{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,21]],"date-time":"2026-05-21T03:39:24Z","timestamp":1779334764119,"version":"3.51.4"},"reference-count":54,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2016,8,25]],"date-time":"2016-08-25T00:00:00Z","timestamp":1472083200000},"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>In this study, four models describing the interferometric coherence of the forest vegetation layer are proposed and compared with the TanDEM-X data. Our focus is on developing tools for hemiboreal forest height estimation from single-pol interferometric SAR measurements, suitable for wide area forest mapping with limited a priori information. The multi-temporal set of 19 TanDEM-X interferometric pairs and the 90th percentile forest height maps are derived from Airborne LiDAR Scanning (ALS), covering an area of 2211 ha of forests over Estonia. Three semi-empirical models along with the Random Volume over Ground (RVoG) model are examined for applicable parameter ranges and model performance under various conditions for over 3000 forest stands. This study shows that all four models performed well in describing the relationship between forest height and interferometric coherence. Use of an advanced model with multiple parameters is not always justified when modeling the volume decorrelation in the boreal and hemiboreal forests. The proposed set of semi-empirical models, show higher robustness compared to a more advanced RVoG model under a range of seasonal and environmental conditions during data acquisition. We also examine the dynamic range of parameters that different models can take and propose optimal conditions for forest stand height inversion for operationally-feasible scenarios.<\/jats:p>","DOI":"10.3390\/rs8090700","type":"journal-article","created":{"date-parts":[[2016,8,25]],"date-time":"2016-08-25T10:11:44Z","timestamp":1472119904000},"page":"700","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":95,"title":["Interferometric SAR Coherence Models for Characterization of Hemiboreal Forests Using TanDEM-X Data"],"prefix":"10.3390","volume":"8","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0807-3082","authenticated-orcid":false,"given":"Aire","family":"Olesk","sequence":"first","affiliation":[{"name":"University of Tartu, Institute of Physics, W. Ostwaldi 1, 50411 Tartu, Estonia"},{"name":"Department of Space Technology, Tartu Observatory, 61602 T\u00f5ravere, Tartumaa, Estonia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jaan","family":"Praks","sequence":"additional","affiliation":[{"name":"Department of Radio Science and Engineering, Aalto University, P.O. Box 13000, 00076 AALTO, Finland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8576-404X","authenticated-orcid":false,"given":"Oleg","family":"Antropov","sequence":"additional","affiliation":[{"name":"Department of Radio Science and Engineering, Aalto University, P.O. Box 13000, 00076 AALTO, Finland"},{"name":"VTT Technical Research Centre of Finland, P.O. Box 1000, 02044 VTT, Finland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Karlis","family":"Zalite","sequence":"additional","affiliation":[{"name":"Department of Space Technology, Tartu Observatory, 61602 T\u00f5ravere, Tartumaa, Estonia"},{"name":"Department of Physical Geography and Ecosystem Science, Lund University, S\u00f6lvegatan 12, 223 62 Lund, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tauri","family":"Arum\u00e4e","sequence":"additional","affiliation":[{"name":"Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, 51014 Tartu, Estonia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kaupo","family":"Voormansik","sequence":"additional","affiliation":[{"name":"Department of Space Technology, Tartu Observatory, 61602 T\u00f5ravere, Tartumaa, Estonia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2016,8,25]]},"reference":[{"key":"ref_1","unstructured":"Food and Agriculture Organization of the United Nations (FAO) Assessment of the Status of the Development of the Standards for Terrestrial Essential Climate Variables: Biomass (T12). Available online: http:\/\/www.fao.org\/gtos\/doc\/ecvs\/t12\/t12.pdf."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"581","DOI":"10.1016\/j.isprsjprs.2010.09.001","article-title":"Status and future of laser scanning, synthetic aperture radar and hyperspectral remote sensing data for forest biomass assessment","volume":"65","author":"Koch","year":"2010","journal-title":"ISPRS J. Photogramm. Remote Sens."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1561","DOI":"10.1016\/j.rse.2010.02.011","article-title":"Forest carbon densities and uncertainties from Lidar, QuickBird, and field measurements in California","volume":"114","author":"Gonzalez","year":"2010","journal-title":"Remote Sens. Environ."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1186\/1750-0680-8-10","article-title":"Uncertainty in the spatial distribution of tropical forest biomass: A comparison of pan-tropical maps","volume":"8","author":"Mitchard","year":"2013","journal-title":"Carbon Balanc. Manag."},{"key":"ref_5","first-page":"1","article-title":"A survey of remote sensing-based aboveground biomass estimation methods in forest ecosystems","volume":"9","author":"Lu","year":"2014","journal-title":"Int. J. Digit. Earth"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1779","DOI":"10.1007\/s13762-015-0750-0","article-title":"A review of radar remote sensing for biomass estimation","volume":"12","author":"Sinha","year":"2015","journal-title":"Int. J. Environ. Sci. Technol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"252","DOI":"10.3390\/f6010252","article-title":"Combining lidar and synthetic aperture radar data to estimate forest biomass: Status and prospects","volume":"6","author":"Kaasalainen","year":"2015","journal-title":"Forests"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"511","DOI":"10.1109\/TGRS.1995.8746034","article-title":"Radar backscatter and biomass saturation: Ramifications for global biomass inventory","volume":"33","author":"Imhoff","year":"1995","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"403","DOI":"10.1109\/36.134089","article-title":"Relating forest biomass to SAR data","volume":"30","author":"Beaudoin","year":"1992","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"388","DOI":"10.1109\/36.295053","article-title":"Mapping biomass of a northern forest using multifrequency SAR data","volume":"32","author":"Ranson","year":"1994","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1260","DOI":"10.1016\/j.rse.2011.01.008","article-title":"Aboveground biomass retrieval in tropical forests\u2014The potential of combined X- and L-band {SAR} data use","volume":"115","author":"Englhart","year":"2011","journal-title":"Remote Sens. Environ."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1197","DOI":"10.1109\/TGRS.2013.2248370","article-title":"TerraSAR-X stereo radargrammetry and airborne scanning LiDAR height metrics in imputation of forest aboveground biomass and stem volume","volume":"52","author":"Vastaranta","year":"2014","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2084","DOI":"10.3390\/rs6032084","article-title":"Forest variable estimation using radargrammetric processing of TerraSAR-X images in boreal forests","volume":"6","author":"Persson","year":"2014","journal-title":"Remote Sens."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"154","DOI":"10.1109\/TGRS.2014.2319853","article-title":"Estimating forest biomass from TerraSAR-X stripmap radargrammetry","volume":"53","author":"Solberg","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_15","unstructured":"Caicoya, A.T., Kugler, F., Hajnsek, I., and Papathanassiou, K. (2012, January 22\u201327). Boreal forest biomass classification with TanDEM-X. Proceedings of the 2012 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Munich, Germany."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"5574","DOI":"10.3390\/rs5115574","article-title":"Model-Based biomass estimation of a hemi-boreal forest from multitemporal TanDEM-X acquisitions","volume":"5","author":"Askne","year":"2013","journal-title":"Remote Sens."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"771","DOI":"10.1109\/LGRS.2014.2361393","article-title":"On the estimation of boreal forest biomass from TanDEM-X Data without training samples","volume":"12","author":"Askne","year":"2015","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"5083","DOI":"10.1109\/TGRS.2015.2417205","article-title":"Estimation of forest biomass from two-level model inversion of single-pass InSAR data","volume":"53","author":"Soja","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"197","DOI":"10.1016\/j.rse.2015.12.012","article-title":"Prediction of stem volume in complex temperate forest stands using TanDEM-X SAR data","volume":"174","author":"Abdullahi","year":"2016","journal-title":"Remote Sens. Environ."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"646","DOI":"10.1109\/LGRS.2014.2354551","article-title":"Estimation of forest height and canopy density from a single InSAR correlation coefficient","volume":"12","author":"Soja","year":"2015","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_21","unstructured":"Metz, B., Davidson, O., Bosch, P., Dave, R., and Meyer, L.A. (2007). Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1186\/s13021-014-0005-2","article-title":"Forest biomass change estimated from height change in interferometric SAR height models","volume":"9","author":"Solberg","year":"2014","journal-title":"Carbon Balanc. Manag."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1016\/j.rse.2014.12.012","article-title":"Tandem-X interferometry in the prediction of forest inventory attributes in managed boreal forests","volume":"159","author":"Karila","year":"2015","journal-title":"Remote Sens. Environ."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Cloude, S. (2009). Polarisation: Applications in Remote Sensing, Oxford University Press.","DOI":"10.1093\/acprof:oso\/9780199569731.001.0001"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1109\/LGRS.2014.2334140","article-title":"Tropical-forest biomass estimation at X-band from the spaceborne TanDEM-X interferometer","volume":"12","author":"Treuhaft","year":"2015","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"255","DOI":"10.1016\/j.rse.2014.11.016","article-title":"TanDEM-X data for aboveground biomass retrieval in a tropical peat swamp forest","volume":"158","author":"Schlund","year":"2015","journal-title":"Remote Sens. Environ."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"60","DOI":"10.1016\/j.rse.2013.07.036","article-title":"Monitoring spruce volume and biomass with InSAR data from TanDEM-X","volume":"139","author":"Solberg","year":"2013","journal-title":"Remote Sens. Environ."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2353","DOI":"10.1016\/j.rse.2010.05.011","article-title":"Estimating spruce and pine biomass with interferometric X-band SAR","volume":"114","author":"Solberg","year":"2010","journal-title":"Remote Sens. Environ."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Cloude, S.R., Chen, H., and Goodenough, D.G. (2013, January 21\u201326). Forest height estimation and validation using Tandem-X polinsar. Proceedings of the 2013 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Melbourne, Australia.","DOI":"10.1109\/IGARSS.2013.6723172"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Praks, J., Hallikainen, M., Antropov, O., and Molina, D. (2012, January 22\u201327). Boreal forest tree height estimation from interferometric TanDEM-X images. Proceedings of 2012 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Munich, Germany.","DOI":"10.1109\/IGARSS.2012.6351309"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"3831","DOI":"10.1109\/TGRS.2012.2185803","article-title":"LIDAR-aided SAR interferometry studies in boreal forest: Scattering phase center and extinction coefficient at X-and L-band","volume":"50","author":"Praks","year":"2012","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"3608","DOI":"10.1109\/JSTARS.2015.2431646","article-title":"TanDEM-X Pol-InSAR inversion for mangrove canopy height estimation","volume":"8","author":"Lee","year":"2015","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"481","DOI":"10.1109\/TGRS.2008.2009437","article-title":"Tropical-Forest-Parameter estimation by means of Pol-InSAR: The INDREX-II campaign","volume":"47","author":"Hajnsek","year":"2009","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"6404","DOI":"10.1109\/TGRS.2013.2296533","article-title":"TanDEM-X Pol-InSAR performance for forest height estimation","volume":"52","author":"Kugler","year":"2014","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"3317","DOI":"10.1109\/TGRS.2007.900693","article-title":"TanDEM-X: A satellite formation for high-resolution SAR interferometry","volume":"45","author":"Krieger","year":"2007","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1449","DOI":"10.1029\/96RS01763","article-title":"Vegetation characteristics and underlying topography from interferometric radar","volume":"31","author":"Treuhaft","year":"1996","journal-title":"Radio Sci."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1049\/ip-rsn:20030449","article-title":"Three-Stage inversion process for polarimetric SAR interferometry","volume":"150","author":"Cloude","year":"2003","journal-title":"IEE Proc. Radar Sonar Navig."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"S345","DOI":"10.1088\/0959-7174\/14\/2\/013","article-title":"The calculated performance of forest structure and biomass estimates from interferometric radar","volume":"14","author":"Treuhaft","year":"2004","journal-title":"Waves Random Complex Mediu."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1109\/36.551931","article-title":"C-band repeat-pass interferometric SAR observations of the forest","volume":"35","author":"Askne","year":"1997","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"466","DOI":"10.1109\/LGRS.2007.898083","article-title":"Height estimation of boreal forest: Interferometric model-based inversion at L-and X-band versus HUTSCAT profiling scatterometer","volume":"4","author":"Praks","year":"2007","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_41","unstructured":"Praks, J., Demirpolat, C., Antropov, O., and Hallikainen, M. (2013, January 24\u201325). On forest height retrieval from spaceborne X-band interferometric SAR images under variable seasonal conditions. Proceedings of the XXXIII Finnish URSI Convention on Radio Science and SMARAD Seminar, Otaniemi, Finland."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1607","DOI":"10.1109\/TGRS.2014.2346473","article-title":"Temporal stability of X-band single-pass InSAR heights in a spruce forest: Effects of acquisition properties and season","volume":"53","author":"Solberg","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_43","doi-asserted-by":"crossref","unstructured":"Olesk, A., Voormansik, K., Tamm, T., Noorma, M., and Praks, J. (2015, January 21\u201324). Seasonal effects on the estimation of height of boreal and deciduous forests from interferometric TanDEM-X coherence data. Proceedings of the 2015 SPIE Remote Sensing. International Society for Optics and Photonics, Toulouse, France.","DOI":"10.1117\/12.2194340"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"5565","DOI":"10.1109\/JSTARS.2015.2501648","article-title":"Seasonal differences in forest height estimation from interferometric TanDEM-X coherence data","volume":"8","author":"Olesk","year":"2015","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"5294","DOI":"10.1109\/TGRS.2015.2420996","article-title":"Forest height estimation by means of Pol-InSAR data inversion: The role of the vertical wavenumber","volume":"53","author":"Kugler","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_46","unstructured":"Estonian Environment Agency (EEIC). Available online: http:\/\/www.keskkonnaagentuur.ee\/."},{"key":"ref_47","unstructured":"Riigi Teataja. Available online: https:\/\/www.riigiteataja.ee\/akt\/MS."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"562","DOI":"10.1109\/JSTARS.2013.2283340","article-title":"Flood mapping with TerraSAR-X in forested regions in Estonia","volume":"7","author":"Voormansik","year":"2014","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"1402","DOI":"10.1109\/JSTARS.2013.2279552","article-title":"Effects of inundated vegetation on X-band HH\u2013VV backscatter and phase difference","volume":"7","author":"Zalite","year":"2014","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_50","unstructured":"Estonian Meteorological and Hydrological Institute. Available online: http:\/\/www.emhi.ee\/."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"27","DOI":"10.2478\/v10132-012-0003-7","article-title":"Estimation of main forest inventory variables from spectral and airborne lidar data in Aegviidu test site, Estonia","volume":"56","author":"Lang","year":"2012","journal-title":"For. Stud.\/Metsanduslikud Uurim."},{"key":"ref_52","unstructured":"McGaughey, R. FUSION\/LDV: Software for LIDAR Data Analysis and Visualization. Available online: http:\/\/forsys.cfr.washington.edu\/fusion\/FUSION_manual.pdf."},{"key":"ref_53","unstructured":"Hoen, E.W. (2001). A Correlation-Based Approach to Modeling Interferometric Radar Observations of the Greenland Ice Sheet. [Ph.D. Thesis, Stanford University]."},{"key":"ref_54","doi-asserted-by":"crossref","unstructured":"Praks, J., Hallikainen, M., Kugler, F., and Papathanassiou, K.P. (2007, January 23\u201327). X-band extinction in boreal forest: Estimation by using E-SAR POLInSAR and HUTSCAT. Proceedings of the 2007 IEEE International Geoscience and Remote Sensing Symposium, Barcelona, Spain.","DOI":"10.1109\/IGARSS.2007.4423001"}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/8\/9\/700\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T19:29:12Z","timestamp":1760210952000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/8\/9\/700"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2016,8,25]]},"references-count":54,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2016,9]]}},"alternative-id":["rs8090700"],"URL":"https:\/\/doi.org\/10.3390\/rs8090700","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2016,8,25]]}}}