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Dr Luke Brown's Outputs (34)

Potential of automated digital hemispherical photography and wireless quantum sensors for routine canopy monitoring and satellite product validation (2021)
Presentation / Conference Contribution

To better characterize the temporal dynamics of vegetation biophysical variables, a variety of automated in situ measurement techniques have been developed in recent years. In this study, we investigated automated digital hemispherical photography (D... Read More about Potential of automated digital hemispherical photography and wireless quantum sensors for routine canopy monitoring and satellite product validation.

Validation of baseline and modified Sentinel-2 level 2 prototype processor leaf area index retrievals over the United States (2021)
Journal Article

The Sentinel-2 Level 2 Prototype Processor (SL2P) is made available to users for the retrieval of vegetation biophysical variables including leaf area index (LAI) from Multispectral Instrument (MSI) data within the Sentinel Application Platform (SNAP... Read More about Validation of baseline and modified Sentinel-2 level 2 prototype processor leaf area index retrievals over the United States.

Deriving leaf area index reference maps using temporally continuous data: a comparison of upscaling approaches (2020)
Journal Article
Brown, L., Ogutu, B., Camacho, F., Fuster, B., & Dash, J. (2020). Deriving leaf area index reference maps using temporally continuous data: a comparison of upscaling approaches. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 14, 624-630. https://doi.org/10.1109/JSTARS.2020.3040080

To further progress the validation of global leaf area index (LAI) products, temporally continuous reference data are a key requirement, as periodic field campaigns fail to adequately characterize temporal dynamics. Progress in cost-effective automat... Read More about Deriving leaf area index reference maps using temporally continuous data: a comparison of upscaling approaches.

Low-cost unmanned aerial vehicle-based digital hemispherical photography for estimating leaf area index: a feasibility assessment (2020)
Journal Article
Brown, L., Sutherland, D., & Dash, J. (2020). Low-cost unmanned aerial vehicle-based digital hemispherical photography for estimating leaf area index: a feasibility assessment. International Journal of Remote Sensing, 41(23), 9064-9074. https://doi.org/10.1080/2150704X.2020.1802527

Unmanned aerial vehicles (UAVs) have the potential to provide highly detailed information on vegetation status useful in precision agriculture. However, challenges are associated with existing techniques for UAV-based retrieval of vegetation biophysi... Read More about Low-cost unmanned aerial vehicle-based digital hemispherical photography for estimating leaf area index: a feasibility assessment.

The Sentinel-3 OLCI Terrestrial Chlorophyll Index (OTCI): algorithm improvements, spatiotemporal consistency and continuity with the MERIS archive (2020)
Journal Article
Pastor-Guzman, J., Brown, L., Morris, H., Bourg, L., Goryl, P., Dransfeld, S., & Dash, J. (2020). The Sentinel-3 OLCI Terrestrial Chlorophyll Index (OTCI): algorithm improvements, spatiotemporal consistency and continuity with the MERIS archive. Remote Sensing, 12(16), https://doi.org/10.3390/rs12162652

The Ocean and Land Colour Instrument (OLCI) on-board Sentinel-3 (2016–present) was designed with similar mechanical and optical characteristics to the Envisat Medium Resolution Imaging Spectrometer (MERIS) (2002–2012) to ensure continuity with a numb... Read More about The Sentinel-3 OLCI Terrestrial Chlorophyll Index (OTCI): algorithm improvements, spatiotemporal consistency and continuity with the MERIS archive.

Evaluation of global leaf area index and fraction of absorbed photosynthetically active radiation products over North America using copernicus ground based observations for validation data (2020)
Journal Article

With a growing number of Earth observation (EO) products available through operational programmes such as the European Union’s Copernicus, there is increasing emphasis on product accuracy and uncertainty, necessitating evaluation against in situ refe... Read More about Evaluation of global leaf area index and fraction of absorbed photosynthetically active radiation products over North America using copernicus ground based observations for validation data.

Tracking forest biophysical properties with automated digital repeat photography: a fisheye perspective using digital hemispherical photography from below the canopy (2020)
Journal Article
Brown, L., Ogutu, B., & Dash, J. (2020). Tracking forest biophysical properties with automated digital repeat photography: a fisheye perspective using digital hemispherical photography from below the canopy. Agricultural and forest meteorology, 287, https://doi.org/10.1016/j.agrformet.2020.107944

In recent years, digital repeat photography has received increasing attention as an inexpensive means by which seasonal changes in vegetation canopies can be monitored. Offering automation and an increased measurement frequency, colour indices derive... Read More about Tracking forest biophysical properties with automated digital repeat photography: a fisheye perspective using digital hemispherical photography from below the canopy.

Estimating peanut leaf chlorophyll content with dorsiventral leaf adjusted indices: minimizing the impact of spectral differences between adaxial and abaxial leaf surfaces (2019)
Journal Article

Relatively little research has assessed the impact of spectral differences among dorsiventral leaves caused by leaf structure on leaf chlorophyll content (LCC) retrieval. Based on reflectance measured from peanut adaxial and abaxial leaves and LCC me... Read More about Estimating peanut leaf chlorophyll content with dorsiventral leaf adjusted indices: minimizing the impact of spectral differences between adaxial and abaxial leaf surfaces.

GBOV (Ground-Based Observation for Validation): a copernicus service for validation of vegetation land products (2019)
Presentation / Conference Contribution

The Copernicus Ground-Based Observations for Validation (GBOV) service aims to develop and distribute robust in-situ datasets from a selection of ground-based monitoring sites for a systematic and quantitative validation of Earth Observation (EO) lan... Read More about GBOV (Ground-Based Observation for Validation): a copernicus service for validation of vegetation land products.

Estimating forest leaf area index and canopy chlorophyll content with Sentinel-2: an evaluation of two hybrid retrieval algorithms (2019)
Journal Article
Brown, L., Ogutu, B., & Dash, J. (2019). Estimating forest leaf area index and canopy chlorophyll content with Sentinel-2: an evaluation of two hybrid retrieval algorithms. Remote Sensing, 11(15), https://doi.org/10.3390/rs11151752

Estimates of biophysical and biochemical variables such as leaf area index (LAI) and canopy chlorophyll content (CCC) are a fundamental requirement for effectively monitoring and managing forest environments. With its red-edge bands and high spatial... Read More about Estimating forest leaf area index and canopy chlorophyll content with Sentinel-2: an evaluation of two hybrid retrieval algorithms.

Synergetic exploitation of the sentinel-2 missions for validating the sentinel-3 ocean and land color instrument terrestrial chlorophyll index over a vineyard dominated Mediterranean environment (2019)
Journal Article
Brown, L., Dash, J., Lidon, A., Lopez-Baeza, E., & Dransfeld, S. (2019). Synergetic exploitation of the sentinel-2 missions for validating the sentinel-3 ocean and land color instrument terrestrial chlorophyll index over a vineyard dominated Mediterranean environment. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 12(7), 2244-2251. https://doi.org/10.1109/jstars.2019.2899998

Continuity to the Medium Resolution Imaging Spectrometer (MERIS) Terrestrial Chlorophyll Index (MTCI) will be provided by the Ocean and Land Color Instrument (OLCI) on-board the Sentinel-3 missions. To ensure its utility in a wide range of scientific... Read More about Synergetic exploitation of the sentinel-2 missions for validating the sentinel-3 ocean and land color instrument terrestrial chlorophyll index over a vineyard dominated Mediterranean environment.

Validation of the Sentinel-3 Ocean and Land Colour Instrument (OLCI) Terrestrial Chlorophyll Index (OTCI): synergetic exploitation of the Sentinel-2 missions (2018)
Presentation / Conference
Brown, L., Dash, J., Lidon, A., Lopez-Baeza, E., & Dransfeld, S. (2018, July). Validation of the Sentinel-3 Ocean and Land Colour Instrument (OLCI) Terrestrial Chlorophyll Index (OTCI): synergetic exploitation of the Sentinel-2 missions. Presented at IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium, Valencia, Spain

Continuity to the Medium Resolution Imaging Spectrometer (MERIS) Terrestrial Chlorophyll Index (MTCI) will be provided by the Sentinel-3 Ocean and Land Colour Instrument (OLCI), and to ensure its utility in a wide range of operational applications, v... Read More about Validation of the Sentinel-3 Ocean and Land Colour Instrument (OLCI) Terrestrial Chlorophyll Index (OTCI): synergetic exploitation of the Sentinel-2 missions.

On the relationship between continuous measures of canopy greenness derived using near-surface remote sensing and satellite-derived vegetation products (2017)
Journal Article
Brown, L., Dash, J., Ogutu, B., & Richardson, A. (2017). On the relationship between continuous measures of canopy greenness derived using near-surface remote sensing and satellite-derived vegetation products. Agricultural and forest meteorology, 247, 280-292. https://doi.org/10.1016/j.agrformet.2017.08.012

Over the last two decades, satellite-derived estimates of biophysical variables have been increasingly used in operational services, requiring quantification of their accuracy and uncertainty. Evaluating satellite-derived vegetation products is chall... Read More about On the relationship between continuous measures of canopy greenness derived using near-surface remote sensing and satellite-derived vegetation products.