Environmental Status of the Lake Michigan Region, Vol. 8 Atmospheric Environment of the Lake Michigan Drainage Basin

*ISWS Miscellaneous Publication no. 77 is listed in the 1995 Publications Catalog as "Gatz, D.F and Changnon, S.A. 1984. Environmental Status of Lake Michigan Region, 164 pp." and in the ISWS Publications Database as "Environmental status of the Lake Michigan region : Volume 8, atmospheric environment of the Lake Michigan drainage basin" also with a publication date of 1984. The MP series statement is included in this record on the basis of this information even though the publication years do not match and there is no reference in the work itself to the ISWS Miscellaneous Publication series. There is no evidence of the existence of a 1984 edition of the work.Climate was the most important factor in producing the Great Lakes we have today. Through glacial action during the Pleistocene Epoch, the surface topography, shape, and depth of Lake Michigan were determined. Today the Lake Michigan region has a humid, continental climate. Summers are hot and humid, and winters are cold and stormy. Lake Michigan, as a reservoir for storing and exchanging heat, is a moderating influence on extreme temperatures. The Lake is also a moisture source, especially during late fall and early winter when Arctic air flows over the still-warm lake. Heavy snows in the lee of the Lake can result. Regional atmospheric dispersion conditions are generally good in locations away from the Lake. Air mass stagnation conditions are expected only four times a year, and three of these should last no longer than two days each. However, over and near the Lake, conditions can be extremely different. During the warm season, when the air over the Lake is relatively cold and stable, onshore airflow can produce a number of conditions leading to high pollutant concentrations within 10 km of the Lake shore. The pollutants also have effects on the weather, including reduced visibility and solar radiation, and increased cloudiness. They may also play a role in producing excess precipitation downwind of large industrial and population centers. Atmospheric pollution also provides an important pathway for the transfer of pollutants deposited on the Lake surface both by dry fallout and in precipitation.Prepared for the U. S. ENERGY RESEARCH AND DEVELOPMENT ADMINISTRATIONOpe