Climatic oscillations triggered by the atmospheric modes of the Northern Hemisphere teleconnection patterns have an important influence on the atmospheric circulation at synoptic scale in Western Mediterranean Basin. Simultaneously, this climate variability could affect a variety of ecological processes. This work provides a first assessment of the effect of North Atlantic Oscillation (NAO), Arctic Oscillation (AO) and Western Mediterranean Oscillation (WeMO) on the atmospheric long-range pollen transport episodes in the North-Eastern Iberian Peninsula for the period 1994–2011. Alnus, Ambrosia, Betula, Corylus and Fagus have been selected as allergenic pollen taxa with potential long-range transport associated to the Northern Hemisphere teleconnection patterns in the Western Mediterranean Basin. The results showed an increase of long range pollen transport episodes of: (1) Alnus, Corylus and Fagus from Western and Central Europe during the negative phase of annual NAO and AO; (2) Ambrosia, Betula and Fagus from Europe during the negative phase of winter WeMO; (3) Corylus and Fagus from Mediterranean area during the positive phase of the annual AO; and (4) Ambrosia from France and Northern Europe during the positive phase of winter WeMO. Conversely, the positive phase of annual NAO and AO are linked with the regional transport of Alnus, Betula and Corylus from Western Iberian Peninsula. The positive phase of annual WeMO was also positively correlated with regional transport of Corylus from this area.Peer Reviewe

Influence of the climate variability on the airborne pollen levels recorded in Catalonia (NW Mediterranean)

Using 22 pollen taxa collected at 6 localities in Catalonia (NE Spain) during the period 1994-2011, we show that climate variability associated with Northern Hemisphere teleconnection patterns (North Atlantic Oscillation, Arctic Oscillation and Western Mediterranean Oscillation) affects both seasonal pollen production and the timing of the airborne pollen season. For most of the studied pollen taxa, positive phases of the 3 climatic indices were related to a decrease in the seasonal pollen index and an advance and enlargement of the pollen season. Furthermore, for most taxa, negative phases of the climatic indices were linked to higher pollen production via an increase in rainfall. A clear relationship between climatic indices and the end of the pollen season was not observed. Since pollen parameters correlate more strongly with the Western Mediterranean Oscillation index (WeMOi) than other indices, the WeMOi negative trend observed over the last decades needs to be confirmed to properly identify its effect on ecosystems and public health in the western Mediterranean basin.Postprint (author's final draft

Modelling of airborne pollen dispersion in the atmosphere in the Catalonia region, Spain: model description, emission scheme and evaluation of model performance for the case of Pinus

Pollination is a biologically-relevant process that affects the structure of ecosystems since pollen contributes to determine the spatial distribution of plant species. It is thus of interest for mapping ecosystem services for policy support and decision making to increase our knowledge of pollen grain behavior in the atmosphere (source, emission, processes involved during their transport, etc.) at fine temporal and spatial scales. First simulations with the Barcelona Supercomputing Center MONARCH dispersion model of Pinus pollen in the atmosphere were performed during a 5-day pollination event observed in Barcelona, Spain, between 27 – 31 March, 2015. MONARCH is an online atmospheric composition model that solves the life cycle of water vapor, gases and aerosols within a meteorological model. A new aerosol emission scheme for pollen grains has been implemented in the system. The emission scheme considers wind speed at 10 m and friction velocity as main drivers of the mobilization of Pinus pollen grains. The meteorological information is available for the emission scheme at each meteorological integration time step. The spatial distribution of the pine species (P. halepensis, P. pinea) that pollinate from February to April in Catalonia has been derived from the Cartography of habitats of Catalonia and the tree density was obtained from the Forest Inventory of Catalonia. A domain over north-east Spain at 9 km x 9 km horizontal resolution covering Catalonia is designed with 48 vertical layers. The initial meteorological conditions are derived from ERA-5. To evaluate the model performances, the simulations are compared (i) to ground-based concentration measurements performed with a Hirst collector in Barcelona downtown, and (ii) to vertically-resolved measurements performed 4 km west of Barcelona downtown with a Micro Pulse Lidar (MPL). A method based on the lidar polarization capabilities was used to retrieve the contribution of the pollen to the total signal. The conversion from optical lidar-retrieved properties to concentration was optimized by minimizing the sum of the squared deviations between the lidar-retrieved concentration at the first height and the true (Hirst) concentration measured at the ground. In terms of ground-based concentration, the simulations look usually good in the morning and worsen in the afternoon. As far as the vertical distribution of airborne Pinus pollen is concerned, simulations reproduce well the shape of the profiles but the intensity tends to be under estimated. Three major limitations are identified with the model runs: (1) the poorly known phenology emission function, (2) the temporal development of the convective planetary boundary layer, which directly affects the vertical structure of the pollen dispersion; (3) the development of the sea breeze and a proper representation of the sea coast line, that plays a significant role on the skills of the meteorological mesoscale model.Peer Reviewe