2 world maps overlain with a color gradient.
Winter (DJF) changes in calculated atmospheric turbulence frequency in the near-tropopause region (200-250 hPa) over the period 1980-2021. Results are shown derived from ERA5 reanalysis (a) and multi-model ensemble mean from CMIP6 simulations (b). Frequency statistics for clear-air turbulence (CAT) are calculated from the large-scale wind fields in reanalysis and model results. The statistics shown are the ratio of calculated trends to interannual standard deviation at each grid point, as a measure of signal-to-noise ratio. Credit: Foudad et al. [2024], Figure 5
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Geophysical Research: Atmospheres

Atmospheric turbulence is responsible for most weather-related aircraft accidents, and clear-air turbulence (CAT, distant from convection and mountain wave effects) is especially difficult to detect and avoid.

Foudad et al. [2024] evaluate past and future changes in CAT based on meteorological reanalysis and coupled climate model experiments. Calculations are based on statistics of upper-level jet shear zones (near the tropopause), which are mainly responsible for generation of CAT. Past changes derived from reanalysis data show positive trends in CAT occurrence during 1980-2021, linked to increases in upper-level jets, with largest changes over the Pacific and North Atlantic oceans, and from North Africa to East Asia (top panel of image above). Forced climate model simulations of the recent past show similar behavior (bottom panel of image), arguing for anthropogenic forcing for some of these changes. Climate projections from the models show continued CAT increases over the Northern Hemisphere in future warming climates.

Citation: Foudad, M., Sanchez-Gomez, E., Jaravel, T., Rochoux, M. C., & Terray, L. (2024). Past and future trends in clear-air turbulence over the northern hemisphere. Journal of Geophysical Research: Atmospheres, 129, e2023JD040261. https://doi.org/10.1029/2023JD040261

—William J. Randel, Editor, JGR: Atmospheres

Text © 2024. The authors. CC BY-NC-ND 3.0
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