THE RESPONSE OF UK VEGETATION TO ELEVATED TEMPERATURES IN 2006: COUPLING ENVISAT MERIS TERRESTRIAL CHLOROPHYLL INDEX (MTCI) AND MEAN AIR TEMPERATURE

摘要

Climate is one of the key variables driving ecosystems at local to global scales. How and to what extent vegetation responds to climate variability is a challenging topic for global change analysis. Autumn 2006 was the warmest in the UK since records began in 1659 (Meteorological Office, 16th October 2006) and this delayed the seasonal senescence of vegetation. Earth observation data provides an opportunity to study this phenomenon and put it into the context of ecosystem dynamics over a longer time period. The European Space Agency (ESA) uses data recorded by the Medium Resolution Imaging Spectrometer (MERIS) in the red/NIR bands to produce an operational product called the MERIS Terrestrial Chlorophyll Index (MTCI). The MTCI is related to the position of the red edge in vegetation spectra and can be used to determine the chlorophyll content of vegetation and thus its phenology. The 2006 growing season was investigated using MTCI data. Weekly MTCI composites for 2003 - 2006 were used to produce land-cover specific MTCI time series which were related to temporally-coincident temperature data. Analysis demonstrated that for forest and heath and grassland (i) the MTCI was sensitive to seasonal variation in inferred chlorophyll content, (ii) the high autumnal temperatures were related to an extended growing season and (ii) there was a strong relationship between seasonal temperature variation and MTCI.