J Unger, N skarbit and T Gál

Department of Climatology and Landscape Ecology, University of Szeged, Egyetem u. 2., 6720 Szeged, Hungary, E-mail: unger@geo.u-szeged.hu

Summary: This study gives a comprehensive picture on the air humidity observation and mapping in urban canopy layer in Szeged, Hungary, analyzing three-year long vapor pressure dataset (e) calculated from observations of a 22-station urban network. The analysis was divided into two directions, namely the urban-rural and intra-urban ones where the latter was partly based on the local climate zone approach. (i) The general features of the annual and diurnal variations of urban-rural absolute humidity difference in cities with mid-latitude climates are also detectable in the case of Szeged. (ii) In the annual and seasonal e means there is no clear zone sequence that would follow the differences in the compactness or building height of the zones and even the built-up versus land cover distinction. (iii) The highest e values and their differences among stations appear in summer, while the lowest ones in winter and the values of transitional seasons are between them. In certain cases the intra-zone differences can exceed the inter-zone ones since the effect of microscale environment is essential. The decisive factors are the permeability of the surface and the vegetation cover. (iv) The diurnal course of the e pattern in normalized 4-hour time steps does not show a regular shape, the patterns are mosaic-like: in all time steps the driest and wettest areas are mainly in the north-western and south-eastern parts, respectively.

Keywords: vapor pressure, urban network, long dataset, urban-rural, intra-urban, local climate zones

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