Vegetation Optical Depth at Enhanced Spatial Resolution: Progress, Challenges, and Perspectives.
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| Title: | Vegetation Optical Depth at Enhanced Spatial Resolution: Progress, Challenges, and Perspectives. |
|---|---|
| Authors: | El-Khayati-Ramouz, Mohamed1 (AUTHOR) mohamed.el.khayati@upc.edu, Portal, Gerard2 (AUTHOR), López-Martínez, Carlos1,2,3 (AUTHOR), Vall-llossera, Mercè1,2,4 (AUTHOR), Chaparro, David1,3 (AUTHOR), Alonso-González, Alberto1,2 (AUTHOR), Camps, Adriano1,2,3,4 (AUTHOR) |
| Source: | Remote Sensing. Aug2026, Vol. 18 Issue 15, p2530. 27p. |
| Subjects: | Spatial resolution, Downscaling (Climatology), Multisensor data fusion, Microwave remote sensing |
| Abstract: | Microwave satellite vegetation parameters are widely used to monitor ecosystem spatiotemporal dynamics. Among these, vegetation optical depth (VOD) stands out as a critical microwave vegetation indicator, widely used for applications such as monitoring crop yield, estimating carbon stocks, and assessing risks threatening forests and their resilience to them. However, current VOD products are available at a coarse resolution, often around tens of kilometers, limiting their usefulness to only large-scale applications or those that do not need high spatial precision. Nevertheless, although extensive research has been conducted to improve the spatial resolution of several geophysical indicators, such as soil moisture, advances have been scarce for VOD. Here, we review the advances conducted to estimate VOD at medium-high spatial resolutions, overviewing the state of the art of different methods and their potentials and limitations. Basedon the available literature, we propose a taxonomy that classifies existing VOD downscaling approaches into proxy-based methods, which exploit the relationship between VOD and auxiliary variables, and data-fusion strategies that combine complementary microwave observations across sensors and frequencies. Also, we synthesize the suitability of different proxy variables according to the VOD frequency band, showing that while optical vegetation indices perform well for high-frequency VOD, the downscaling of low-frequency VOD benefits from the integration of complementary radar-derived proxies. Additionally, we examine the effectiveness and affordability of current validation methods and review the potential of emerging ones, such as GNSS technology and land surface models, to guarantee the reliable quality of future VOD downscaled products. Finally, we highlight the capabilities of future missions, particularly the upcoming CIMR multiresolution capability across frequency bands, which could considerably aid in obtaining VOD at better spatial scales. [ABSTRACT FROM AUTHOR] |
| Copyright of Remote Sensing is the property of MDPI and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
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| Header | DbId: egs DbLabel: Engineering Source An: 196272210 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Vegetation Optical Depth at Enhanced Spatial Resolution: Progress, Challenges, and Perspectives. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22El-Khayati-Ramouz%2C+Mohamed%22">El-Khayati-Ramouz, Mohamed</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> mohamed.el.khayati@upc.edu</i><br /><searchLink fieldCode="AR" term="%22Portal%2C+Gerard%22">Portal, Gerard</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22López-Martínez%2C+Carlos%22">López-Martínez, Carlos</searchLink><relatesTo>1,2,3</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Vall-llossera%2C+Mercè%22">Vall-llossera, Mercè</searchLink><relatesTo>1,2,4</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Chaparro%2C+David%22">Chaparro, David</searchLink><relatesTo>1,3</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Alonso-González%2C+Alberto%22">Alonso-González, Alberto</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Camps%2C+Adriano%22">Camps, Adriano</searchLink><relatesTo>1,2,3,4</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Remote+Sensing%22">Remote Sensing</searchLink>. Aug2026, Vol. 18 Issue 15, p2530. 27p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Spatial+resolution%22">Spatial resolution</searchLink><br /><searchLink fieldCode="DE" term="%22Downscaling+%28Climatology%29%22">Downscaling (Climatology)</searchLink><br /><searchLink fieldCode="DE" term="%22Multisensor+data+fusion%22">Multisensor data fusion</searchLink><br /><searchLink fieldCode="DE" term="%22Microwave+remote+sensing%22">Microwave remote sensing</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Microwave satellite vegetation parameters are widely used to monitor ecosystem spatiotemporal dynamics. Among these, vegetation optical depth (VOD) stands out as a critical microwave vegetation indicator, widely used for applications such as monitoring crop yield, estimating carbon stocks, and assessing risks threatening forests and their resilience to them. However, current VOD products are available at a coarse resolution, often around tens of kilometers, limiting their usefulness to only large-scale applications or those that do not need high spatial precision. Nevertheless, although extensive research has been conducted to improve the spatial resolution of several geophysical indicators, such as soil moisture, advances have been scarce for VOD. Here, we review the advances conducted to estimate VOD at medium-high spatial resolutions, overviewing the state of the art of different methods and their potentials and limitations. Basedon the available literature, we propose a taxonomy that classifies existing VOD downscaling approaches into proxy-based methods, which exploit the relationship between VOD and auxiliary variables, and data-fusion strategies that combine complementary microwave observations across sensors and frequencies. Also, we synthesize the suitability of different proxy variables according to the VOD frequency band, showing that while optical vegetation indices perform well for high-frequency VOD, the downscaling of low-frequency VOD benefits from the integration of complementary radar-derived proxies. Additionally, we examine the effectiveness and affordability of current validation methods and review the potential of emerging ones, such as GNSS technology and land surface models, to guarantee the reliable quality of future VOD downscaled products. Finally, we highlight the capabilities of future missions, particularly the upcoming CIMR multiresolution capability across frequency bands, which could considerably aid in obtaining VOD at better spatial scales. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Remote Sensing is the property of MDPI and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.3390/rs18152530 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 27 StartPage: 2530 Subjects: – SubjectFull: Spatial resolution Type: general – SubjectFull: Downscaling (Climatology) Type: general – SubjectFull: Multisensor data fusion Type: general – SubjectFull: Microwave remote sensing Type: general Titles: – TitleFull: Vegetation Optical Depth at Enhanced Spatial Resolution: Progress, Challenges, and Perspectives. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: El-Khayati-Ramouz, Mohamed – PersonEntity: Name: NameFull: Portal, Gerard – PersonEntity: Name: NameFull: López-Martínez, Carlos – PersonEntity: Name: NameFull: Vall-llossera, Mercè – PersonEntity: Name: NameFull: Chaparro, David – PersonEntity: Name: NameFull: Alonso-González, Alberto – PersonEntity: Name: NameFull: Camps, Adriano IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 08 Text: Aug2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 20724292 Numbering: – Type: volume Value: 18 – Type: issue Value: 15 Titles: – TitleFull: Remote Sensing Type: main |
| ResultId | 1 |
