North Atlantic Oscillation Questions And
Answers With Verified Solutions
What is the North Atlantic Oscillation? (Barry, Chorley 2009) - ANSWER The
North Atlantic oscillation is a fluctuation in the pressure gradient between the
Azores High (40N) and the Icelandic low (65N) involving their mutual
strengthening or weakening.
When both are strong the NAO is in positive phase. When both are weak it is in
negative phase.
What is the NAO (Vallis 2011) - ANSWER An internal mode of climate variability
in the North Atlantic on multiple timescales.
Whilst it drives monthly variance it also shows persistence in its mean state over
decadal periods.
Controls 30% of variability in North Atlantic
It is a control on the position and strength of the jet
When is the NAO most strongly expressed? - ANSWER Winter (Barry, Chorley
2009) when the jet is strongest due to the highest temperature gradient
Is the NAO's impact more or less extensive than El Nino? - ANSWER Less
(Uppenbrinke 1999)
, What is the positive phase of the NAO associated with? - ANSWER Azores high
is higher
The icelandic low is lower
The westerlies are stronger
The jet is stronger and tilts northwards bring warm, wet weather systems to
northern Europe this brings milder conditions and more precipitaiton, also leads
to enhanced storm conditions.
There is more wind and rain in the UK
There are mild conditions in the UK as warm air advects northwards
There are dry conditions in Spain (Met Office, Vallis 2011)
What is the low phase of the NAO associated with - ANSWER The Azores high
is weak
The Icelandic low is shallow
The weakened pressure gradient causes the storm tracks to swing further south
leading to cooler weather in northern Europe as less heat advects Northwards and
more wild, wet waether in southern Europe
Clear and still in UK
Answers With Verified Solutions
What is the North Atlantic Oscillation? (Barry, Chorley 2009) - ANSWER The
North Atlantic oscillation is a fluctuation in the pressure gradient between the
Azores High (40N) and the Icelandic low (65N) involving their mutual
strengthening or weakening.
When both are strong the NAO is in positive phase. When both are weak it is in
negative phase.
What is the NAO (Vallis 2011) - ANSWER An internal mode of climate variability
in the North Atlantic on multiple timescales.
Whilst it drives monthly variance it also shows persistence in its mean state over
decadal periods.
Controls 30% of variability in North Atlantic
It is a control on the position and strength of the jet
When is the NAO most strongly expressed? - ANSWER Winter (Barry, Chorley
2009) when the jet is strongest due to the highest temperature gradient
Is the NAO's impact more or less extensive than El Nino? - ANSWER Less
(Uppenbrinke 1999)
, What is the positive phase of the NAO associated with? - ANSWER Azores high
is higher
The icelandic low is lower
The westerlies are stronger
The jet is stronger and tilts northwards bring warm, wet weather systems to
northern Europe this brings milder conditions and more precipitaiton, also leads
to enhanced storm conditions.
There is more wind and rain in the UK
There are mild conditions in the UK as warm air advects northwards
There are dry conditions in Spain (Met Office, Vallis 2011)
What is the low phase of the NAO associated with - ANSWER The Azores high
is weak
The Icelandic low is shallow
The weakened pressure gradient causes the storm tracks to swing further south
leading to cooler weather in northern Europe as less heat advects Northwards and
more wild, wet waether in southern Europe
Clear and still in UK
