基于小波分析的汀江水沙通量变化规律研究

利用1951-2007年月平均水沙通量资料,采用Morlet小波函数,对汀江上杭水文站近60年来的年际和年代际变化特征进行小波分析,揭示了汀江水沙通量的多时间尺度变化特征和突变点,并根据小波能量谱(能量集中区)所对应的主周期进行了趋势分析.计算结果表明,洪季水沙通量的多时间尺度振荡趋势和位相与水沙通量的年变化特征相一致；洪季(4-9月)和年径流量均存在18年左右时间尺度的主振荡周期,6 -9年时间尺度的次主周期；洪季(年)沙通量均存在28年左右时间尺度的主振荡周期,16年时间尺度的次主周期；经小波趋势分析,未来10 -20年,汀江水沙通量与正常值相比呈降低趋势.

Characteristics of water discharge and sediment load variability of Tingjiang River by wavelet analysis

On the basis of monthly mean data of water discharges and sediment loads observed at Shanghang hydrological station from 1951 to 2007,the yearly and decadal variations,abrupt changes and trends are extracted by using Morlet function,a basic function of wavelet analysis.Calculated results show that the multi-scale oscillations of the mean water discharge and mean sediment load in the flood seasons are identical with those of annual mean.Both the chief oscillation period of annual water discharge and the mean discharge in the flood season(April to Sept.)were 18a,and both the second chief oscillation period were 6～9a.Both the chief oscillation period of annual sediment load and the mean sediment load in the flood season were 28a,and both the second chief oscillation period was 16a.On the basis of trends analysis by wavelet,the water discharge and sediment load of the Tingjiang River will be less than the normal value in future 10 ～20 years.