Characteristics of Hydrological Cycle in North China

This paper studies the characteristics of hydrological cycle for 40 years in north China with the water balance principle of land-atmosphere system under considering the effect of the natural climate change and anthropogenic activities. In the high flow period of 1950s, the rainfall is more than evaporation, the relationship among precipitation, run-off and evaporation was in balance. After 1960s the rainfall became less than evaporation. The negative value of (P—E) inhenced with decreasing of rainfall and increasing of amount of groundwater extracted. During the drought years the value of moisture outflow is more than that of inflow ever north China. The loss of moisture in the atmosphere could be compensated by the excess evaporation from the lost amount of ground water in this area