MAX-DOAS retrieval of aerosol extinction properties in Madrid, Spain

• Main Authors: S. Wang, C. A. Cuevas, U. Frieß, A. Saiz-Lopez
• Format: Article
• Language: English
• Published: Copernicus Publications 2016-10-01
• Series: Atmospheric Measurement Techniques
• Online Access: http://www.atmos-meas-tech.net/9/5089/2016/amt-9-5089-2016.pdf

Multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements were performed in the urban environment of Madrid, Spain, from March to September 2015. The O₄ absorption in the ultraviolet (UV) spectral region was used to retrieve the aerosol extinction profile using an inversion algorithm. The results show a good agreement between the hourly retrieved aerosol optical depth (AOD) and the correlative Aerosol Robotic Network (AERONET) product, with a correlation coefficient of <i>R</i> =  0.87. Higher AODs are found in the summer season due to the more frequent occurrence of Saharan dust intrusions. The surface aerosol extinction coefficient as retrieved by the MAX-DOAS measurements was also compared to in situ PM_2.5 concentrations. The level of agreement between both measurements indicates that the MAX-DOAS retrieval has the ability to characterize the extinction of aerosol particles near the surface. The retrieval algorithm was also used to study a case of severe dust intrusion on 12 May 2015. The capability of the MAX-DOAS retrieval to recognize the dust event including an elevated particle layer is investigated along with air mass back-trajectory analysis.