Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.3390/atmos9100376 |
Potential Impacts of Land Cover Change on the Interannual Variability of Rainfall and Surface Temperature over West Africa | |
Diba, Ibrahima1,2; Camara, Moctar1; Sarr, Alioune Badara1; Diedhiou, Arona2 | |
通讯作者 | Camara, Moctar |
来源期刊 | ATMOSPHERE
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ISSN | 2073-4433 |
出版年 | 2018 |
卷号 | 9期号:10 |
英文摘要 | We used the Abdu Salam International Centre for Theoretical Physics (ICTP) Regional Climate Model version 4.5 (RegCM4.5), to investigate the potential impacts of land cover change of the Sahel-Sahara interface on the West African climate over an interannual timescale from 1990 to 2009. A simulation at 50 km grid spacing is performed with the standard version of the RegCM4.5 model (control run), followed by three vegetation change experiments at the Sahel-Sahara interface (15 degrees N and 20 degrees N): forest, tall grass, and short grass savanna. The impacts of land cover change are assessed by analyzing the difference between the altered runs and the control one in different sub-domains (western Sahel, central Sahel, eastern Sahel, and Guinea). Results show that the presence of forest, tall grass, and short grass savanna at the Sahel-Sahara interface tends to decrease the mean summer surface temperature in the whole domain. Nevertheless, this decrease is more pronounced over the Central Sahel when considering the forest experiment. This temperature decrease is associated with a weakening (strengthening) of the sensible (latent) heat flux in the whole domain. An analysis of the radiation field is performed to better explain the changes noted in the latent heat flux, the sensible heat flux, and the surface temperature. When considering the rainfall signal, the analysis shows that the afforestation options tend to alter the precipitation in the considered sub-domains substantially by increasing it in the whole Sahel region, with strong interannual variability. This rainfall increase is associated with an increase of the atmospheric moisture. Finally, we investigated the impacts of the afforestation options on some features of the rainfall events, and on the atmospheric dynamics during wet and dry years. All afforestation options tend to increase the frequency of the number of rainy days in regions located south of 18 degrees N during both periods. Nevertheless, this increase is stronger over the Central and Eastern Sahel during wet years in the forest case. All afforestation experiments induce an increase (decrease) of the low-levels monsoon flux in the Eastern Sahel (western Sahel) during both periods. At the mid-levels, the three afforestation options tend to move northward and to decrease the intensity of the African Easterly Jet (AEJ) south of 13 degrees N during wet and dry years.The intensity of the AEJ is weaker during the wet period. The vegetation change experiments also affect the Tropical Easterly Jet (TEJ), especially during wet years, by increasing its intensity over the southern Sahel. The analysis of the activity of African Easterly Waves (AEWs) patterns exhibits a decrease of the intensity of these disturbances over the Sahel during both periods. This may be due to the weakening of the meridional temperature contrast between the continent and the Gulf of Guinea due to the Sahel-Sahara surface temperature cooling induced by the afforestation. In summary, this study shows that during both periods, the increase of the atmospheric moisture due to the afforestation is associated with favorable AEJ/TEJ configurations (weaker and northward position of the AEJ; stronger TEJ) which in turn may create a stronger convection and then, an increase in the Sahel rainfall. This Sahel rainfall increase is associated with a strengthening of the intense and heavy rainfall events which may impact diversely local populations. |
英文关键词 | RegCM4 reforestation rainfall temperature wind dynamics interannual variability West Africa |
类型 | Article |
语种 | 英语 |
国家 | Senegal ; France |
收录类别 | SCI-E |
WOS记录号 | WOS:000448543200011 |
WOS关键词 | REGIONAL CLIMATE MODELS ; SAHEL DROUGHT ; EASTERLY WAVES ; PART II ; PRECIPITATION ; SIMULATION ; MONSOON ; REGCM3 ; DESERTIFICATION ; DYNAMICS |
WOS类目 | Meteorology & Atmospheric Sciences |
WOS研究方向 | Meteorology & Atmospheric Sciences |
来源机构 | French National Research Institute for Sustainable Development |
资源类型 | 期刊论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/207871 |
作者单位 | 1.Univ SECK Ziguinchor, UFR Sci & Technol, LOSEC, Ziguinchor 270000, Senegal; 2.Univ Grenoble Alpes, Grenoble INP, IGE, IRD,CNRS, F-38000 Grenoble, France |
推荐引用方式 GB/T 7714 | Diba, Ibrahima,Camara, Moctar,Sarr, Alioune Badara,et al. Potential Impacts of Land Cover Change on the Interannual Variability of Rainfall and Surface Temperature over West Africa[J]. French National Research Institute for Sustainable Development,2018,9(10). |
APA | Diba, Ibrahima,Camara, Moctar,Sarr, Alioune Badara,&Diedhiou, Arona.(2018).Potential Impacts of Land Cover Change on the Interannual Variability of Rainfall and Surface Temperature over West Africa.ATMOSPHERE,9(10). |
MLA | Diba, Ibrahima,et al."Potential Impacts of Land Cover Change on the Interannual Variability of Rainfall and Surface Temperature over West Africa".ATMOSPHERE 9.10(2018). |
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