Climatology of Arctic temperature inversions in current and future climates
2022
Ruman, Caio Jorge | Monahan, Adam Hugh | Sushama, Laxmi
Temperature inversions are a common feature of the Arctic climate, affecting the surface energy budget and planetary boundary layer transports. This study investigates the evolution of large-scale temperature inversions (between 925 hPa and 2 m) in the context of a changing climate. To this end, two five-member regional climate model (RCM) ensembles, driven by the Canadian Earth System Model, spanning the 1950–2099 period, corresponding to two greenhouse gas emission scenarios (RCP 4.5 and 8.5), are considered. An ERA-Interim driven simulation for the 1979–2005 period is also considered to assess model performance. A comparison of observed atmospheric soundings with the boundary layer variations in the reanalysis-driven simulation indicates that the model captures the temperature inversion characteristics reasonably well, with some positive biases in the temperature inversion strength and frequency. The transient regional climate change simulations suggest substantial decreases in both temperature inversion strength and frequency in winter in future climate for both emission scenarios. These changes are consistent with the reduced sea ice cover and the associated increase in cloud cover that reduce the surface radiative cooling necessary for the formation of strong temperature inversions. Some increases in the frequency and strength of temperature inversions are projected for summer over the Arctic Ocean, possibly linked with increased poleward moisture transport.
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