Zur Ökoklimatologie der Kallawaya-Region (Bolivien)

Abstract

The following paper deals with the description of the climatic conditions in the Kallawaya-Region (North-Bolivia), which have a strong influence on the life and the economy of the population. The marked contrast between the rainy season in summer and the dry season in winter, as well as several pecularities of the meso-climate operate on vegetation and land use. Based on insolation and the position of the sun as astronomical factors, the potential solar radiation of the area under investigation was calculated and compared with the actual one measured at the reference station Charazani (3,300 m a.s.l.). The maps show a clear spatial difference between slopes exposed to the north with radiation surplus and slopes exposed to the south with radiation deficit. In accordance with the rates of insolation the soil temperature at 50 cm depth was used as a micro-ecological measure of heat, uninfluenced by the course of the day. With the help of a larger group of these measurements an actual thermic-spatial classification was worked out for the end of the dry season. Furthermore it was possible to construct models for the variation of soil temperatures as a function of inclination, exposition, and elevation - for a specific elevation (3,000 m) even for several points of time in the course of a year. Several gradients of temperature versus altitude, partly depending on exposition, were calculated from soil temperatures, which depend on height. Their values were similar to those of the air temperature gradients. The generally linear decline of the temperature according to altitude is only disturbed by two mesoclimatic phenomena: the regular accumulation of cold air in the morning (below 3,200 m), which can be registrated in the air temperature as well as in the soil, and a frequent inversion-layer of varying thickness between 3,400 m and 4,100 m elevation. Resulting from these meso- as well as micro-climatic factors, clear altitudinal limits for vegetation and land use exist, differing according to the exposition and the inclination of the slopes.