Abatmct-Measurements of temperature, humidity and wind velocity made from 1973 to 1978 at several special stations near Lake Michigan are analyzed to determine true lake breeze occurnnccs, movement inland and effects of cloudiness and wind speed on lake breeze behavior. A total of 187 true lake breezes occurred in the 6 year period, with July and August having the most frequent occurrences. Nearly half of these moved inland as far as 19 km. Fifty retreated lakeward after having moved inland. The formation and behavior of true lake breezes are discussed in relation to the strength of the offshore wind and cloudiness. Vertical temperature differences associated with the passage, duration and retreat of true lake breezes are presented and discussed.

Two years of visibility measurements made about 1 and 19 km from Lake Michigan are analyzed to determine occurrences of advection-radiation fog. Occurrences at both stations are most frequent in the summer months, and the l-km station has about twice as many hours of fog as the 19-km station. The reason is that a combination of onshore gradient winds and lake breezes acts to maintain higher average relative humidities at the l-km station. with terrain differences of secondary importance.

Twenty-five meteorological stations are in operation inland from two nuclear power plants located on the Lake Michigan shoreline in southwestern lower Michigan. Their purpose is to provide data to enable meteorological effects of mechanical-draft cooling towers at the Palisades Nuclear Plant and a once-through cooling system at the Donald C. Cook Nuclear Plant to be evaluated. Temperature, relative humidity, and precipitation are measured at all stations, total solar radiation and wind velocity at four, and visibility at three. The stations, equipment, and calibration methods are described, and examples of types of meteorological analyses are presented.

Optical scintillation was measured for horizontal paths 120 to 600 meters long, about 1.5 meters above uniform surfaces, both snow and grass. The results are related to temperature profiles, wind speeds, Richardson numbers, and path lengths. Power spectra of scintillation measured under various conditions of stably stratified flow are presented and discussed.

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