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  • Author: Zbigniew Caputa x
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Abstract

Comprehensive environmental studies taking under consideration the structure of the radiation balance during the vegetation growing seasons of 2001 and 2002 were carried out on the open sandy surface of the area called the Błędów ‘desert’ located on Silesian Upland. The research in each site covered the composition of plant species, their age and height, the condition of the substratum, the composition and structure of the soil and the meteorological conditions with elements of the radiation balance. The article presents some part of the research on meteorological elements and their impact on ecosystem. Special attention was devoted to radiation conditions on the open sandy surface in the context of the formation of BSC (biological soil crust). Having presumed that the values obtained on the grassy surface constituted 100%, the values of radiation reflection measured on the open sandy surface were 185% higher and the values of net longwave radiation were 105% higher in day time and 137% in night time. Values of net radiation of about 63% lower were observed on the sandy surface during a typical sunny summer day. It was found that a strong irradiation of the sandy surface (26 MJ·m–2d–1) creates extremely difficult conditions for the initiation of the process of ecosystem formation (including BSC or plant succession). The elements of the radiation balance, net radiation, albedo and temperature of the open sandy surface were represented quantitatively. The test surfaces were classified based on the value of the albedo: group I with low albedo values, up to 0.15 (spore-bearing plants on a dark surface), including BSC; group II with mean values of the albedo from 0.16 to 0.24 (spore-bearing plants and seed on a dark grey surface); and group III with high albedo values, above 0.25 (plants growing on bare or loose sands).

Abstract

The paper presents results of the research on the impact of solar radiation on the formation of the thermal conditions of the exposed rock surfaces of the Kraków-Częstochowa Upland. The research comprised the structure of the radiation balance of the active surface of the bottom of the canyon, the temperature of the surface and the layer at the depth of −5 cm in limestone rock on the southern wall of the canyon. The tests were performed in various types of weather. The strongest mesoclimate contrasts were observed in the radiation type of weather: differences in insolation and in the balance of radiation, thermal differences and variations within the heat flux in the rock. The longwave stream of radiation which was emitted by the heated rocks exerted an impact on the microclimate conditions and on the radiation balance at the bottom of the canyon during the night. A diverse relief of the terrain constituted a local factor differentiating the radiation balance and the distribution of the rock temperature. The quantitatively determined structure of the radiation balance and the thermal contrasts of the canyon, particularly of the rock surfaces, point to the importance of the relief in shaping the mesoclimate of even small karst areas. These characteristics determine the heat flux in the rock, weathering processes and others. The mesoclimate and microclimate of the rocks affect the biodiversity of the rock surfaces of the Kraków-Częstochowa Upland. In addition, they shape the ecotopy of the karst canyon, among others – the vegetation on the limestone rocks.