{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,3]],"date-time":"2026-04-03T04:55:48Z","timestamp":1775192148957,"version":"3.50.1"},"reference-count":50,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2021,3,17]],"date-time":"2021-03-17T00:00:00Z","timestamp":1615939200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the three-year action plan for nurturing and developing new industries in the northeastern region of the National Development and Reform Commission","award":["[2016]512"],"award-info":[{"award-number":["[2016]512"]}]},{"name":"the central government budget, special construction plan for provincial and university, the program for JLU Science and Technology Innovative Research Team","award":["JLUSTIRT, 2017TD-26"],"award-info":[{"award-number":["JLUSTIRT, 2017TD-26"]}]},{"name":"Graduate Innovation Fund of Jilin University","award":["101832020CX231"],"award-info":[{"award-number":["101832020CX231"]}]},{"DOI":"10.13039\/501100004543","name":"China Scholarship Council","doi-asserted-by":"publisher","award":["CSC, 201906170236"],"award-info":[{"award-number":["CSC, 201906170236"]}],"id":[{"id":"10.13039\/501100004543","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Saturation effects limit the application of vegetation indices (VIs) in dense vegetation areas. The possibility to mitigate them by adopting a negative soil adjustment factor X is addressed. Two leaf area index (LAI) data sets are analyzed using the Google Earth Engine (GEE) for validation. The first one is derived from observations of MODerate resolution Imaging Spectroradiometer (MODIS) from 16 April 2013, to 21 October 2020, in the Apiac\u00e1s area. Its corresponding VIs are calculated from a combination of Sentinel-2 and Landsat-8 surface reflectance products. The second one is a global LAI dataset with VIs calculated from Landsat-5 surface reflectance products. A linear regression model is applied to both datasets to evaluate four VIs that are commonly used to estimate LAI: normalized difference vegetation index (NDVI), soil adjusted vegetation index (SAVI), transformed SAVI (TSAVI), and enhanced vegetation index (EVI). The optimal soil adjustment factor of SAVI for LAI estimation is determined using an exhaustive search. The Dickey-Fuller test indicates that the time series of LAI data are stable with a confidence level of 99%. The linear regression results stress significant saturation effects in all VIs. Finally, the exhaustive searching results show that a negative soil adjustment factor of SAVI can mitigate the SAVIs\u2019 saturation in the Apiac\u00e1s area (i.e., X = \u22120.148 for mean LAI = 5.35), and more generally in areas with large LAI values (e.g., X = \u22120.183 for mean LAI = 6.72). Our study further confirms that the lower boundary of the soil adjustment factor can be negative and that using a negative soil adjustment factor improves the computation of time series of LAI.<\/jats:p>","DOI":"10.3390\/s21062115","type":"journal-article","created":{"date-parts":[[2021,3,17]],"date-time":"2021-03-17T21:43:31Z","timestamp":1616017411000},"page":"2115","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":103,"title":["Using the Negative Soil Adjustment Factor of Soil Adjusted Vegetation Index (SAVI) to Resist Saturation Effects and Estimate Leaf Area Index (LAI) in Dense Vegetation Areas"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3488-9007","authenticated-orcid":false,"given":"Zhijun","family":"Zhen","sequence":"first","affiliation":[{"name":"College of Geoexploration Science and Technology, Jilin University, Changchun 130026, China"},{"name":"CESBIO\u2014UPS, CNES, CNRS, IRD, Universit\u00e9 de Toulouse, CEDEX 9, 31401 Toulouse, France"}]},{"given":"Shengbo","family":"Chen","sequence":"additional","affiliation":[{"name":"College of Geoexploration Science and Technology, Jilin University, Changchun 130026, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2149-6004","authenticated-orcid":false,"given":"Tiangang","family":"Yin","sequence":"additional","affiliation":[{"name":"Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20740-3823, USA"}]},{"given":"Eric","family":"Chavanon","sequence":"additional","affiliation":[{"name":"CESBIO\u2014UPS, CNES, CNRS, IRD, Universit\u00e9 de Toulouse, CEDEX 9, 31401 Toulouse, France"}]},{"given":"Nicolas","family":"Lauret","sequence":"additional","affiliation":[{"name":"CESBIO\u2014UPS, CNES, CNRS, IRD, Universit\u00e9 de Toulouse, CEDEX 9, 31401 Toulouse, France"}]},{"given":"Jordan","family":"Guilleux","sequence":"additional","affiliation":[{"name":"CESBIO\u2014UPS, CNES, CNRS, IRD, Universit\u00e9 de Toulouse, CEDEX 9, 31401 Toulouse, France"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0673-3873","authenticated-orcid":false,"given":"Michael","family":"Henke","sequence":"additional","affiliation":[{"name":"Leibniz Institute of Plant Genetics and Crop Plant Research (IPK Gatersleben), OT Gatersleben, Corrensstr 3, Stadt Seeland, D-06466 Gatersleben, Germany"}]},{"given":"Wenhan","family":"Qin","sequence":"additional","affiliation":[{"name":"College of Geoexploration Science and Technology, Jilin University, Changchun 130026, China"}]},{"given":"Lisai","family":"Cao","sequence":"additional","affiliation":[{"name":"College of Geoexploration Science and Technology, Jilin University, Changchun 130026, China"}]},{"given":"Jian","family":"Li","sequence":"additional","affiliation":[{"name":"College of Geoexploration Science and Technology, Jilin University, Changchun 130026, China"}]},{"given":"Peng","family":"Lu","sequence":"additional","affiliation":[{"name":"College of Geoexploration Science and Technology, Jilin University, Changchun 130026, China"}]},{"given":"Jean-Philippe","family":"Gastellu-Etchegorry","sequence":"additional","affiliation":[{"name":"CESBIO\u2014UPS, CNES, CNRS, IRD, Universit\u00e9 de Toulouse, CEDEX 9, 31401 Toulouse, France"}]}],"member":"1968","published-online":{"date-parts":[[2021,3,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1019","DOI":"10.14214\/sf.1019","article-title":"Reconstructing leaf growth based on non-destructive digitizing and low-parametric shape evolution for plant modelling over a growth cycle","volume":"48","author":"Henke","year":"2014","journal-title":"Silva. Fenn."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Gastellu-Etchegorry, J., Wang, Y., Regaieg, O., Yin, T., Malenovsky, Z., Zhen, Z., Yang, X., Tao, Z., Landier, L., and Al Bitar, A. (2020, January 2\u20135). Why to Model Remote Sensing Measurements in 3d? Recent Advances in dart: Atmosphere, Topography, Large Landscape, Chlorophyll Fluorescence and Satellite Image Inversion. Proceedings of the 2020 5th International Conference on Advanced Technologies for Signal and Image Processing (ATSIP), Sousse, Tunisia.","DOI":"10.1109\/ATSIP49331.2020.9231884"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"213","DOI":"10.1016\/j.rse.2013.03.030","article-title":"A new approach of direction discretization and oversampling for 3d anisotropic radiative transfer modeling","volume":"135","author":"Yin","year":"2013","journal-title":"Remote Sens. Environ."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"819","DOI":"10.5194\/isprs-archives-XLII-3-819-2018","article-title":"Analysis of accuracy of modis brdf product (mcd43 c6) based on misr land surface brf product-a case study of the central part of northeast asia","volume":"42","author":"Li","year":"2018","journal-title":"Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"3475","DOI":"10.1109\/TGRS.2016.2519098","article-title":"Scale effect in indirect measurement of leaf area index","volume":"54","author":"Yan","year":"2016","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1667","DOI":"10.3390\/rs70201667","article-title":"Discrete anisotropic radiative transfer (dart 5) for modeling airborne and satellite spectroradiometer and lidar acquisitions of natural and urban landscapes","volume":"7","author":"Yin","year":"2015","journal-title":"Remote Sens."},{"key":"ref_7","first-page":"958","article-title":"Review of indirect methods for leaf area index measurement (in chinese with english abstract)","volume":"20","author":"Yan","year":"2016","journal-title":"J. Remote Sens."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"5092","DOI":"10.1109\/TGRS.2020.2972297","article-title":"Potentials and limits of vegetation indices with brdf signatures for soil-noise resistance and estimation of leaf area index","volume":"58","author":"Zhen","year":"2020","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"663","DOI":"10.2307\/1936256","article-title":"Derivation of leaf-area index from quality of light on the forest floor","volume":"50","author":"Jordan","year":"1969","journal-title":"Ecology"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1016\/0034-4257(85)90097-5","article-title":"Satellite remote sensing of total herbaceous biomass production in the senegalese sahel: 1980\u20131984","volume":"17","author":"Tucker","year":"1985","journal-title":"Remote Sens. Environ."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"295","DOI":"10.1016\/0034-4257(88)90106-X","article-title":"A soil-adjusted vegetation index (savi)","volume":"25","author":"Huete","year":"1988","journal-title":"Remote Sens. Environ."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"161","DOI":"10.1016\/0034-4257(91)90009-U","article-title":"Potentials and limits of vegetation indices for lai and apar assessment","volume":"35","author":"Baret","year":"1991","journal-title":"Remote Sens. Environ."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"119","DOI":"10.1016\/0034-4257(94)90134-1","article-title":"A modified soil adjusted vegetation index","volume":"48","author":"Qi","year":"1994","journal-title":"Remote Sens. Envrion."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"173","DOI":"10.1111\/1755-6724.14281","article-title":"A modified transformed soil adjusted vegetation index for cropland in jilin province, china","volume":"93","author":"Zhen","year":"2019","journal-title":"Acta Geol. Sin. Engl. Ed."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1016\/0034-4257(95)00186-7","article-title":"Optimization of soil-adjusted vegetation indices","volume":"55","author":"Rondeaux","year":"1996","journal-title":"Remote Sens. Environ."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"303","DOI":"10.1016\/S0034-4257(02)00048-2","article-title":"A generalized soil-adjusted vegetation index","volume":"82","author":"Gilabert","year":"2002","journal-title":"Remote Sens. Environ."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"261","DOI":"10.1109\/36.134076","article-title":"Atmospherically resistant vegetation index (arvi) for eos-modis","volume":"30","author":"Kaufman","year":"1992","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1007\/BF00031911","article-title":"Gemi: A non-linear index to monitor global vegetation from satellites","volume":"101","author":"Pinty","year":"1992","journal-title":"Vegetatio"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"440","DOI":"10.1016\/S0034-4257(96)00112-5","article-title":"A comparison of vegetation indices over a global set of tm images for eos-modis","volume":"59","author":"Huete","year":"1997","journal-title":"Remote Sens. Environ."},{"key":"ref_20","unstructured":"Huete, A.R., Liu, H., and van Leeuwen, W.J. (1997, January 3\u20138). The Use of Vegetation Indices in Forested Regions: Issues of Linearity and Saturation. Proceedings of the IGARSS\u201997. 1997 IEEE International Geoscience and Remote Sensing Symposium Proceedings. Remote Sensing-A Scientific Vision for Sustainable Development, Singapore."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1575","DOI":"10.1109\/TGRS.2004.826787","article-title":"Linearized vegetation indices based on a formal statistical framework","volume":"42","author":"Unsalan","year":"2004","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2506","DOI":"10.1109\/TGRS.2006.873205","article-title":"An analysis of angle-based with ratio-based vegetation indices","volume":"44","author":"Jiang","year":"2006","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1078\/0176-1617-01176","article-title":"Wide dynamic range vegetation index for remote quantification of biophysical characteristics of vegetation","volume":"161","author":"Gitelson","year":"2004","journal-title":"J. Plant Physiol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"4219","DOI":"10.1080\/01431160410001680464","article-title":"The contribution of probability theory in assessing the efficiency of two frequently used vegetation indices","volume":"25","author":"Vaiopoulos","year":"2004","journal-title":"Int. J. Remote Sens."},{"key":"ref_25","unstructured":"(2021, March 11). Unidade de Conserva\u00e7\u00e3o: Parque Nacional do Juruena, Available online: http:\/\/sistemas.mma.gov.br\/cnuc\/index.php?ido=relatorioparametrizado.exibeRelatorio&relatorioPadrao=true&idUc=281."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Mutanga, O., and Kumar, L. (2019). Google earth engine applications. Remote Sens., 11.","DOI":"10.3390\/rs11050591"},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Kumar, L., and Mutanga, O. (2018). Google earth engine applications since inception: Usage, trends, and potential. Remote Sens., 10.","DOI":"10.3390\/rs10101509"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1016\/j.rse.2017.06.031","article-title":"Google earth engine: Planetary-scale geospatial analysis for everyone","volume":"202","author":"Gorelick","year":"2017","journal-title":"Remote Sens. Environ."},{"key":"ref_29","unstructured":"Henrich, V., Krauss, G., G\u00f6tze, C., and Sandow, C. (2021, March 12). The Indexdatabase. Available online: https:\/\/www.indexdatabase.de\/."},{"key":"ref_30","first-page":"1","article-title":"Sentinel-2 msi\u2014level 2a products algorithm theoretical basis document","volume":"49","author":"Richter","year":"2012","journal-title":"ESASP"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1563","DOI":"10.1007\/s12524-018-0794-y","article-title":"A fast reprojection method for modis products with sinusoidal projection","volume":"46","author":"Li","year":"2018","journal-title":"J. Indian Soc. Remote Sens."},{"key":"ref_32","unstructured":"Scurlock, J., Asner, G., and Gower, S. (2001). Global Leaf Area Index from Field Measurements, 1932\u20132000."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Hamilton, J.D. (1994). Time Series Analysis, Princeton University Press.","DOI":"10.1515\/9780691218632"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"727","DOI":"10.1029\/WR020i006p00727","article-title":"A nonparametric trend test for seasonal data with serial dependence","volume":"20","author":"Hirsch","year":"1984","journal-title":"Water Resour. Res."},{"key":"ref_35","unstructured":"Montgomery, D.C., Peck, E.A., and Vining, G.G. (2016). Introduction to Linear Regression Analysis, Wiley-Interscience."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"514","DOI":"10.1016\/j.rse.2009.10.005","article-title":"Improving the estimation of leaf area index by using remotely sensed ndvi with brdf signatures","volume":"114","author":"Hasegawa","year":"2010","journal-title":"Remote Sens. Environ."},{"key":"ref_37","unstructured":"Weisstein, E.W. (2021, March 11). Exhaustive Search. Available online: https:\/\/mathworld.wolfram.com\/ExhaustiveSearch.html."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"439","DOI":"10.1016\/j.rse.2018.02.068","article-title":"Using negative soil adjustment factor in soil-adjusted vegetation index (savi) for aboveground living biomass estimation in arid grasslands","volume":"209","author":"Ren","year":"2018","journal-title":"Remote Sens. Environ."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"2640","DOI":"10.1109\/JSTARS.2017.2685528","article-title":"Dart: Recent advances in remote sensing data modeling with atmosphere, polarization, and chlorophyll fluorescence","volume":"10","author":"Lauret","year":"2017","journal-title":"IEEE J. Sel. Top. Appl. Earth Observ."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"418","DOI":"10.1016\/j.rse.2016.07.010","article-title":"Simulation of satellite, airborne and terrestrial lidar with dart (i): Waveform simulation with quasi-monte carlo ray tracing","volume":"184","author":"Yin","year":"2016","journal-title":"Remote Sens. Environ."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Gastellu-Etchegorry, J.P., Lauret, N., Yin, T., Landier, L., Al, B.A., Guilleux, J., Jan, C., and Chavanon, E. (2016, January 10\u201315). Dart: Radiative transfer modeling for simulating terrain, airborne and satellite spectroradiometer and lidar acquisitions and 3d radiative budget of natural and urban landscapes. Proceedings of the 2016 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Beijing, China.","DOI":"10.1109\/IGARSS.2016.7729941"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"131","DOI":"10.1016\/0034-4257(95)00253-7","article-title":"Modeling radiative transfer in heterogeneous 3-d vegetation canopies","volume":"58","author":"Demarez","year":"1996","journal-title":"Remote Sens. Environ."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0034-4257(00)00189-9","article-title":"A modeling approach to assess the robustness of spectrometric predictive equations for canopy chemistry","volume":"76","year":"2001","journal-title":"Remote Sens. Environ."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"454","DOI":"10.1016\/j.rse.2016.07.009","article-title":"Simulation of satellite, airborne and terrestrial lidar with dart (ii): Als and tls multi-pulse acquisitions, photon counting, and solar noise","volume":"184","author":"Yin","year":"2016","journal-title":"Remote Sens. Environ."},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Yin, T., Feret, J.B., Gastellu-Etchegorry, J.P., and Lauret, N. (2016, January 10\u201315). Data simulation and fusion of imaging spectrometer and lidar multi-sensor system through dart model. Proceedings of the 2016 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Beijing, China.","DOI":"10.1109\/IGARSS.2016.7729943"},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Yin, T., Kotthaus, S., Gastellu-Etchegorry, J.-P., Morrison, W., Norford, L., Grimmond, C., Lauret, N., Chrysoulakis, N., Al Bitar, A., and Landier, L. (2017, January 23\u201328). Atmospheric correction of ground-based thermal infrared camera through dart model. Proceedings of the IGARSS 2017\u20142017 IEEE International Geoscience and Remote Sensing Symposium, Fort Worth, TX, USA.","DOI":"10.1109\/IGARSS.2017.8128348"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1080\/01431160600647217","article-title":"Using multi-directional high-resolution imagery from polder sensor to retrieve leaf area index","volume":"28","author":"Gascon","year":"2007","journal-title":"Int. J. Remote Sens."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"5601","DOI":"10.1080\/01431160412331291305","article-title":"Retrieval of forest biophysical variables by inverting a 3-d radiative transfer model and using high and very high resolution imagery","volume":"25","author":"Gascon","year":"2004","journal-title":"Int. J. Remote Sens."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"385","DOI":"10.1016\/j.biosystemseng.2011.05.004","article-title":"Estimation of green aboveground biomass of desert steppe in inner mongolia based on red-edge reflectance curve area method","volume":"109","author":"Ren","year":"2011","journal-title":"Biosys. Eng."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"3999","DOI":"10.1080\/01431160310001654923","article-title":"Narrow band vegetation indices overcome the saturation problem in biomass estimation","volume":"25","author":"Mutanga","year":"2004","journal-title":"Int. J. Remote Sens."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/6\/2115\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T05:37:19Z","timestamp":1760161039000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/6\/2115"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,3,17]]},"references-count":50,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2021,3]]}},"alternative-id":["s21062115"],"URL":"https:\/\/doi.org\/10.3390\/s21062115","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,3,17]]}}}