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Natural climate change and variability
North Atlantic Oscillation
The negative phase
During the negative phase of the NAO, the atmospheric mass is more evenly spread out so that the Icelandic low. and subtropical high are weaker than usual. Because of the reduced pressure gradient, there are fewer storms crossing the Atlantic. It is cold and dry in northern Europe, but wetter than usual in the Mediterranean. Also, it is more common for cold air to extend into eastern North America, and the trade winds are weaker than usual.
Over the past 30 years, there have been an increasing number of years with a positive phase of the NAO. This indicates a shift in the wintertime storm tracks and the polar jet stream toward the Poles. Scientists are researching the NAO to figure out why this is occurring and its possible links to human-caused climate change.
Next page -> Antarctic Oscillation
Links and resources
North Atlantic Oscillation
The negative phaseDuring the negative phase of the NAO, the atmospheric mass is more evenly spread out so that the Icelandic low. and subtropical high are weaker than usual. Because of the reduced pressure gradient, there are fewer storms crossing the Atlantic. It is cold and dry in northern Europe, but wetter than usual in the Mediterranean. Also, it is more common for cold air to extend into eastern North America, and the trade winds are weaker than usual.
Over the past 30 years, there have been an increasing number of years with a positive phase of the NAO. This indicates a shift in the wintertime storm tracks and the polar jet stream toward the Poles. Scientists are researching the NAO to figure out why this is occurring and its possible links to human-caused climate change.
Next page -> Antarctic Oscillation
Links and resources
