Spanish and Portuguese¹ researchers have analysed the composition and radiative effect of desert aerosols³ during two episodes which simultaneously⁴ affected⁵ Badajoz (Spain) and Évora (Portugal) in August 2012. Results show that the intrusion of dust from the Sahara Desert caused radiative cooling of Earth's surface. Atmospheric⁶ aerosols (solid or liquid particles suspended in the atmosphere) are difficult to examine for various reasons. Firstly, they remain in the atmosphere for a short time and secondly⁷, their cause may be natural or anthropogenic.

 

Yet there is no doubt that research into atmospheric aerosols is becoming increasingly important due to the effects that they can have on the global temperature of Earth, given that solar radiation is the main source of energy for Earth-Atmosphere system. Aerosols also affect human health, ecosystems⁸ and the water cycle.

 

For this reason, a group of researchers from Extremadura (Spain) and Portugal has analysed the radiative effect of a type of natural aerosol² (the dust from the desert areas), of great interest to the Iberian Peninsula due to the proximity⁹ of the Sahara desert.

 

The scientists focused their study, published in the journal 'Atmospheric Research', on two desert aerosol intrusions which occurred in August 2013 and that affected two monitoring stations in the south-west of the Iberian Peninsula, in Évora and Badajoz, which belong to the AErosol RObotic NETwork (AERONET) and are managed by NASA.

 

During these two significant events, "the amount of radiation that reached the surface was less than that which would done if these aerosols had not been there," Mª Ángeles Obregón, researcher in the Physics department of the University of Extremadura (UEx) and the University of Évora (Portugal) and lead author of this study, explains.

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