Understanding rainfall prediction skill over the Sahel in NMME seasonal forecast
Entendiendo la destreza de los modelos de predicción estacional del NMME para predecir la precipitación en el Sahel

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Martín Gómez, Verónica and Mohino Harris, Elsa and Rodríguez Fonseca, Belén and Sánchez Gómez, Emilia (2022) Understanding rainfall prediction skill over the Sahel in NMME seasonal forecast. Climate dynamics . ISSN 0930-7575

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Official URL: https://doi.org/10.1007/s00382-022-06263-8



Abstract

Sahelian rainfall presents large interannual variability which is partly controlled by the sea surface temperature anomalies (SSTa) over the eastern Mediterranean, equatorial Pacifc and Atlantic oceans, making seasonal prediction of rainfall changes in Sahel potentially possible. However, it is not clear whether seasonal forecast models present skill to predict the Sahelian rainfall anomalies. Here, we consider the set of models from the North American Multi-model ensemble (NMME) and analyze their skill in predicting the Sahelian precipitation and address the sources of this skill.

Results show that though the skill in predicting the Sahelian rainfall is generally low, it can be mostly explained by a combination of how well models predict
the SSTa in the Mediterranean and in the equatorial Pacifc regions, and how well they simulate the teleconnections of these SSTa with Sahelian rainfall. Our results suggest that Sahelian rainfall skill is improved for those models in which the Pacifc SST—Sahel rainfall teleconnection is correctly simulated. On the other hand, models present a good ability to reproduce the sign of the Mediterranean SSTa—Sahel teleconnection, albeit with underestimated amplitude due to an underestimation of the variance of the SSTa over this oceanic region. However, they fail to correctly predict the SSTa over this basin, which is the main reason for the poor Sahel rainfall skill in models. Therefore, results suggest models need to improve their ability to reproduce the variability of the SSTa over the Mediterranean as well as the teleconnections of Sahelian rainfall with Pacifc
and Mediterranean SSTa.


Item Type:Article
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CRUE-CSIC (Acuerdos Transformativos 2022)

Uncontrolled Keywords:Seasonal prediction systems Rainfall variability over Sahel Climate teleconnections
Palabras clave (otros idiomas):Sistemas de predicción estacional Variabilidad de las precipitciones en el Sahel Teleconexiones climáticas
Subjects:Sciences > Physics > Atmospheric physics
Sciences > Physics > Meteorology
ID Code:71713
Deposited On:20 Apr 2022 08:03
Last Modified:05 May 2022 07:49

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