LONG-TERM FLUCTUATIONS OF GLACIER PROCESSES AND RIVER RUNOFF IN CENTRAL ASIA UNDER CURRENT CLIMATIC CONDITIONS

摘要

Space and time variation of statistical parameters of the long-term series of river runoff averaged over the year and the growing season (April-September) in the Amu Darya and Syr Darya basins is studied using measurements at 30 hy-drological stations for the periods 1932-1961 and 1962-1991. Analysis has shown that there was a decrease in annual and seasonal discharges in the Amu Darya and Syr Darya basins in 1962-1991. Compared with a relatively weak change in the long-term mean, its variability has increased by 22-24% on average. The mean, maximum, and minimum changes in the variation coefficients of annual and seasonal runoff proved to be nearly the same. The 30-year impact of decreased glacier processes in the Pamir and Gissaro-AIai is evaluated by the example of large catchments in Central Asia. A regional empirical relation is determined between the mean rate of glaciation decrease and the mean statistical probability of the climatic index of the accumulation and ablation balance.