Michiel van den Broeke
Polar Meteorology, Utrecht University

News

In Publications see an exciting study led by colleague Jason Box in which he reconstructs the surface accumulation on the Greenland ice sheet back to AD1600, and new results on future mass changes of the Greenland and Antarctic ice sheets and Canadian ice caps.

Watch the largest iceberg calving event caught on tape thus far: Jacobshavn Isbrae, west Greenland. Footage is part of a recently released documentary film on the world's disappearing ice.

On 30 November 2012 the journal Science published the IMBIE paper (Ice sheet Mass Balance Intercomparison Experiment). Also listen to the interview on Radio 1 (in Dutch).

On 26 April 2012 the journal Nature published a paper on the detection and attribution of ice shelf thinning in Antarctica. Have a look at this television interview for NOS Journaal (in Dutch).

Introduction

I am a professor of Polar Meteorology at Utrecht University. My main research interest at present is to understand the past, present and future climate and mass balance of the large ice sheets of Greenland and Antarctica. I perform my research at the Institute for Marine and Atmospheric Research Utrecht (IMAU) in the Ice and Climate research group. Our group combines experimental fieldwork (in situ meteorological experiments, automatic weather stations and surface mass balance observations) with regional climate models, the latter in close collaboration with the research department of the Royal Netherlands Meteorological Institute (KNMI).

AWS on glaciers

We operate a network of automatic weather stations (AWS) on glaciers: eight in Antarctica, four in west Greenland and several others in Svalbard, Norway and the European Alps. Data of these AWS enable us to close the surface energy balance and calculate melt intensity, helping us to improve our understanding of the melt process and its representation in our regional climate model. More information can be found on the IMAU AWS website and on the Projects page.

IMAU AWS near the ice margin in west Greenland, August 2010

Regional climate/firn modelling

The next step in the research process is to scale up the local AWS measurements in space and time. To that end we use a regional climate model (RACMO2), developed at the Royal Netherlands Meteorological Institute (KNMI) and adpated for use over ice sheets and larger ice caps. Major adaptations are the description of drifting snow, a prognostic snow albedo scheme, a background ice albedo for Greenland and subsurface processes in the snow/firn (meltwater penetration, retention and refreezing). Because RACMO2 is computationally too expensive for sensitivity tests, we have developed a high-resolution firn model for offline calculations. Forced with output of RACMO2 at its upper boundary, the model is used to optimize estimates of firn layer mass and depth. These data can be used to convert ice sheet volume change (as measured by altimeters onboard airplanes and satellite), to mass change. More information can be found on the Projects page.

Ice sheet surface mass balance (in mm water equivalent per year) from RACMO2