Date of Award

12-1-1983

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Geography & Geographic Information Science

Abstract

The climate of southwestern North Dakota is typical for the Great Plains of the central and west-central United States. The Rocky Mountains influence the climatic condi tions by providing an orographic obstacle to air circula tion. Statistical analysis through correlation and regres sion of 30 years of climatic data from southwestern North Dakota and nearby stations in South Dakota and Montana is consistent with climatic relationships that have been de fined by previous research. The influence of the Rocky Mountains is quantified through a variable that represents the linear distance from each weather station to the front range.

The natural vegetation of southwestern North Dakota is mixed grasses; however, in the Badlands of the Little Missouri River, many varieties of plants are encountered. Flora range from desert plants, through mixed grasses, to woodland vegetation of higher elevations. Overall climate is modified into local climates by rough terrain, which provides extremes of conditions that create suitable habitats for migrant species in addition to grasses common to the region. Differences between general climate and terrain climate are contributable to unequal receipt of solar radiation, which causes variations in temperature, humidity, and other related parameters. Radiation estimates (and consequent variable equivalent latitude) are computed for nine sta tions that have been in the same location for a majority of the 30 year period. Additional correlation shows signifi cant relationships between radiation and average temperature of some fall and winter months. Equivalent latitude proves to be a valuable tool in analyzing the complex interaction of slope and azimuth for a given latitude in regression analysis .

Significant differences between slopes are computed through several analyses of drainageways in the North Kill- deer Mountain area. Wilcoxon Tests for Paired Samples show variations in slope angles between east and west, and for northeast and southwest slopes. Chi-square analysis re veals significant results using north/south, northeast/ southwest, northeast/west, north/southwest , and northwest/ south azimuth pairs, and woodland, shrubland, and native prairie vegetation categories. Radiation estimates are calculated for sample slopes, and comparison of radiation conditions is made.

Vegetation patterns found in Theodore Roosevelt Na tional Park in a previous study are depicted using a circle method to represent azimuth and slope angle. Twelve plants are analyzed, and individual patterns emerge.

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