The Radiative Forcing of Aerosols in a West Africa Sahelian Urban City: Case Study of Ouagadougou

• 作者: Bruno Korgo Pétronille Kafando Bernard Zouma Nebon Bado Issa Zerbo Jean-Claude Roger Joseph D. Bathiebo
• 来源期刊: 大气和气候科学(英文)
• 学科: 经济
• 关键词: AEROSOLS Radiative Forcing Scattering Absorption GAME Code AERONET
• 年，卷（期）: dqhqhkxyw_2021,（1）
• 页码范围: 73-85
• 页数: 13页
• 分类号: F42

摘要

This paper is an assessment of radiative forcing caused by atmospheric aerosols in an urban city in West Africa. It is carried out in Ouagadougou in Burkina Faso and is an illustration of the radiative impact in most of the large Sahelian urban cities which are under the same climatic influences and whose populations present similarities in their socio-economic aspects. Using the GAME code, the radiative forcing was calculated at the top of the atmosphere, in the atmospheric layer and at the earth’s surface. The results showed overall a cooling effect at the top of the atmosphere due to the backscattering in space of the incident radiation, a heating in the atmospheric layer due to the absorption effect and a surface cooling justified by the attenuation of radiation crossing the atmosphere. Using monthly average values of optical properties, vertical temperature and humidity profiles, daily temperatures and surface albedo, the simulation yielded forcing values ranging from -6.77 W/m² to -2.56 W/m² at the top of the atmosphere, from 15.8 W/m² to 34.7 W/m² in the atmospheric layer and from -41.00 W/m² to -21.68 W/m² at the earth’s surface. In addition, the warming was simulated in the first atmospheric layer (in contact with the surface), and the results show values ranging from 0.8<span style="white-space:nowrap;">&deg;</span>C to 1.8<span style="white-space:nowrap;">&deg;</span>C. The study of the annual variability of the results showed a strong correlation between the radiative forcing and the seasonal succession characteristic of the climate in West Africa with the extreme values in the month of March (characteristic of the dry and hot season) and in the month of August (characteristic of the rainy season).