Measurement and Modelling of the Variability of Lake Ice Growth and Decay in Alaska

Investigator: Martin O. Jeffries   (Principal Investigator current)
              Kim Morris  (Co-Principal Investigator current)

Abstract

Abstract Jefferies OPP-01-17645

Since 1846, the duration of the ice cover on Northern Hemisphere lakes and rivers has decreased by almost 20 days. A three week reduction in ice duration on lakes in Ontario, Canada since 1969 has caused major limnological and ecological changes. Since the late 1980s/early 1990s, there has been significant environmental change in the ocean, atmosphere, and cryosphere of the Arctic. The recently released third assessment of the Intergovernmental Panel on Climate Change, 2001 indicates that the sensitive and already changing northern high latitude cryosphere faces further change as winter temperatures and precipitation increase at high northern latitudes.  Lake ice in Alaska may be responding to late twentieth century environmental changes and may respond to further climatic perturbations. However, the observational record is neither sufficiently long and continuous, nor covers the appropriate period to allow for a proper assessment of past lake ice variability and the likely magnitude of future change. The objective of this study is to use numerical modeling to simulate the variability of lake ice growth and decay at the present time and during the period of meteorological record in the different climate zones of Alaska, and to understand the factors responsible for that variability in order to predict the response of the ice to future climate change.

Lake ice growth and decay variables include freezing, ice thickness, modes of thickening [congelation ice, snow ice], and break-up.  This is a larger and more comprehensive set of variables than has been considered previously and they integrate the effects of both temperature and precipitation variability.   Successful completion of this study will yield well-validated lake ice growth and decay model that will enable us to identify the key factors responsible for the variability of lake ice growth and decay. This will fill a major gap in the knowledge and understanding of the response of the Arctic and sub-Arctic cryosphere to past climate variability and change, and the prediction of future response. This will benefit physical, chemical, and biological limnologists, and ecological and water resource managers. Teacher and student participation will give them a better appreciation for teaching and learning in the local context, an understanding of the scientific process, and interesting and relevant examples of the impact of climate variability and change on Alaska physical processes and interactions.