Brückner cycle[′bru̇k·nər ‚sī·kəl]
a long-term climatic fluctuation expressed in a change from cold, moist years to warm, dry years over an average period of 35 years. In isolated cases, the duration of the Brückner cycle may vary from 25 to 50 years. As early as the 17th century this cycle was noted in temperature conditions of northwestern Europe. At the end of the 19th century, E. Brückner found that the cycle had a wider planetary character and, in particular, established its existence in variations in the level of the Caspian Sea, in the pattern of precipitation, and in the retreat and advance of glaciers in a number of mountain systems. In the 20th century the Brückner cycle has barely manifested itself. It is possible that its amplitude has decreased and that it is masked by more intense fluctuations of climate. Doubts concerning its actual existence have also been expressed.
S. P. KHROMOV