An increase in average air temperature across the island of Ireland has resulted in a change in the seasonality of
vegetation. Current ground-based methods of monitoring seasonality are species-specific and limited to a few point
locations across the country. Medium resolution satellite data, e.g. MERIS, provide a means of acquiring multi-year time
series of imagery that can be used to capture the spatio-temporal dynamics in vegetation seasonality over the whole
island. For this study, a geophysical measure of vegetation growth, the Fraction of Absorbed Photosynthetically Active
Radiation (FAPAR), derived from MERIS Global Vegetation Index (MGVI) data is being used to determine seasonality.
Tiles, extracted from a rectangular global grid, covering the island of Ireland have been processed through the European
Space Agency's (ESA) Grid Processing on Demand (GPOD) service. Initial analysis of the imagery has consisted of
defining an optimal time composite period in order to minimise cloud effects for daily MGVI values using ancillary
cloud data from a meteorological observatory. Methods of in-situ observation of seasonality in mixed woodland have
also been explored. Initial findings suggest that a 10-day composite period should be optimal for Ireland given the high
occurrence of cloud cover.