长江流域旱涝年低频风场分布和演变的差异  

MLCB LOW FREQUENCY WIND IN FLOOD/DROUGHT YEARS AND ITS INTERANNUAL DIFFERENCE

作　　者：黄静[1,2] 朱乾根[1,2] 

机构地区：[1]南京气象学院气象学系 [2]广东省中山市气象局

出　　处：《南京气象学院学报》1996年第3期276-282,共7页Journal of Nanjing Institute of Meteorology

基　　金：国家自然科学基金

摘　　要：从低频风场出发研究低频振荡在旱涝年的年际差异以及与降水的关系。研究表明：旱涝年我国东部环流系统低频分量所占比重显著不同；与长江流域降水变化联系的低频风场的特点及变化有显著不同。１９８０年（长江流域涝年）降水的变化与东亚季风区内的低频振荡有密切的关系，尤其是副热带季风的低频振荡。低频振荡在东亚季风区内阶段性地向北传播，且具有准８候的周期，从而导致降水的周期变化。而１９８８年（长江流域旱年）降水的变化与东亚季风的低频振荡无关，而与控制东亚北部的强大的低频涡旋有着密切的关系，这个强大的低频涡旋是由日本岛以东洋面上的低频涡旋北进西旋发展演变而来，且这种移动和演变也具有准８候的特点，并且伴随着降水的增加或减少。Based on the low frequency windfields, study is made of the difference in low frequency oscillation (LFO) between flood and drought hit years and the relation to rainfall. Results suggest that in such years the low frequency component makes up greatly varying portion for the circulation systems in east China and the MLCB (mid lower Changjiang basins) rainfall related wind features and variation are quite distinct; in 1980 as the flood year over the MLCB the change in precipitation is closely associated with the LFO in the East Asian monsoon region, especially in subtropical monsoon, with its northward propagation in a phatic manner, marked by a quasi 8 pentad period, thus responsible for the periodic variation in rainfall whilst in 1988 as the year of drought the rainfall change bears no relation to East Asian monsoon′s LFO but to a vigorous low frequency vortex dominating the northern portion of East Asia, which originates from the one over the waters east of Japan moving north and then turning west, and the movement and development are at a quasi 8 pentad period, too, leading to change in rainfall over the MLCB.

关 键 词：低频振荡 旱涝 降水 风场分布 长江流域 

分 类 号：P426.616[天文地球—大气科学及气象学] P425.3