Long-Term Ecological Research (LTER)/NTL013: Lake Evaporation from Sparkling Lake, Wisconsin

LTER - Long-Term Ecological Research Program/North Temperate Lakes (NTL)

LTER/NTL013 [Summary adapted from the LTER Core Data Set Catalog]:

Questions relating to the flux of solute elements to and from lakes require accurate water budgets. Evaporation rates are a critical component of the water budget of lakes. An instrumented raft is put on the lake over the ice-free season to measure micrometeorological parameters from which evaporation can be calculated. Raft measurements of relative humidity and air temperature (2 m height), wind velocity (1, 2, and 3 m heights), and water temperatures at 1-m intervals are combined with measurements of total long-wave and short-wave radiation data from a nearby shore station to determine evaporation by the energy budget technique. Comparable evaporation estimates from mass transfer techniques are calibrated against energy budget estimates to produce a lake-specific mass transfer coefficient for use in measuring humidities over longer periods of time using the mass transfer technique alone. Evaporation is calculated using both energy budget and mass transfer techniques.

Special Comments: Data are measured every minute, averaged to one hour periods and recorded using Campbell dataloggers. Twenty-four averages are calculated and stored from the one hour averages.

The North Temperate Lakes (NTL) site is affiliated with the Center for Limnology at the University of Wisconsin, Madison. The NTL site focuses its research on north temperate lake ecosystems in the Northern Highland Lakes District of Wisconsin. The Northern Highland Lakes District, has an area of approximately 10,000 sq. km. and has one of the highest concentrations of lakes in the world. Lakes range in size from 0.1 to 1,500 ha, in depth from 1 to 33 m, and in fertility from oligotrophic to eutrophic. Other representative limnological conditions include: rainwater dominated, groundwater dominated and drainage lakes; dystrophic lakes; lakes with varved sediments, winterkill lakes, temporary and permanent forest ponds, and reservoirs. Lakes are influenced by strong seasonality and are usually ice covered from late November to late April. Lakes within the Northern Highland exhibit near-natural water quality conditions. Nearly 80% of the land area and two-thirds of the lake frontage are protected.

Information about LTER is also available at 'http://lternet.edu/'