Water Balance and Phase of Hydrocycle Dynamics

Abstract

Climate dynamics in the Czech Republic has been increasing during the past 20 years and even before it was already characterized by high variability. The number of weather extremes increases, there is a statistically significant increase of air temperature, but not of precipitation. Precipitation deficit during vegetation period is often associated with high temperatures and occurrence of tropical days (maximum day air temperature equal to or above 30 °C), lower relative air humidity, lower cloudiness, and a higher number of sunshine hours. Precipitation is the only source of water in the Czech Republic. The only source of water in the region of the Czech Republic is atmospheric precipitation. Annual precipitation amount for the entire Czech Republic slightly increases. It is necessary to emphasize that the occurrence, course, and intensity of drought in the Czech Republic are different in individual years. Drought in the Czech Republic is a random event with an irregular occurrence. The more and more dynamic weather in the last two decades is undeniable evidence of changes of the Czech climate. When evaluating the amount of water in the landscape, where soil moisture and other hydropedological characteristics play an important role, one must take into account that extremes in precipitation are a major cause of drought—but not the only cause. There is a significant increase in air temperature between 1961 and 2010 and statistically constant annual precipitation amount. This means that the course of drought is affected by the increasing potential evapotranspiration due to increased air temperatures.