EGU23-17058, updated on 15 Dec 2023
https://doi.org/10.5194/egusphere-egu23-17058
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Measuring meso-scale gradients in the Arctic during HALO-(AC)³

Fiona Paulus1, Roel Neggers1, Gunilla Svensson2, and Michail Karalis2
Fiona Paulus et al.
  • 1Universität Köln, Institut für Geophysik und Meteorologie, Germany (fpaulus@uni-koeln.de)
  • 2Department of Meteorology and Bolin Centre for Climate research, Stockholm University

Boundary layer cloud transitions at high latitudes play a key role in Arctic climate change, and are partially controlled by large-scale dynamics such as subsidence. While measuring large- and mesoscale divergence has proven notoriously difficult, the recent NARVAL and EUREC4A airborne campaigns in the subtropics have finally achieved this goal using multiple dropsondes releases in circular patterns. If this method also works at high latitudes is still an open research question, given the considerable differences in atmospheric dynamics. Answering this question was one of the main objectives of the recent HALO-(AC)^3 field campaign near Svalbard in Spring 2022. Circular dropsonde patterns were realized during various research flights by two airplanes, independently sampling Cold Air Outbreaks (CAO) in the Fram Strait with multiple dropsondes. This study presents a first overview of the results. We find that the method indeed yields reliable estimates of mesoscale gradients in the Arctic, yeilding robust vertical profiles of both subsidence and vorticity. Sensitivity to aspects of the method is investigated, including dependence on sampling area and the divergence calculation. Ongoing work to drive targeted Lagrangian high resolution simulations of the observed CAOs exclusively with HALO-(AC)³ data will be briefly discussed.

How to cite: Paulus, F., Neggers, R., Svensson, G., and Karalis, M.: Measuring meso-scale gradients in the Arctic during HALO-(AC)³, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17058, https://doi.org/10.5194/egusphere-egu23-17058, 2023.