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

Abstract

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 over Southern British Islands reinforced by a low-pressure system 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.

CO2 AND CH4 URBAN PLUME OVER A MEDITERRANEAN SEMI-NATURAL SITE IN THE IBERIAN PENINSULA

“…On the one hand, the rural mean back trajectory travelling from the western part of the Iberian Peninsula and reaching the CIB station after crossing the northern area of the peninsula (blue line) could be observed. The same airflow was described by Izquierdo et al [1]. The effect of the orography on the atmospheric transport patterns was noticeable, as pointed out by Izquierdo et al [1], since the Cantabrian range appears to act as a barrier to the transport and dispersion of air masses arriving at the measuring point from the rural sectors.…”

“…Back trajectories for urban and rural sectors were computed separately. The pathway drawn by the mean back trajectories allow for a more refined interpretation of the air mass arrival to the study area [1]. Fig.…”

“…Atmospheric back trajectories and transport models have been extensively used to identify potential emission sources at receptor locations by combining mixing ratio measurements with back trajectory analysis [1]. Back trajectories obtained using air models reveal the movement of an air parcel reaching the receptor point, where mixing ratios were measured.…”

“…Thus, the pollutant origin could be inferred [2]. The atmospheric transport paths and the origin regions were established by means of back trajectory analysis and source-receptor methodologies, which determine the relationship between a receptor point and the probable source areas [1], [3].…”

Alder pollen concentrations in the air during snowfall

“…In many aerobiological studies, an unusual increase in airborne pollen concentration has been attributed to long-distance transport. This phenomenon has been described for airborne pollen during the full growing season of various plants, e.g., Betula, Ambrosia, and Fagus (Belmonte et al 2008;Grewling et al 2016;Izquierdo et al 2017). No description of similar situations during the winter or early spring seems to exist, and such a situation could have occurred in the case of Alnus in Rzeszow in 2018.…”