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C305: Antarctic Clouds (Lead Supervisor: Tom Lachlan-Cope, British Antarctic Survey)

Supervisors: Tom Lachlan-Cope (British Antarctic Survey), Michael Herzog (Geography), Howard Roscoe (British Antarctic Survey)

Importance of the area of research:

The largest uncertainties in future climate predictions highlighted by the Intergovernmental Panel on Climate change (IPCC 2007) arise from our lack of knowledge of the interaction of clouds with solar and terrestrial radiation (Dufresene & Bony, 2008).

Although there are many measurements of the microphysical properties of cloud at mid-latitudes in the Antarctic these measurements are largely lacking. Studies with numerical models of the atmosphere show large errors in the surface radiation balance over the Southern Ocean and the coast of Antarctica and these are thought to be a result of the incorrect representation of the high latitude cloud physics in the model. The project will look at data from Halley in the eastern Weddell Sea and Rothera on the west coast of the Antarctic Peninsula – an area that has large temperature increase over the last 50 years.

Project summary:

Although limited in situ cloud measurements have been made by the British Antarctic Survey at their Antarctic station there is no long term climatology of cloud parameters. This project will develop a method to retrieve a climatology of cloud properties using the long term records from ground based instruments (radiometers, sun photometer, laser ceilometer and all sky camera)  installed at two Antarctic Stations (Rothera and Halley). The retrieved climatology will be used to study if the clouds have changed over the length of the record, and to compare this record with climate model results.

What the student will do:

The student will retrieve cloud parameters (liquid water content, effective radius, phase etc), using optimal estimation methods if possible, from the existing ground based instrumentation at Halley and Rothera stations. To this mix of instrument observations we would add visual cloud observations, radiosonde ascents and reanalysis products simultaneous with the instrument observations, to add information to the retrieval.

When a time series of cloud parameters has been retrieved this will be compared with aircraft in situ measurements and climate model runs. The retrieved cloud properties will be used to validate surface meteorological cloud observations so that these observations can be used to investigate long term changes in cloud amount over the length surface record (60 years for Halley and 40 years for Rothera.

Please contact the lead supervisor directly for further information relating to what the successful applicant will be expected to do, training to be provided, and any specific educational background requirements.

References:

Lachlan-Cope, T., Listowski, C., and O’Shea, S.: The Microphysics of Clouds over the Antarctic Peninsula – Part 1: Observations, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2016-331, in review, 2016.

Van Tricht, K., Gorodetskaya, I. V., Lhermitte, S., Turner, D. D., Schween, J. H., and Van Lipzig, N. P. M.: An improved algorithm for polar cloud-base detection by ceilometer over the ice sheets, Atmos. Meas. Tech., 7, 1153-1167, doi:10.5194/amt-7-1153-2014, 2014.

Follow this link to find out about applying for this project.

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