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Publicação
The North Atlantic oscillation and European vegetation dynamics
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Orientador(es)
Resumo(s)
The relationship between vegetation greenness and the North Atlantic Oscillation (NAO) is assessed over
Europe. The study covers the 21-year period from 1982 to 2002 and is based on monthly composites of the Normalised
Difference Vegetation Index (NDVI) and Brightness Temperature from the Global Inventory Monitoring and Modelling
System (GIMMS) as well as on monthly precipitation from the Global Precipitation Climatology Centre (GPCC).
A systematic analysis is first performed of point correlation fields over the 21-year period between the winter NAO
index and spring and summer NDVI, followed by an assessment of the vegetation response to precipitation and temperature
conditions in winter, over two contrasting regions, namely the Iberian Peninsula and Northeastern Europe. Finally, the
impact of NAO on vegetation dynamics over the two regions is evaluated by studying the corresponding annual cycles of
NDVI and comparing their behaviour for years associated with opposite NAO phases.
Over the Iberian Peninsula there is strong evidence that positive (negative) values of winter NAO induce low (high)
vegetation activity in the following spring and summer seasons. This feature is mainly associated with the impact of NAO
on winter precipitation, together with the strong dependence of spring and summer NDVI on water availability during the
previous winter. Northeastern Europe shows a different behaviour, with positive (negative) values of winter NAO inducing
high (low) values of NDVI in spring, but low (high) values of NDVI in summer. This behaviour mainly results from the
strong impact of NAO on winter temperature, associated with the critical dependence of vegetation growth on the combined
effect of warm conditions and water availability during the winter season
Descrição
Palavras-chave
NDVI vegetation cycle NAO climate impacts Iberia Northeastern Europe
Contexto Educativo
Citação
"International Journal of Climatology". ISSN 0899-8418. 28 (2008) 1835-1847