地球自转速率变化与河道演变及泥沙灾害关系初探

A PRELIMINARY STUDY ON THE RELATIONSHIP BETWEEN VARIATION OF THE EARTH'S ROTATION CHANNEL EVOLUTION AND SEDIMENT DISASTER

丰沙期及低频率、高强度洪水往往酿成泥沙灾害和洪涝灾害。地球自转变化是影响河道演变与诱发泥沙灾害的重要的自然因素,由长江、黄河及淮河的部分水沙资料及地球自转日长变化资料的初步分析表明,当地球自转由加速转向减速时,黄河下游出现枯水、少沙时期,长江中下游及淮河出现高频率、低强度洪水;而地球自转由减速转向加速时,黄河下游出现丰水期和中、丰沙期,长江与淮河出现低频率、高强度洪水,长江下游处于切滩旺盛期。在地球自转变化的转折点之间,河道处于相对稳定演变阶段,一般不会发生严重的洪涝与泥沙灾害。

The variation of the Earth's rotation rate is an important factor to influence channel evolution and to induce sediment disaster. According to a preliminary data analysis of the Yangtze R. , the Yellow R. and the Huaihe R. it is indicated that there exists a relationship between flood, sediment transportation, channel evolution and the variation of the Earth rotation. As the Earth rotates from faster to slower, the lower flood and sediment transportation in the lower Yellow R. , and the flood with a high frequency and lower intensity in the middle and lower Yangtze R. And the Huaihe R. occur. When the Earth rotates from slower to faster, the periods of high flood, medium and lower sediment transportation in the lower Yellow R. , the flood with a lower frequency and higher intensity in the middle and lower Yangtze R. and the Huaihe R. take place, and it is just the most vigorous of chute cutoff for alternative bars in the Yangtze R. , thus induce flood and sediment disaster. Between the two turning points of the variation of the Earth rotation, the channel develops gently and disasters of flood and sediment aren't induced in general.