Midway evaluation in Environmental Engineering - Darri Eyþórsson

Ph.D. student: Darri Eyþórsson 

Dissertation title: Climate Change Impacts on Snow Resources 

Doctoral committee: 

Dr. Sigurdur Magnus Gardarsson, Professor, Dean of Engineering and Natural Sciences, University of Iceland

Dr. Oli Gretar Blondal Sveinsson, Executive Vice President, R&D Division, Landsvirkjun

Dr. Birgir Hrafnkelsson, Professor, Department of Mathematics, University of Iceland

Dr. Bart Nijssen, Professor, Civil & Environmental Engineering, University of Washington

Abstract:

The storage of water in snow and ice is an important component of the hydrological cycle in many regions of the world. Changing climate is predicted to impact the spatial and temporal distribution of these resources in the future. Therefore, improved predictions of changes to the snow regime are crucial for the successful adaptation of water resources managment to climate change. This study presents an analysis of the impacts of historical and predicted trends in climate change on snow resources. The key physical factors determining the seasonal melt characteristics in a cold region catchment were determined by the application of a statistical model framework. Historical trends in Snow Cover Frequency (SCF) were estimated based on satellite remote sensing data

(MODIS/Terra) and compared to historical changes in Koppen-Geiger climate classifications, estimated by the ensamble average of downscaled and bias corrected CMIP5 projections for the RCP45 emissions scenario. Future changes to climate classifications were estimated and the associated impacts to snow resources are being modelled using a conceptual snow model (SNOW17) forced with the CMIP5 model ensamble for the RCP45 and RCP85 emission scenarios.

The results show that significant changes have occured in the snow regime in the period of MODIS observations (2001-2016), SCF has decreased in lower latitudes while further north, around the arctic coastline many areas exhibited an increasing SCF. These changes to the snow regime have occured at the same time as warmer climate classes are spreading further north. The trend observed climate trends are expected to continue throughout the current century and by 2100 we expect the currently dominant Arctic climate class, Cold climate with cold summers and no dry season to decline by about 40% and be replaced by climate classes associated with warm and hot summers.

Modelling results show that SCF will continue decreasing at low latitudes and increase at higher latitudes in the far north. The predicted changes are more severe given the RCP85 scenario compared to RCP45.