南美洲巴拉那河流域水文气象要素演变特征及径流变化的气候响应

基于1951-2014年巴拉那河流域月尺度降水、气温、径流3个要素的观测数据,运用线性回归与MannKendall方法分析了序列的趋势性,运用小波方法分析了序列多时间尺度特征及气象因子与水文要素的内在联系。结果表明:在研究时段内,3个要素均有不同程度的增大趋势,气温与径流量显著上升,降水量不显著上升;在月尺度特征方面,3个要素均存在12个月左右的主周期,同时不同要素存在不同的次周期,其中气温存在微弱的6个月左右的次周期,月均降水量无明显次周期,径流量具有约36个月、48个月、64个月、100个月的次周期;在年尺度特征方面,3个要素均无明显主周期存在,降水量存在约3、4、8、10 a的次周期,气温无明显连续次周期,径流量的次周期特征与降水相似;交叉小波凝聚谱显示,巴拉那河流域月降水量的变化对径流量的影响远大于月均气温变化对其的影响;结合趋势性分析与小波分析可以清晰地了解流域内水文气象要素的变化规律与内在联系。

Evolution characteristics of hydro meteorological variables and runoff response to climate change in the Parana River Basin

Based on the monthly precipitation, monthly mean air temperature and monthly mean runoff data of the Parana River Basin from 1951-2014, linear regression and Mann-Kendall method are adopted to analyze the tendency of time series, meanwhile, wavelet analysis is used to analyze the multi time scale characteristics of time series and the inner link between meteorological factors and hydrological factors. The result suggested that during the study period, the three factors of precipitation, temperature and runoff all showed a rising trend to different degrees, the temperature and runoff increased significantly, whereas the precipitation increased insignificantly. On the monthly scale, the three factors all had a main cycle of about 12 months, however they all had different sub cycles. Among them, air temperature had a weak sub cycle of about 6 months, runoff had sub cycles of about 36 months, 48 months, 64 months and 100 months, whereas monthly mean precipitation had no significant sub cycle. On the annual scale, there was no significant main cycle for all three factors, but precipitation had three sub cycles of about 3 a, 4 a, 8 a and 10 a, runoff had the same sub cycles as the precipitation, temperature had no significant and continuous sub cycle. Wavelet coherence spectrum results showed that monthly precipitation had a greater impact on the runoff of the Parana River Basin than monthly mean air temperature. The approach combining trend analysis with wavelet analysis can be applied to the analysis of the change patterns of hydro meteorological variables and their inner links on basin scale with satisfactory results.