The role of individual terrain units in the water balance of wetland tundra

Abstract

During two unusually dry periods, the peatlands remained wet, which indicates a lack of water mobility when the water table drops below the surface of the wetland. Stream-flow response to rainfall during these periods was small in comparison to early summer when the frost table was near the surface, or to wet periods when the water table rose above the surface. Energy balance measurements showed the lakes and ponds to have about 15% higher net radiation than wetlands and 29% greater than upland lichen-heath. From 9 to 18% of net radiation was used in thawing and heating the ground whereas the latent heat flux for the various terrain types utilized from 49 to 83% of net radiation. Even with unusually large rainfalls that occurred in July, evaporation exceeded precipitation over the course of the summer. Despite this, runoff was high and required a large negative change in groundwater storage to account for it. -from Authors