{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,9]],"date-time":"2026-03-09T09:52:57Z","timestamp":1773049977514,"version":"3.50.1"},"reference-count":59,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2020,7,10]],"date-time":"2020-07-10T00:00:00Z","timestamp":1594339200000},"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>Urban surface albedo is important for investigating urban surface\u2013atmosphere radiative heat exchanges. For modeling surface energy balance (SEB) at local and neighborhood scales, ground or unmanned aerial vehicle (UAV)-based multispectral remote sensing (RS) can be used to obtain high-spatial-resolution multispectral information for both horizontal and vertical urban surfaces. The existing narrow-to-broadband (NTB) conversion models, developed for satellite\/high-altitude observation and large homogeneous rural\/vegetated\/snow zones, may not be suitable for downscaling to the local and neighborhood scales or the urban complex texture. We developed three NTB models following published methodologies for three common UAV-based multispectral cameras according to Sample_D, a sample group of extensive spectral albedos of artificial urban surfaces, and evaluated their performance and sensitivities to solar conditions and surface material class. The proposed models were validated with independent samples (Sample_V). A model considering albedo physics was improved by multiplying different variables with respect to the camera (termed as \u201cModel_phy_reg\u201d), which initially proved to be the most accurate with a root mean square error of up to 0.02 for Sample_D and approximately 0.029 for Sample_V, meeting the required accuracy of total shortwave albedo for SEB modeling. The accuracy of Model_phy_reg was not much prone to the solar conditions.<\/jats:p>","DOI":"10.3390\/rs12142214","type":"journal-article","created":{"date-parts":[[2020,7,10]],"date-time":"2020-07-10T09:25:28Z","timestamp":1594373128000},"page":"2214","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Narrow-to-Broadband Conversion for Albedo Estimation on Urban Surfaces by UAV-Based Multispectral Camera"],"prefix":"10.3390","volume":"12","author":[{"given":"Xi","family":"Xu","sequence":"first","affiliation":[{"name":"Department of Architecture and Building Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midroi-ku, Yokohama 226-8502, Kanagawa, Japan"}]},{"given":"Takashi","family":"Asawa","sequence":"additional","affiliation":[{"name":"Department of Architecture and Building Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midroi-ku, Yokohama 226-8502, Kanagawa, Japan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9319-0621","authenticated-orcid":false,"given":"Hideki","family":"Kobayashi","sequence":"additional","affiliation":[{"name":"Department of Architecture and Building Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midroi-ku, Yokohama 226-8502, Kanagawa, Japan"},{"name":"Institute of Arctic Climate and Environmental Research, Japan Agency for Marine-Earth Science and Technology, 3173-25, Showa-machi, Kanazawa-ku, Yokohama 236-0001, Kanagawa, Japan"}]}],"member":"1968","published-online":{"date-parts":[[2020,7,10]]},"reference":[{"key":"ref_1","unstructured":"Liang, S., Li, X., and Wang, J. (2012). Broadband Albedo In Advanced Remote Sensing, Academic Press: Boston, MA, USA. Chapter 7- Broadband Albedo."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Oke, T.R., Mills, G., Christen, A., and Voogt, J.A. (2017). Urban Climates, Cambridge University Press.","DOI":"10.1017\/9781139016476"},{"key":"ref_3","first-page":"1","article-title":"The energetic basis of the urban heat island","volume":"108","author":"Oke","year":"1982","journal-title":"Q. J. R. Meteorol. Soc."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1084","DOI":"10.1002\/2017EF000569","article-title":"Albedo, Land Cover, and Daytime Surface Temperature Variation Across an Urbanized Landscape","volume":"5","author":"Trlica","year":"2017","journal-title":"Earth\u2019s Futur."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1694","DOI":"10.1175\/1520-0450-34.7.1694","article-title":"Simulated Urban Climate Response to Modifications in Surface Albedo and Vegetative Cover","volume":"34","author":"Sailor","year":"1995","journal-title":"J. Appl. Meteorol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"106485","DOI":"10.1016\/j.buildenv.2019.106485","article-title":"Systematic numerical study on the effect of thermal properties of building surface on its temperature and sensible heat flux","volume":"168","author":"Xu","year":"2020","journal-title":"Build. Environ."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"597","DOI":"10.1016\/j.solener.2018.08.006","article-title":"Green and cool roofs \u2019 urban heat island mitigation potential in tropical climate","volume":"173","author":"Yang","year":"2018","journal-title":"Sol. Energy"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"106542","DOI":"10.1016\/j.buildenv.2019.106542","article-title":"Passive building characteristics, and summertime residential energy use: A spatial analysis of energy efficiency in Gainesville, FL","volume":"169","author":"Douthat","year":"2020","journal-title":"Build. Environ."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1016\/0360-1323(88)90033-9","article-title":"Residential cooling loads and the urban heat island\u2014the effects of albedo","volume":"23","author":"Taha","year":"1988","journal-title":"Build. Environ."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"110","DOI":"10.1029\/2004JD005493","article-title":"Mapping daily snow\/ice shortwave broadband albedo from Moderate Resolution Imaging Spectroradiometer (MODIS): The improved direct retrieval algorithm and validation with Greenland in situ measurement","volume":"110","author":"Liang","year":"2005","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"199","DOI":"10.1016\/j.rse.2013.07.023","article-title":"Re-evaluation of MODIS MCD43 Greenland albedo accuracy and trends","volume":"138","author":"Stroeve","year":"2013","journal-title":"Remote. Sens. Environ."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"118","DOI":"10.1016\/j.rse.2013.08.044","article-title":"Comparing MODIS daily snow albedo to spectral albedo field measurements in Central Greenland","volume":"140","author":"Wright","year":"2014","journal-title":"Remote. Sens. Environ."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"45","DOI":"10.3189\/172756402781817662","article-title":"Development and validation of a snow albedo algorithm for the MODIS instrument","volume":"34","author":"Klein","year":"2002","journal-title":"Ann. Glaciol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"213","DOI":"10.1016\/S0034-4257(00)00205-4","article-title":"Narrowband to broadband conversions of land surface albedo I","volume":"76","author":"Liang","year":"2001","journal-title":"Remote Sens. Environ."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1016\/S0034-4257(02)00091-3","article-title":"First operational BRDF, albedo nadir reflectance products from MODIS","volume":"83","author":"Schaaf","year":"2002","journal-title":"Remote Sens. Environ."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"598","DOI":"10.1016\/j.rse.2018.07.014","article-title":"Coral reef applications of Sentinel-2: Coverage, characteristics, bathymetry and benthic mapping with comparison to Landsat 8","volume":"216","author":"Hedley","year":"2018","journal-title":"Remote Sens. Environ."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Bonafoni, S., and Sekertekin, A. (2020). Albedo Retrieval from Sentinel-2 by New Narrow-to-Broadband Conversion Coefficients. IEEE Geosci. Remote Sens. Lett., 1\u20135.","DOI":"10.1109\/LGRS.2020.2967085"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Cao, C., Lee, X., Muhlhausen, J., Bonneau, L., and Xu, J. (2018). Measuring Landscape Albedo Using Unmanned Aerial Vehicles. Remote Sens., 10.","DOI":"10.3390\/rs10111812"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Calleja, J.F., Recondo, C., Pe\u00f3n, J., Fern\u00e1ndez, S., De La Cruz, F., and Gonz\u00e1lez-Piqueras, J. (2016). A New Method for the Estimation of Broadband Apparent Albedo Using Hyperspectral Airborne Hemispherical Directional Reflectance Factor Values. Remote Sens., 8.","DOI":"10.3390\/rs8030183"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Markelin, L., Simis, S.G., Hunter, P., Spyrakos, E., Tyler, A., Clewley, D., and Groom, S. (2016). Atmospheric Correction Performance of Hyperspectral Airborne Imagery over a Small Eutrophic Lake under Changing Cloud Cover. Remote Sens., 9.","DOI":"10.3390\/rs9010002"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"106","DOI":"10.1016\/j.isprsjprs.2017.01.009","article-title":"Integration of remote sensing based surface information into a three-dimensional microclimate model","volume":"125","author":"Heldens","year":"2017","journal-title":"ISPRS J. Photogramm. Remote. Sens."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Canisius, F., Wang, S., Croft, H., Leblanc, S.G., Russell, H.A., Chen, J.M., and Wang, R. (2019). A UAV-Based Sensor System for Measuring Land Surface Albedo: Tested over a Boreal Peatland Ecosystem. Drones, 3.","DOI":"10.3390\/drones3010027"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1499","DOI":"10.1515\/acgeo-2015-0036","article-title":"Relating Hyperspectral Airborne Data to Ground Measurements in a Complex and Discontinuous Canopy","volume":"63","author":"Calleja","year":"2015","journal-title":"Acta Geophys."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Arroyo-Mora, J.P., Kalacska, M., Inamdar, D., Soffer, R., Lucanus, O., Gorman, J., Naprstek, T., Schaaf, E.S., Ifimov, G., and Elmer, K. (2019). Implementation of a UAV\u2013Hyperspectral Pushbroom Imager for Ecological Monitoring. Drones, 3.","DOI":"10.3390\/drones3010012"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"124","DOI":"10.1016\/j.isprsjprs.2018.09.008","article-title":"UAV-based multispectral remote sensing for precision agriculture: A comparison between different cameras","volume":"146","author":"Lei","year":"2018","journal-title":"ISPRS J. Photogramm. Remote. Sens."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1080\/17538947.2019.1597189","article-title":"Remote sensing of earth\u2019s energy budget: Synthesis and review","volume":"12","author":"Liang","year":"2019","journal-title":"Int. J. Digit. Earth"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"433","DOI":"10.1007\/s10546-006-9153-6","article-title":"A microscale three-dimensional urban energy balance model for studying surface temperatures","volume":"123","author":"Krayenhoff","year":"2007","journal-title":"Bound. Layer Meteorol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1262","DOI":"10.1016\/j.buildenv.2009.11.011","article-title":"An application of the thermo-radiative model SOLENE for the evaluation of street canyon energy balance","volume":"45","author":"Idczak","year":"2010","journal-title":"Build. Environ."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/S0034-4257(02)00068-8","article-title":"Narrowband to broadband conversions of land surface albedo: II. Validation","volume":"84","author":"Liang","year":"2003","journal-title":"Remote Sens. Environ."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"990","DOI":"10.3390\/rs70100990","article-title":"Mapping Surface Broadband Albedo from Satellite Observations: A Review of Literatures on Algorithms and Products","volume":"7","author":"Qu","year":"2015","journal-title":"Remote Sens."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1016\/j.rse.2016.02.059","article-title":"Early spring post-fire snow albedo dynamics in high latitude boreal forests using Landsat-8 OLI data","volume":"185","author":"Wang","year":"2016","journal-title":"Remote. Sens. Environ."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"2204","DOI":"10.1016\/j.rse.2011.04.019","article-title":"An algorithm for the retrieval of 30-m snow-free albedo from Landsat surface reflectance and MODIS BRDF","volume":"115","author":"Shuai","year":"2011","journal-title":"Remot. Sens. Environ."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"819","DOI":"10.3390\/rs2030819","article-title":"Acquisition of Bidirectional Reflectance Factor Dataset Using a Micro Unmanned Aerial Vehicle and a Consumer Camera","volume":"2","author":"Hakala","year":"2010","journal-title":"Remote Sens."},{"key":"ref_34","unstructured":"Strahler, A.H., Muller, J., Lucht, W., Schaaf, C., Tsang, T., Gao, F., Li, X., Lewis, P., and Barnsley, M.J. (1999). MODIS BRDF\/Albedo product: Algorithm theoretical basis document version 5.0, NASA."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Ryan, J.C., Hubbard, A., Box, J.E., Brough, S., Cameron, K.A., Cook, J.M., Cooper, M.G., Doyle, S.H., Edwards, A., and Holt, T.O. (2017). Derivation of High Spatial Resolution Albedo from UAV Digital Imagery: Application over the Greenland Ice Sheet. Front. Earth Sci., 5.","DOI":"10.3389\/feart.2017.00040"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1147","DOI":"10.1080\/01431169508954468","article-title":"Narrow-band to broad-band conversion for Meteosat-visiible channel and broad-band albedo using both AVHRR-1 and -2 channels","volume":"16","author":"Valiente","year":"1995","journal-title":"Int. J. Remote Sens."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Akkermans, T., and Clerbaux, N. (2020). Narrowband-to-Broadband Conversions for Top-of-Atmosphere Reflectance from the Advanced Very High Resolution Radiometer (AVHRR). Remote Sens., 12.","DOI":"10.3390\/rs12020305"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1175\/1520-0450(1999)038<0239:AIMTDS>2.0.CO;2","article-title":"An Improved Method to Derive Surface Albedo from Narrowband AVHRR Satellite Data: Narrowband to Broadband Conversion","volume":"38","author":"Song","year":"1999","journal-title":"J. Appl. Meteorol."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Peng, S., Wen, J., Xiao, Q., You, D., Dou, B., Liu, Q., and Tang, Y. (2017). Multi-Staged NDVI Dependent Snow-Free Land-Surface Shortwave Albedo Narrowband-to-Broadband (NTB) Coefficients and Their Sensitivity Analysis. Remote. Sens., 9.","DOI":"10.3390\/rs9010093"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"51","DOI":"10.1061\/(ASCE)1084-0699(2008)13:2(51)","article-title":"At-Surface Reflectance and Albedo from Satellite for Operational Calculation of Land Surface Energy Balance","volume":"13","author":"Tasumi","year":"2008","journal-title":"J. Hydrol. Eng."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"352","DOI":"10.1016\/j.rse.2018.08.025","article-title":"Preliminary assessment of 20-m surface albedo retrievals from sentinel-2A surface reflectance and MODIS\/VIIRS surface anisotropy measures","volume":"217","author":"Li","year":"2018","journal-title":"Remote Sens. Environ."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Ying, W., Wu, H., and Li, Z.-L. (2018, January 22\u201327). Net Surface Shortwave Radiation Retrieval Using Viirs Data. Proceedings of the IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium, Valencia, Spain.","DOI":"10.1109\/IGARSS.2018.8518858"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"256","DOI":"10.1016\/j.rse.2017.09.020","article-title":"Evaluation of the VIIRS BRDF, Albedo and NBAR products suite and an assessment of continuity with the long term MODIS record","volume":"201","author":"Liu","year":"2017","journal-title":"Remote Sens. Environ."},{"key":"ref_44","first-page":"49","article-title":"Spectral Analysis of Building Materials Used in Japan Int. Arch. Photogramm","volume":"37","author":"Mori","year":"2004","journal-title":"Remote Sens. Spat. Inf. Sci."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"97","DOI":"10.3130\/aije.72.97_1","article-title":"3D-CAD MODELING OF A SUBSTANTIAL URBAN AREA AND HEAT ISLAND POTENTIAL OF URBAN BLOCKS IN SUMMER: Analysis of the thermal environment in a substantial urban area with regard to land use and land cover using numerical simulation Part 1","volume":"72","author":"Hoyano","year":"2007","journal-title":"J. Environ. Eng."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"163","DOI":"10.5194\/bg-12-163-2015","article-title":"Deploying four optical UAV-based sensors over grassland: Challenges and limitations","volume":"12","author":"Burkart","year":"2015","journal-title":"Biogeosciences"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/JSTARS.2017.2721549","article-title":"Albedo Retrieval from Multispectral Landsat 8 Observation in Urban Environment: Algorithm Validation by in situ Measurements","volume":"10","author":"Baldinelli","year":"2017","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"194","DOI":"10.1016\/j.isprsjprs.2014.05.005","article-title":"Derivation of an urban materials spectral library through emittance and reflectance spectroscopy","volume":"94","author":"Kotthaus","year":"2014","journal-title":"ISPRS J. Photogramm. Remote Sens."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1126\/science.245.4914.165","article-title":"Spectral Reflectance Properties of Hydrocarbons: Remote-Sensing Implications","volume":"245","author":"Cloutis","year":"1989","journal-title":"Science"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"325","DOI":"10.1016\/S0038-092X(01)00054-8","article-title":"Parameterized transmittance model for direct beam and circumsolar spectral irradiance","volume":"71","author":"Gueymard","year":"2001","journal-title":"Sol. Energy"},{"key":"ref_51","unstructured":"Gueymard, C.A. (1995). SMARTS2, A Simple Model. of the Atmospheric Radiative Transfer of Sunshine: Algorithms and Performance Assessment, Florida Solar Energy Center. FSEC-PF-270-95."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1016\/j.solener.2019.05.048","article-title":"The SMARTS spectral irradiance model after 25 years: New developments and validation of reference spectra","volume":"187","author":"Gueymard","year":"2019","journal-title":"Sol. Energy"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"1551","DOI":"10.1016\/j.energy.2004.04.032","article-title":"Interdisciplinary applications of a versatile spectral solar irradiance model: A review","volume":"30","author":"Gueymard","year":"2005","journal-title":"Energy"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"260","DOI":"10.1016\/j.solener.2007.04.007","article-title":"Prediction and validation of cloudless shortwave solar spectra incident on horizontal, tilted, or tracking surfaces","volume":"82","author":"Gueymard","year":"2008","journal-title":"Sol. Energy"},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"493","DOI":"10.1109\/JSTARS.2014.2330691","article-title":"Effects of Soil Surface Irregularities on the Diurnal Variation of Soil Broadband Blue-Sky Albedo","volume":"8","author":"Cierniewski","year":"2015","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_56","unstructured":"MicaSense-RedEdge TM (2015). User Manual Multispectral Camera, MicaSense, Inc."},{"key":"ref_57","doi-asserted-by":"crossref","unstructured":"Gul, M., Kotak, Y., Muneer, T., and Ivanova, S. (2018). Enhancement of Albedo for Solar Energy Gain with Particular Emphasis on Overcast Skies. Energies, 11.","DOI":"10.3390\/en11112881"},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"351","DOI":"10.1080\/01431168708948646","article-title":"Deriving surface albedo measurements from narrow band satellite data","volume":"8","author":"Brest","year":"1987","journal-title":"Int. J. Remote Sens."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"185","DOI":"10.3389\/feart.2018.00185","article-title":"Toward Landsat and Sentinel-2 BRDF Normalization and Albedo Estimation: A Case Study in the Peruvian Amazon Forest","volume":"6","author":"Franch","year":"2018","journal-title":"Front. Earth Sci."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/12\/14\/2214\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:49:53Z","timestamp":1760176193000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/12\/14\/2214"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,7,10]]},"references-count":59,"journal-issue":{"issue":"14","published-online":{"date-parts":[[2020,7]]}},"alternative-id":["rs12142214"],"URL":"https:\/\/doi.org\/10.3390\/rs12142214","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,7,10]]}}}