Die Arktische Oszillation (AO) (engl. The presence of continents and large landmasses disrupts the ringlike structure at the Arctic pole, while anomalies surrounding the Antarctic pole are nearly circular. When the AO index is positive, surface pressure is high in the polar region.

It is an important Arctic climate index with positive and negative phases representing the state of atmospheric circulation over the Arctic.

For more information on the AO, please see Please note that year-round monthly mean anomaly data have been used to obtain … The AO loading pattern has been chosen as the first mode of EOF analysis using monthly mean 1000 millibar height anomaly data from 1979 to 2000 over 20°N-90°N. Larson, J., Y. Zhou and R. W. Higgins, 2004: Characteristics of landfalling tropical cyclones in the United States and Mexico: Climatology and Interannual Variability Zhou, S., A. J. Miller, J. Wang, and J. K. Angell, 2001: Trends of NAO and AO and their associations with stratospheric processes. The AO is a climate pattern characterized by winds circulating counterclockwise around the Arctic at around 55°N latitude. The Arctic Oscillation (AO) refers to an atmospheric circulation pattern over the mid-to-high latitudes of the Northern Hemisphere. CPC Web Team HOME > Climate & Weather Linkage > Teleconnections > Antarctic Oscillation : Current Conditions; Outlooks; References : Current Conditions; The daily AAO index is constructed by projecting the daily (00Z) 700mb height anomalies poleward of 20°S onto the loading pattern of the AAO. In that month, the Arctic oscillation reached its most negative monthly mean value at about −4.266, in the entire post-1950 era (the period of accurate record-keeping).The greatest negative value for the Arctic oscillation since 1950 in January was −3.767 in 1977, which coincided with the coldest mean January temperature in New York City, Washington, D.C., Baltimore, and many other mid-Atlantic locations in that span of time, although the January Arctic oscillation has been negative only 60.6% of the time between 1950 and 2010, nine of the ten coldest Januarys in New York City since 1950 have coincided with negative Arctic oscillations.National Weather Service Climate Prediction Center and NWS Forecast Office, as of 2010

The AO is a climate pattern characterized by winds circulating counterclockwise around the Arctic at around 55°N latitude. The Arctic oscillation (AO) or Northern Annular Mode/Northern Hemisphere Annular Mode (NAM) is a weather phenomenon at the Arctic poles north of 20 degrees latitude.It is an important mode of climate variability for the Northern Hemisphere.

CPC Search. Please note that year-round monthly mean anomaly data have been used to obtain … Arktische - und antarktische Oszillation - sind große Systeme der Telekonnektion der Erde, s. … The index varies over time with no particular periodicity, and is characterized by non-seasonal sea-level pressureanomalies of one sign in the Arctic, balanced by ano… The Arctic Oscillation (AO) is a large scale mode of climate variability, also referred to as the Northern Hemisphere annular mode. The southern hemisphere analogue is called the Antarctic oscillation or Southern Annular Mode (SAM).
NCEP/Climate Prediction Center ATLAS 8. The following statement from the A further, quite graphic illustration of the effects of the negative phase of the oscillation occurred in February 2010. The current negative AO is reflective of mostly positive pressure/geopotential height anomalies across the Arctic with mixed pressure/geopotential height anomalies across the mid-latitudes.
This helps the middle latitude jet stream to blow strongly and consistently from west to east, thus keeping cold Arctic air locked in the polar region. Arctic Oscillation AO The Arctic Oscillation (AO) refers to variations in the difference in the atmospheric pressure patterns between northern mid-latitudes (about 45 degrees North) and the Arctic. CPC Information CPC Web Team HOME > Climate & Weather Linkage > Teleconnections > Arctic Oscillation : Current Conditions; Outlooks; References : Current Conditions; The daily AO index is constructed by projecting the daily (00Z) 1000mb height anomalies poleward of 20°N onto the loading pattern of the AO. ( Higgins, R. W., A. Leetmaa, Y. Xue, and A. Barnston, 2000: Dominant factors influencing the seasonal predictability of U.S. precipitation and surface air temperature.