Details

Autor(en) / Beteiligte

• Xu, Feng
• Harten, Gerard
• Diner, David J.
• Kalashnikova, Olga V.
• Seidel, Felix C.
• Bruegge, Carol J.
• Dubovik, Oleg

Titel

Coupled retrieval of aerosol properties and land surface reflection using the Airborne Multiangle SpectroPolarimetric Imager

Ist Teil von

• Journal of geophysical research. Atmospheres, 2017-07, Vol.122 (13), p.7004-7026

Ort / Verlag

Washington: Blackwell Publishing Ltd

Erscheinungsjahr

2017

Link zum Volltext

Quelle

Wiley Online Library All Journals

Beschreibungen/Notizen

• The Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) has been flying aboard the NASA ER‐2 high‐altitude aircraft since October 2010. In step‐and‐stare operation mode, AirMSPI acquires radiance and polarization data in bands centered at 355, 380, 445, 470*, 555, 660*, 865*, and 935 nm (* denotes polarimetric bands). The imaged area covers about 10 km by 11 km and is typically observed from nine viewing angles between ±66° off nadir. For a simultaneous retrieval of aerosol properties and surface reflection using AirMSPI, an efficient and flexible retrieval algorithm has been developed. It imposes multiple types of physical constraints on spectral and spatial variations of aerosol properties as well as spectral and temporal variations of surface reflection. Retrieval uncertainty is formulated by accounting for both instrumental errors and physical constraints. A hybrid Markov‐chain/adding‐doubling radiative transfer (RT) model is developed to combine the computational strengths of these two methods in modeling polarized RT in vertically inhomogeneous and homogeneous media, respectively. Our retrieval approach is tested using 27 AirMSPI data sets with low to moderately high aerosol loadings, acquired during four NASA field campaigns plus one AirMSPI preengineering test flight. The retrieval results including aerosol optical depth, single‐scattering albedo, aerosol size and refractive index are compared with Aerosol Robotic Network reference data. We identify the best angular combinations for 2, 3, 5, and 7 angle observations from the retrieval quality assessment of various angular combinations. We also explore the benefits of polarimetric and multiangular measurements and target revisits in constraining aerosol property and surface reflection retrieval. Key Points An reliable retrieval algorithm has been developed for simultaneous retrieval of aerosol properties and surface reflection using AirMSPI We identify the best angular combinations for multiangle observations from the retrieval quality assessment We explore the benefits of polarimetric and multiangular measurements and target revisits in constraining aerosol and surface retrieval