{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,16]],"date-time":"2026-05-16T09:36:14Z","timestamp":1778924174201,"version":"3.51.4"},"reference-count":53,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2016,3,1]],"date-time":"2016-03-01T00:00:00Z","timestamp":1456790400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"European Union Seventh Framework Programme","award":["606983"],"award-info":[{"award-number":["606983"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Leaf area index (LAI) is a key biophysical parameter used to determine foliage cover and crop growth in environmental studies in order to assess crop yield. Frequently, plant canopy analyzers (LAI-2000) and digital cameras for hemispherical photography (DHP) are used for indirect effective plant area index (PAIeff) estimates. Nevertheless, these instruments are expensive and have the disadvantages of low portability and maintenance. Recently, a smartphone app called PocketLAI was presented and tested for acquiring PAIeff measurements. It was used during an entire rice season for indirect PAIeff estimations and for deriving reference high-resolution PAIeff maps. Ground PAIeff values acquired with PocketLAI, LAI-2000, and DHP were well correlated (R2 = 0.95, RMSE = 0.21 m2\/m2 for Licor-2000, and R2 = 0.94, RMSE = 0.6 m2\/m2 for DHP). Complementary data such as phenology and leaf chlorophyll content were acquired to complement seasonal rice plant information provided by PAIeff. High-resolution PAIeff maps, which can be used for the validation of remote sensing products, have been derived using a global transfer function (TF) made of several measuring dates and their associated satellite radiances.<\/jats:p>","DOI":"10.3390\/rs8030202","type":"journal-article","created":{"date-parts":[[2016,3,1]],"date-time":"2016-03-01T11:07:19Z","timestamp":1456830439000},"page":"202","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":40,"title":["Multitemporal Monitoring of Plant Area Index in the Valencia Rice District with PocketLAI"],"prefix":"10.3390","volume":"8","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5929-3942","authenticated-orcid":false,"given":"Manuel","family":"Campos-Taberner","sequence":"first","affiliation":[{"name":"Department of Earth Physics and Thermodynamics, Faculty of Physics, Universitat de Val\u00e8ncia, Dr. Moliner, Burjassot 46100, Val\u00e8ncia, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5888-0061","authenticated-orcid":false,"given":"Franciso","family":"Garc\u00eda-Haro","sequence":"additional","affiliation":[{"name":"Department of Earth Physics and Thermodynamics, Faculty of Physics, Universitat de Val\u00e8ncia, Dr. Moliner, Burjassot 46100, Val\u00e8ncia, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Roberto","family":"Confalonieri","sequence":"additional","affiliation":[{"name":"Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy, Cassandra Lab, Universit\u00e0 degli Studi di Milano, Via Celoria 2, 20133 Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Beatriz","family":"Mart\u00ednez","sequence":"additional","affiliation":[{"name":"Department of Earth Physics and Thermodynamics, Faculty of Physics, Universitat de Val\u00e8ncia, Dr. Moliner, Burjassot 46100, Val\u00e8ncia, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"\u00c1lvaro","family":"Moreno","sequence":"additional","affiliation":[{"name":"Department of Earth Physics and Thermodynamics, Faculty of Physics, Universitat de Val\u00e8ncia, Dr. Moliner, Burjassot 46100, Val\u00e8ncia, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4849-9918","authenticated-orcid":false,"given":"Sergio","family":"S\u00e1nchez-Ruiz","sequence":"additional","affiliation":[{"name":"Department of Earth Physics and Thermodynamics, Faculty of Physics, Universitat de Val\u00e8ncia, Dr. Moliner, Burjassot 46100, Val\u00e8ncia, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3548-1524","authenticated-orcid":false,"given":"Mar\u00eda","family":"Gilabert","sequence":"additional","affiliation":[{"name":"Department of Earth Physics and Thermodynamics, Faculty of Physics, Universitat de Val\u00e8ncia, Dr. Moliner, Burjassot 46100, Val\u00e8ncia, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fernando","family":"Camacho","sequence":"additional","affiliation":[{"name":"EOLAB, Parc Cient\u00edfic Universitat de Val\u00e8ncia, Catedr\u00e1tico A. Escardino, 46980 Paterna, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2156-4166","authenticated-orcid":false,"given":"Mirco","family":"Boschetti","sequence":"additional","affiliation":[{"name":"Institute for Electromagnetic Sensing of the Environment, Italian National Research Council, Via Bassini 15, 20133 Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9634-6038","authenticated-orcid":false,"given":"Lorenzo","family":"Busetto","sequence":"additional","affiliation":[{"name":"Institute for Electromagnetic Sensing of the Environment, Italian National Research Council, Via Bassini 15, 20133 Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2016,3,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1023\/A:1011838806489","article-title":"The \u201cNull Hypothesis\u201d of precision agriculture management","volume":"2","author":"Whelan","year":"2000","journal-title":"Precis. Agric."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"267","DOI":"10.1006\/jaer.2000.0577","article-title":"Implementing precision agriculture in the 21st Century","volume":"76","author":"Stafford","year":"2000","journal-title":"J. Agr. Eeng. Res."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"949","DOI":"10.3390\/rs5020949","article-title":"Advances in remote sensing of agriculture: Context description, existing operational monitoring systems and major information needs","volume":"5","author":"Atzberger","year":"2013","journal-title":"Remote Sens."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"3462","DOI":"10.3390\/rs4113462","article-title":"Mapping savanna tree species at ecosystem scales using support vector machine classification and BRDF correction on airborne hyperspectral and LiDAR data","volume":"4","author":"Colgan","year":"2012","journal-title":"Remote Sens."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"3390","DOI":"10.3390\/rs4113390","article-title":"Unmanned Aerial Vehicle (UAV) for monitoring soil erosion in Morocco","volume":"4","author":"Marzolff","year":"2012","journal-title":"Remote Sens."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"808","DOI":"10.3390\/rs70100808","article-title":"Developing in situ non-destructive estimates of crop biomass to address issues of scale in remote sensing","volume":"7","author":"Marshall","year":"2015","journal-title":"Remote Sens."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"135","DOI":"10.3390\/rs6010135","article-title":"A phenology-based classification of time-series MODIS data for rice crop monitoring in Mekong Delta, Vietnam","volume":"6","author":"Son","year":"2013","journal-title":"Remote Sens."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2977","DOI":"10.1109\/TGRS.2013.2268319","article-title":"Polarimetric response of rice fields at C-Band: Analysis and phenology retrieval","volume":"52","author":"Cloude","year":"2014","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"10773","DOI":"10.3390\/rs61110773","article-title":"Towards an operational SAR-Based rice monitoring system in ASIA: Examples from 13 demonstration sites across asia in the RIICE project","volume":"6","author":"Nelson","year":"2014","journal-title":"Remote Sens."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"4090","DOI":"10.3390\/rs6054090","article-title":"Monitoring changes in rice cultivated area from SAR and optical satellite images in Ben Tre and Tra Vinh Provinces in Mekong Delta, Vietnam","volume":"6","author":"Karila","year":"2014","journal-title":"Remote Sens."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"421","DOI":"10.1111\/j.1365-3040.1992.tb00992.x","article-title":"Defining leaf area index for non-flat leaves","volume":"15","author":"Chen","year":"1992","journal-title":"Plant Cell Environ."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1274","DOI":"10.3390\/rs5031274","article-title":"Estimation of Leaf Area Index using DEIMOS-1 data: Application and transferability of a semi-empirical relationship between two agricultural areas","volume":"5","author":"Vuolo","year":"2013","journal-title":"Remote Sens."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"561","DOI":"10.3390\/rs4030561","article-title":"Optimal exploitation of the Sentinel-2 spectral capabilities for crop leaf area index mapping","volume":"4","author":"Richter","year":"2012","journal-title":"Remote Sens."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"337","DOI":"10.1016\/j.rse.2003.12.013","article-title":"Hyperspectral vegetation indices and novel algorithms for predicting green LAI of crop canopies: Modeling and validation in the context of precision agriculture","volume":"90","author":"Haboudane","year":"2004","journal-title":"Remote Sens. Environ."},{"key":"ref_15","unstructured":"GCOS (2011). World Meteorological Organization (WMO)."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2403","DOI":"10.1093\/jxb\/erg263","article-title":"Ground-based measurements of leaf area index: A review of methods, instruments and current controversies","volume":"54","author":"Breda","year":"2003","journal-title":"J. Exp. Bot."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1016\/j.agrformet.2003.08.001","article-title":"Review of methods for in situ leaf area index (LAI) determination: Part II. Estimation of LAI, errors and sampling","volume":"121","author":"Weiss","year":"2004","journal-title":"Agric. For. Meteorol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1016\/j.fcr.2005.09.008","article-title":"Analysis of rice sample size variability due to development stage, nitrogen fertilization, sowing technique and variety using the visual jackknife","volume":"97","author":"Confalonieri","year":"2006","journal-title":"F. Crop. Res."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1016\/j.agrformet.2003.08.027","article-title":"Review of methods for in situ leaf area index determination: Part I. Theories, sensors and hemispherical photography","volume":"121","author":"Jonckheere","year":"2004","journal-title":"Agric. For. Meteorol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1071\/BT9630095","article-title":"Estimation of foliage denseness and foliage angle by inclined point quadrats","volume":"11","year":"1963","journal-title":"Aust. J. Bot."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Ross, J. (1981). The Radiation Regime and Architecture of Plant Stands, Springer Science & Business Media.","DOI":"10.1007\/978-94-009-8647-3"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1193","DOI":"10.1016\/j.agrformet.2008.02.014","article-title":"Intercomparison and sensitivity analysis of Leaf Area Index retrievals from LAI-2000, AccuPAR, and digital hemispherical photography over croplands","volume":"148","author":"Garrigues","year":"2008","journal-title":"Agric. For. Meteorol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"3849","DOI":"10.1080\/01431160903118809","article-title":"Accuracy assessment of fraction of vegetation cover and leaf area index estimates from pragmatic methods in a cropland area","volume":"30","author":"Verger","year":"2009","journal-title":"Int. J. Remote Sens."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1016\/j.compag.2013.04.019","article-title":"Development of an app for estimating leaf area index using a smartphone. Trueness and precision determination and comparison with other indirect methods","volume":"96","author":"Confalonieri","year":"2013","journal-title":"Comput. Electron. Agric."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"38","DOI":"10.1016\/j.fcr.2013.09.024","article-title":"Comparison of leaf area index estimates by ceptometer and PocketLAI smart app in canopies with different structures","volume":"155","author":"Francone","year":"2014","journal-title":"F. Crop. Res."},{"key":"ref_26","unstructured":"Frazer, G.W., Trofymow, J.A., and Lertzman, K.P. (1997). A Method for Estimating Canopy Openness, Effective Leaf Area Index, and Photosynthetically Active Photon Flux Density using Hemispherical Photography and Computerized Image Analysis Techniques, Pacific Forestry Centre. Technical report BC-X-373."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1016\/0168-1923(91)90108-3","article-title":"Evaluation of hemispherical photography for determining plant area index and geometry of a forest stand","volume":"56","author":"Chen","year":"1991","journal-title":"Agric. For. Meteorol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"644","DOI":"10.1016\/j.agrformet.2007.11.015","article-title":"Estimation of leaf area and clumping indexes of crops with hemispherical photographs","volume":"148","author":"Demarez","year":"2008","journal-title":"Agric. For. Meteorol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"126","DOI":"10.1016\/j.agrformet.2014.08.005","article-title":"Seasonal variation of leaf area index (LAI) over paddy rice fields in NE China: Intercomparison of destructive sampling, LAI-2200, digital hemispherical photography (DHP), and AccuPAR methods","volume":"198\u2013199","author":"Fang","year":"2014","journal-title":"Agric. For. Meteorol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1393","DOI":"10.1016\/j.agrformet.2010.04.011","article-title":"GAI estimates of row crops from downward looking digital photos taken perpendicular to rows at 57.5\u00b0 zenith angle: Theoretical considerations based on 3D architecture models and application to wheat crops","volume":"150","author":"Baret","year":"2010","journal-title":"Agric. For. Meteorol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"561","DOI":"10.1111\/j.1744-7348.1991.tb04895.x","article-title":"A uniform decimal code for growth stages of crops and weeds","volume":"119","author":"Lancashire","year":"1991","journal-title":"Ann. Appl. Biol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1109\/LGRS.2014.2334371","article-title":"Influence of incidence angle on the coherent copolar polarimetric response of rice at X-Band","volume":"12","author":"Cloude","year":"2015","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1007\/BF00377192","article-title":"Photosynthesis and nitrogen relationships in leaves of C3 plants","volume":"78","author":"Evans","year":"1989","journal-title":"Oecolog."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"440","DOI":"10.1016\/j.rse.2011.10.021","article-title":"Remote estimation of gross primary productivity in soybean and maize based on total crop chlorophyll content","volume":"117","author":"Peng","year":"2012","journal-title":"Remote Sens. Environ."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"574","DOI":"10.1109\/JSTARS.2011.2176468","article-title":"Using hyperspectral remote sensing data for retrieving canopy Chlorophyll and nitrogen content","volume":"5","author":"Clevers","year":"2012","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"34","DOI":"10.1016\/j.ecolind.2014.01.002","article-title":"Chlorophyll content mapping of urban vegetation in the city of Valencia based on the hyperspectral NAOC index","volume":"40","author":"Delegido","year":"2014","journal-title":"Ecol. Indic."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"3220","DOI":"10.1109\/TGRS.2013.2271813","article-title":"Empirical estimation of leaf Chlorophyll density in winter wheat canopies using Sentinel-2 spectral resolution","volume":"52","author":"Vincini","year":"2014","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"4589","DOI":"10.1109\/JSTARS.2014.2360069","article-title":"Newly combined spectral indices to improve estimation of total leaf Chlorophyll content in cotton","volume":"7","author":"Jin","year":"2014","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"4368","DOI":"10.1109\/JSTARS.2014.2325812","article-title":"Modeling leaf image, Chlorophyll fluorescence, reflectance from SPAD readings","volume":"7","author":"Hu","year":"2014","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"439","DOI":"10.1109\/JSTARS.2014.2342257","article-title":"Validating GEOV1 fractional vegetation cover derived from coarse-resolution remote sensing images over croplands","volume":"8","author":"Mu","year":"2015","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"310","DOI":"10.1016\/j.rse.2013.02.030","article-title":"GEOV1: LAI, FAPAR essential climate variables and FCOVER global time series capitalizing over existing products. Part 2: Validation and intercomparison with reference products","volume":"137","author":"Camacho","year":"2013","journal-title":"Remote Sens. Environ."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"458","DOI":"10.1109\/JSTARS.2013.2280466","article-title":"Inter-Comparison and validation of the FY-3A\/MERSI LAI product over mainland China","volume":"7","author":"Zhu","year":"2014","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_43","unstructured":"Schaepman-Strub, G., Rom\u00e1n, M., and Nickeson, J. (2014). Global leaf area index product validation good practices. Version 2.0, Best Practice for Satellite-Derived Land Product Validation: Land Product Validation Subgroup (WGCV\/CEOS)."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"130","DOI":"10.1016\/j.agrformet.2008.07.014","article-title":"Derivation of high-resolution leaf area index maps in support of validation activities: Application to the cropland Barrax site","volume":"149","year":"2009","journal-title":"Agric. For. Meteorol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1016\/j.rse.2007.03.001","article-title":"LAI and fAPAR CYCLOPES global products derived from VEGETATION. Part 2: Validation and comparison with MODIS collection 4 products","volume":"110","author":"Weiss","year":"2007","journal-title":"Remote Sens. Environ."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0034-4257(99)00053-X","article-title":"Validating MODIS terrestrial ecology products: Linking in situ and satellite measurements","volume":"70","author":"Cohen","year":"1999","journal-title":"Remote Sens. Environ."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/0002-1571(71)90092-6","article-title":"A theoretical analysis of the frequency of gaps in plant stands","volume":"8","author":"Nilson","year":"1971","journal-title":"Agric. Meteorol."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"255","DOI":"10.1016\/0002-1571(74)90024-7","article-title":"Plant modification for more efficient water use a critical review of light models for estimating the shortwave radiation regime of plant canopies","volume":"14","author":"Lemeur","year":"1974","journal-title":"Agric. Meteorol."},{"key":"ref_49","unstructured":"Weiss, M., and Baret, F. (2010). CAN-EYE V6.313 User Manual, INRA."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"141","DOI":"10.1071\/BT9670141","article-title":"A formula for average foliage density","volume":"15","author":"Miller","year":"1967","journal-title":"Aust. J. Bot."},{"key":"ref_51","doi-asserted-by":"crossref","unstructured":"Campos-Taberner, M., Garc\u00eda-Haro, F., Moreno, A., Gilabert, M., Mart\u00ednez, B., S\u00e1nchez-Ruiz, S., and Camps-Valls, G. (2015, January 26\u201331). Development of an earth observation processing chain for crop bio-physical parameters at local scale. Proceedings of the 2015 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Milan, Italy.","DOI":"10.1109\/IGARSS.2015.7325689"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"191","DOI":"10.1046\/j.1466-822X.2003.00026.x","article-title":"Global synthesis of leaf area index observations: implications for ecological and remote sensing studies","volume":"12","author":"Asner","year":"2003","journal-title":"Global Ecol. Biogeogr."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"350","DOI":"10.1016\/j.rse.2007.03.029","article-title":"Vegetation water content during SMEX04 from ground data and Landsat 5 Thematic Mapper imagery","volume":"112","author":"Yilmaz","year":"2008","journal-title":"Remote Sens. Environ."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/8\/3\/202\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T19:19:57Z","timestamp":1760210397000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/8\/3\/202"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2016,3,1]]},"references-count":53,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2016,3]]}},"alternative-id":["rs8030202"],"URL":"https:\/\/doi.org\/10.3390\/rs8030202","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2016,3,1]]}}}