Water resources in Bulgaria under climate variability and change

摘要

Variability of air temperature, precipitation and river runoff during the twentieth century in Bulgaria was investigated. Possible scenarios for air temperature, precipitation and annual runoff in the country were created. According to GCMs (Global Circulation Models) air temperature is expected to increase by between 3 and 5℃ before the end of the twenty-first century. Precipitation is expected to increase during the winter and to decrease during the warm half-year. The total precipitation amount during the actual crop-growing season is projected to decrease due to the GCM simulated decrease of precipitation and because of shortening of the actual crop-growing season. The Decision Support System for Agrotechnology Transfer (DSSAT) was used to simulate the impact of climate variability and climate change scenarios on the parameters of the soil water balance during the maize growing season. Adaptation strategies and options in respect to water resources including irrigation under climate change are also considered.