title: Mapping the birch and grass pollen seasons in the UK using satellite sensor time-series.
abstract: Grass and birch pollen are two major causes of seasonal allergic rhinitis (hay fever) in the UK and parts of Europe affecting around 15-20% of the population. Current prediction of these allergens in the UK is based on (i) measurements of pollen concentrations at a limited number of monitoring stations across the country and (ii) general information about the phenological status of the vegetation. Thus, the current prediction methodology provides information at a coarse spatial resolution only. Most station-based approaches take into account only local observations of flowering, while only a small number of approaches take into account remote observations of land surface phenology. The systematic gathering of detailed information about vegetation status nationwide would therefore be of great potential utility. In particular, there exists an opportunity to use remote sensing to estimate phenological variables that are related to the flowering phenophase and, thus, pollen release. In turn, these estimates can be used to predict pollen release at a fine spatial resolution. In this study, time-series of MERIS Terrestrial Chlorophyll Index (MTCI) data were used to predict two key phenological variables: the start of season and peak of season. A technique was then developed to estimate the flowering phenophase of birch and grass from the MTCI time-series. For birch, the timing of flowering was defined as the time after the start of the growing season when the MTCI value reached 25% of the maximum. Similarly, for grass this was defined as the time when the MTCI value reached 75% of the maximum. The predicted pollen release dates were validated with data from nine pollen monitoring stations in the UK. For both birch and grass, we obtained large positive correlations between the MTCI-derived start of pollen season and the start of the pollen season defined using station data, with a slightly larger correlation observed for birch than for grass. The technique was applied to produce detailed maps for the flowering of birch and grass across the UK for each of the years from 2003 to 2010. The results demonstrate that the remote sensing-based maps of onset flowering of birch and grass for the UK together with the pollen forecast from the Meteorology Office and National Pollen and Aerobiology Research Unit (NPARU) can potentially provide more accurate information to pollen allergy sufferers in the UK.
authors.affiliation: Department of Biology, College of Education, University of Sulaimani, City Campus, Iraqi Kurdistan Region, Iraq; Global Environmental Change and Earth Observation Research Group, Geography and Environment, University of Southampton, Highfield, Southampton SO17 1BJ, UK. Electronic address: nabaz.khwarahm@univsul.edu.iq.
authors.forename: Nabaz R
authors.initials: NR
authors.lastname: Khwarahm
authors.affiliation: Global Environmental Change and Earth Observation Research Group, Geography and Environment, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
authors.forename: Jadunandan
authors.initials: J
authors.lastname: Dash
authors.affiliation: National Pollen and Aerobiological Research Unit, Institute of Scienceand the Environment, University of Worcester, Henwick Grove, WR2 6AJ, Worcester, UK.
authors.forename: C A
authors.initials: CA
authors.lastname: Skjøth
authors.affiliation: School of Geography, Environment & Earth Sciences, Victoria University of Wellington, PO, Box 600, Wellington, New Zealand.
authors.forename: R M
authors.initials: RM
authors.lastname: Newnham
authors.affiliation: National Pollen and Aerobiological Research Unit, Institute of Scienceand the Environment, University of Worcester, Henwick Grove, WR2 6AJ, Worcester, UK.
authors.forename: B
authors.initials: B
authors.lastname: Adams-Groom
authors.affiliation: School of Geography, Earth & Environmental Sciences, University of Plymouth, Plymouth, UK.
authors.forename: K
authors.initials: K
authors.lastname: Head
authors.affiliation: Centre Director & Hon. University Research Fellow, Scottish Centre for Pollen Studies, Edinburgh Napier University, School of Life Science, Edinburgh, UK.
authors.forename: Eric
authors.initials: E
authors.lastname: Caulton
authors.affiliation: Faculty of Science and Technology, Engineering Building, Lancaster University, Lancaster LA1 4YR, UK; Faculty of Geosciences, University of Utrecht, Heidelberglaan 2, 3584 CS Utrecht, The Netherlands; School of Geography, Archaeology and Palaeoecology, Queen's University Belfast, BT7 1NN, Northern Ireland, UK.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Atkinson
mesh_terms: D000485:Allergens / Q000032:analysis*; D029662:Betula / Q000502:physiology*; D005060:Europe; D006109:Poaceae / Q000502:physiology*; D011058:Pollen; D063809:Satellite Imagery; D012621:Seasons; D062211:Spatio-Temporal Analysis; D006113:United Kingdom
chemical_list: D000485:Allergens
keywords: Aerobiology; Birch pollen; Grass pollen; Hay fever; MERIS MTCI; Onset of birch flowering; Onset of grass flowering; Onset of greenness; Phenology; Predicting model