MACC regional multi-model ensemble simulations of birch pollen dispersion in Europe

M Sofiev ,Uwe Berger ,Olga Ritenberga ,Ujjwal Kumar ,F Meleux ,E Friese ,Robert Gehrig ,Dmitry Khvorostyanov ,Virginie Marécal ,Hendrik Elbern ,Elena Severova ,Lennart Robertson ,Richard Kranenburg ,Anna-Mari Pessi ,Pilvi Siljamo ,Erik Teinemaa ,Marje Prank ,Karl‐Christian Bergmann ,Julius Vira ,M Thibaudon ,Carmen Rueda Galán ,Jordina Belmonte ,Ingrida Šaulienė ,Victoria Rodinkova ,Arjo Segers ,Annika Saarto ,F Chéroux ,Joaquim Arteta ,Birthe Marie Steensen ,Laurent Menut ,Vincent‐Henri Peuch

doi:10.5194/acp-15-8115-2015

Abstract

Abstract. This paper presents the first ensemble modelling experiment in relation to birch pollen in Europe. The seven-model European ensemble of MACC-ENS, tested in trial simulations over the flowering season of 2010, was run through the flowering season of 2013. The simulations have been compared with observations in 11 countries, all members of the European Aeroallergen Network, for both individual models and the ensemble mean and median. It is shown that the models successfully reproduced the timing of the very late season of 2013, generally within a couple of days from the observed start of the season. The end of the season was generally predicted later than observed, by 5 days or more, which is a known feature of the source term used in the study. Absolute pollen concentrations during the season were somewhat underestimated in the southern part of the birch habitat. In the northern part of Europe, a record-low pollen season was strongly overestimated by all models. The median of the multi-model ensemble demonstrated robust performance, successfully eliminating the impact of outliers, which was particularly useful since for most models this was the first experience of pollen forecasting.

Highlights

During the last 30 years, the prevalence of airborne allergy and asthma in Europe has increased 4-fold, reaching 15– 40 % of the population
The dispersion models used in the study comprise the MACC-II European ensemble, which is described in detail in Marécal et al (2015)
The following issues are considered: (i) the ability of the model ensemble to predict the key features of the 2013 birch pollen season, (ii) main uncertainties of the current ensemble, (iii) specific features of the individual ensemble members, and (iv) parameters of the season, for which the use of the ensemble predictions is more beneficial than single-model simulations

Summary

Introduction

During the last 30 years, the prevalence of airborne allergy and asthma in Europe has increased 4-fold, reaching 15– 40 % of the population. According to the European Federation of Allergy and Airway Diseases Patients Associations, 80 million (24.4 %) adults living in Europe are allergic. The allergy prevalence in children is 30–40 % and increasing (Laatikainen et al, 2011; Rönmark et al, 2009). Allergy to various types of pollen in the air, exacerbated by co-exposure to chemical pollutants and fine aerosols, is the number one chronic disease in Europe, overshadowing allergy to house dust mite and affecting over 20 % of the population (Bousquet et al, 2007). Grass and birch pollen affect about 40 and 25 % of all hay fever sufferers in Europe respectively (Heinzerling et al, 2009). The distribution of silver birch (Betula pendula Roth.) and downy birch (B. pubescens L.) extends from mountains in the temperate climate of southern Europe to Fennoscandia and Siberia (Atkinson, 1992; OECD, 2003)

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