GRASP is a state-of-the-art retrieval algorithm for generating enhanced aerosol and surface products from diverse space-borne and ground-based measurements (Dubovik et al. 2011, 2014, 2021). GRASP retrieval is implemented as a highly advanced statistically optimized fitting of all available observations. For example, GRASP uses an innovative multi-pixel concept in which the fitting is realized simultaneously for a large group of “pixels” (coordinated observations). This principle is especially useful for improving satellite retrievals where it allows to benefit from known a priori limitations on space and time variability of different surface and aerosol parameters. This helps reliable discrimination between aerosol and surface contributions in observation that is generally known as a challenging issue.
The GRASP multi-pixel retrieval concept has already been successfully applied to the observations of different single space-borne instruments: polar-orbiting like POLDER/PARASOL, MERIS, AATSR/ENVISAT, OLCI/Sentinel-3, TROPOMI/S-5p and geostationary, for example, Himawari, satellites. Moreover, the synergetic approaches were successfully approved on the synergy of MERIS and AATSR measurements (ESA CAWA-2 project) as well as on the synergy of the ground-based and satellite (AERONET+OLCI, AERONET+ TROPOMI/Sentinel-5p etc retrieval) measurements (ESA GROSAT project).
GRASP algorithm is planned to be used for aerosol and surface near-real-time characterization from future space-borne polarimetric mission like 3MI, CO2M MAP, GAPMAP etc.
Dubovik O., Fuertes D., Litvinov P., et al.: A Comprehensive Description of Multi-Term LSM for Applying Multiple a Priori Constraints in Problems of Atmospheric Remote Sensing: GRASP Algorithm, Concept, and Applications. Front. Remote Sens. 2:706851, 2021. doi:10.3389/frsen.2021.706851
Dubovik, O., Herman, M., Holdak, et al.: Statistically optimized inversion algorithm for enhanced retrieval of aerosol properties from spectral multi-angle polarimetric satellite observations, Atmos. Meas. Tech., 4, 975-1018, 2011. doi:10.5194/amt-4-975-2011
Chen, C., Dubovik, O., Fuertes, et al.: Validation of GRASP algorithm product from POLDER/PARASOL data and assessment of multi-angular polarimetry potential for aerosol monitoring, Earth Syst. Sci. Data, 12, 3573–3620, 2020. doi:10.5194/essd-12-3573-2020
Li, L., Derimian, Y., Chen, et al.: Climatology of aerosol component concentrations derived from multi-angular polarimetric POLDER-3 observations using GRASP algorithm, Earth Syst. Sci. Data, 14, 3439–3469, 2022. doi:10.5194/essd-14-3439-2022
Zhang, X., L. Li, C. Chen, et al.: Validation of the aerosol optical property products derived by the GRASP/Component approach from multi-angular polarimetric observations, Atmospheric Research, 263, 105802, 2021. doi:10.1016/j.atmosres.2021.105802
Chen, C., Dubovik, O., Litvinov, P. et al.: Properties of aerosol and surface derived from OLCI/Sentinel-3A using GRASP approach: Retrieval development and preliminary validation, Remote Sensing of Environment, 280, 113142, 2022. doi:10.1016/j.rse.2022.113142