- 1British Antarctic Survey, Atmosphere, Ice and Climate team, United Kingdom of Great Britain – England, Scotland, Wales (flovan@bas.ac.uk)
- 2University of East Anglia, School of Environmental Sciences, United Kingdom of Great Britain – England, Scotland, Wales
- 3University of Manchester School of Earth, Atmospheric and Environmental Sciences, United Kingdom of Great Britain – England, Scotland, Wales
- 4University of Exeter, Earth and Environmental Science, United Kingdom of Great Britain – England, Scotland, Wales
Clouds are a major source of uncertainty in climate model projections over the Southern Ocean and Antarctica1. The inaccurate representation of clouds in climate models results in biases in the net radiative balance which has knock-on effects on the ability of models to represent sea surface temperatures, ocean heat uptake, sea ice cover, and ultimately large-scale circulation in the Southern Hemisphere2,3,4,5,6. Evidence suggests that this is due to the poor representation of mixed phase clouds in models—the dominant cloud type in this region.
As part of the Southern Ocean Clouds project, we have conducted two flying campaigns out of Rothera research station which is located on the Antarctic peninsula, in order to investigate the composition of clouds over the Southern Ocean. Over the course of two field seasons (one in the 2022-23, and one in the 2024-25 Antarctic season) we performed more then 40 flights consisting of over 140 flying hours. During these flights we measured ice crystal, water droplet and aerosol number concentrations and sizes. We also collected Ice Nucleating Particles on filters in addition to performing measurements of meteorological parameters, turbulence, and radiative balance.
Here we will present an overview of the flying campaign of the 2024-25 season, and compare the observations conducted this year to those which were made during our previous campaign in the 2022-23 season. Although we saw higher droplet number concentrations for the 2024-25 campaign than during the 2022-23 campaign, both revealed the presence of higher droplet number concentrations at higher altitudes (> 2000 m asl) indicating a potential long range source for these.
1 Bodas-Salcedo, A., et al., 2014: Origins of the Solar Radiation Biases over the Southern Ocean in CFMIP2 Models. J. Climate, 27, 41–56, https://doi.org/10.1175/JCLI-D-13-00169.1.
2 Lauer, A., et al., 2018: Process-level improvements in CMIP5 models and their impact on tropical variability, the Southern Ocean and monsoons. Earth Syst. Dynam., 9, 33–67, https://doi.org/10.5194/esd-9-33-2018.
3 Frölicher, T. L., et al., 2015: Dominance of the Southern Ocean in Anthropogenic Carbon and Heat Uptake in CMIP5 Models. J. Climate, 28, 862–886, https://doi.org/10.1175/JCLI-D-14-00117.1.
4 Ferrari and Ferreira 2011: what processes drive the ocean heat transport? Ocean. Model., 38, 171-186, https://doi.org/10.1016/j.ocemod.2011.02.013.
5: Ceppi P., et al., 2012: Southern Hemisphere Jet latitude biases in CMIP5 models linked to shortwave cloud forcing. Geophys. Res. Lett, 39, 19: https://doi.org/10.1029/2012GL053115.
6 Y. Hwang, D.M.W. Frierson, 2013: Link between the double-Intertropical Convergence Zone problem and cloud biases over the Southern Ocean, Proc. Natl. Acad. Sci. U.S.A., 110 (13) 4935-4940, https://doi.org/10.1073/pnas.1213302110
How to cite: van den Heuvel, F., Smith, D., Squires, F., Witherstone, J., Flynn, M., Girdwood, J., Xu, J., and Lachlan-Cope, T.: Airborne in-situ cloud observations around the Antarctic peninsula from the Southern Ocean Clouds project , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19981, https://doi.org/10.5194/egusphere-egu25-19981, 2025.
