Fleming Sean W, Quilty Edward J
Aquatic Informatics Inc., Vancouver, BC, Canada.
Ground Water. 2006 Jul-Aug;44(4):595-9. doi: 10.1111/j.1745-6584.2006.00187.x.
We used climatological composite analysis to investigate El Niño-Southern Oscillation (ENSO) signals in long-term shallow ground water level observations from four wells in the lower Fraser Valley of British Columbia. Significance of differences between warm-phase, cold-phase, and neutral climate states was assessed with a Monte Carlo bootstrap technique. We also considered time series of local precipitation and streamflow for comparison. Composite annual hyetographs suggest that ENSO precipitation impacts are largely limited to winter and spring, with higher and lower rainfall occurring, respectively, under cold-phase and warm-phase episodes. This is consistent with prior work in the region and is found to be directly reflected in both streamflow and ground water level data. The mean magnitude of ENSO terrestrial hydrologic anomalies can be up to approximately 50% of the average seasonal cycle amplitude. ENSO does not appear to systematically affect annual hydrometeorological cycle timing in this study area. However, relative to the surface hydrologic systems considered, aquifers are observed to retain a stronger memory of seasonal ENSO-related precipitation anomalies, with changes potentially extending through the following summer, presumably reflecting storage effects. Most responses appear to be somewhat nonlinear.
我们运用气候综合分析方法，对不列颠哥伦比亚省弗雷泽河谷下游四口井的长期浅层地下水位观测数据中的厄尔尼诺-南方涛动（ENSO）信号进行了研究。采用蒙特卡洛自助法评估了暖相位、冷相位和中性气候状态之间差异的显著性。我们还考虑了当地降水和径流的时间序列以作比较。综合年雨量图表明，ENSO对降水的影响主要限于冬季和春季，在冷相位和暖相位期间分别出现较高和较低的降雨量。这与该地区先前的研究结果一致，并且在径流和地下水位数据中均有直接体现。ENSO陆地水文异常的平均幅度可达平均季节循环幅度的约50%。在本研究区域，ENSO似乎并未系统性地影响年水文气象循环的时间。然而，相对于所考虑的地表水文系统，观测发现含水层对季节性ENSO相关降水异常的记忆更强，这种变化可能会持续到次年夏季，大概反映了存储效应。大多数响应似乎都有一定的非线性。
