Lake Level Research

Lake Level Research. . , Water levels on the Great Lakes seem to be swinging rapidly, causing destruction when levels are high and shipping concerns when low. Understanding these swings is a focus of research undertaken, in part, from Mackinaw City. , Lake levels are determined by the net of , . precipitation and runoff bringing water into the lakes , . evaporation and drainage taking water out. , Evaporation is the least understood and most complex of these flows. High evaporation requires three factors: , 1. a large temperature difference between water and air (ie., warm water and cold air), , 2. low relative humidity, and , 3. high wind speeds. , (sidebar) , November is a pivotal month. , . Just one very cold, windy spell in November can evaporate ½ inch of water across all of the Great Lakes. , . Evaporation removes both water and heat from the lake. , . The heat loss will cause ice to form. , . Once the lake is ice covered evaporation ceases. , . Evaporation and lake levels are related but in a very complicated way. , Warming temperatures causing wider swings. ”The cooling effects of evaporation exert important feedbacks on lake temperature and ice cover that can actually result in above-normal evaporation rates immediately prior to winters with high ice cover. Conversely, winters with low ice cover are typically followed by warm summer water temperatures and an early start to the evaporation season. This latter effect has been especially noticeable during recent warm winters, which has dire implications for Great Lakes water levels as the climate continues to warm.” Source: glisa.umich.edu