Recommended citation: Pérez-Alarcón, A., Sorí, R., Stojanovic, M., Salah, Z., El-sehwagy, A., Trigo, R.M., Nieto, R., Gimeno, L. (2025). Unveiling the contribution of Mediterranean cyclones to precipitation totals in the North Africa region. International Geographical Union Thematic Conference 2025. Cairo, Egypt. 12-19 April 2025.

Abstact

The Mediterranean region is recognized as a ‘hotspot’ for climate change and records several cyclones each year. This work aims to reveal the contribution of Mediterranean cyclones (MCs) to precipitation totals in the North Africa (NA) region from 1980 to 2023 using the high-resolution Multi-Source Weighted-Ensemble Precipitation dataset. Cyclone tracks were obtained by applying the CyTRACK framework to the 6-hourly European Centre for Medium-Range Weather Forecasts ERA5 reanalysis data. Meanwhile, MC-related precipitation is defined as the rainfall occurring within a 350 km radius of the cyclone centre. On average, approximately 50% of the annual MC count contributes to precipitation in the NA region, with south of Morocco, Algeria, and Tunisia identified as the most significant sinks, consistent with the nucleus of cyclone genesis in this area. Although most MC-related precipitation occurs inland close to the coast, the spatial pattern of MC contribution to annual precipitation shows the highest values in the western NA region, reaching ~50-70% in central Algeria and decreasing to ~5-15% closer to the coast. Overall, the MCs account for ~10% of the total precipitation in the whole NA region. Additionally, this contribution has a marked seasonal behaviour with the highest values from November to May, albeit subtle differences are observed in the spatial pattern. We also found an opposite response to the phases of the North Atlantic Oscillation (NAO) and Western Mediterranean Oscillation index (WeMOi), with the highest MC contribution during the positive (~5.9%) and negative (~6.4%) phases of NAO and WeMOi, respectively. Furthermore, during the study period, we detected a statistically significant increasing trend (~1.5-2.5 % per decade) in northern and central Algeria and a decreasing trend (~3 % per decade) in the boundary between Libya and Egypt, which suggest future changes in the MC contribution under global warming. In summary, these results hold promise for improving hydrological management strategies in this region.