The Interdecadal Variability of Atmospheric Teleconnections from 1851 to 2014

The Interdecadal variability of atmospheric teleconnections from 1851 to 2014

Alex D. Kaltenbaugh¹ and Steven B. Feldstein²

1. Department of Earth Sciences, Millersville University, Millersville, Pennsylvania

2. Department of Meteorology and Atmospheric Science, The Pennsylvania State University, University Park, Pennsylvania

Abstract

 Atmospheric teleconnections are large-scale spatial patterns that characterize the linkages between different weather conditions in different locations around the world. These patterns are long-lasting and can have great impacts on weather and climate over time. This study used SOM (self-organizing map) analysis to generate the dominant sea-level pressure (SLP) anomalies over the time period from 1851 to 2014 as well as each pattern’s frequency of occurrence for the months from December to February.

A 2X2 SOM grid for the North Pacific and for the North Atlantic was generated.  For the North Pacific, the dominant patterns are the positive and negative phases of Pacific/North American (PNA) and Western Pacific (WP) patterns. The corresponding North Atlantic teleconnections are the two phases of the North Atlantic Oscillation (NAO) and East Atlantic (EA) patterns. These patterns were identified by correlating the SOM frequencies with indices of major teleconnection patterns for the time period from 1950 to 2014. The positive PNA decreased in frequency from 1850 to 1940, while the WP patterns underwent two large-amplitude oscillations over the time period. On the other hand, the North Atlantic patterns did not exhibit any large amplitude trends or oscillations. In addition to this, both phases of the PNA were found to have statistically significant coherence with the Niño 3.4 SST time series at periods of 4 and 3 years, while the positive WP and PNA patterns showed statistically significant coherence with the September/October Barents and Kara Seas sea ice concentration at periods of 4 and 2 years.