Regional water balance trends and evaporation-transpiration partitioning from a stable isotope survey of lakes in northern Canada
Article first published online: 26 JUN 2002
Copyright 2002 by the American Geophysical Union.
Global Biogeochemical Cycles
Volume 16, Issue 2, pages 10-1–10-14, June 2002
How to Cite
Regional water balance trends and evaporation-transpiration partitioning from a stable isotope survey of lakes in northern Canada, Global Biogeochem. Cycles, 16(2), doi:10.1029/2001GB001839, 2002., and ,
- Issue published online: 26 JUN 2002
- Article first published online: 26 JUN 2002
- Manuscript Accepted: 4 APR 2002
- Manuscript Revised: 8 FEB 2002
- Manuscript Received: 27 NOV 2001
- stable isotopes;
- regional water balance;
- spatial variability
 Regional variations in evaporation losses and water budget are interpreted from systematic isotopic patterns in surface waters across a 275,000 km2 region of northern Canada. Differential heavy isotope enrichment in a set of >255 nonheadwater lakes sampled by floatplane during 1993 and 1994 is strongly correlated to varying hydroclimatic conditions across the region. Calculated catchment-weighted evaporation losses typically range from ∼10–15% in tundra areas draining into the Arctic Ocean to as high as 60% in forested subarctic areas draining to the Mackenzie River via Great Bear or Great Slave Lakes. Because of the diversity in drainage order and the ratio of catchment to surface area, lakes in the region may inherit as little as 30% to as much as 99% of their isotopic enrichment signal from upstream water bodies. Open-water evaporation generally decreases with increasing latitude and accounts for 5–50% of total evapotranspiration. Coupling of meteorological and isotopic data permits a novel assessment of regional evaporation-transpiration flux partitioning in the three major ecoclimatic zones (high-boreal forest, subarctic forest-tundra, and low-arctic shrub tundra), while the differing frequency distributions of lake water balance in these zones provides a new index of landscape-scale hydroclimatology that may have significant potential for investigating ongoing (or past) changes in response to high-latitude climate change.