| Summary: | Two different rainfall-runoff models are applied to river basins in northern Sweden and Finland to study the effect of changed climate on peak flows. Hypothetical meteorological data series are constructed by increasing observed values by given amounts and fractions. In a Swedish moderately large basin snowmelt and daily precipitation were considered, and in two small Finnish basins, hourly precipitation. The winter temperature is found to be crucial for the runoff peak in the spring. Increased daily winter temperatures of a few degrees result in considerably reduced peak flows. The annual runoff increases in a climate of increasing precipitation, as does the autumn peak runoff. However, the rain intensity and the soil moisture conditions at the time of the rainfall are found to be much more important for the runoff peaks than the seasonal rainfall depth.
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