The Influence of Teleconnections on the Presence of North Atlantic Icebergs South of 48°N: 1983 - 2020
O'Brien, Shayne R.
The International Ice Patrol (IIP) has been responsible for the safety of maritime activity related to icebergs in the North Atlantic since their founding in the wake of the Titanic disaster in April 1912. In the century to follow, the Ice Patrol, their mission, methods, and technology have evolved. Today, a century of iceberg observation data collected by the IIP has led to a growing field of climatological and hazards sciences related study. This study examines the North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) as drivers of iceberg presence south of 48°N through direct and secondary influence between 1983 and 2020. This study is divided into five sections which examine different aspects of the relationship between teleconnections and icebergs south of 48°N (I48N). The first section identifies that the NAO and AO have statistically significant correlation with the number of I48Ns at a 1-year lag, through the use of linear regression modelling. The second section determines through the use of logistic regression that there is a statistically significant increase likelihood of an Extreme (>1399) iceberg year in years following a high annual NAO Index. Section three includes the comparison of AIC values for different AO/NAO models, which concluded that NAO is a stronger driver of North Atlantic icebergs than the AO. Section four involves a twofold analysis of the role of sea ice in iceberg-teleconnection interactions. These analyses resulted in the finding that sea ice has a significant correlation with I48N counts at 0- and 1-year lags. Additionally, this section indicates a significant correlation between sea ice and AO at a 1-year lag. Section five consists of comparing reanalysis(NCEP/NCAR Reanalysis, NCEP/DOE R2) data of meteorological and oceanographic factors in the 3 most-recent high and low iceberg years. This comparison identified areas of future study including geopotential height, sea level pressure and sea surface temperature.
icebergs, North Atlantic, teleconnections, climatology, oceanography, reanalysis
O'Brien, S. R. (2022). The influence of teleconnections on the presence of North Atlantic icebergs south of 48°N: 1983 - 2020 (Unpublished dissertation). Texas State University, San Marcos, Texas.