Contribution of cross time-frequency analysis in assessment of possible relationships between large-scale climatic fluctuations and rainfall of northern central Algeria

A new regionalization of rainfall patterns based on wavelet transform information and hierarchical cluster analysis in northeastern Algeria

“…These observed trends (Figs. 11,12,13) concern all rain gauges in northern Algeria and the Mediterranean basin, which confirms the existence of significant rainfall deficits in the 1970s, 1980s and 1990s (Bouabdelli et al, 2020;Khedimallah et al, 2020;Zerouali et al, 2020;Peña-Angulo et al, 2019;Jemai et al, 2018;Taibi et al, 2017Taibi et al, , 2019Mrad et al, 2019;Zerouali et al, 2018;Caloiero et al, 2018;Merabti et al, 2018a,b;Zeroual et al, 2017;Da Silva et al, 2015;Gocic and Trajkovic, 2014;Hamlaoui-Moulai et al, 2013;Meddi et al, 2010).…”

“…3a, 7) with a rupture in the blue color that reveals the disturbance in the continuity. The dominance of 1-year and 1-3-year fluctuations was also observed in the Sebaou River basin (northern central Algeria) (Zerouali et al 2018).…”

“…This pattern is particular to Algeria (Fig. 1b, c) (Meddour 2010;Zerouali et al, 2018;Merabti et al, 2018a,b;Meddi et al, 2010).…”

“…Additionally, all emission scenarios listed in the reports of the Intergovernmental Panel on Climate Change (IPCC 2014) indicate that warming over the next two decades will increase by approximately 0.2 °C per decade. The IPCC documented that many semiarid regions, such as the Mediterranean region, western North America, Southern Africa and northeast South America, particularly Brazil, will suffer from a lack of water resources resulting from climate change (Zerouali et al, 2018). Spatiotemporal drought was analyzed between 1960 and 2010 on the plains of northwestern Algeria (Cheliff watershed) using the standardized precipitation index (Achour et al, 2020).…”

“…From these results, we can conclude that the northern part of Algeria (G1) is dominated by annual periodic fluctuations in rainfall of 8-16 months. This indicates that the increase in average rainfall due to the humid climate may be responsible for the formation of periodic components, particularly annual fluctuations (Zerouali et al, 2018).…”