Atmospheric Anomalies in 1997: Links to ENSO?

• Main Authors: James E. Overl, Nicholas A. Bond, Jennifer Miletta Adams
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Bering Sea; Gulf of Alaska; Pacific; Alaska
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.360.1153; http://www.pices.int/publications/scientific_reports/Report10/overland.pdf

In the summer of 1997, positive sea surface temperature anomalies (SSTA) of greater than 2°C extended across the Gulf of Alaska (GOA) and into the eastern Bering Sea (EBS). The SSTA in the EBS are at least in part due to atmospheric causes. Anomalously high 700-mb geopotential heights occurred over the region during April through August. This resulted in enhanced warming of the GOA and EBS due to increased insolation. The pattern of positive 700 mb height anomalies for April through August 1997 is similar to its counterpart formed by compositing the April through August anomalies that occurred during previous El Niños. The warming in the Bering Sea and North Pacific during summer 1997 appears to be due to the confluence of three factors: a decadal trend toward higher 700-mb heights, the El Niño, and a particularly strong blocking ridge weather pattern in May. As fall 1997 progressed, the SSTA in the EBS and non-coastal GOA dissipated due to increased storm activity, a winter signature of El Niño. More complete documentation is found at