{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:12:51Z","timestamp":1760242371906,"version":"build-2065373602"},"reference-count":33,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2017,6,5]],"date-time":"2017-06-05T00:00:00Z","timestamp":1496620800000},"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>CAR (Cloud Absorption Radiometer) is a multi-angular and multi-spectral airborne radiometer instrument, whose radiometric and geometric characteristics are well calibrated and adjusted before and after each flight campaign. CAR was built by NASA (National Aeronautics and Space Administration) in 1984. On 16 May 2008, a CAR flight campaign took place over the well-known calibration and validation site of Railroad Valley in Nevada, USA (38.504\u00b0N, 115.692\u00b0W). The campaign coincided with the overpasses of several key EO (Earth Observation) satellites such as Landsat-7, Envisat and Terra. Thus, there are nearly simultaneous measurements from these satellites and the CAR airborne sensor over the same calibration site. The CAR spectral bands are close to those of most EO satellites. CAR has the ability to cover the whole range of azimuth view angles and a variety of zenith angles depending on altitude and, as a consequence, the biases seen between satellite and CAR measurements due to both unmatched spectral bands and unmatched angles can be significantly reduced. A comparison is presented here between CAR\u2019s land surface reflectance (BRF or Bidirectional Reflectance Factor) with those derived from Terra\/MODIS (MOD09 and MAIAC), Terra\/MISR, Envisat\/MERIS and Landsat-7. In this study, we utilized CAR data from low altitude flights (approx. 180 m above the surface) in order to minimize the effects of the atmosphere on these measurements and then obtain a valuable ground-truth data set of surface reflectance. Furthermore, this study shows that differences between measurements caused by surface heterogeneity can be tolerated, thanks to the high homogeneity of the study site on the one hand, and on the other hand, to the spatial sampling and the large number of CAR samples. These results demonstrate that satellite BRF measurements over this site are in good agreement with CAR with variable biases across different spectral bands. This is most likely due to residual aerosol effects in the EO derived reflectances.<\/jats:p>","DOI":"10.3390\/rs9060562","type":"journal-article","created":{"date-parts":[[2017,6,6]],"date-time":"2017-06-06T10:53:09Z","timestamp":1496746389000},"page":"562","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Assessment of Satellite-Derived Surface Reflectances by NASA\u2019s CAR Airborne Radiometer over Railroad Valley Playa"],"prefix":"10.3390","volume":"9","author":[{"given":"Said","family":"Kharbouche","sequence":"first","affiliation":[{"name":"Imaging Group, Mullard Space Science Laboratory, University College London, Department of Space and Climate Physics, Holmbury St Mary, RH5-6NT, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5077-3736","authenticated-orcid":false,"given":"Jan-Peter","family":"Muller","sequence":"additional","affiliation":[{"name":"Imaging Group, Mullard Space Science Laboratory, University College London, Department of Space and Climate Physics, Holmbury St Mary, RH5-6NT, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9261-2239","authenticated-orcid":false,"given":"Charles","family":"Gatebe","sequence":"additional","affiliation":[{"name":"NASA GSFC and Universities Space Research Association, Greenbelt, MD 20771, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tracy","family":"Scanlon","sequence":"additional","affiliation":[{"name":"National Physical Laboratory, Teddington TW11-0LW, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5142-1433","authenticated-orcid":false,"given":"Andrew","family":"Banks","sequence":"additional","affiliation":[{"name":"National Physical Laboratory, Teddington TW11-0LW, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2017,6,5]]},"reference":[{"key":"ref_1","unstructured":"Ward, S. (2015, November 01). The Earth Observation Handbook. Available online: www.eohandbook.com."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"875","DOI":"10.1038\/nclimate1908","article-title":"The role of satellite remote sensing in climate change studies","volume":"3","author":"Yang","year":"2013","journal-title":"Nat. Clim. Chang."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1109\/MGRS.2016.2586852","article-title":"A Special Issue on Big Data from Space for Geoscience and Remote Sensing [From the Guest Editors]","volume":"4","author":"Marchetti","year":"2016","journal-title":"IEEE Geosci. Remote Sens. Mag."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"11217","DOI":"10.5194\/acp-15-11217-2015","article-title":"Influence of aerosols and surface reflectance on satellite NO2 retrieval: seasonal and spatial characteristics and implications for NOx emission constraints","volume":"15","author":"Lin","year":"2015","journal-title":"Atmos. Chem. Phys."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Foody, G.M., and Atkinson, P.M. (2002). Uncertainty in Remote Sensing And GIS, Wiley Online Library.","DOI":"10.1002\/0470035269"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1016\/j.rse.2014.07.020","article-title":"Uncertainties of LAI estimation from satellite imaging due to atmospheric correction","volume":"153","author":"Mannschatz","year":"2014","journal-title":"Remote Sens. Environ."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1016\/j.rse.2006.03.002","article-title":"Reflectance quantities in optical remote sensing\u2014Definitions and case studies","volume":"103","author":"Schaepman","year":"2006","journal-title":"Remote Sens. Environ."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"75","DOI":"10.1080\/02757250009532411","article-title":"PARABOLA III: A sphere-scanning radiometer for field determination of surface anisotropic reflectance functions","volume":"19","author":"Bruegge","year":"2000","journal-title":"Remote Sens. Rev."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"978","DOI":"10.1109\/36.752216","article-title":"A field goniometer system (FIGOS) for acquisition of hyperspectral BRDF data","volume":"37","author":"Sandmeier","year":"1999","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_10","unstructured":"Pegrum-Browning, H., Fox, N., and Milton, E. (2008, January 15\u201317). The NPL Gonio RAdiometric Spectrometer System (GRASS). Proceedings of the Remote Sensing and Photogrammetry Society Conference: \u201cMeasuring Change in the Earth System\u201d, University of Exeter, Exeter, UK."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1016\/S0034-4257(02)00092-5","article-title":"Validating MODIS land surface reflectance and albedo products: Methods and preliminary results","volume":"83","author":"Liang","year":"2002","journal-title":"Remote Sens. Environ."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1016\/S0034-4257(00)00195-4","article-title":"The MODIS\/ASTER airborne simulator (MASTER)\u2014A new instrument for earth science studies","volume":"76","author":"Hook","year":"2001","journal-title":"Remote Sens. Environ."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1339","DOI":"10.1109\/36.701083","article-title":"The Airborne Multi-angle Imaging SpectroRadiometer (AirMISR): Instrument description and first results","volume":"36","author":"Diner","year":"1998","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1016\/0034-4257(95)00229-4","article-title":"Angular signatures of surface reflectances from airborne POLDER data","volume":"57","author":"Leroy","year":"1996","journal-title":"Remote Sens. Environ."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1109\/36.103294","article-title":"An off-nadir-pointing imaging spectroradiometer for terrestrial ecosystem studies","volume":"29","author":"Irons","year":"1991","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"338","DOI":"10.1016\/S0034-4257(01)00213-9","article-title":"Vicarious calibration: A reflectance-based experiment with AirMISR","volume":"77","author":"Abdou","year":"2001","journal-title":"Remote Sens. Environ."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"131","DOI":"10.1016\/j.rse.2016.03.029","article-title":"Airborne spectral BRDF of various surface types (ocean, vegetation, snow, desert, wetlands, cloud decks, smoke layers) for remote sensing applications","volume":"179","author":"Gatebe","year":"2016","journal-title":"Remote Sens. Environ."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"2184","DOI":"10.1016\/j.rse.2011.04.012","article-title":"Variability in surface BRDF at different spatial scales (30 m\u2013500 m) over a mixed agricultural landscape as retrieved from airborne and satellite spectral measurements","volume":"115","author":"Gatebe","year":"2011","journal-title":"Remote Sens. Environ."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1393","DOI":"10.1109\/TGRS.2013.2243457","article-title":"Use of in situ and airborne multiangle data to assess MODIS-and Landsat-based estimates of directional reflectance and albedo","volume":"51","author":"Gatebe","year":"2013","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"158","DOI":"10.1117\/12.256090","article-title":"Evaluation of the Railroad Valley Playa for use in vicarious calibration","volume":"2818","author":"Scott","year":"1996","journal-title":"Proc. SPIE"},{"key":"ref_21","unstructured":"Van De Hulst, H.C. (1980). Multiple Light Scattering: Tables, Formulas and Applications, Academic Press."},{"key":"ref_22","unstructured":"(2015, May 01). MODIS Surface Reflectance User\u2019s Guide, Collection 6. Available online: http:\/\/modis-sr.ltdri.org\/guide\/MOD09_UserGuidev1.4.pdf."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"675","DOI":"10.1109\/36.581987","article-title":"Second simulation of the satellite signal in the solar spectrum, 6S: An overview","volume":"35","author":"Vermote","year":"1997","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Vermote, E.F., and Kotchenova, S. (2008). Atmospheric correction for the monitoring of land surfaces. J. Geophys. Res. Atmos., 113.","DOI":"10.1029\/2007JD009662"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"385","DOI":"10.1016\/j.rse.2012.09.002","article-title":"Multi-angle implementation of atmospheric correction for MODIS (MAIAC): 3. Atmospheric correction","volume":"127","author":"Lyapustin","year":"2012","journal-title":"Remote Sens. Environ."},{"key":"ref_26","unstructured":"(2011, August 01). MERIS Product Handbook. Available online: http:\/\/envisat.esa.int\/handbooks\/meris\/CNTR.html."},{"key":"ref_27","unstructured":"Moore, G., and Lavender, S. (2011, August 01). Algorithm Identification: Case II. S Bright Pixel Atmospheric Correction (MERIS ATBD 2.6). Available online: https:\/\/earth.esa.int\/documents\/700255\/2042855\/MERISATBD2.6v5.0+-+2011.pdf."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"68","DOI":"10.1109\/LGRS.2005.857030","article-title":"A Landsat surface reflectance dataset for North America, 1990\u20132000","volume":"3","author":"Masek","year":"2006","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_29","unstructured":"(2016, September 30). Landsat 4-7 Surface Reflectance (LEDAPS) Product, How Published, Available online: https:\/\/landsat.usgs.gov\/sites\/default\/files\/documents\/ledaps_product_guide.pdf."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"4","DOI":"10.1016\/S0034-4257(99)00054-1","article-title":"Operational atmospheric correction of Landsat TM data","volume":"70","author":"Ouaidrari","year":"1999","journal-title":"Remote Sens. Environ."},{"key":"ref_31","unstructured":"(2012, May 07). MISR Science Data Product Guide, Available online: https:\/\/eosweb.larc.nasa.gov\/sites\/default\/files\/project\/misr\/guide\/MISR_Science_DataProduct_Guide.pdf."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1016\/j.rse.2004.09.009","article-title":"Using angular and spectral shape similarity constraints to improve MISR aerosol and surface retrievals over land","volume":"94","author":"Diner","year":"2005","journal-title":"Remote Sens. Environ."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"21077","DOI":"10.1029\/95JD02371","article-title":"On the derivation of kernels for kernel-driven models of bidirectional reflectance","volume":"100","author":"Wanner","year":"1995","journal-title":"J. Geophys. Res. Atmos."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/9\/6\/562\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T18:38:02Z","timestamp":1760207882000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/9\/6\/562"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,6,5]]},"references-count":33,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2017,6]]}},"alternative-id":["rs9060562"],"URL":"https:\/\/doi.org\/10.3390\/rs9060562","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2017,6,5]]}}}