Co-occurrence of atmospheric deserts over Europe with strong positive temperature anomalies, thunderstorms, and dust events

Atmospheric deserts are air masses originating in hot, dry, and deep convective boundary layers over arid and/or elevated regions and are advected across cooler, moister regions while possibly being modified by diabatic processes and differential advection. They are frequently advected over Europe and can modify temperature profiles throughout the free troposphere, with implications for convective potential. Atmospheric deserts generalise elevated mixed layers, which are known to influence near-surface temperatures and the formation of thunderstorms, but it remains unknown how frequently atmospheric deserts co-occur with strong positive temperature anomalies and lightning. We also investigate if atmospheric deserts frequently co-occur with dust events, since the source region for European atmospheric deserts is also the main source region for dust events. Atmospheric desert air is tracked during the study period from May 2022 to April 2024, using a direct detection method based on Lagrangian trajectories initiated at a very high spatio-temporal resolution. Positive temperature anomaly events, thunderstorms, and dust events are identified from reanalysis datasets and ground based lightning observation data. Conditional probabilities and corresponding standardised log-odds ratios provide insight into whether the mentioned extreme events occur more frequently in the presence of atmospheric deserts. The probability of events with strong positive temperature anomalies, thunderstorms, or dust anomalies is enhanced in the presence of atmospheric deserts in almost the entire domain. In most of the domain, strong positive temperature anomaly events are more likely given the presence of atmospheric desert air, but it could not be confirmed that the limitation of boundary layer growth by the capping stable layer was the main driver. Lightning probability is clearly enhanced along the atmospheric desert edges, and, in contrast to expectations, also in the atmospheric desert centres. In western Europe, up to 50 % of occurrences of atmospheric desert air are accompanied by unusually high amounts of dust. Dust events co-occur almost exclusively with atmospheric deserts.