Effect of the African greenbelt position on West African summer climate: a regional climate modeling study

Abstract

This modeling study is conducted to examine the potential impact of the reforestation (greenbelt) location (either in Sahel or in Guinean region) on West African summer climate system. To this end, three simulations using the regional climate model RegCM4 driven by ERA-Interim reanalysis were performed at 50 km horizontal resolution over a West African domain for the period 2000-2011. The first experiment, namely the control (CTRL), uses the standard vegetation cover, while the two others incorporate throughout the model integration, a zonal reforestation band of evergreen broadleaf over different locations: (i) over a 13°N-17°N band latitudes in a Sahel-Sahara region (experiment hereafter referred to as GB15N) and (ii) between 8. 5°N-11.5°N in the Guinea Coast region (experiment hereafter referred to as GB10N). A comparison of the CTRL experiment with observation reveals a faithful reproduction of the mean boreal and summer seasonal precipitation pattern, though substantial dry/wet biases remain, especially in the Atlantic Ocean. In addition, the seasonal cycle over sub-regions matches satisfactory the observed pattern. The GB15N reforestation leads to a precipitation increase in the range of 2-4 mm/day over the forested areas, whereas in the GB10N reforestation, precipitation increase is weaker and not necessarily located in the forested areas. Temperature cooling is observed over the reforested area and may be explained by a decrease of ground heat flux related to a reduction of the surface albedo.

Dynamical downscaling the impact of spring Western US land surface temperature on the 2015 flood extremes at the Southern Great Plains: effect of domain choice, dynamic cores and land surface parameterization

“…We should note that, the assessments for the LST/SUBT effect here are likely affected by the models weaknesses/ errors. Additionally, it is worth pointing out that, this factor (LST/SUBT) as well as others elements such as SST , soil moisture (Xue et al 2004;Koster et al 2016;Saini et al 2016), vegetation (Xue et al 1996;Bamba et al 2018), and atmospheric internal variability Lee et al 2018) may have also contributed to the observed anomaly. Jee and Kim (2017) analyzed the influence of spin up time using the WRF version 3.6 on the simulation of heavy rainfall over Seoul and its adjacent cities.…”

Late 21st Century Projected Changes in the Relationship between Precipitation, African Easterly Jet, and African Easterly Waves

“…More recently, there have been remarkable efforts to improve our understanding of the West African climate system using a regional climate modeling approach [28][29][30][31][32][33][34][35]. For instance, a number of projects have been developed to advance the understanding of the WAM system [31][32][33][34][35] and to comparatively assess the modeling of the WAM mean climatology and its projected changes [29,36,37].…”

The possible role of the Sahel Greenbelt on the occurrence of climate extremes over the West African Sahel

“…(), based on satellite observations, suggest a rapid regional intensification of Mesoscale Convective Systems (MCSs) whose potential drivers may include mineral aerosol concentrations and vegetation cover. Further investigations, using model‐based simulations, often indicate that reforestation/afforestation may increase the average rainfall and decrease mean temperature during summer season (Abiodun et al ., ; Hagos et al ., ; Bamba et al ., ), along with increasing (decreasing) the number of heatwave events over the reforested area (Sahel and Guinea coast) or causing a decrease (increase) of droughts occurrence over the Savanna and Guinea coast (Sahel) especially from July to September (Diasso and Abiodun, ; Odoulami et al ., ).…”