{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,25]],"date-time":"2026-04-25T14:09:51Z","timestamp":1777126191875,"version":"3.51.4"},"reference-count":33,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2017,2,15]],"date-time":"2017-02-15T00:00:00Z","timestamp":1487116800000},"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>Water is an essential natural resource, and information about surface water conditions can support a wide variety of applications, including urban planning, agronomy, hydrology, electrical power generation, disaster relief, ecology and preservation of natural areas. Synthetic Aperture Radar (SAR) is recognized as an important source of data for monitoring surface water, especially under inclement weather conditions, and is used operationally for flood mapping applications. The canopy penetration capability of the microwaves also allows for mapping of flooded vegetation as a result of enhanced backscatter from what is generally believed to be a double-bounce scattering mechanism between the water and emergent vegetation. Recent investigations have shown that, under certain conditions, the SAR response signal from flooded vegetation may remain coherent during repeat satellite over-passes, which can be exploited for interferometric SAR (InSAR) measurements to estimate changes in water levels and water topography. InSAR results also suggest that coherence change detection (CCD) might be applied to wetland monitoring applications. This study examines wetland vegetation characteristics that lead to coherence in RADARSAT-2 InSAR data of an area in eastern Canada with many small wetlands, and determines the annual variation in the coherence of these wetlands using multi-temporal radar data. The results for a three-year period demonstrate that most swamps and marshes maintain coherence throughout the ice-\/snow-free time period for the 24-day repeat cycle of RADARSAT-2. However, open water areas without emergent aquatic vegetation generally do not have suitable coherence for CCD or InSAR water level estimation. We have found that wetlands with tree cover exhibit the highest coherence and the least variance; wetlands with herbaceous cover exhibit high coherence, but also high variability of coherence; and wetlands with shrub cover exhibit high coherence, but variability intermediate between treed and herbaceous wetlands. From this knowledge, we have developed a novel image product that combines information about the magnitude of coherence and its variability with radar brightness (backscatter intensity). This product clearly displays the multitude of small wetlands over a wide area. With an interpretation key we have also developed, it is possible to distinguish different wetland types and assess year-to-year changes. In the next few years, satellite SAR systems, such as the European Sentinel and the Canadian RADARSAT Constellation Mission (RCM), will provide rapid revisit capabilities and standard data collection modes, enhancing the operational application of SAR data for assessing wetland conditions and monitoring water levels using InSAR techniques.<\/jats:p>","DOI":"10.3390\/rs9020158","type":"journal-article","created":{"date-parts":[[2017,2,15]],"date-time":"2017-02-15T10:09:07Z","timestamp":1487153347000},"page":"158","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":65,"title":["Seasonal Change in Wetland Coherence as an Aid to Wetland Monitoring"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8439-362X","authenticated-orcid":false,"given":"Brian","family":"Brisco","sequence":"first","affiliation":[{"name":"Canada Centre for Mapping and Earth Observation, 560 Rochester St., Ottawa, ON K1A 0E4, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Frank","family":"Ahern","sequence":"additional","affiliation":[{"name":"TerreVista Earth Imaging, 441 Cormac Road, Cormac, ON K0J 1M0, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kevin","family":"Murnaghan","sequence":"additional","affiliation":[{"name":"Canada Centre for Mapping and Earth Observation, 560 Rochester St., Ottawa, ON K1A 0E4, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lori","family":"White","sequence":"additional","affiliation":[{"name":"Environment Canada, 1125 Colonel by Drive, Ottawa, ON K1A 0H3, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Francis","family":"Canisus","sequence":"additional","affiliation":[{"name":"Canada Centre for Mapping and Earth Observation, 560 Rochester St., Ottawa, ON K1A 0E4, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Philip","family":"Lancaster","sequence":"additional","affiliation":[{"name":"Lancaster Geographics, 187 Mulberry Lane, Lake Clear, RR 2, Eganville, ON K0J 1T0, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2017,2,15]]},"reference":[{"key":"ref_1","unstructured":"IPCC (Intergovernmental Panel on Climate Change) (2008). Climate Change and Water, IPCC."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"130","DOI":"10.1080\/17538940701782577","article-title":"Water resource applications with RADARSAT-2\u2014A preview","volume":"1","author":"Brisco","year":"2008","journal-title":"Int. J. Digit. Earth"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"336","DOI":"10.5589\/m09-025","article-title":"A semi-automated tool for surface water mapping with RADARSAT-1","volume":"35","author":"Brisco","year":"2009","journal-title":"Can. J. Remote Sens."},{"key":"ref_4","unstructured":"MacDonald, H.C., Waite, W.P., and Demarcke, J.S. (1980, January 7\u201310). Use of Seasat satellite radar imagery for the detection of standing water beneath forest vegetation. Proceedings of the Rainbow 80; Fall Technical Meeting, Niagara Falls, NY, USA."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1313","DOI":"10.1080\/01431169008955095","article-title":"Radar detection of flooding beneath the forest canopy: A review","volume":"11","author":"Hess","year":"1990","journal-title":"Int. J. Remote Sens."},{"key":"ref_6","first-page":"281","article-title":"Monitoring South Florida wetlands using ERS-1 SAR imagery","volume":"63","author":"Kasischke","year":"1997","journal-title":"Photogram. Eng. Remote Sens."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1016\/S0034-4257(96)00151-4","article-title":"Detecting seasonal flooding cycles in marshes of the Yucatan Peninsula with SIR-C polarimetric radar imagery","volume":"59","author":"Pope","year":"1997","journal-title":"Remote Sens. Environ."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"443","DOI":"10.1080\/01431160010014738","article-title":"Relationship between forest structure and the detection of flood inundation in forested wetlands using C-band SAR","volume":"23","author":"Townsend","year":"2002","journal-title":"Remote Sens. Environ."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"423","DOI":"10.1016\/j.rse.2003.08.016","article-title":"Effects of seasonal hydrologic patterns in south Florida wetlands on radar backscatter measured from ERS-2 SAR imagery","volume":"88","author":"Kasischke","year":"2003","journal-title":"Remote Sens. Environ."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"423","DOI":"10.1109\/36.905250","article-title":"Amazon floodplain water level changes measured with interferometric SIR-C radar","volume":"39","author":"Alsdorf","year":"2001","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2167","DOI":"10.1109\/TGRS.2008.917271","article-title":"Radarsat-1 and ERS InSAR analysis over southeastern coastal Louisiana: Implications for mapping water-level changes beneath swamp forests","volume":"46","author":"Lu","year":"2008","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"681","DOI":"10.1016\/j.rse.2007.06.008","article-title":"Space based detection of wetlands\u2019 surface water level changes from L band SAR interferometry","volume":"112","author":"Wdowinski","year":"2008","journal-title":"Remote Sens. Environ."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2356","DOI":"10.1016\/j.rse.2009.06.014","article-title":"Integrated analysis of PALSAR\/Radarsat-1 InSAR and ENVISAT altimeter data for mapping of absolute water level changes in Louisiana wetlands","volume":"113","author":"Kim","year":"2009","journal-title":"Remote Sens. Environ."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2436","DOI":"10.1016\/j.rse.2010.05.019","article-title":"Multi-temporal monitoring of wetland water levels in the Florida Everglades using Interferometric Synthetic Aperture Radar (INSAR)","volume":"114","author":"Hong","year":"2010","journal-title":"Remote Sens. Environ."},{"key":"ref_15","unstructured":"Brisco, B., Ahern, F.J., and Murnaghan, K. (2011). InSAR for Monitoring Water Level Changes in Canadian Wetlands, Canadian Space Agency Info Days."},{"key":"ref_16","unstructured":"Murnaghan, K., Brisco, B., Ahern, F.J., Lancaster, P., and Wdowinski, S. (2013, January 15\u201318). Ambiguity resolution using radar reflectors for InSAR monitoring of water level. Proceedings of the Canadian Space Agency Advanced SAR Conference, St. Hubert, QB, Canada."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1109\/7.249119","article-title":"Improving resolution of stationary objects with multiple SAR surveys","volume":"29","author":"Prati","year":"1993","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3390\/rs8090700","article-title":"Interferometric SAR coherence models for characterization of hemiboreal forests using TanDEM-X Data","volume":"8","author":"Olesk","year":"2016","journal-title":"Remote Sens."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1109\/TGRS.1995.8746014","article-title":"Repeat-pass SAR interferometry over forested terrain","volume":"33","author":"Hagberg","year":"1995","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/TGRS.2012.2231418","article-title":"Interferometric coherence analysis of the everglades wetlands, South Florida","volume":"51","author":"Kim","year":"2013","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"881","DOI":"10.1080\/01431160902902609","article-title":"Repeat-pass multi-temporal interferometric SAR coherence variations with Amazon floodplain and lake habitats","volume":"31","author":"Jung","year":"2010","journal-title":"Int. J. Remote Sens."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"3039","DOI":"10.1109\/TGRS.2013.2268853","article-title":"Double bounce component in cross-polarimtric SAR from a new scattering target decomposition","volume":"52","author":"Hong","year":"2013","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"3585","DOI":"10.1109\/JSTARS.2015.2414714","article-title":"Polarimetric decompositions of temperate wetlands at C-Band","volume":"8","author":"Brisco","year":"2015","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1109\/36.551930","article-title":"Retrieval of vegetation parameters with SAR interferometry","volume":"35","author":"Wegmuller","year":"1997","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"283","DOI":"10.2747\/1548-1603.43.4.283","article-title":"Multiple baseline radar interferometry applied to coastal land cover classification and change analyses","volume":"43","author":"Ramsey","year":"2006","journal-title":"GISci. Remote Sens."},{"key":"ref_26","unstructured":"Ahern, F.J. (2011). An Assessment of Candidate Wetlands for Coherent Detection of Water Level Changes with RADARSAT-2 Data, Canada Centre for Remote Sensing."},{"key":"ref_27","unstructured":"Eyles, N. (2002). Ontario Rocks: Three Billion Years of Environmental Change, Fitzhenry and Whiteside."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1139\/e99-074","article-title":"Geologic transect across the Grenville orogeny of Ontario and New York","volume":"37","author":"Carr","year":"2000","journal-title":"Can. J. Earth Sci."},{"key":"ref_29","unstructured":"Barnett, P.J., and Ainsworth, B. (1982). Quaternary Geology of the Brudenell Area, Southern Ontario."},{"key":"ref_30","unstructured":"Chambers, B.A., Naylor, B.J., Niepola, J., Merchant, B., and Uhlig, P. (1997). Field Guide to Forest Ecosystems of Central Ontario, Ontario Ministry of Natural Resources."},{"key":"ref_31","first-page":"45","article-title":"The Canadian system of wetland classification and its application to circumboreal wetlands","volume":"21","author":"Wells","year":"1985","journal-title":"Aquilo Ser. Bot."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"431","DOI":"10.1080\/07038992.2015.1104636","article-title":"Evaluation of RADARSAT-2 acquisition modes for wetland monitoring applications","volume":"41","author":"Brisco","year":"2015","journal-title":"Can. J. Remote Sens."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1016\/j.rse.2014.03.031","article-title":"Monitoring Everglades freshwater marsh water level using L-band synthetic aperture radar backscatter","volume":"150","author":"Kim","year":"2014","journal-title":"Remote Sens. Environ."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/9\/2\/158\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T18:28:21Z","timestamp":1760207301000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/9\/2\/158"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,2,15]]},"references-count":33,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2017,2]]}},"alternative-id":["rs9020158"],"URL":"https:\/\/doi.org\/10.3390\/rs9020158","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2017,2,15]]}}}