author = "Krisna, Trismono C. and Wendisch, Manfred and Ehrlich, Andr{\'e} 
                         and J{\"a}kel, Evelyn and Werner, Frank and Weigel, Ralf and 
                         Borrmann, Stephan and Mahnke, Christoph and P{\"o}schl, Ulrich 
                         and Andreae, Meinrat O. and Voigt, Christiane and Machado, Luiz 
                         Augusto Toledo",
          affiliation = "{Universit{\"a}t Leipzig} and {Universit{\"a}t Leipzig} and 
                         {Universit{\"a}t Leipzig} and {Universit{\"a}t Leipzig} and 
                         {Universit{\"a}t Leipzig} and {Johannes 
                         Gutenberg-Universit{\"a}t Mainz} and {Johannes 
                         Gutenberg-Universit{\"a}t Mainz} and {Johannes 
                         Gutenberg-Universit{\"a}t Mainz} and {Max Planck Institute for 
                         Chemistry (MPIC)} and {Max Planck Institute for Chemistry (MPIC)} 
                         and {Deutsches Zentrum f{\"u}r Luft und Raumfahrt (DLR)} and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "Comparing airborne and satellite retrievals of optical and 
                         microphysical properties of cirrus and deep convective clouds 
                         using a radiance ratio technique",
              journal = "Atmospheric Chemistry and Physics Discussions",
                 year = "2017",
               volume = "758",
             abstract = "t. Solar radiation reflected by cirrus and deep convective clouds 
                         (DCCs) was measured by the Spectral Modular Airborne Radiation 
                         Measurement System (SMART) installed on the German HALO (High 
                         Altitude and Long Range Research Aircraft) during the ML-CIRRUS 
                         and the ACRIDICON-CHUVA campaigns. In particular flights, HALO 
                         performed closely collocated measurements with overpasses of the 
                         Moderate Resolution Imaging Spectroradiometer (MODIS) on board of 
                         Aqua 5 satellite. Based on the nadir upward radiance, the optical 
                         thickness \τ and bulk particle effective radius reff of 
                         cirrus and DCC are retrieved using a radiance ratio algorithm 
                         which considers the cloud thermodynamic phase, the cloud vertical 
                         profile, multi layer clouds, and heterogeneity of the surface 
                         albedo. For the cirrus case, the comparison of \τci and 
                         reff,ci retrieved on the basis of SMART and MODIS upward radiances 
                         yields a normalized mean absolute deviation of 0.5% for \τci 
                         and 2.5% for reff,ci. While for the DCC case, the respective 
                         deviation is 5.9% for \τdcc and 13.2% for reff,dcc. The 
                         larger deviations in case 10 of DCC are mainly attributed to the 
                         fast cloud evolution and three-dimensional radiative effects. 
                         Measurements of spectral radiance at near-infrared wavelengths 
                         with different absorption by cloud particles are employed to 
                         investigate the vertical profile of cirrus effective radius. The 
                         retrieved values of cirrus effective radius are further compared 
                         with corresponding in situ measurements using a vertical weighting 
                         method. Compared to the MODIS observation, spectral measurements 
                         of SMART provide an increased amount of information on the 
                         vertical distribution of particle sizes at cloud top, and 
                         therefore allow 15 to reconstruct the profile of effective radius 
                         at cloud top. The retrieved effective radius differs to in situ 
                         measurements with a normalized mean absolute deviation between 4 
                         \− 19%, depending on the wavelength chosen in the retrieval 
                         algorithm. While, the MODIS cloud product underestimates the in 
                         situ measurements by 48%. The presence of liquid water clouds 
                         below the cirrus, the variability of particle size distributions, 
                         and the simplification in the retrieval algorithm assuming 
                         vertically homogeneous cloud are identified as the potential error 
                  doi = "10.5194/acp-2017-758",
                  url = "http://dx.doi.org/10.5194/acp-2017-758",
                 issn = "1680-7367",
             language = "en",
           targetfile = "krisna_comparing.pdf",
        urlaccessdate = "17 jan. 2021"