Diurnal Changes of a Harmful Algal Bloom in the East China Sea: Observations from GOCI

Xiulin Lou; Chuanmin Hu

doi:10.1016/j.rse.2013.09.031

Diurnal Changes of a Harmful Algal Bloom in the East China Sea: Observations from GOCI

Xiulin Lou, Chuanmin Hu

College of Marine Science

Research output: Contribution to journal › Article › peer-review

Abstract

<a title="Learn more about Harmful Algal Blooms from ScienceDirect's AI-generated Topic Pages"> Harmful algal blooms </a> (HABs) in the East China Sea (ECS) have been reported every year in the last decade, and satellite <a title="Learn more about Remote Sensing from ScienceDirect's AI-generated Topic Pages"> remote sensing </a> has often been used to study the bloom size and duration. Yet <a title="Learn more about Satellite Remote Sensing from ScienceDirect's AI-generated Topic Pages"> satellite remote sensing </a> suffered from lack of reliable algorithms to detect HABs in optically complex coastal waters and from frequent cloud cover. Thus, it has not been possible to document short-term changes of HABs in synoptic scales. Here, using measurements from the Geo-stationary Ocean Color Imager (GOCI), we studied diurnal changes of a HAB of the <a title="Learn more about Dinoflagellate from ScienceDirect's AI-generated Topic Pages"> dinoflagellate </a> Prorocentrum donghaiense in the <a title="Learn more about European Communications Satellite from ScienceDirect's AI-generated Topic Pages"> ECS </a> in May 2011. The standard remote sensing reflectance ( R rs ) products from the GDPS processing algorithms showed promise in delineating HABs in turbid coastal waters, yet the cloud-masking is often too tight to reveal valid cloud-free data. An alternative approach was developed to circumvent this difficulty by using the Rayleigh-corrected reflectance ( R rc ) and a normalization technique. A modified red tide index (RI) was developed from the normalized R rc data at 443, 490 and 555 nm, and proven effective in delineating the P. donghaiense bloom in sediment-rich waters. The hourly RI images on 29 and 30 May 2011 (8 images per day from 8:30 to 15:30) showed consistent bloom evolution through the course of a day, with physical locations driven by tides while its surface expression increased significantly from early morning to early afternoon (maximum around 14:30 local time, a 124% and 163% increase from 9:30, respectively). The maximum coverage of the HAB at 14:30 on 29 May 2011, when no cloud was observed, reached 6620 km 2 . While the short-term changes in the surface expression could be a result of the horizontal dilution due to tides, vertical migration of the dinoflagellate from early morning to afternoon, as reported elsewhere, may be a dominant reason. The case study here demonstrates the unique value of a geostationary <a title="Learn more about Extraterrestrial Ocean from ScienceDirect's AI-generated Topic Pages"> satellite ocean </a> color sensor in revealing short-term dynamics of HABs.

Original language	American English
Journal	Remote Sensing of Environment
Volume	140
DOIs	https://doi.org/10.1016/j.rse.2013.09.031
State	Published - Jan 1 2014

Keywords

Harmful algal blooms
Red tides
East China Sea
GOCI
Remote sensing
Diurnal change
Prorocentrum donghaiense

Disciplines

Life Sciences

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10.1016/j.rse.2013.09.031License: CC BY

https://doi.org/10.1016/j.rse.2013.09.031

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title = "Diurnal Changes of a Harmful Algal Bloom in the East China Sea: Observations from GOCI",

abstract = " Harmful algal blooms (HABs) in the East China Sea (ECS) have been reported every year in the last decade, and satellite remote sensing has often been used to study the bloom size and duration. Yet satellite remote sensing suffered from lack of reliable algorithms to detect HABs in optically complex coastal waters and from frequent cloud cover. Thus, it has not been possible to document short-term changes of HABs in synoptic scales. Here, using measurements from the Geo-stationary Ocean Color Imager (GOCI), we studied diurnal changes of a HAB of the dinoflagellate Prorocentrum donghaiense in the ECS in May 2011. The standard remote sensing reflectance ( R rs ) products from the GDPS processing algorithms showed promise in delineating HABs in turbid coastal waters, yet the cloud-masking is often too tight to reveal valid cloud-free data. An alternative approach was developed to circumvent this difficulty by using the Rayleigh-corrected reflectance ( R rc ) and a normalization technique. A modified red tide index (RI) was developed from the normalized R rc data at 443, 490 and 555 nm, and proven effective in delineating the P. donghaiense bloom in sediment-rich waters. The hourly RI images on 29 and 30 May 2011 (8 images per day from 8:30 to 15:30) showed consistent bloom evolution through the course of a day, with physical locations driven by tides while its surface expression increased significantly from early morning to early afternoon (maximum around 14:30 local time, a 124% and 163% increase from 9:30, respectively). The maximum coverage of the HAB at 14:30 on 29 May 2011, when no cloud was observed, reached 6620 km 2 . While the short-term changes in the surface expression could be a result of the horizontal dilution due to tides, vertical migration of the dinoflagellate from early morning to afternoon, as reported elsewhere, may be a dominant reason. The case study here demonstrates the unique value of a geostationary satellite ocean color sensor in revealing short-term dynamics of HABs. ",

keywords = "Harmful algal blooms, Red tides, East China Sea, GOCI, Remote sensing, Diurnal change, Prorocentrum donghaiense",

author = "Xiulin Lou and Chuanmin Hu",

year = "2014",

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doi = "10.1016/j.rse.2013.09.031",

language = "American English",

volume = "140",

journal = "Remote Sensing of Environment",

}

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T1 - Diurnal Changes of a Harmful Algal Bloom in the East China Sea: Observations from GOCI

AU - Lou, Xiulin

AU - Hu, Chuanmin

PY - 2014/1/1

Y1 - 2014/1/1

N2 - Harmful algal blooms (HABs) in the East China Sea (ECS) have been reported every year in the last decade, and satellite remote sensing has often been used to study the bloom size and duration. Yet satellite remote sensing suffered from lack of reliable algorithms to detect HABs in optically complex coastal waters and from frequent cloud cover. Thus, it has not been possible to document short-term changes of HABs in synoptic scales. Here, using measurements from the Geo-stationary Ocean Color Imager (GOCI), we studied diurnal changes of a HAB of the dinoflagellate Prorocentrum donghaiense in the ECS in May 2011. The standard remote sensing reflectance ( R rs ) products from the GDPS processing algorithms showed promise in delineating HABs in turbid coastal waters, yet the cloud-masking is often too tight to reveal valid cloud-free data. An alternative approach was developed to circumvent this difficulty by using the Rayleigh-corrected reflectance ( R rc ) and a normalization technique. A modified red tide index (RI) was developed from the normalized R rc data at 443, 490 and 555 nm, and proven effective in delineating the P. donghaiense bloom in sediment-rich waters. The hourly RI images on 29 and 30 May 2011 (8 images per day from 8:30 to 15:30) showed consistent bloom evolution through the course of a day, with physical locations driven by tides while its surface expression increased significantly from early morning to early afternoon (maximum around 14:30 local time, a 124% and 163% increase from 9:30, respectively). The maximum coverage of the HAB at 14:30 on 29 May 2011, when no cloud was observed, reached 6620 km 2 . While the short-term changes in the surface expression could be a result of the horizontal dilution due to tides, vertical migration of the dinoflagellate from early morning to afternoon, as reported elsewhere, may be a dominant reason. The case study here demonstrates the unique value of a geostationary satellite ocean color sensor in revealing short-term dynamics of HABs.

AB - Harmful algal blooms (HABs) in the East China Sea (ECS) have been reported every year in the last decade, and satellite remote sensing has often been used to study the bloom size and duration. Yet satellite remote sensing suffered from lack of reliable algorithms to detect HABs in optically complex coastal waters and from frequent cloud cover. Thus, it has not been possible to document short-term changes of HABs in synoptic scales. Here, using measurements from the Geo-stationary Ocean Color Imager (GOCI), we studied diurnal changes of a HAB of the dinoflagellate Prorocentrum donghaiense in the ECS in May 2011. The standard remote sensing reflectance ( R rs ) products from the GDPS processing algorithms showed promise in delineating HABs in turbid coastal waters, yet the cloud-masking is often too tight to reveal valid cloud-free data. An alternative approach was developed to circumvent this difficulty by using the Rayleigh-corrected reflectance ( R rc ) and a normalization technique. A modified red tide index (RI) was developed from the normalized R rc data at 443, 490 and 555 nm, and proven effective in delineating the P. donghaiense bloom in sediment-rich waters. The hourly RI images on 29 and 30 May 2011 (8 images per day from 8:30 to 15:30) showed consistent bloom evolution through the course of a day, with physical locations driven by tides while its surface expression increased significantly from early morning to early afternoon (maximum around 14:30 local time, a 124% and 163% increase from 9:30, respectively). The maximum coverage of the HAB at 14:30 on 29 May 2011, when no cloud was observed, reached 6620 km 2 . While the short-term changes in the surface expression could be a result of the horizontal dilution due to tides, vertical migration of the dinoflagellate from early morning to afternoon, as reported elsewhere, may be a dominant reason. The case study here demonstrates the unique value of a geostationary satellite ocean color sensor in revealing short-term dynamics of HABs.

KW - Harmful algal blooms

KW - Red tides

KW - East China Sea

KW - GOCI

KW - Remote sensing

KW - Diurnal change

KW - Prorocentrum donghaiense

UR - https://digitalcommons.usf.edu/msc_facpub/1929

UR - https://doi.org/10.1016/j.rse.2013.09.031

U2 - 10.1016/j.rse.2013.09.031

DO - 10.1016/j.rse.2013.09.031

M3 - Article

VL - 140

JO - Remote Sensing of Environment

JF - Remote Sensing of Environment

ER -

Diurnal Changes of a Harmful Algal Bloom in the East China Sea: Observations from GOCI

Abstract

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