Weekly forecasts of harmful algal bloom conditions in Lake Erie have started for the 2012 season. Two forecasts have already been issued, and they will be disseminated throughout the bloom season—which lasts from June to October. Earlier, NOAA issued its first seasonal forecast for the lake's notorious algae, advising water utilities, recreational anglers, and others who live and work on the lake to anticipate a milder season than many previous years.
The forecasts had been jeopardized when a European satellite scientists had depended upon for data stopped working last April. Now data come from a NASA satellite that carries an instrument called the Moderate Resolution Imaging Spectrometer. Because the satellite, called Aqua, detects different algae spectral signatures than the European satellite, the scientists had to recalibrate their algorithm to account for the difference. To test this algorithm, they analyzed it against three previous years of data to determine that their forecasts would be as accurate as ever.
In addition to satellite data, the scientists rely on a sophisticated computer model that predicts how conditions such as winds, temperature, and currents on the lake's surface influence whether the bloom will grow or shrink as well as where it will drift. Together, they produce a near-real-time forecast that helps water treatment plant operators know when to use extra carbon filtration to preserve the quality of their drinking water.
For more information, contact Richard.Stumpf@noaa.gov.