Modelling melting, structure and microbial activity of an ice sheet surface #

Tilly Woods, Ian Hewitt

10:50 Tuesday in 2Q49.

Part of the IMA Lighthill-Thwaites prize session.

Abstract #

The structure of an ice sheet surface is one factor affecting the amount of surface melting and runoff into the ocean. One such structure is the weathering crust - a porous near-surface layer formed by the penetration of solar radiation causing internal melting. The weathering crust is a dynamic hydrological system that provides a home to impurities and microbial life. The interplay between the ice structure and the microbial life leads to potential feedbacks that can enhance melting. We have developed a mathematical model, incorporating thermodynamics and population dynamics, for the evolution of such layers. The model accounts for conservation of mass and energy, for internal and surface-absorbed radiation, and for logistic growth of a microbial species mediated by nutrients that are sourced from the melting ice. I will demonstrate how one-dimensional steady and time dependent solutions to the model can be used to understand the response of the weathering crust to variable weather conditions and climate change. Moreover, I will discuss the potential feedbacks between microbes, structure and melting.