Performance and Applicability of Water Column Correction Models in Optically Complex Coastal Waters
Maps of submerged aquatic vegetation (SAV) are of primary importance for the sustainable management of coastal areas and serve as a basis for fundamental ecological studies. Various water column correction (WCC) models are successfully applied in clear Case-1 waters to compensate for the variable wa...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-06-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/12/11/1861 |
| _version_ | 1797565763303768064 |
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| author | Ele Vahtmäe Tiit Kutser Birgot Paavel |
| author_facet | Ele Vahtmäe Tiit Kutser Birgot Paavel |
| author_sort | Ele Vahtmäe |
| collection | DOAJ |
| description | Maps of submerged aquatic vegetation (SAV) are of primary importance for the sustainable management of coastal areas and serve as a basis for fundamental ecological studies. Various water column correction (WCC) models are successfully applied in clear Case-1 waters to compensate for the variable water depth effect. The performance of the WCC in less clear Case-2 waters is rarely assessed. In this study, the performance and applicability of model-based WCC algorithms in the complex Baltic Sea were analyzed. The bottom reflectance was retrieved from the Compact Airborne Spectrographic Imager (CASI) water surface reflectance by applying the Maritorena and Lee WCC algorithms. The Maritorena model retrieved bottom spectra that showed large variations in reflectance magnitudes. The Lee model was more successful in retrieving reasonable spectral magnitudes, although only in a rather narrow wavelength region (550–600 nm). Shorter and longer spectral regions were significantly overcorrected, resulting in unrealistic spectral shapes. Sensitivity analysis indicated that slight under- or overestimation of water depth and water column constituents affect retrieval of correct bottom spectra in Case-2 waters. To assess the performance of WCC models in improving the SAV quantification, the surface reflectance, as well as the retrieved bottom reflectance, were correlated with the corresponding in situ estimated SAV percent cover (%SAV). Although the quality of the Lee WCC model was not considered high, the spectral region least affected by the input parameters variations (550–600 nm) can be used for the SAV quantification. Application of the Lee model provided better results in %SAV assessment than not performing the WCC correction. |
| first_indexed | 2024-03-10T19:17:36Z |
| format | Article |
| id | doaj.art-151cc67302a3495c9c25a6e0a122b170 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T19:17:36Z |
| publishDate | 2020-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-151cc67302a3495c9c25a6e0a122b1702023-11-20T03:13:05ZengMDPI AGRemote Sensing2072-42922020-06-011211186110.3390/rs12111861Performance and Applicability of Water Column Correction Models in Optically Complex Coastal WatersEle Vahtmäe0Tiit Kutser1Birgot Paavel2Estonian Marine Institute, University of Tartu, Mäealuse 14, 12618 Tallinn, EstoniaEstonian Marine Institute, University of Tartu, Mäealuse 14, 12618 Tallinn, EstoniaEstonian Marine Institute, University of Tartu, Mäealuse 14, 12618 Tallinn, EstoniaMaps of submerged aquatic vegetation (SAV) are of primary importance for the sustainable management of coastal areas and serve as a basis for fundamental ecological studies. Various water column correction (WCC) models are successfully applied in clear Case-1 waters to compensate for the variable water depth effect. The performance of the WCC in less clear Case-2 waters is rarely assessed. In this study, the performance and applicability of model-based WCC algorithms in the complex Baltic Sea were analyzed. The bottom reflectance was retrieved from the Compact Airborne Spectrographic Imager (CASI) water surface reflectance by applying the Maritorena and Lee WCC algorithms. The Maritorena model retrieved bottom spectra that showed large variations in reflectance magnitudes. The Lee model was more successful in retrieving reasonable spectral magnitudes, although only in a rather narrow wavelength region (550–600 nm). Shorter and longer spectral regions were significantly overcorrected, resulting in unrealistic spectral shapes. Sensitivity analysis indicated that slight under- or overestimation of water depth and water column constituents affect retrieval of correct bottom spectra in Case-2 waters. To assess the performance of WCC models in improving the SAV quantification, the surface reflectance, as well as the retrieved bottom reflectance, were correlated with the corresponding in situ estimated SAV percent cover (%SAV). Although the quality of the Lee WCC model was not considered high, the spectral region least affected by the input parameters variations (550–600 nm) can be used for the SAV quantification. Application of the Lee model provided better results in %SAV assessment than not performing the WCC correction.https://www.mdpi.com/2072-4292/12/11/1861water column correctionCase-2 waterCASIsubmerged aquatic vegetation |
| spellingShingle | Ele Vahtmäe Tiit Kutser Birgot Paavel Performance and Applicability of Water Column Correction Models in Optically Complex Coastal Waters Remote Sensing water column correction Case-2 water CASI submerged aquatic vegetation |
| title | Performance and Applicability of Water Column Correction Models in Optically Complex Coastal Waters |
| title_full | Performance and Applicability of Water Column Correction Models in Optically Complex Coastal Waters |
| title_fullStr | Performance and Applicability of Water Column Correction Models in Optically Complex Coastal Waters |
| title_full_unstemmed | Performance and Applicability of Water Column Correction Models in Optically Complex Coastal Waters |
| title_short | Performance and Applicability of Water Column Correction Models in Optically Complex Coastal Waters |
| title_sort | performance and applicability of water column correction models in optically complex coastal waters |
| topic | water column correction Case-2 water CASI submerged aquatic vegetation |
| url | https://www.mdpi.com/2072-4292/12/11/1861 |
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