High-Resolution Sea Surface Temperatures Derived from Landsat 8: A Study of Submesoscale Frontal Structures on the Pacific Shelf off the Hokkaido Coast, Japan
Coastal and offshore waters are generally separated by a barrier or “ocean front” on the continental shelf. A basic question arises as to what the representative spatial scale across the front may be. To answer this question, we simply corrected skin sea surface temperatures (SSTs) estimated from La...
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| Format: | Article |
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MDPI AG
2020-10-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/12/20/3326 |
| _version_ | 1797551252085669888 |
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| author | Hiroshi Kuroda Yuko Toya |
| author_facet | Hiroshi Kuroda Yuko Toya |
| author_sort | Hiroshi Kuroda |
| collection | DOAJ |
| description | Coastal and offshore waters are generally separated by a barrier or “ocean front” on the continental shelf. A basic question arises as to what the representative spatial scale across the front may be. To answer this question, we simply corrected skin sea surface temperatures (SSTs) estimated from Landsat 8 imagery with a resolution of 100 m using skin SSTs estimated from geostationary meteorological satellite Himawari 8 with a resolution of 2 km. We analyzed snapshot images of skin SSTs on 13 October 2016, when we performed a simultaneous ship survey. We focused in particular on submesoscale thermal fronts on the Pacific shelf off the southeastern coast of Hokkaido, Japan. The overall spatial distribution of skin SSTs was consistent between Landsat 8 and Himawari 8; however, the spatial distribution of horizontal gradients of skin SSTs differed greatly between the two datasets. Some parts of strong fronts on the order of 1 °C km<sup>−1</sup> were underestimated with Himawari 8, mainly because of low resolution, whereas weak fronts on the order of 0.1 °C km<sup>−1</sup> were obscured in the Landsat 8 imagery because the signal-to-noise ratios were low. The widths of the strong fronts were estimated to be 114–461 m via Landsat 8 imagery and 539–1050 m via in situ ship survey. The difference was probably attributable to the difference in measurement depth of the SST, i.e., about 10-μm skin layer by satellite and a few dozen centimeters below the sea surface by the in situ survey. Our results indicated that an ocean model with a grid size of no more than ≤100–200 m is essential for realistic simulation of the frontal structure on the shelf. |
| first_indexed | 2024-03-10T15:41:56Z |
| format | Article |
| id | doaj.art-f5e29483a50f4bf89d9b13c42aa01b47 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T15:41:56Z |
| publishDate | 2020-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-f5e29483a50f4bf89d9b13c42aa01b472023-11-20T16:49:43ZengMDPI AGRemote Sensing2072-42922020-10-011220332610.3390/rs12203326High-Resolution Sea Surface Temperatures Derived from Landsat 8: A Study of Submesoscale Frontal Structures on the Pacific Shelf off the Hokkaido Coast, JapanHiroshi Kuroda0Yuko Toya1Fisheries Resources Institute (Kushiro), Japan Fisheries Research and Education Agency, Kushiro 0850802, JapanFisheries Resources Institute (Sapporo), Japan Fisheries Research and Education Agency, Sapporo 0620922, JapanCoastal and offshore waters are generally separated by a barrier or “ocean front” on the continental shelf. A basic question arises as to what the representative spatial scale across the front may be. To answer this question, we simply corrected skin sea surface temperatures (SSTs) estimated from Landsat 8 imagery with a resolution of 100 m using skin SSTs estimated from geostationary meteorological satellite Himawari 8 with a resolution of 2 km. We analyzed snapshot images of skin SSTs on 13 October 2016, when we performed a simultaneous ship survey. We focused in particular on submesoscale thermal fronts on the Pacific shelf off the southeastern coast of Hokkaido, Japan. The overall spatial distribution of skin SSTs was consistent between Landsat 8 and Himawari 8; however, the spatial distribution of horizontal gradients of skin SSTs differed greatly between the two datasets. Some parts of strong fronts on the order of 1 °C km<sup>−1</sup> were underestimated with Himawari 8, mainly because of low resolution, whereas weak fronts on the order of 0.1 °C km<sup>−1</sup> were obscured in the Landsat 8 imagery because the signal-to-noise ratios were low. The widths of the strong fronts were estimated to be 114–461 m via Landsat 8 imagery and 539–1050 m via in situ ship survey. The difference was probably attributable to the difference in measurement depth of the SST, i.e., about 10-μm skin layer by satellite and a few dozen centimeters below the sea surface by the in situ survey. Our results indicated that an ocean model with a grid size of no more than ≤100–200 m is essential for realistic simulation of the frontal structure on the shelf.https://www.mdpi.com/2072-4292/12/20/3326sea surface temperature (SST)Landsat 8Himawari 8thermal frontsubmesoscalecontinental shelf |
| spellingShingle | Hiroshi Kuroda Yuko Toya High-Resolution Sea Surface Temperatures Derived from Landsat 8: A Study of Submesoscale Frontal Structures on the Pacific Shelf off the Hokkaido Coast, Japan Remote Sensing sea surface temperature (SST) Landsat 8 Himawari 8 thermal front submesoscale continental shelf |
| title | High-Resolution Sea Surface Temperatures Derived from Landsat 8: A Study of Submesoscale Frontal Structures on the Pacific Shelf off the Hokkaido Coast, Japan |
| title_full | High-Resolution Sea Surface Temperatures Derived from Landsat 8: A Study of Submesoscale Frontal Structures on the Pacific Shelf off the Hokkaido Coast, Japan |
| title_fullStr | High-Resolution Sea Surface Temperatures Derived from Landsat 8: A Study of Submesoscale Frontal Structures on the Pacific Shelf off the Hokkaido Coast, Japan |
| title_full_unstemmed | High-Resolution Sea Surface Temperatures Derived from Landsat 8: A Study of Submesoscale Frontal Structures on the Pacific Shelf off the Hokkaido Coast, Japan |
| title_short | High-Resolution Sea Surface Temperatures Derived from Landsat 8: A Study of Submesoscale Frontal Structures on the Pacific Shelf off the Hokkaido Coast, Japan |
| title_sort | high resolution sea surface temperatures derived from landsat 8 a study of submesoscale frontal structures on the pacific shelf off the hokkaido coast japan |
| topic | sea surface temperature (SST) Landsat 8 Himawari 8 thermal front submesoscale continental shelf |
| url | https://www.mdpi.com/2072-4292/12/20/3326 |
| work_keys_str_mv | AT hiroshikuroda highresolutionseasurfacetemperaturesderivedfromlandsat8astudyofsubmesoscalefrontalstructuresonthepacificshelfoffthehokkaidocoastjapan AT yukotoya highresolutionseasurfacetemperaturesderivedfromlandsat8astudyofsubmesoscalefrontalstructuresonthepacificshelfoffthehokkaidocoastjapan |