The history of Columbia County, Wisconsin, containing an account of its settlement, growth, development and resources; an extensive and minute sketch of its cities, towns and villages--their improvements, industries, manufactories, churches, schools and societies; its war record, biographical sketches, portraits of prominent men and early settlers; the whole preceded by a history of Wisconsin, statistics of the state, and an abstract of its laws and constitution and of the constitution of the United States
Oldenhage, H. H.
Climatology of Wisconsin, pp. -128 PDF (3.9 MB)
HISTORY OF WISCONSIN. Among local influences which modify climate, the nature of the soil is one of the.most important. As water absorbs much heat, wet, marshy ground usually lowers the mean tempera- ture. A sandy waste presents the greatest extremes. The extremes of temperature are also modi- fied by extensive forests, which prevent the soil from being as much warmed and cooled as it would be if bare. Evaporation goes on more slowly under the trees, since the soil is screened from the sun. And as the air among the trees is little agitated by the wind, the vapor is left to accumulate, and hence the humidity of the air is increased. Climate is modified in a similar man- ner by lakes and other large surfaces of water. During summer the water cools the air and reduces the-temperature of the locality. In winter, on the other hand, the opposite effect is pro- duced. The surface water which is cooled sinks to lower levels; the warmer water rising to the surface, radiates heat into the air and thus raises the temperature of the neighboring region. This influence is well illustrated, on a great scale, in our own state by Lake Michigan. It is, lastly, of importance whether a given tract of country is diversified by hills, valleys and mountains. Winds with their warm vapor strike the sides of mountains and are forced up into higher levels of the atmosphere, where the vapor is condensed into clouds. Air coming in con- tact, during the night or in winter, with the cooled declivities of hills and rising grounds becomes cooled and consequently denser and sinks to the low-lying grounds, displacing the warmer and lighter air. Hence, frosts often occur at these places, when no trace of them can be found at higher levels. For the same reason the cold of winter is generally more intense in ravines and valleys than on hill tops and high grounds, the valleys being a receptacle for the cold-air currents which descend from all sides. These currents give rise to gusts and blasts of cold wind, which are simply the out-rush of cold air from such basins. This is a subje~ct of great practical impor- tance to fruit-growers. In order to understand the principal features of the climate of Wisconsin, and the conditions on which these depend, it is necessary to consider the general climatology of the eastern United States. The chief characteristic of this area as a whole is, that ,t is subject to great extremes-to all those variations of temperature which prevail from the tropical to the Arctic regions. This is principally due to the topographical conditions of our continent. The Rocky mountains con- densing the moisture of the warm winds from the Pacific and preventing them from reaching far inland,, separate the climate of the Mississippi valley widely from that of the Pacific slope. Between the Gulf of Mexico and the Arctic sea there is no elevation to exceed 2,ooo feet to arrest the flow of the hot southerly winds of summer, or the cold northerly winds of winter. From this results a variation of temperature hardly equaled in any part of the world. In determining the climates of the United States, western Europe is usually taken as the basis of comparison. The contrast between these regions is indeed very great. New York is in the same latitude with Madrid, Naples and Constantinople. Quebec is not so far north as Paris. London and Labrador are equi-distant from the equator ; but while England, with her mild, moist climate, produces an abundance of vegetation, in Labrador all cultivation ceases. In the latitude of Stockholm and St. Petersburg, at the 6oth parallel, we find in eastern North America vast ice- fields which seldom melt. The moist and equable climate of western Europe in high latitudes is due tolthe Gulf Stream and-the southwest winds of the Atlantic, which sprea@l their warmth and moisture over the western coast. Comparison, however, shows.that the climate of the Pacific coast of North America is quite as mild as that of western Europe; and this is due to the same kind of influences, namely, to the warm, moist winds and the currents of the Pacific. And to con- tinue the comparisoli still further, in proceeding on both continents from west to east, or froM' ocean into the interior, we find a general resemblance of climatic conditions, modified greatly, it ...is true, by local influences. 122
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