PhD-defence: Andreas Westergaard-Nielsen

Andreas Westergaard-Nielsen defends his PhD thesis: 

Improvements in spatiotemporal ecosystem monitoring in Greenland – processes, methods, and scales

Supervisor
Associate Professor Birger Ulf Hansen, IGN 

Assessment Committee
Associate Professor Thomas Friborg (Chairman), IGN
Assistant Professor Signe Normand, Aarhus University
Professor Lars Eklundh, Lund University 

After the PhD defence there will be a reception in ’Rød Stue’, Øster Voldgade 10, Area 6, First floor – and everybody is welcome.

Abstract
The Arctic is currently undergoing rapid changes due to climatic warming in the region. During the past few decades the Arctic has warmed approximately twice as much as the northern hemisphere on average due to feedback mechanisms. This phenomenon, referred to as the Arctic amplification, has resulted in a marked decline in sea ice and changes in magnitude of terrestrial snow cover. In combination with warmer surface air temperatures, this is expected to have severe implications for the ecological, physical, and cultural systems in the region. Moreover, a number of these implications are likely to be irreversible and accelerate due to positive feedbacks. However, the ecological consequences of climate change in the Arctic such as shifts in snowmelt timing, changes in ecosystem productivity, and shifts in phenology are not widely studied when taking the magnitude of abiotic changes into account. Long term ecosystem monitoring at several spatial scales are consequently of great importance when evaluating methods to adapt to and mitigate climatic changes in the Arctic.

This PhD defense will focus on the use and scaling of multiplatform remotely sensed data in the monitoring of snow cover dynamics, vegetation productivity and phenology in Greenland. Specifically, emphasis will be put on: the application of broad band digital cameras in the monitoring of Arctic phenology; the use of digital camera data as a proxy for ecosystem productivity in sparsely vegetated biomes; investigations of the interactions between snow cover distribution and vegetation growth patterns; evaluation of the future ecosystem productivity in Southwest Greenland and the possible consequences for farming in the region; the assessment the representativeness of single research sites in Northeast Greenland in an upscaling of gas fluxes. 

The thesis is available from the PhD administration office 04.1.409