Evaluating the Performance of Sentinel-3A OLCI Products in the Subarctic Northeast Pacific
The subarctic northeast Pacific (SNEP) is a high-nitrate, low-chlorophyll (HNLC) region in the ocean, where phytoplankton growth and productivity are limited by iron. Moreover, there is a limited application of high spatial (300 m) and temporal resolution (daily) ocean color (OC) satellite imagery i...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-06-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/15/13/3244 |
| _version_ | 1797590925823705088 |
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| author | Perumthuruthil Suseelan Vishnu Maycira Costa |
| author_facet | Perumthuruthil Suseelan Vishnu Maycira Costa |
| author_sort | Perumthuruthil Suseelan Vishnu |
| collection | DOAJ |
| description | The subarctic northeast Pacific (SNEP) is a high-nitrate, low-chlorophyll (HNLC) region in the ocean, where phytoplankton growth and productivity are limited by iron. Moreover, there is a limited application of high spatial (300 m) and temporal resolution (daily) ocean color (OC) satellite imagery in studying the phytoplankton dynamics in this region. To address this issue, we aim to validate the remote sensing reflectance (Rrs; sr<sup>−1</sup>(λ)) and chlorophyll-a (Chla) concentration derived from the Polymer atmospheric correction algorithm against in situ data for the SNEP obtained during 2019 and 2020. Additionally, we performed qualitative analysis using weekly binned surface Chla maps to determine whether the product reflects the general pattern over a latitudinal and longitudinal domain. We processed the daily Level-1 image using Polymer and binned them weekly using Graphic Processing Tool (GPT). The validation results indicate that Polymer exhibits higher radiometric performance in the blue and green bands and fails to represent in situ Rrs in the red band. Furthermore, the Polymer slightly over- and underestimates reflectance between 0.0012 and 0.0018 sr<sup>−1</sup> in the green band. On the other hand, excellent agreement was found between satellite-derived versus in situ Chla, followed by a slight overestimation of in situ Chla in the range from 0.17 to 0.28 mg/m<sup>3</sup>. The weekly binned Chla spatial map revealed a spatially homogeneous distribution of surface Chla in Central Alaska, but a substantial increase in Chla (≥0.7 mg/m<sup>3</sup>) was recorded toward Southeast Alaska (SEA) and the British Columbia (BC) shelf. Furthermore, Chla derived from latitudinal and longitudinal transects indicates high Chla toward 57°N and −135°W, respectively. Overall, the results of this study emphasize the need to obtain high-quality matchups from under-sampled oligotrophic waters, which are crucial for satellite validation, in addition to highlighting the importance of using high spatial and temporal resolution satellite imagery to study phytoplankton dynamics in the SNEP. |
| first_indexed | 2024-03-11T01:30:47Z |
| format | Article |
| id | doaj.art-e0d5c7bc4dce4241ad721b242ec8de87 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-11T01:30:47Z |
| publishDate | 2023-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-e0d5c7bc4dce4241ad721b242ec8de872023-11-18T17:23:27ZengMDPI AGRemote Sensing2072-42922023-06-011513324410.3390/rs15133244Evaluating the Performance of Sentinel-3A OLCI Products in the Subarctic Northeast PacificPerumthuruthil Suseelan Vishnu0Maycira Costa1SPECTRAL Remote Sensing Laboratory, Department of Geography, University of Victoria, Victoria, BC V8P 5C2, CanadaSPECTRAL Remote Sensing Laboratory, Department of Geography, University of Victoria, Victoria, BC V8P 5C2, CanadaThe subarctic northeast Pacific (SNEP) is a high-nitrate, low-chlorophyll (HNLC) region in the ocean, where phytoplankton growth and productivity are limited by iron. Moreover, there is a limited application of high spatial (300 m) and temporal resolution (daily) ocean color (OC) satellite imagery in studying the phytoplankton dynamics in this region. To address this issue, we aim to validate the remote sensing reflectance (Rrs; sr<sup>−1</sup>(λ)) and chlorophyll-a (Chla) concentration derived from the Polymer atmospheric correction algorithm against in situ data for the SNEP obtained during 2019 and 2020. Additionally, we performed qualitative analysis using weekly binned surface Chla maps to determine whether the product reflects the general pattern over a latitudinal and longitudinal domain. We processed the daily Level-1 image using Polymer and binned them weekly using Graphic Processing Tool (GPT). The validation results indicate that Polymer exhibits higher radiometric performance in the blue and green bands and fails to represent in situ Rrs in the red band. Furthermore, the Polymer slightly over- and underestimates reflectance between 0.0012 and 0.0018 sr<sup>−1</sup> in the green band. On the other hand, excellent agreement was found between satellite-derived versus in situ Chla, followed by a slight overestimation of in situ Chla in the range from 0.17 to 0.28 mg/m<sup>3</sup>. The weekly binned Chla spatial map revealed a spatially homogeneous distribution of surface Chla in Central Alaska, but a substantial increase in Chla (≥0.7 mg/m<sup>3</sup>) was recorded toward Southeast Alaska (SEA) and the British Columbia (BC) shelf. Furthermore, Chla derived from latitudinal and longitudinal transects indicates high Chla toward 57°N and −135°W, respectively. Overall, the results of this study emphasize the need to obtain high-quality matchups from under-sampled oligotrophic waters, which are crucial for satellite validation, in addition to highlighting the importance of using high spatial and temporal resolution satellite imagery to study phytoplankton dynamics in the SNEP.https://www.mdpi.com/2072-4292/15/13/3244northeast Pacific Oceanphytoplanktonchlorophyll-aocean colorremote sensingOLCI Sentinel-3A |
| spellingShingle | Perumthuruthil Suseelan Vishnu Maycira Costa Evaluating the Performance of Sentinel-3A OLCI Products in the Subarctic Northeast Pacific Remote Sensing northeast Pacific Ocean phytoplankton chlorophyll-a ocean color remote sensing OLCI Sentinel-3A |
| title | Evaluating the Performance of Sentinel-3A OLCI Products in the Subarctic Northeast Pacific |
| title_full | Evaluating the Performance of Sentinel-3A OLCI Products in the Subarctic Northeast Pacific |
| title_fullStr | Evaluating the Performance of Sentinel-3A OLCI Products in the Subarctic Northeast Pacific |
| title_full_unstemmed | Evaluating the Performance of Sentinel-3A OLCI Products in the Subarctic Northeast Pacific |
| title_short | Evaluating the Performance of Sentinel-3A OLCI Products in the Subarctic Northeast Pacific |
| title_sort | evaluating the performance of sentinel 3a olci products in the subarctic northeast pacific |
| topic | northeast Pacific Ocean phytoplankton chlorophyll-a ocean color remote sensing OLCI Sentinel-3A |
| url | https://www.mdpi.com/2072-4292/15/13/3244 |
| work_keys_str_mv | AT perumthuruthilsuseelanvishnu evaluatingtheperformanceofsentinel3aolciproductsinthesubarcticnortheastpacific AT mayciracosta evaluatingtheperformanceofsentinel3aolciproductsinthesubarcticnortheastpacific |