The estimation of the energy balance of a lake from simple weather data

The energy balance of a lake with an area of approximately 46000 ha and a depth of 3 m has been estimated from simple weather data measured along the perimeter of the lake. These measurements are dry-bulb temperature and relative humidity, both at 1.5-m height, windspeed at 3-m height and sunshine duration. The estimated energy balance values were compared with the values computed from the measurements at the station situated at the centre of the lake. At this station, net radiation, water temperature, dry-bulb and wet-bulb temperature at a height of 2 m were measured. It is possible to estimate the daily evaporation from the lake with an error of 0.6 mm day^–1, if the location of measurement is downwind from the lake.