An analysis of rainfall and hydrometric regimes was carried out over the period from 1968 to 2013 on the Cheliff basin situated in the west and the Medjerda basin in the east of Algeria. The Mann–Kendal and Pettitt tests have shown significant downward trends for rainfall, about 30% for the Cheliff basin, and 36% for the Medjerda basin, and about 61% and 43% for the flows at the level of the Cheliff and Medjerda basins, respectively. The continuous wavelet method, used during the study period, has shown three major discontinuities from the wavelet spectrum for the decades 1970s, 1980s and 1990s. Several modes of variability for different stations have been observed: annual (1 yr), interannual (2, 2–4 and 4–8 yrs), and multi-decadal (8–16) yrs. The different scales of precipitation and runoff variability seem to be clearly related to the NAO with different degrees of correlation. Continuous wavelet coherence indicates a strong correlation between the NAO climate index and precipitation with correlations ranging from 60 to 84%, and a strong relationship between the NAO and the runoff with correlations ranging from 67 to 74% for both watersheds.

1968年至2013年期间，对阿尔及利亚西部的切尔夫盆地和东部的梅杰达盆地进行了降雨和水文情势分析。Mann-Kendal和Pettitt测试表明降雨有明显的下降趋势，切尔夫盆地约为30％，梅杰达盆地约为36％，切尔夫盆地和梅杰达盆地水平的流量分别约为61％和43％ ， 分别。在研究期间使用的连续小波方法从1970年代，1980年代和1990年代的几十个小波频谱中显示了三个主要的不连续性。已经观测到不同站的几种变化模式：每年（1年），年际（2、2-4和4-8年）和十年（8-16年）。降水量和径流变异性的不同尺度似乎与不同相关程度的NAO明显相关。连续的小波相干性表明两个流域的NAO气候指数与降水之间有很强的相关性，相关性在60％到84％之间，而NAO与径流之间的相关性很强，相关性在67％到74％之间。