North Atlantic Oscillation
Welcome to this thematic web site which
I started in August 1997. It aims to collect together useful information about this
important climatic phenomenon. Please contact me if you have any comments or constructive remarks.
What is the NAO ?
A large-scale mode of natural climate variability having large
impacts on weather and climate in the North Atlantic region
and surrounding continents.
The NAO response in surface air temperature has been known
about since at least 1770 (if not earlier !). Scientists have
been studying it since the 1880s.
The NAO can be characterised by various types of indices which
all reveal that it has a broad band spectrum with no significant
dominant periodicities (unlike ENSO!).
Physically based climate models are capable of simulating many of
the known features of the NAO and may be able to tell us how it
might change in the future due to man-made emissions.
Despite being a noisey extra-tropical phenomenon, there is some
ability to forecast the NAO especially on longer decadal time scales.
Impacts of the NAO
The NAO has strong impacts on weather and climate in the North
Atlantic region and surrounding continents and is a dominant
exogenous factor in many biological systems.