Temporal Changes in Static Stability in Arctic Boundary Layer

Global climate change is considered to have great impacts on Arctic regions because of the melting of the ice. Increases in air temperature during the past several decades have caused changes in other components of the Arctic climate system. For example, air warming of the lower Arctic boundary layer can probably engender changes in the static stability. Therefore, the objective of this research is to investigate the temporal changes in the atmospheric static stability of the Arctic boundary layer in Alert, Nuvavut, Canada. The climate station resides at the most northern land site (82°30Œ05N, 62°20Œ20W) in the Northern Hemisphere. Upper air data were utilized to determine the changes in the Arctic boundary layer static stability. For each day, there were two upper air soundings taken at 00:00 Universal Time Coordinate (UTC) and 12:00 UTC. Virtual potential temperature was used to determine the static stability of the given air layers above the Alert climate station. The period ranging from 1977 to 2011 was included in the data analyses. Data for air layers were selected from surface to 2000 m. Both average virtually potential temperature and its gradient were utilized to yield the static stability. The resulting temporal trends were analyzed to identify the changes in static stability. Temporal trends in the static stability showed little fluctuation in response to having nearly invariant virtual potential temperature in past 35 year. Thus, the static stability pattern in 2000s remained almost unchanged compared to that in the 1980s. Little evidence was found that atmospheric warming meaningfully impacted the atmospheric stability in Arctic boundary layer. One conclusion from this investigation is that the influence of climate change on atmospheric stability in Arctic was limited.