Insolation, Topography, and Settlement in the Alps

THEN on a mountain summit one seldom tires of watching the movement of sunlight and shadow over the landscape. Even if the day is cloudless there is constant fascination in the dwindling and shifting of the shadow patterns as the morning advances; in their widening and merging into new forms as the sun sinks (Fig. 2). These changing forms give the geographer food for thought; for he knows well the value of solar radiation to dwellers in mountain regions.' He knows that crops that ripen early on slopes exposed to the sun may fail to ripen at all on the opposite side of a valley. He knows that in the Alps north-facing mountain slopes are generally left to forest but that pastures extend high on south-facing slopes. These facts he recognizes in general terms. The shifting play of shadows, moving as they do in accordance with rigid mathematical laws, may suggest to him the possibility of precise investigation of the interrelationships of insolation, topography, and human life in mountain regions. The present study is a development of this thought. In regions of high altitude and where Alpine land forms predominate, insolation is especially important as a geographical factor, partly because the solar radiation received at the earth's surface increases with altitude and partly because the boldness of the topography causes sharp local contrasts in the duration and intensity of insolation. Methods of map analysis are suggested in the following paragraphs as a means of discovering and isolating the effects of topography on insolation. Three types of map have been selected to show correlations of geographical significance for the particular regions under discussion. The maps show (I) the winter noonday shadow area, (2) time periods of sunshine at the equinoxes, and (3) the noonday intensity of insolation at the equinoxes, all as determined by topography. How these maps were constructed will first be explained; then the maps themselves will be interpreted in the light of what they reveal; and finally some further refinements of the method will be suggested. The time-period and intensity maps, it must be observed, show potential, not actual, amounts of sunshine. Given clear weather from sunrise to sunset, the frequencies indicated would be experienced

Archaeology · Climatology · Geography · Insolation · Physical geography · Settlement (finance · Geology · Land Use and Ecosystem Services

• Influences of Native American land use on the Colonial Euro-American settlement of the South Carolina Piedmont

  Open Access•Michael R Coughlan, Donald R Nelson et al.•PLoS ONE•2018

  Add to list

• The importance of aspect to historic farmstead site location in the green mountains of vermont

  Peter B Mires•Historical Archaeology•1993

  Add to list

• Trends and Methods in Land Form Geography

  Barbara Zakrzewska•Annals of the Association of…•1967

  Add to list