Different strategies to retrieve aerosol properties at night-time with the GRASP algorithm

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Benavent-Oltra, Jose Antonio, Román, Roberto, Casquero-Vera, Juan Andrés, Pérez-Ramírez, Daniel, Lyamani, Hassan, Ortiz-Amezcua, Pablo, Bedoya-Velásquez, Andrés Esteban, de Arruda Moreira, Gregori, Barreto, África, Lopatin, Anton, Fuertes, David, Herrera, Milagros, Torres, Benjamin, Dubovik, O., Guerrero-Rascado, Juan Luis, Goloub, Philippe, Olmo-Reyes, Francisco Jose, Alados-Arboledas, Lucas
• Other Authors: Laboratoire d’Optique Atmosphérique - UMR 8518 (LOA), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: [SDE]Environmental Sciences; Aerosol Robotic Network
• Online Access: https://hal.archives-ouvertes.fr/hal-03009131; https://hal.archives-ouvertes.fr/hal-03009131/document; https://hal.archives-ouvertes.fr/hal-03009131/file/Benavent-Oltra_acp-19-14149-2019.pdf; https://doi.org/10.5194/acp-19-14149-2019

International audience This study evaluates the potential of the GRASP algorithm (Generalized Retrieval of Aerosol and Surface Properties) to retrieve continuous day-tonight aerosol properties , both column-integrated and vertically resolved. The study is focused on the evaluation of GRASP retrievals during an intense Saharan dust event that occurred during the Sierra Nevada Lidar aerOsol Profiling Experiment I (SLOPE I) field campaign. For daytime aerosol retrievals, we combined the measurements of the ground-based li-dar from EARLINET (European Aerosol Research Lidar Network) station and sun-sky photometer from AERONET (Aerosol Robotic Network), both instruments co-located in Granada (Spain). However, for night-time retrievals three different combinations of active and passive remote-sensing measurements are proposed. The first scheme (N 0) uses li-dar night-time measurements in combination with the interpolation of sun-sky daytime measurements. The other two schemes combine lidar night-time measurements with night-time aerosol optical depth obtained by lunar photometry either using intensive properties of the aerosol retrieved during sun-sky daytime measurements (N 1) or using the Moon au-reole radiance obtained by sky camera images (N 2). Evaluations of the columnar aerosol properties retrieved by GRASP are done versus standard AERONET retrievals. The coherence of day-tonight evolutions of the different aerosol properties retrieved by GRASP is also studied. The extinction coefficient vertical profiles retrieved by GRASP are compared with the profiles calculated by the Raman technique at night-time with differences below 30 % for all schemes at 355, 532 and 1064 nm. Finally, the volume concentration and scattering coefficient retrieved by GRASP at 2500 m a.s.l. are evaluated by in situ measurements at this height at Sierra Nevada Station. The differences between GRASP and in situ measurements are similar for the different schemes, with differences below 30 % for both volume concentration and scattering ...