{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,3]],"date-time":"2025-12-03T18:05:00Z","timestamp":1764785100598,"version":"build-2065373602"},"reference-count":27,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2023,3,14]],"date-time":"2023-03-14T00:00:00Z","timestamp":1678752000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Water droplet size, or effective radius, of water clouds can be retrieved using measurements of the total reflectance in near-infrared channels (bi-spectral method) or the linearly polarized radiance of the cloud rainbow (polarimetric method). The retrieved droplet sizes from the bi-spectral method can be significantly larger than those from the polarimetric method. Droplet size vertical heterogeneity is considered as a likely cause of this difference. In this radiative transfer theoretical study, we find that partially melting droplets in mixed-phase clouds can be another cause of this difference. The theoretical study suggests that, when the clouds are dominated by large particles, the existence of partially melting droplets could cause the polarimetric method to underestimate the particle size; but for moderate-sized particles, the polarimetric method should be able to retrieve accurate particle size no matter if the clouds consist of partially melting droplets or not. However, the droplet effective radius of partially melting droplets retrieved by the bi-spectral method can be overestimated if the infrared channel of the bi-spectral method is at 1.6 \u03bcm, but is relatively insensitive to the presence of partially melted spherical droplets when the infrared channel is at 2.1 \u03bcm. The retrieved droplet size difference between droplet sizes from 1.6 \u03bcm and 2.1 \u03bcm channels can be used for detecting partially melting droplets.<\/jats:p>","DOI":"10.3390\/rs15061576","type":"journal-article","created":{"date-parts":[[2023,3,14]],"date-time":"2023-03-14T06:14:58Z","timestamp":1678774498000},"page":"1576","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Effect of Partially Melting Droplets on Polarimetric and Bi-Spectral Retrieval of Water Cloud Particle Size"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9901-6031","authenticated-orcid":false,"given":"Wenbo","family":"Sun","sequence":"first","affiliation":[{"name":"Science Systems and Applications, Inc., Hampton, VA 23681, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8526-108X","authenticated-orcid":false,"given":"Yongxiang","family":"Hu","sequence":"additional","affiliation":[{"name":"NASA Langley Research Center, Hampton, VA 23668, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Snorre A.","family":"Stamnes","sequence":"additional","affiliation":[{"name":"NASA Langley Research Center, Hampton, VA 23668, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Charles R.","family":"Trepte","sequence":"additional","affiliation":[{"name":"NASA Langley Research Center, Hampton, VA 23668, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1871-9235","authenticated-orcid":false,"given":"Ali H.","family":"Omar","sequence":"additional","affiliation":[{"name":"NASA Langley Research Center, Hampton, VA 23668, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rosemary R.","family":"Baize","sequence":"additional","affiliation":[{"name":"NASA Langley Research Center, Hampton, VA 23668, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,3,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1290","DOI":"10.1175\/1520-0477(1984)065<1290:OFROSM>2.0.CO;2","article-title":"Outlook for research on marine subtropical stratocumulus clouds","volume":"65","author":"Randall","year":"1984","journal-title":"Bull. Amer. Meteor. Soc."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1038\/343049a0","article-title":"Sensitivity of the Earth\u2019s radiation budget to changes in low clouds","volume":"343","author":"Slingo","year":"1990","journal-title":"Nature"},{"key":"ref_3","first-page":"1878","article-title":"Determination of the optical thickness and effective particle radius of clouds from reflected solar radiation measurements","volume":"47","author":"Nakajima","year":"1990","journal-title":"Part I Theory J. Atmos. Sci."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1175\/1520-0477(1991)072<0002:ICDP>2.0.CO;2","article-title":"ISCCP cloud data products","volume":"72","author":"Rossow","year":"1991","journal-title":"B. Am. Meteorol. Soc."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"459","DOI":"10.1109\/TGRS.2002.808301","article-title":"The MODIS cloud products: Algorithms and examples from terra","volume":"41","author":"Platnick","year":"2003","journal-title":"IEEE T. Geosci. Remote"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1142","DOI":"10.1109\/TGRS.2013.2247768","article-title":"Early on-orbit performance of the Visible Infrared Imaging Radiometer Suite onboard the Suomi National Polar-orbiting Partnership (S-NPP) satellite","volume":"52","author":"Cao","year":"2014","journal-title":"IEEE T. Geosci. Remote"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"151","DOI":"10.2151\/jmsj.2016-009","article-title":"An introduction to Himawari-8\/9\u2013Japan\u2019s new-generation geostationary meteorological satellites","volume":"94","author":"Bessho","year":"2016","journal-title":"J. Meteorol. Soc. Jpn."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Cairns, B., Russell, E.E., and Travis, L.D. (1999, January 25). Research Scanning Polarimeter: Calibration and ground-based measurements. Proceedings of the SPIE 3754, Polarization: Measurement, Analysis, and Remote Sensing II, Denver, CO, USA.","DOI":"10.1117\/12.366329"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1796","DOI":"10.1109\/TGRS.2005.852838","article-title":"A comparison of cloud droplet radii measured from space","volume":"43","year":"2005","journal-title":"IEEE T. Geosci. Remote"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"92","DOI":"10.1016\/j.rse.2012.07.012","article-title":"Accuracy assessments of cloud droplet size retrievals from polarized reflectance measurements by the research scanning polarimeter","volume":"125","author":"Alexandrov","year":"2012","journal-title":"Remote Sens. Environ."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1016\/j.rse.2015.07.029","article-title":"Liquid water cloud properties during the Polarimeter Definition Experiment (PODEX)","volume":"169","author":"Alexandrov","year":"2015","journal-title":"Remote Sens. Environ."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"728","DOI":"10.1175\/1520-0469(1991)048<0728:DOTOTA>2.0.CO;2","article-title":"Determination of the optical thickness and effective particle radius of clouds from reflected solar radiation measurements. Part II: Marine stratocumulus observations","volume":"48","author":"Nakajima","year":"1991","journal-title":"J. Atmos. Sci."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2985","DOI":"10.1175\/1520-0469(1995)052<2985:AVOASC>2.0.CO;2","article-title":"A validation of a satellite cloud retrieval during ASTEX","volume":"52","author":"Platnick","year":"1995","journal-title":"J. Atmos. Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"D21","DOI":"10.1029\/2012JD017624","article-title":"CalNex cloud properties retrieved from a ship-based spectrometer and comparisons with satellite and aircraft retrieved cloud properties","volume":"117","author":"McBride","year":"2012","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"7661","DOI":"10.1002\/2015JD023256","article-title":"Bias in MODIS cloud drop effective radius for oceanic water clouds as deduced from optical thickness variability across scattering angles","volume":"120","author":"Liang","year":"2015","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"13182","DOI":"10.1029\/2019JD031063","article-title":"Regional biases in MODIS marine liquid water cloud drop effective radius deduced through fusion with MISR","volume":"124","author":"Fu","year":"2019","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"8259","DOI":"10.5194\/acp-22-8259-2022","article-title":"An evaluation of the liquid cloud droplet effective radius derived from MODIS, airborne remote sensing, and in situ measurements from CAMP2Ex","volume":"22","author":"Fu","year":"2022","journal-title":"Atmos. Chem. Phys."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"2310","DOI":"10.1175\/2009JTECHA1281.1","article-title":"Overview of the CALIPSO mission and CALIOP data processing algorithms","volume":"226","author":"Winker","year":"2009","journal-title":"J. Atmos. Oceanic. Technol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"3353","DOI":"10.5194\/acp-7-3353-2007","article-title":"Global Statistics of Liquid Water Content and Effective Number Concentration of Water Clouds over Ocean Derived from Combined CALIPSO and MODIS Measurements","volume":"7","author":"Hu","year":"2007","journal-title":"Atmos. Chem. Phys."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2293","DOI":"10.1175\/2009JTECHA1280.1","article-title":"CALIPSO\/CALIOP Cloud Phase Discrimination Algorithm","volume":"26","author":"Hu","year":"2009","journal-title":"J. Atmos. Oceanic. Technol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"25","DOI":"10.3389\/frsen.2021.724615","article-title":"Liquid Phase Cloud Microphysical Property Estimates from CALIPSO Measurements","volume":"2","author":"Hu","year":"2021","journal-title":"Front. Remote Sens."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"377","DOI":"10.1002\/andp.19083300302","article-title":"Beitr\u00e4ge zur Optik tr\u00fcber Medien, speziell kolloidaler Metall\u00f6sungen","volume":"330","author":"Mie","year":"1908","journal-title":"Ann. Phys."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"108107","DOI":"10.1016\/j.jqsrt.2022.108107","article-title":"Partially melting droplets strongly enhance lidar backscatter","volume":"281","author":"Sun","year":"2022","journal-title":"J. Quant. Spectrosc. Radiat. Trans."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"3657","DOI":"10.1364\/AO.20.003657","article-title":"Algorithms for the calculation of scattering by stratified spheres","volume":"20","author":"Toon","year":"1981","journal-title":"Appl. Opt."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"483","DOI":"10.1016\/S0022-4073(03)00101-8","article-title":"Light scattering by coated sphere immersed in absorbing medium: A comparison between the FDTD and analytic solutions","volume":"83","author":"Sun","year":"2004","journal-title":"J. Quant. Spectrosc. Radiat. Trans."},{"key":"ref_26","unstructured":"Deirmendjian, D. (1969). Electromagnetic Scattering on Spherical Polydispersions, American Elsevier Publishing Company, Inc."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"10303","DOI":"10.5194\/acp-13-10303-2013","article-title":"Modeling polarized solar radiation from ocean-atmosphere system for CLARREO inter-calibration applications","volume":"13","author":"Sun","year":"2013","journal-title":"Atmos. Chem. Phys."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/15\/6\/1576\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T18:54:42Z","timestamp":1760122482000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/15\/6\/1576"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,3,14]]},"references-count":27,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2023,3]]}},"alternative-id":["rs15061576"],"URL":"https:\/\/doi.org\/10.3390\/rs15061576","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2023,3,14]]}}}