| Autor: |
Audu, E. O., Dixon, R. D., Diallo, I. |
| Předmět: |
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| Zdroj: |
Geophysical Research Letters; 10/28/2024, Vol. 51 Issue 20, p1-10, 10p |
| Abstrakt: |
The uncertainty in precipitation projections across the Sahel has persisted across generations of climate models. Many projections show a zonal dipole in the sign of precipitation change, with wetting across the Central Sahel and drying across the Western Sahel. We analyze the outputs from an ensemble of current climate models to explain why some produce this dipole and understand the inter‐model variability in the transition region for these models. Models projecting the dipole tend to shift the Atlantic Intertropical Convergence Zone (ITCZ) to the south, while models that do not tend to shift the ITCZ to the north. We find that the strong relationship between the change in Sahel precipitation and surface temperature‐based indices is highly driven by the non‐dipole models. These indices do not explain most of the variance in where models transition. This suggests that understanding zonal variability in Sahel precipitation change must go beyond these temperature‐based analysis. Plain Language Summary: Precipitation across the Sahel is vital for sustaining a rapidly growing population and the region's sensitive ecosystem. Uncertainty in Sahel rainfall projections presents a significant challenge for stakeholders. At the end of the 21st century, many climate models predict a dipole pattern, characterized by a drought across western Sahel and an increased rainfall across the central Sahel. This study delves into the outputs of the current state‐of‐the‐art global climate models to investigate and explain why certain models show this drought and increased rainfall pattern across the Western and Central Sahel, respectively, while others do not. Additionally, we seek to comprehend the substantial disparity in the location where these models transition from drought to increased rainfall in this region. Our findings indicate that models depicting these spatial distribution patterns tend to position their band of maximum rainfall farther south compared to models that do not exhibit this pattern. Furthermore, we observe that the strong correlation between Sahel rainfall and temperature‐based indices is predominantly heightened by the group of models lacking this rainfall dipole pattern. This study suggests that to gain a deeper understanding of this drought and increased rainfall projections in the Sahel, we must explore factors beyond these temperature‐based indices. Key Points: Zonal intermodel variability in projections of Sahelian precipitation cannot be fully explained using traditional temperature‐based indicesModels with non‐dipole Sahel precipitation change drive strong correlations between temperature‐based indices and Sahel precipitation changeModels with (without) the zonal dipole pattern tend to produce a southward (northward) shift in the rainbands across the tropical Atlantic [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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