Climatology of Multilayered Temperature Inversions in the Arctic Lower Troposphere

Frequent and persistent low-level atmospheric temperature inversions have long been noted as a characteristic of the Arctic atmosphere. Primary inversions (the inversion layer closest to the surface) in particular have been a focus of research due to their impact on surface fluxes of heat, moisture, and momentum. Elevated inversion layers are typically only included in climatologies when they are also the primary inversion. However, the Arctic atmospheric boundary layer often decouples from the surface, and surface and elevated inversions can form and evolve independently. Arctic low clouds and elevated inversion layers can affect each other. Elevated inversion layers sometimes act as a cap to stratus cloud layers, as is common in lower latitudes. Results from studies using co-located cloud radars and balloon soundings show that Arctic clouds, particularly low-level mixed phase clouds, frequently penetrate elevated inversion layers. Here, multilayered temperature inversions and cloud layers are identified in radiosonde soundings from the Integrated Global Radiosonde Archive at 25 Arctic land-based stations for the 20-year period starting in January 2000. In this dataset, multiple inversions are the norm rather than the exception. At most locations and during most seasons, secondary and primary elevated inversion strength distributions are very similar. Surface inversions tend to be stronger than elevated inversions. Strong regional differences in seasonal cycles and vertical characteristics of clouds and temperature inversions are apparent. Particularly at North American stations, secondary inversions represent the bulk of detected inversion layers above 500 m above ground level during the winter.