Effect of the African greenbelt position on West African summer climate: a regional climate modeling study
Effect of the African greenbelt position on West African summer climate: a regional climate modeling study
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DOI：
10.1007/s00704-018-2589-z
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发表时间：
2019-07-01
影响因子：
3.4
通讯作者：
Tall, Moustapha
中科院分区：
文献类型：
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作者：
Bamba, Adama;Diallo, Ismaila;Tall, Moustapha
本模型研究旨在研究重新造林（绿地）位置（无论是在萨赫勒地区还是在几内亚地区）对西非夏季气候系统的潜在影响。为此，利用区域气候模式RegCM4在ERA-Interim再分析的驱动下，在2000-2011年期间对西非区域进行了3次50公里水平分辨率的模拟。第一个实验，即对照（CTRL），使用标准植被覆盖，而另外两个实验在整个模型整合过程中，在不同地点纳入了一个常绿阔叶的地带性再造林带：(i)萨赫勒-撒哈拉地区13°N-17°N带纬度（实验以下简称GB15N）和（ii）几内亚海岸地区8.5°N-11.5°N（实验以下简称GB10N）。CTRL试验与观测结果的比较表明，尽管干/湿偏倚仍然存在，特别是在大西洋，但仍忠实地再现了平均北方和夏季季节降水模式。此外，各分区域的季节周期与观测到的模式相符。GB15N再造林导致林区降水增加幅度在2 ~ 4mm/d之间，而GB10N再造林降水增加幅度较弱，并不一定发生在林区。在重新造林的地区观测到温度下降，这可以用与地表反照率降低有关的地表热通量减少来解释。
This modeling study is conducted to examine the potential impact of the reforestation (greenbelt) location (either in Sahel or in Guinean region) on West Africansummer climate system. To this end, three simulations using the regional climate model RegCM4 driven by ERA-Interim reanalysis were performed at 50km 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 degrees N-17 degrees N band latitudes in a Sahel-Sahara region (experiment hereafter referred to as GB15N) and (ii) between 8.5 degrees N-11.5 degrees 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 2-4mm/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.