A GIS approach to spatialize selected climatological parameters for wine-growing in Lower Silesia, Poland M. SZYMANOWSKI, M. KRYZA and M. SMAZA Institute of Geography and Regional Development, University of Wroclaw, pl. Uniwersytecki 1, 50-137 Wroclaw, Poland (e-mail: szymanowski@geogr.uni.wroc.pl) Abstract Tis paper investigates presents the results of a study of selected thermal parameters important for wine-growing: SAT (Sum of Active Temperatures), GDD (Growing Degree-Days), TY (annual mean temperature) and TJ (mean temperature of July) in their spatial context. In the first part, four selected interpolation algorithms: inverse distance weighting (IDW), ordinary kriging (OK), multiple linear regression method (MLR) and residual kriging (RK) are evaluated due to the quality and plausibility of spatial information, using cross-validation technique and visual inspection of maps. Te MLR method is finally found to be the most accurate - in each case regression explains 94-95% of variation, so the inclusion of physically meaningful „environmental“ relationships is found to improve prediction accuracies and quality of maps. A set o potential predictors, including coordinates and DEM-originated: elevation, convexity/concavity, foehn and solar radiation indices, show a great importance for air temperature parameters. In the second part of the paper, the obtained spatial information is designated for further processing in GIS that allows to delineate 3 regions of different suitability for wine-growing in Lower Silesia, SW Poland. Tese regions are dedicated mostly for moderately early, late and very late ripening grape’s varieties and cover almost 85% of analyzed area. Střelcová, K., Škvarenina, J. & Blaženec, M. (eds.): “BIOCLIMATOLOGY AND NATURAL HAZARDS” International Scientific Conference, Poľana nad Detvou, Slovakia, September 17 - 20, 2007, ISBN 978-80-228-17-60-8 M. Szymanowski et al. Key words: spatial interpolation, temperature, climate maps, grapevine, GIS, Lower Silesia Introduction Up to the 20 th century, Lower Silesia in south-west Poland was a traditional area of viticulture and wine- making. In spite of slow but continuous reduction of vineyards which has been observed since the 17 th century, the first half of 20 th century was in fact crucial for wine-growing in this region. In the beginning of the century, the total area of vineyards in Lower Silesia was still close to 1500 ha, whereas in 1929 there were only about 150 ha left. The last mass-producing vineyards were definitively closed in 1970s. Even though the main reason leading to decline of wine-growing trade was of economic and social nature, also unfavorable climatic conditions played an important role in that process. Climate change, distinctly marked in the last 20- 30 years, brought a vital improvement of climatic conditions especially as far as thermal conditions are concerned (Jones, 2005). One can observe growing trends of such important for vine parameters as sum of active temperatures, growing degree-days, mean annual and monthly temperatures, elongating growing seasons and others. On the other hand, nowadays new, frost- and disease-resistant vine varieties can be cultivated. Additionally, the accession of Poland to the European Union inspired changes in law and economic conditions and made wine-growing and grape-processing again possible and potentially profitable. Poland was classified into zone A of viticulture, where climatic conditions are not favorable (cool climate zone) but where there are no limitations on vineyards’ areas and wine production. All these factors are conducive to gradual revival of wine-growing traditions in Lower Silesia. This tendency is observed in foundation of new and revival of old vineyards. Success in wine-growing and wine-making is to a large extent determined by natural, environmental conditions of vineyard that can be expressed by a term terroir (Gladstones, 1992). The terroir is the coming together of climate, soil and landscape. It is the combination of an infinite number of factors: temperatures, rainfall distribution, hours of sunlight, soil acidity, presence of minerals, water retention, exposure to sunlight, slope and drainage as an example. All of these factors react with each other to form, in each part of the vineyard, what wine-growers call a terroir. The influence of climatic conditions can be observed both in local and regional scale. Thus the first step in searching for a good location for a future vineyard is to determine areas of favorable climate conditions in regional scale and then to recognize remaining factors (local climate, soils, geology etc.).