Research

 
ICE STREAMS : The evenly spaced troughs on the continental shelf are thought to be carved by ice streams (Clark and Spagnolo 2016). The regularity of the pattern strongly suggests that an instability may be at its origin

ICE STREAMS: The evenly spaced troughs on the continental shelf are thought to be carved by ice streams (Clark and Spagnolo 2016). The regularity of the pattern strongly suggests that an instability may be at its origin

 
ENGLACIAL LAYERS:  Colors mark the slope of englacial layers (red sloping downward, blue sloping upwards) computed with a novel SAR processing technique that correct for destructive intereference affecting steeply dipping internal reflectors (Castelletti et al. 2019, accepted).

ENGLACIAL LAYERS: Colors mark the slope of englacial layers (red sloping downward, blue sloping upwards) computed with a novel SAR processing technique that correct for destructive intereference affecting steeply dipping internal reflectors (Castelletti et al. 2019, accepted).

 
ICE/OCEAN INTERACTIONS : Different modes of ice shelf melting (From Silvano et al 2016)

ICE/OCEAN INTERACTIONS: Different modes of ice shelf melting (From Silvano et al 2016)

My research spans a variety of topics in glaciology, including the dynamics of fast ice flow, subglacial and surface hydrology, basal sliding, and ice-ocean interactions.

The common thread among these diverse set of subjects is that the processes involved have the potential to drive the dynamics and evolution of a whole ice sheet. Understanding how and when this may happen is the ultimate goal of my research.

To achieve this, I build off a diverse skill set that is grounded in continuum mechanics and applied mathematics, which I combine with observation-driven work. As a theorist by training, I see observational work as a key step to test models predictions in the real world, and ultimately improve models themselves. Whether through collaborations, or going to the field myself, I strive to blend both approaches in my research.

Below is a brief description of ongoing projects that I am leading, while past projects are listed at the bottom. I also have the privilege to work with a number of talented students, whose work is described here

Ongoing projects

1. Ice stream formation and dynamics as an instability of basal thermal transitions

Ice streams are narrow bands of rapidly flowing ice which have the potential to cause rapid shrinkage of the ice sheet through their high discharge. A prominent feature of these ice streams is that they exhibit complex spatial and temporal dynamics: they can emerge spontaneously out of an otherwise uniform flow, self-organize in space, and switch on and off over time, with major implications for ice sheet mass loss.

Even though ice streams have been long studied, the processes responsible for their initiation are still poorly understood. Motivated by observations that ice flows slowly where it is frozen to the bed, while streams are at the melting point, in this project (in collaboration with Christian Schoof at the University of British Columbia) I am investigating the role of thermally activated basal sliding with respect to fast flow initiation and patterning in ice sheet velocity [link to AGU 2018 abstract].


2. Constraints on ice sheet basal conditions from the architecture of englacial layers
Englacial layers are an ubiquitous indicator of internal deformation within ice sheets, as well as a common finding in radio echo sounding data. In spite of this, placing direct constraints on present or past ice flow through englacial layers remains, to date, a challenging task.

In this project (in collaboration with Dusty Schroeder and Jenny Suckale at Stanford University), I leverage recent advances in the processing of airborne radar sounding data along with modelling work to address this challenge. One current application is to constraining abrupt changes in basal friction in the onset regions of ice streams

3. Parameterizations of melt at the bottom of ice shelves
Melting at the base of ice shelves (the floating portions of ice sheets) forced by warm ocean water is a key driver of mass loss in marine-terminating glaciers. However, dynamic coupling of ice sheet models and ocean models remains challenging, thus parameterizations of basal melt are required in order to predict future ice sheet loss driven by ocean forcing.

In this project (in collaboration with Olga Sergienko at Princeton), I use asymptotic and numerical techniques to move beyond traditional parameterizations of basal melt based on depth-integrated buoyant plume models.

 

Past Projects

4. The effect of climate variability on ice sheet dynamics [publications]

Politecnico di Torino, with M. Bertagni and L. Ridolfi

5. Physical drivers of spatial organization in glacier surface hydrology [publications]
Politecnico di Torino, with C. Camporeale and L. Ridolfi

6. Hydrodynamic instability in flows over porous media [publications]
Politecnico di Torino, with C. Manes and C. Camporeale