Dr Gillian Young McCusker

Profile

I joined the Institute for Climate and Atmospheric Science (ICAS) in March 2019 as a Research Fellow on the Microbiology-Ocean-Cloud Coupling in the High Arctic (MOCCHA) project, modelling central Arctic clouds with the Met Office Unified Model and Met Office NERC Cloud model. Prior to Leeds, I worked as a cloud physicist at the British Antarctic Survey on the Microphysics of Antarctic Clouds (MAC) campaign, modelling Antarctic cloud physics with the Weather Research and Forecasting model. I completed my PhD in Atmospheric Physics at the University of Manchester in 2016, as part of the Aerosol-Cloud-Coupling And Climate Interactions in the Arctic (ACCACIA) campaign, using both measurements and a large eddy simulation model to further our understanding of Arctic cloud physics and aerosol-cloud interactions. 

As of Jan 2022, I hold a NERC Independent Research Fellowship within ICAS, working on the Tackling the Arctic Cloud Problem project.

External to Leeds: 

• Chair/Co-Founder of the Quantifying the Indirect Effect: from Sources to Climate Effects of Natural and Transported aerosol in the Arctic (QuIESCENT Arctic) initiative (2019—).
• Secretary of the International Arctic Science Committee Atmosphere Working Group (2021—). 
• IASC Atmosphere Working Group Early Career Fellow (2018—21).
• Member: Scientific Committee on Antarctic Research (SCAR) Antarctic Clouds and Aerosols Action Group (2018—).
• Member: air Pollution in the Arctic: Climate, Environment, and Societies (PACES) scientific steering committee (2019—).
• Member: the Cryosphere and ATmospheric CHemistry (CATCH) scientific steering committee (2022—).

Research interests

As a cloud physicist, I study the small-scale interactions in polar clouds which drive their development, evolution, and lifetime. I've used a number of numerical models – at large eddy simulation, numerical weather prediction, and global scales – to conduct detailed studies of the physical processes within Arctic and Antarctic clouds.

The interaction between aerosol particles and clouds is a key uncertainty in general circulation models, and I am interested in the how these interactions affect cloud microphysical properties in the unique polar environment. Polar clouds differ from their mid-latitude counterparts in a number of ways but, most importantly, they are often mixed-phase (containing both liquid cloud droplets and ice crystals), long-lived, and therefore very difficult to model. I use observations to develop the representation of present-day polar clouds in high-resolution numerical models, improving our understanding of the small-scale physical processes which occur within them and enabling us to make judgements about how they may be affected by a changing climate. A key problem with making predictions of polar clouds is their microphysical sensitivity to different particle sources and meteorological forcings, both of which large-scale models fail to capture correctly. Polar aerosol sources range from local to distant – via long-range transport pathways – thus adding further complexity into understanding aerosol-cloud interactions: if we don’t know what aerosol are there, then we cannot truly understand how important they are in influencing the clouds in the region.

In review:

Young, G., Vüllers, J., Achtert, P., Field, P., Day, J. J., Forbes, R., Price, R., O'Connor, E., Tjernström, M., Prytherch, J., Neely III, R., and Brooks, I. M.: Evaluating Arctic clouds modelled with the Unified Model and Integrated Forecasting System, Atmos. Chem. Phys. Discuss. [preprint], https://doi.org/10.5194/acp-2021-662, in review, 2021.

• Tackling the Arctic Cloud Problem

Qualifications

• PhD Atmospheric Physics, University of Manchester (2016)
• MSci Physics and Astronomy, University of Glasgow (2013)

Professional memberships

• International Arctic Science Committee

Research groups and institutes

• Atmospheric and Cloud Dynamics
• Atmospheric Chemistry and Aerosols
• Institute for Climate and Atmospheric Science