@article{fdi:010089586,
  title = {{I}mpact of {A}tlantic multidecadal variability on rainfall intensity distribution and timing of the {W}est {A}frican monsoon},
  author = {{M}ohino, {E}. and {M}onerie, {P}. {A}. and {M}ignot, {J}uliette and {D}iakhate, {M}. and {D}onat, {M}. and {R}oberts, {C}. {D}. and {D}oblas-{R}eyes, {F}.},
  editor = {},
  language = {{ENG}},
  abstract = {{P}revious studies agree on an impact of the {A}tlantic multidecadal variability ({AMV}) on the total seasonal rainfall amounts over the {S}ahel. {H}owever, whether and how the {AMV} affects the distribution of rainfall or the timing of the {W}est {A}frican monsoon is not well known. {H}ere we seek to explore these impacts by analyzing daily rainfall outputs from climate model simulations with an idealized {AMV} forcing imposed in the {N}orth {A}tlantic, which is representative of the observed one. {T}he setup follows a protocol largely consistent with the one proposed by the {C}omponent {C} of the {D}ecadal {C}limate {P}rediction {P}roject ({DCPP}-{C}). {W}e start by evaluating model's performance in simulating precipitation, showing that models underestimate it over the {S}ahel, where the mean intensity is consistently smaller than observations. {C}onversely, models overestimate precipitation over the {G}uinea coast, where too many rainy days are simulated. {I}n addition, most models underestimate the average length of the rainy season over the {S}ahel; some are due to a monsoon onset that is too late and others due to a cessation that is too early. {I}n response to a persistent positive {AMV} pattern, models show an enhancement in total summer rainfall over continental {W}est {A}frica, including the {S}ahel. {U}nder a positive {AMV} phase, the number of wet days and the intensity of daily rainfall events are also enhanced over the {S}ahel. {T}he former explains most of the changes in seasonal rainfall in the northern fringe, while the latter is more relevant in the southern region, where higher rainfall anomalies occur. {T}his dominance is connected to the changes in the number of days per type of event; the frequency of both moderate and heavy events increases over the {S}ahel's northern fringe. {C}onversely, over the southern limit, it is mostly the frequency of heavy events which is enhanced, thus affecting the mean rainfall intensity there. {E}xtreme rainfall events are also enhanced over the whole {S}ahel in response to a positive phase of the {AMV}. {O}ver the {S}ahel, models with stronger negative biases in rainfall amounts compared to observations show weaker changes in response to {AMV}, suggesting that systematic biases could affect the simulated responses. {T}he monsoon onset over the {S}ahel shows no clear response to {AMV}, while the demise tends to be delayed, and the overall length of the monsoon season enhanced between 2 and 5 d with the positive {AMV} pattern. {T}he effect of {AMV} on the seasonality of the monsoon is more consistent to the west of 10 circle {W}, with all models showing a statistically significant earlier onset, later demise, and enhanced monsoon season with the positive phase of the {AMV}. {O}ur results suggest a potential for the decadal prediction of changes in the intraseasonal characteristics of rainfall over the {S}ahel, including the occurrence of extreme events.},
  keywords = {{AFRIQUE} {DE} {L}'{OUEST} ; {ATLANTIQUE}},
  booktitle = {},
  journal = {{E}arth {S}ystem {D}ynamics},
  volume = {15},
  numero = {1},
  pages = {15--40},
  ISSN = {2190-4979},
  year = {2024},
  DOI = {10.5194/esd-15-15-2024},
  URL = {https://www.documentation.ird.fr/hor/fdi:010089586},
}