Submitted to: Mississippi Water Resources Research Conference Proceedings
Publication Type: Abstract only
Publication Acceptance Date: 6/3/1999
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Late winter/early spring is an important part of the hydrologic year in the Upper Midwest. Water released during snowmelt, combined with still-frozen soils that have low infiltration rates can produce runoff, contamination of surface waters by agricultural chemicals, and disastrous flooding. Possible control and mitigation of these problems requires better prediction of the timing of snowmelt. We measured all components of the surface energy balance during spring snowmelt to determine the relative importance of the factors contributing to snowmelt, and to test a newly developed model of surface energy exchange based on satellite imagery. We found that in the spring of 1998, all snow melted during a weeklong period of complete cloud cover in mid-February. Despite the absence of direct solar radiation, radiant energy still provided 70% of the energy consumed in snowmelt via diffuse solar radiation filtered through the cloud deck. Sensible heat transfer, indicative of large-scale advection, provided the other 30 percent. We were unable to test the satellite-based model due to the persistent presence of clouds. This is a serious weakness of models based on relotely sensed data, and indicates the need for continued ground-based measurements during the snowmelt period.