Surface-based temperature inversions in Alaska from a climate perspective

Alaska surface-based temperature inversions were analyzed using radiosonde observations from Barrow, Fairbanks, McGrath, Anchorage, Kotzebue, Bethel and King Salmon, which represent different climate zones in Alaska. Inversion climatology, variability and links to the large-scale climate were investigated for the period of 1957–2008 when high quality radiosonde data are available.Inversion parameters, such as depth, temperature difference, and frequency, have a long-term decreasing trend, which is not simply linear but displays multi-decadal variations. Inversion depth decreased from 1957 to the late 1980s and has been increasing since. The multi-decadal signal has been detected at all stations but is particularly dominant for Interior stations. The relationship between Alaska inversion and the Pacific Decadal Oscillation changes over time and was found to be stronger before 1989 than in recent years. Alaska inversions also demonstrate strikingly similar interannual variability, suggesting an important role of large-scale circulation.