Regional Monitoring of Natural Environment 2002, No 3, 109-116
DIFFERENTIATION OF KIELCE BIOCLIMATE IN SUMMER SEASON
The aim of the present study was to determine the degree of differentiation of biotopoclimatic conditions on the area of Kielce during summer season. An attempt at estimation of the effect of individual factors upon these conditions was made too.
The measurements were made in 8 places located in various topographical situations (max. distance 4,5 km). Downtown points SQUARE (PLAC) and STATION (DWORZEC) represented build–up area, the point PARK was situated in City Park and CATHEDRAL (KATEDRA) was located on the cathedral hill. The points SILNICA and LAKE (ZALEW) were situated (respectively) at the bottom of the river valley, and in the vicinity of the artificial lake. The point HOSPITAL (SZPITAL) was on the hill near a wide road. The stand GARDEN (OGRÓDEK) was located outside the town and was treated as a relation point (fig. 1). The synchronous all day and every hour measurements were conducted in June and July of 1999, 2000 and 2001 during sunny and dry weather. The measurements of air temperature and humidity were made by Assmann’s aspiration psychrometers at 130 cm above the ground. The cooling power was measured by Kata thermometers at the same level. The speed of wind was measured by Robinson’s anemometer at height 200 cm. Statistical characteristics of some meteorological elements and biometeorological indices are presented in table 1.
Relationships between hourly values of ground surface temperature outside the city (GARDEN) and appropriate values at the remaining points were calculated (tab. 2). The temperature of the ground (active surface) most differentiated measured points. Its role as differentiation factor increased in conditions of intense insolation at midday. Relationships between active surface temperature outside the town (GARDEN) and on the other points were obtained in the form of logarithmic functions (fig. 2). These functions revealed 3 groups of points: very warm (SQUARE, STATION, CATHEDRAL), moderately warm (LAKE, HOSPITAL) and cool (PARK, SILNICA). The first group of points has usually a higher air temperature in relation to the suburban. The frequency of sultry states was calculated using Leitsner scale of equivalent temperature (Prott formula) and Scharlau’s criterion of actual vapour pressure (fig. 5). Sultry periods occurred most often in the vicinity of water (LAKE and SILNICA) and inside compact building (STATION and SQUARE).
Bioclimatic conditions in the town with respect to dry cooling power using Kacvisnsky and Petrovič scale were estimated too. The comfort conditions “calm” were most often in points GARDEN and LAKE. On the other hand thermal condition “hot” were noted most often on stands SILNICA and STATION because these places are sheltered. The conditions “cool” occurred only at points GARDEN and HOSPITAL (fig. 8).
Tree clustering analysis was conducted in order to determine bioclimatic differentiation on the basis of average values of individual elements and all elements jointly. The results are presented in the form of dendrograms using Manhattan distance method (figs. 3, 6, 7). The highest degree of bioclimatic similarity in recpect of mean values distinguished CATHEDRAL and HOSPITAL – the points situated on hill with grass as active surface. The second set forms SILNICA and PARK, which characterised by small ventilation. The most individual character of its bioclimate appeared SQUARE and STATION, which represented concrete–covered active surfaces. In conclusion one may state that differentiation of biotopoclimate in Kielce during radiation weather is determined above all by physical properties of the active surface.