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

摘要: Abstract. This study evaluates the potential of GRASP algorithm (Generalized Retrieval Aerosol and Surface Properties) to retrieve continuous day-to-night aerosol properties, both column-integrated and vertically resolved. The is focused on evaluation GRASP retrievals during an intense Saharan dust event that occurred the Sierra Nevada Lidar aerOsol Profiling Experiment I (SLOPE I) field campaign. For daytime retrievals, we combined measurements ground-based lidar from EARLINET (European Research Network) station sun–sky photometer AERONET (Aerosol Robotic Network), instruments co-located in Granada (Spain). However, for night-time retrievals three different combinations active passive remote-sensing are proposed. first scheme ( N0 ) uses combination with interpolation measurements. other two schemes combine optical depth obtained by lunar photometry either using intensive properties retrieved measurements ( N1 or Moon aureole radiance sky camera images ( N2 ). Evaluations columnar done versus standard retrievals. coherence day-to-night evolutions of also studied. The extinction coefficient vertical profiles compared with calculated Raman technique at with differences below 30 % all at 355, 532 and 1064 nm. Finally, the volume concentration scattering at 2500 m a.s.l. are evaluated situ this height Sierra Station. differences between similar schemes, coefficient. In general, coefficient, GRASP  and  show better results than while concentration, shows lowest against (around 10 %) high values.