Sea ice is an important element affecting the climate of the polar regions and its interaction with the atmosphere and the ocean has a deep impact on the global climate system. In particular the drift of sea ice, which strongly depends on the wind stress from the atmosphere and on the ocean currents, enhances the transport of fresh water out of the Arctic ocean and the formation of new areas of open water.
The present state-of-the-art sea-ice models are able to reasonably reproduce the extent of the sea ice and the major processes of the interaction with atmosphere and ocean but work is still needed to better understand and parameterize small scale processes like ice ridges and the effects of ice roughness on atmosphere-ice-ocean interaction.
The objective of this thesis is to study the effect of the wind stress on a rough surface and on the dynamics of ice floes. Analyzing the movement of rough ice on the ocean will provide information on the Ekman transport and thus on the global circulation and on the transport of tracers in the ocean. A better understanding of these processes allows a parameterization that will enhance large-scale global circulation models.


Start of doctoral thesis: 1st September, 2011

Defence of doctoral thesis: 14th November, 2014 (view thesis)

Supervisor : Prof. Dr. Rüdiger Gerdes

Further members : Dr. Martin Losch, Dr. Christof Lüpkes

• 2011 Giudici M., F. Baratelli, G. Castellani and C. Vassena, Modeling the Antarctic Ice Sheet and Ice Shelves: Assessing the Effects of Uncertainty on the Model Parameters by Sensitivity Analysis, in ICE SHEETS: DYNAMICS, FORMATION AND ENVIRONMENTAL CONCERNS. Nova Science Publishers.

• 2014 Castellani G., C. Lüpkes, S. Hendricks and R. Gerdes, Variability of Arctic sea ice topography and its impact on the atmospheric surface drag , JGR - Oceans.

• 2015 Castellani G., R. Gerdes, M. Losch and C. Lüpkes, Impact of sea-ice bottom topography on the Ekman pumping, (Book Chapter), Springer ed.

Helmholtz Research School on Earth System Science, Annual Retreat 2012, Bremerhaven, “Deutsches Auswandererhaus“, Poster Presentation: Castellani, G et al., “Impact of sea-ice surface roughness on the momentum exchange between atmosphere, sea ice and oceans“ 30 November, 2012.

Programming tools / data analysis tools used / computational skills:
Fortran, Linux, LaTex

• 2012 Sea ice winter ecology course, Tvärminne zoological station, Helsinki, Finland.

• 2012 RV Heinke, North Sea - Helgoland, MultiNet.

• 2013-2014 RV Polarstern - PS-82, Weddel Sea - Filchner ice-shelf, CTD, Sea-ice buoy deployments.

• 2014-2015 RV Polarstern - PS-89, Weddel Sea, Sea-ice coring for algae concentration analysis, under ice light measurements. SUIT (Surface and Under Ice Trawl) physical sensors deployment

• 2015 RV Polarstern - PS-92, Arctic Ocean, Sea-ice coring for algae analysis, under ice light measurements. SUIT (surface and under ice trawl) physical sensors deployment

• 2012 Best master thesis for the year 2011 related to glacier research - Assigned by the Italian Glacier Committee (CGI)

• 2013 Gordon Research Conference: best poster

• 2014 Best presentation. ERRSeS annual retreat