Description of Chlorophyll a:
Phytoplankton are microscopic plants at the base of most marine food webs and produce nearly half of the Earth’s oxygen. One way we estimate the number of phytoplankton in the ocean is by measuring the amount of chlorophyll a in the water. Chlorophyll a is a green pigment (the same pigment that makes tree leaves appear green) that the phytoplankton use to absorb sunlight. The amount (or concentration) of chlorophyll a in surface waters can be calculated by measuring the color of the water (also referred to as “ocean color”). Satellite sensors measure water color, similar to how your eyes see the color of the ocean. Blue water has low chlorophyll, while green waters have high chlorophyll. Environmental and oceanographic factors continuously influence the abundance, species composition, spatial distribution, and productivity of phytoplankton. Tracking the amount of phytoplankton in the ocean conveys how much food is available at the base of the food web for other animals. Changes in the amount of phytoplankton in the ocean are part of the natural seasonal cycle (similar to seasonal changes of plants on land), but can also indicate an ecosystem’s response to a major external disturbance such as a hurricane or typhoon.
Data Source:
Chlorophyll-a concentration values for this indicator were obtained using data from the European Spatial Agency (ESA) that is a validated, error-characterized, Essential Climate Variable (ECV) and climate data record (CDR) from satellite observations specifically developed for climate studies. The dataset (v6.0) is created by bandshifting the reflectances values from SeaWiFS, MODIS and VIIRS to MERIS wavebands if necessary, and SeaWiFS and MODIS were corrected for inter-sensor bias when compared with MERIS in the 2003-2007 period. VIIRS and OLCI were also corrected to MERIS levels, via a two-stage process comparing against the MODIS-corrected-to-MERIS-levels (2012-2013 for VIIRS and 2016-2019 for OLCI).
Source: https://climate.esa.int/en/projects/ocean-colour/key-documents/
https://docs.pml.space/share/s/fzNSPb4aQaSDvO7xBNOCIw
For the most up to date data, please reference the original source above.
Understanding the Time series plots
Time series plots show the changes in each indicator as a function of time, over the period 1980-present. Each plot also shows horizontal lines that indicate the median (middle) value of that indicator, as well as the 10th and 90th percentiles, each calculated for the entire period of measurement. Time series plots were only developed for datasets with at least 10 years of data. Two symbols located to the right of each plot describe how recent values of an indicator compare against the overall series. A black circle indicates whether the indicator values over the last five years are on average above the series 90th percentile (plus sign), below the 10th percentile (minus sign), or between those two values (solid circle). Beneath that an arrow reflects the trend of the indicator over the last five years; an increase or decrease greater than one standard deviation is reflected in upward or downward arrows respectively, while a change of less than one standard deviation is recorded by a left-right arrow.
Hawai'i
During the last five years there has been a significant downward trend and values have remained within the 10th and 90th percentiles of all observed data in the time series.
Chlorophyll a, a pigment produced by phytoplankton, can be measured to determine the amount of phytoplankton present in water bodies. From a human perspective, high values of chlorophyll a can be good (abundance of nutritious diatoms as food for fish) or bad (Harmful Algal Blooms that may cause respiratory distress for people), based on the associated phytoplankton species.
Data Interpretation:
Time series: This time series shows the average concentration levels of chlorophyll a for the Hawaiian Islands region. During the last five years there has been a significant downward trend and values have remained within the 10th and 90th percentiles of all observed data in the time series.
Indicator and source information:
Chlorophyll-a concentration values for this indicator were obtained using data from the European Spatial Agency (ESA) that is a validated, error-characterized, Essential Climate Variable (ECV) and climate data record (CDR) from satellite observations specifically developed for climate studies. The dataset (v56.0) is created by bandshifting the reflectances values from SeaWiFS, MODIS and VIIRS to MERIS wavebands if necessary, and SeaWiFS and MODIS were corrected for inter-sensor bias when compared with MERIS in the 2003-2007 period. VIIRS and OLCI were also corrected to MERIS levels, via a two-stage process comparing against the MODIS-corrected-to-MERIS-levels (2012-2013 for VIIRS and 2016-2019 for OLCI).
Source: https://climate.esa.int/en/projects/ocean-colour/key-documents/
https://docs.pml.space/share/s/fzNSPb4aQaSDvO7xBNOCIw
Annual means for each LME were calculated from the average of the 12 monthly means in that year on a pixel by pixel basis. Then for each year, the median average was taken spatially to yield one value per year per LME. The overall “National Annual Mean” mean was calculated as the average of all LME annual means. See the Data Background section for more details.
Data background and limitations:
Satellite chlorophyll a data was extracted for each LME from the ESA OC-CCI v6.0 product. These 4 km mapped, monthly composited data were - averaged over each year to produce pixel by pixel annual composites, then the spatial median was calculated for each LME, resulting in one value per year per LME. This technique was used for each LME from North America and Hawaii. The overall “National Annual Mean” was calculated as the average of all the LME annual means. Phytoplankton concentrations are highly variable (spatially and temporally), largely driven by changing oceanographic conditions and seasonal variability.
California Current
During the last five years there has been a significant upward trend while values have remained within the 10th and 90th percentiles of all observed data in the time series.
Chlorophyll a, a pigment produced by phytoplankton, can be measured to determine the amount of phytoplankton present in water bodies. From a human perspective, high values of chlorophyll a can be good (abundance of nutritious diatoms as food for fish) or bad (Harmful Algal Blooms that may cause respiratory distress for people), based on the associated phytoplankton species.
Data Interpretation:
Time series: This time series shows the average concentration levels of chlorophyll a for the California Current region. During the last five years there has been a significant upward trend while values have remained within the 10th and 90th percentiles of all observed data in the time series.
Indicator and source information:
Chlorophyll-a concentration values for this indicator were obtained using data from the European Spatial Agency (ESA) that is a validated, error-characterized, Essential Climate Variable (ECV) and climate data record (CDR) from satellite observations specifically developed for climate studies. The dataset (v56.0) is created by bandshifting the reflectances values from SeaWiFS, MODIS and VIIRS to MERIS wavebands if necessary, and SeaWiFS and MODIS were corrected for inter-sensor bias when compared with MERIS in the 2003-2007 period. VIIRS and OLCI were also corrected to MERIS levels, via a two-stage process comparing against the MODIS-corrected-to-MERIS-levels (2012-2013 for VIIRS and 2016-2019 for OLCI).
Source: https://climate.esa.int/en/projects/ocean-colour/key-documents/
https://docs.pml.space/share/s/fzNSPb4aQaSDvO7xBNOCIw
Annual means for each LME were calculated from the average of the 12 monthly means in that year on a pixel by pixel basis. Then for each year, the median average was taken spatially to yield one value per year per LME. The overall “National Annual Mean” mean was calculated as the average of all LME annual means. See the Data Background section for more details.
Data background and limitations:
Satellite chlorophyll a data was extracted for each LME from the ESA OC-CCI v6.0 product. These 4 km mapped, monthly composited data were - averaged over each year to produce pixel by pixel annual composites, then the spatial median was calculated for each LME, resulting in one value per year per LME. This technique was used for each LME from North America and Hawaii. The overall “National Annual Mean” was calculated as the average of all the LME annual means. Phytoplankton concentrations are highly variable (spatially and temporally), largely driven by changing oceanographic conditions and seasonal variability.
Gulf of Mexico
Between 2016 and 2021 the average concentration levels of chlorophyll a in the Gulf of Mexico region were considerably higher than the long term median of all chlorophyll a concentration levels between 1998 and 2021.
Chlorophyll a, a pigment produced by phytoplankton, can be measured to determine the amount of phytoplankton present in water bodies. From a human perspective, high values of chlorophyll a can be good (abundance of nutritious diatoms as food for fish) or bad (Harmful Algal Blooms that may cause respiratory distress for people), based on the associated phytoplankton species.
Data Interpretation:
Time series: This time series shows the average concentration levels of chlorophyll a for the Gulf of Mexico region. During the last five years there has been no trend and values have remained within the 10th and 90th percentiles of all observed data in the time series.
Indicator and source information:
Chlorophyll-a concentration values for this indicator were obtained using data from the European Spatial Agency (ESA) that is a validated, error-characterized, Essential Climate Variable (ECV) and climate data record (CDR) from satellite observations specifically developed for climate studies. The dataset (v56.0) is created by bandshifting the reflectances values from SeaWiFS, MODIS and VIIRS to MERIS wavebands if necessary, and SeaWiFS and MODIS were corrected for inter-sensor bias when compared with MERIS in the 2003-2007 period. VIIRS and OLCI were also corrected to MERIS levels, via a two-stage process comparing against the MODIS-corrected-to-MERIS-levels (2012-2013 for VIIRS and 2016-2019 for OLCI).
Source: https://climate.esa.int/en/projects/ocean-colour/key-documents/
https://docs.pml.space/share/s/fzNSPb4aQaSDvO7xBNOCIw
Annual means for each LME were calculated from the average of the 12 monthly means in that year on a pixel by pixel basis. Then for each year, the median average was taken spatially to yield one value per year per LME. The overall “National Annual Mean” mean was calculated as the average of all LME annual means. See the Data Background section for more details.
Data background and limitations:
Satellite chlorophyll a data was extracted for each LME from the ESA OC-CCI v6.0 product. These 4 km mapped, monthly composited data were - averaged over each year to produce pixel by pixel annual composites, then the spatial median was calculated for each LME, resulting in one value per year per LME. This technique was used for each LME from North America and Hawaii. The overall “National Annual Mean” was calculated as the average of all the LME annual means. Phytoplankton concentrations are highly variable (spatially and temporally), largely driven by changing oceanographic conditions and seasonal variability.
Caribbean Sea
This time series shows the average concentration levels of chlorophyll a for the Caribbean region. During the last five years there has been no significant trend and values have remained within the 10th and 90th percentiles of all observed data in the time series.
Chlorophyll a, a pigment produced by phytoplankton, can be measured to determine the amount of phytoplankton present in water bodies. From a human perspective, high values of chlorophyll a can be good (abundance of nutritious diatoms as food for fish) or bad (Harmful Algal Blooms that may cause respiratory distress for people), based on the associated phytoplankton species.
Data Interpretation:
Time series: This time series shows the average concentration levels of chlorophyll a for the Caribbean region. During the last five years there has been no significant trend and values have remained within the 10th and 90th percentiles of all observed data in the time series.
Indicator and source information:
Chlorophyll-a concentration values for this indicator were obtained using data from the European Spatial Agency (ESA) that is a validated, error-characterized, Essential Climate Variable (ECV) and climate data record (CDR) from satellite observations specifically developed for climate studies. The dataset (v56.0) is created by bandshifting the reflectances values from SeaWiFS, MODIS and VIIRS to MERIS wavebands if necessary, and SeaWiFS and MODIS were corrected for inter-sensor bias when compared with MERIS in the 2003-2007 period. VIIRS and OLCI were also corrected to MERIS levels, via a two-stage process comparing against the MODIS-corrected-to-MERIS-levels (2012-2013 for VIIRS and 2016-2019 for OLCI).
Source: https://climate.esa.int/en/projects/ocean-colour/key-documents/
https://docs.pml.space/share/s/fzNSPb4aQaSDvO7xBNOCIw
Annual means for each LME were calculated from the average of the 12 monthly means in that year on a pixel by pixel basis. Then for each year, the median average was taken spatially to yield one value per year per LME. The overall “National Annual Mean” mean was calculated as the average of all LME annual means. See the Data Background section for more details.
Data background and limitations:
Satellite chlorophyll a data was extracted for each LME from the ESA OC-CCI v6.0 product. These 4 km mapped, monthly composited data were - averaged over each year to produce pixel by pixel annual composites, then the spatial median was calculated for each LME, resulting in one value per year per LME. This technique was used for each LME from North America and Hawaii. The overall “National Annual Mean” was calculated as the average of all the LME annual means. Phytoplankton concentrations are highly variable (spatially and temporally), largely driven by changing oceanographic conditions and seasonal variability.
Southeast US
During the last five years there has been a significant downward trend and values were between the 10th and 90th percentiles of all observed data in the time series.
Chlorophyll a, a pigment produced by phytoplankton, can be measured to determine the amount of phytoplankton present in water bodies. From a human perspective, high values of chlorophyll a can be good (abundance of nutritious diatoms as food for fish) or bad (Harmful Algal Blooms that may cause respiratory distress for people), based on the associated phytoplankton species.
Data Interpretation:
Time series: This time series shows the average concentration levels of chlorophyll a for the Southeast U.S. region. During the last five years there has been a significant downward trend and values were between the 10th and 90th percentiles of all observed data in the time series.
Indicator and source information:
Chlorophyll-a concentration values for this indicator were obtained using data from the European Spatial Agency (ESA) that is a validated, error-characterized, Essential Climate Variable (ECV) and climate data record (CDR) from satellite observations specifically developed for climate studies. The dataset (v56.0) is created by bandshifting the reflectances values from SeaWiFS, MODIS and VIIRS to MERIS wavebands if necessary, and SeaWiFS and MODIS were corrected for inter-sensor bias when compared with MERIS in the 2003-2007 period. VIIRS and OLCI were also corrected to MERIS levels, via a two-stage process comparing against the MODIS-corrected-to-MERIS-levels (2012-2013 for VIIRS and 2016-2019 for OLCI).
Source: https://climate.esa.int/en/projects/ocean-colour/key-documents/
https://docs.pml.space/share/s/fzNSPb4aQaSDvO7xBNOCIw
Annual means for each LME were calculated from the average of the 12 monthly means in that year on a pixel by pixel basis. Then for each year, the median average was taken spatially to yield one value per year per LME. The overall “National Annual Mean” mean was calculated as the average of all LME annual means. See the Data Background section for more details.
Data background and limitations:
Satellite chlorophyll a data was extracted for each LME from the ESA OC-CCI v6.0 product. These 4 km mapped, monthly composited data were - averaged over each year to produce pixel by pixel annual composites, then the spatial median was calculated for each LME, resulting in one value per year per LME. This technique was used for each LME from North America and Hawaii. The overall “National Annual Mean” was calculated as the average of all the LME annual means. Phytoplankton concentrations are highly variable (spatially and temporally), largely driven by changing oceanographic conditions and seasonal variability.
Northeast US
During the last five years there has been no significant trend and values are generally within the 10th and 90th percentiles of all observed data in the time series.
Chlorophyll a, a pigment produced by phytoplankton, can be measured to determine the amount of phytoplankton present in water bodies. From a human perspective, high values of chlorophyll a can be good (abundance of nutritious diatoms as food for fish) or bad (Harmful Algal Blooms that may cause respiratory distress for people), based on the associated phytoplankton species.
Data Interpretation:
Time series: This time series shows the average concentration levels of chlorophyll a for the Northeast U.S. region. During the last five years there has been no significant trend and values are generally within the 10th and 90th percentiles of all observed data in the time series.
Indicator and source information:
Chlorophyll-a concentration values for this indicator were obtained using data from the European Spatial Agency (ESA) that is a validated, error-characterized, Essential Climate Variable (ECV) and climate data record (CDR) from satellite observations specifically developed for climate studies. The dataset (v56.0) is created by bandshifting the reflectances values from SeaWiFS, MODIS and VIIRS to MERIS wavebands if necessary, and SeaWiFS and MODIS were corrected for inter-sensor bias when compared with MERIS in the 2003-2007 period. VIIRS and OLCI were also corrected to MERIS levels, via a two-stage process comparing against the MODIS-corrected-to-MERIS-levels (2012-2013 for VIIRS and 2016-2019 for OLCI).
Source: https://climate.esa.int/en/projects/ocean-colour/key-documents/
https://docs.pml.space/share/s/fzNSPb4aQaSDvO7xBNOCIw
Annual means for each LME were calculated from the average of the 12 monthly means in that year on a pixel by pixel basis. Then for each year, the median average was taken spatially to yield one value per year per LME. The overall “National Annual Mean” mean was calculated as the average of all LME annual means. See the Data Background section for more details.
Data background and limitations:
Satellite chlorophyll a data was extracted for each LME from the ESA OC-CCI v6.0 product. These 4 km mapped, monthly composited data were - averaged over each year to produce pixel by pixel annual composites, then the spatial median was calculated for each LME, resulting in one value per year per LME. This technique was used for each LME from North America and Hawaii. The overall “National Annual Mean” was calculated as the average of all the LME annual means. Phytoplankton concentrations are highly variable (spatially and temporally), largely driven by changing oceanographic conditions and seasonal variability.
Great Lakes
Between 2015 and 2020 the average concentration levels of chlorophyll a in the Great Lakes region were lower than the long term median of all chlorophyll ɑ concentration levels between 1998 and 2020.
The time series shows monthly averages of satellite-derived surface chlorophyll concentration estimates by year
Data Interpretation:
Time series: This time series shows the average concentration levels of chlorophyll ɑ for the Great Lakes region. During the last five years there has been no significant trend and values have remained within the 10th and 90th percentiles of all observed data in the time series.
Gauge: The gauge value of 30 indicates that between 2015 and 2020 the average concentration levels of chlorophyll a in the Great Lakes region were lower than the long term median of all chlorophyll ɑ concentration levels between 1998 and 2020.
Description of Indicator
The U.S. Environmental Protection Agency (U.S. EPA) Great Lakes National Program Office (GLNPO) makes estimates of surface chlorophyll-a concentrations derived from satellite observations of the surface waters of the Great Lakes. These data are used to supplement data collected during GLNPO’s in-situ Great Lakes monitoring programs. The satellite-derived estimates reported here are based on a band-ratio retrieval algorithm developed using GLNPO monitoring data (Lesht et al. 2013; 2016) applied to data from the Sea-viewing Wide Field-of-view (SeaWiFS, 1998–2007) and Moderate resolution imaging spectroradiometer (MODIS, 2002–present) ocean color sensors. Source data are extracted from NASA Level-L2 image files at each GLNPO station location. This workbook contains the monthly averages of satellite-derived surface chlorophyll concentration estimates in this lake by year for the period 1998-present. By contouring the month/year averages in this file this analysis is intended to illustrate long-term trends in surface chlorophyll concentrations with temporal detail not possible using the twice-a-year regular monitoring data.
Data Background and Caveats
Data obtained from NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Ocean Biology Processing Group; (2014): Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Ocean Color Data, NASA OB.DAAC. doi: 10.5067/ORBVIEW-2/SEASWIFS_OC.2014.0 and Moderate-resolution imaging spectroradiometer (MODIS) Ocean Color Data; 2018 Reprocessing. NASA OB.DAAC. doi: 10.5067/AQUA/MODIS/L2/OC/2018. Accessed on various dates.
Source data are extracted from daily NASA Level-L2 image files. Pixels in a 5x5 pixel box surrounding each station location are examined and the average, standard deviation, and number of valid pixels within the box are calculated for each daily image. The daily images are sorted by month and for each month those daily station averages for which there are 19 or more valid pixels (of the 25) and for which the standard deviation is less than 0.5*max_allowable_value (lake/basin dependent) and for which the mean + standard deviation is less than 1.1*max_allowable_value and for which the mean - one standard deviation is greater than zero are averaged to provide the monthly average for that station. Then the monthly values for the stations are averaged to produce the lake average.
1. Data have been subjected to GLNPO’s quality assurance procedures, and approved by the GLNPO program technical lead and database manager. GLNPO contractors and grantees are responsible for verifying their data before submitting it to GLNPO. Once received by GLNPO, the data are evaluated for completeness, accuracy, transcription errors, and compliance with quality documentation requirements. Unless otherwise noted by data qualifiers, these data meet all quality standards relative to their original purpose. It is the user's responsibility to validate these data consistent with their intended purpose. Data is provided on the condition that neither GLNPO nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information. GLNPO, USEPA, and the US Government provide no warranty, nor accept any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data.
2. Any presentation or publication of this information should include an acknowledgement of USEPA GLNPO by stating "information for this work was provided in part by USEPA GLNPO's Monitoring Program." When possible, references to the specific dataset should also be included.
Lake Ontario
Between 2015 and 2020 the average concentration levels of chlorophyll a in Lake Ontario were slightly higher than the long term median of all chlorophyll ɑ concentration levels between 1998 and 2020.
The time series shows monthly averages of satellite-derived surface chlorophyll concentration estimates by year
Data Interpretation:
Time series: This time series shows the average concentration levels of chlorophyll ɑ for Lake Ontario. During the last five years there has been no significant trend and values have remained within the 10th and 90th percentiles of all observed data in the time series.
Gauge: The gauge value of 52 indicates that between 2015 and 2020 the average concentration levels of chlorophyll a in Lake Ontario were slightly higher than the long term median of all chlorophyll ɑ concentration levels between 1998 and 2020.
Description of Indicator
The U.S. Environmental Protection Agency (U.S. EPA) Great Lakes National Program Office (GLNPO) makes estimates of surface chlorophyll-a concentrations derived from satellite observations of the surface waters of the Great Lakes. These data are used to supplement data collected during GLNPO’s in-situ Great Lakes monitoring programs. The satellite-derived estimates reported here are based on a band-ratio retrieval algorithm developed using GLNPO monitoring data (Lesht et al. 2013; 2016) applied to data from the Sea-viewing Wide Field-of-view (SeaWiFS, 1998–2007) and Moderate resolution imaging spectroradiometer (MODIS, 2002–present) ocean color sensors. Source data are extracted from NASA Level-L2 image files at each GLNPO station location. This workbook contains the monthly averages of satellite-derived surface chlorophyll concentration estimates in this lake by year for the period 1998-present. By contouring the month/year averages in this file this analysis is intended to illustrate long-term trends in surface chlorophyll concentrations with temporal detail not possible using the twice-a-year regular monitoring data.
Lake Ontario Description
Lake Ontario has a water surface area of 19,009 square kilometers or 7,340 square miles. In total 5.6 million people live along Lake Ontario with about 2.8 million residents from the United States and Canada each. From Lake Ontario, water leaves the Great Lakes Basin and ecosystem and flows to the Atlantic Ocean through the St. Lawrence River.
Data Background and Caveats
Data obtained from NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Ocean Biology Processing Group; (2014): Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Ocean Color Data, NASA OB.DAAC. doi: 10.5067/ORBVIEW-2/SEASWIFS_OC.2014.0 and Moderate-resolution imaging spectroradiometer (MODIS) Ocean Color Data; 2018 Reprocessing. NASA OB.DAAC. doi: 10.5067/AQUA/MODIS/L2/OC/2018. Accessed on various dates.
Source data are extracted from daily NASA Level-L2 image files. Pixels in a 5x5 pixel box surrounding each station location are examined and the average, standard deviation, and number of valid pixels within the box are calculated for each daily image. The daily images are sorted by month and for each month those daily station averages for which there are 19 or more valid pixels (of the 25) and for which the standard deviation is less than 0.5*max_allowable_value (lake/basin dependent) and for which the mean + standard deviation is less than 1.1*max_allowable_value and for which the mean - one standard deviation is greater than zero are averaged to provide the monthly average for that station. Then the monthly values for the stations are averaged to produce the lake average.
1. Data have been subjected to GLNPO’s quality assurance procedures, and approved by the GLNPO program technical lead and database manager. GLNPO contractors and grantees are responsible for verifying their data before submitting it to GLNPO. Once received by GLNPO, the data are evaluated for completeness, accuracy, transcription errors, and compliance with quality documentation requirements. Unless otherwise noted by data qualifiers, these data meet all quality standards relative to their original purpose. It is the user's responsibility to validate these data consistent with their intended purpose. Data is provided on the condition that neither GLNPO nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information. GLNPO, USEPA, and the US Government provide no warranty, nor accept any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data.
2. Any presentation or publication of this information should include an acknowledgement of USEPA GLNPO by stating "information for this work was provided in part by USEPA GLNPO's Monitoring Program." When possible, references to the specific dataset should also be included.
Lake Erie
Between 2015 and 2020 the average concentration levels of chlorophyll a in Lake Erie were slightly lower than the long term median of all chlorophyll ɑ concentration levels between 1998 and 2020.
The time series shows monthly averages of satellite-derived surface chlorophyll concentration estimates by year
Data Interpretation:
Time series: This time series shows the average concentration levels of chlorophyll ɑ for Lake Erie. During the last five years there has been no significant trend and values have remained within the 10th and 90th percentiles of all observed data in the time series.
Gauge: The gauge value of 43 indicates that between 2015 and 2020 the average concentration levels of chlorophyll a in Lake Erie were slightly lower than the long term median of all chlorophyll ɑ concentration levels between 1998 and 2020.
Description of Indicator
The U.S. Environmental Protection Agency (U.S. EPA) Great Lakes National Program Office (GLNPO) makes estimates of surface chlorophyll-a concentrations derived from satellite observations of the surface waters of the Great Lakes. These data are used to supplement data collected during GLNPO’s in-situ Great Lakes monitoring programs. The satellite-derived estimates reported here are based on a band-ratio retrieval algorithm developed using GLNPO monitoring data (Lesht et al. 2013; 2016) applied to data from the Sea-viewing Wide Field-of-view (SeaWiFS, 1998–2007) and Moderate resolution imaging spectroradiometer (MODIS, 2002–present) ocean color sensors. Source data are extracted from NASA Level-L2 image files at each GLNPO station location. This workbook contains the monthly averages of satellite-derived surface chlorophyll concentration estimates in this lake by year for the period 1998-present. By contouring the month/year averages in this file this analysis is intended to illustrate long-term trends in surface chlorophyll concentrations with temporal detail not possible using the twice-a-year regular monitoring data.
Lake Erie Description
Lake Erie is the shallowest of the five Great Lakes with a maximum depth of 64 m or 210 ft. While only the fourth largest Great Lake with a water surface area of 25,655 square kilometers or 9,910 square miles. In the United States, about 10.5 million US residents live along Lake Erie and in Canada, roughly 1.9 million Canadians live near Lake Erie.
Data Background and Caveats
Data obtained from NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Ocean Biology Processing Group; (2014): Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Ocean Color Data, NASA OB.DAAC. doi: 10.5067/ORBVIEW-2/SEASWIFS_OC.2014.0 and Moderate-resolution imaging spectroradiometer (MODIS) Ocean Color Data; 2018 Reprocessing. NASA OB.DAAC. doi: 10.5067/AQUA/MODIS/L2/OC/2018. Accessed on various dates.
Source data are extracted from daily NASA Level-L2 image files. Pixels in a 5x5 pixel box surrounding each station location are examined and the average, standard deviation, and number of valid pixels within the box are calculated for each daily image. The daily images are sorted by month and for each month those daily station averages for which there are 19 or more valid pixels (of the 25) and for which the standard deviation is less than 0.5*max_allowable_value (lake/basin dependent) and for which the mean + standard deviation is less than 1.1*max_allowable_value and for which the mean - one standard deviation is greater than zero are averaged to provide the monthly average for that station. Then the monthly values for the stations are averaged to produce the lake average.
1. Data have been subjected to GLNPO’s quality assurance procedures, and approved by the GLNPO program technical lead and database manager. GLNPO contractors and grantees are responsible for verifying their data before submitting it to GLNPO. Once received by GLNPO, the data are evaluated for completeness, accuracy, transcription errors, and compliance with quality documentation requirements. Unless otherwise noted by data qualifiers, these data meet all quality standards relative to their original purpose. It is the user's responsibility to validate these data consistent with their intended purpose. Data is provided on the condition that neither GLNPO nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information. GLNPO, USEPA, and the US Government provide no warranty, nor accept any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data.
2. Any presentation or publication of this information should include an acknowledgement of USEPA GLNPO by stating "information for this work was provided in part by USEPA GLNPO's Monitoring Program." When possible, references to the specific dataset should also be included.
Lake Huron
Between 2015 and 2020 the average concentration levels of chlorophyll a in Lake Huron were slightly lower than the long term median of all chlorophyll ɑ concentration levels between 1998 and 2020.
The time series shows monthly averages of satellite-derived surface chlorophyll concentration estimates by year
Data Interpretation:
Time series: This time series shows the average concentration levels of chlorophyll ɑ for Lake Huron. During the last five years there has been no significant trend and values have remained within the 10th and 90th percentiles of all observed data in the time series.
Gauge: The gauge value of 48 indicates that between 2015 and 2020 the average concentration levels of chlorophyll a in Lake Huron were slightly lower than the long term median of all chlorophyll ɑ concentration levels between 1998 and 2020.
Description of Indicator
The U.S. Environmental Protection Agency (U.S. EPA) Great Lakes National Program Office (GLNPO) makes estimates of surface chlorophyll-a concentrations derived from satellite observations of the surface waters of the Great Lakes. These data are used to supplement data collected during GLNPO’s in-situ Great Lakes monitoring programs. The satellite-derived estimates reported here are based on a band-ratio retrieval algorithm developed using GLNPO monitoring data (Lesht et al. 2013; 2016) applied to data from the Sea-viewing Wide Field-of-view (SeaWiFS, 1998–2007) and Moderate resolution imaging spectroradiometer (MODIS, 2002–present) ocean color sensors. Source data are extracted from NASA Level-L2 image files at each GLNPO station location. This workbook contains the monthly averages of satellite-derived surface chlorophyll concentration estimates in this lake by year for the period 1998-present. By contouring the month/year averages in this file this analysis is intended to illustrate long-term trends in surface chlorophyll concentrations with temporal detail not possible using the twice-a-year regular monitoring data.
Lake Huron Description
Lake Huron is the second largest Great Lake with a water surface area of 59,565 square kilometers or 23,000 square miles. About 1.5 million US residents and 1.5 million Canadians live along Lake Huron.
Data Background and Caveats
Data obtained from NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Ocean Biology Processing Group; (2014): Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Ocean Color Data, NASA OB.DAAC. doi: 10.5067/ORBVIEW-2/SEASWIFS_OC.2014.0 and Moderate-resolution imaging spectroradiometer (MODIS) Ocean Color Data; 2018 Reprocessing. NASA OB.DAAC. doi: 10.5067/AQUA/MODIS/L2/OC/2018. Accessed on various dates.
Source data are extracted from daily NASA Level-L2 image files. Pixels in a 5x5 pixel box surrounding each station location are examined and the average, standard deviation, and number of valid pixels within the box are calculated for each daily image. The daily images are sorted by month and for each month those daily station averages for which there are 19 or more valid pixels (of the 25) and for which the standard deviation is less than 0.5*max_allowable_value (lake/basin dependent) and for which the mean + standard deviation is less than 1.1*max_allowable_value and for which the mean - one standard deviation is greater than zero are averaged to provide the monthly average for that station. Then the monthly values for the stations are averaged to produce the lake average.
1. Data have been subjected to GLNPO’s quality assurance procedures, and approved by the GLNPO program technical lead and database manager. GLNPO contractors and grantees are responsible for verifying their data before submitting it to GLNPO. Once received by GLNPO, the data are evaluated for completeness, accuracy, transcription errors, and compliance with quality documentation requirements. Unless otherwise noted by data qualifiers, these data meet all quality standards relative to their original purpose. It is the user's responsibility to validate these data consistent with their intended purpose. Data is provided on the condition that neither GLNPO nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information. GLNPO, USEPA, and the US Government provide no warranty, nor accept any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data.
2. Any presentation or publication of this information should include an acknowledgement of USEPA GLNPO by stating "information for this work was provided in part by USEPA GLNPO's Monitoring Program." When possible, references to the specific dataset should also be included.
Lake Michigan
Between 2015 and 2020 the average concentration levels of chlorophyll a in Lake Michigan were much lower than the long term median of all chlorophyll ɑ concentration levels between 1998 and 2020.
The time series shows monthly averages of satellite-derived surface chlorophyll concentration estimates by year
Data Interpretation:
Time series: This time series shows the average concentration levels of chlorophyll ɑ for Lake Michigan. During the last five years there has been no significant trend and values have remained within the 10th and 90th percentiles of all observed data in the time series.
Gauge: The gauge value of 22 indicates that between 2015 and 2020 the average concentration levels of chlorophyll a in Lake Michigan were much lower than the long term median of all chlorophyll ɑ concentration levels between 1998 and 2020.
Description of Indicator
The U.S. Environmental Protection Agency (U.S. EPA) Great Lakes National Program Office (GLNPO) makes estimates of surface chlorophyll-a concentrations derived from satellite observations of the surface waters of the Great Lakes. These data are used to supplement data collected during GLNPO’s in-situ Great Lakes monitoring programs. The satellite-derived estimates reported here are based on a band-ratio retrieval algorithm developed using GLNPO monitoring data (Lesht et al. 2013; 2016) applied to data from the Sea-viewing Wide Field-of-view (SeaWiFS, 1998–2007) and Moderate resolution imaging spectroradiometer (MODIS, 2002–present) ocean color sensors. Source data are extracted from NASA Level-L2 image files at each GLNPO station location. This workbook contains the monthly averages of satellite-derived surface chlorophyll concentration estimates in this lake by year for the period 1998-present. By contouring the month/year averages in this file this analysis is intended to illustrate long-term trends in surface chlorophyll concentrations with temporal detail not possible using the twice-a-year regular monitoring data.
Lake Michigan Description
Lake Michigan is the third largest Great Lake and has a water surface area of 57,573 square kilometers or 22,300 square miles. Unlike the other four Great Lakes, Lake Michigan is entirely within the United States. Roughly 12 million people live along the shores of Lake Michigan. (While Lakes Michigan and Huron are often referred to as two separate lakes, technically they are one hydrologic system connected by the Straits of Mackinac.)
Data Background and Caveats
Data obtained from NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Ocean Biology Processing Group; (2014): Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Ocean Color Data, NASA OB.DAAC. doi: 10.5067/ORBVIEW-2/SEASWIFS_OC.2014.0 and Moderate-resolution imaging spectroradiometer (MODIS) Ocean Color Data; 2018 Reprocessing. NASA OB.DAAC. doi: 10.5067/AQUA/MODIS/L2/OC/2018. Accessed on various dates.
Source data are extracted from daily NASA Level-L2 image files. Pixels in a 5x5 pixel box surrounding each station location are examined and the average, standard deviation, and number of valid pixels within the box are calculated for each daily image. The daily images are sorted by month and for each month those daily station averages for which there are 19 or more valid pixels (of the 25) and for which the standard deviation is less than 0.5*max_allowable_value (lake/basin dependent) and for which the mean + standard deviation is less than 1.1*max_allowable_value and for which the mean - one standard deviation is greater than zero are averaged to provide the monthly average for that station. Then the monthly values for the stations are averaged to produce the lake average.
1. Data have been subjected to GLNPO’s quality assurance procedures, and approved by the GLNPO program technical lead and database manager. GLNPO contractors and grantees are responsible for verifying their data before submitting it to GLNPO. Once received by GLNPO, the data are evaluated for completeness, accuracy, transcription errors, and compliance with quality documentation requirements. Unless otherwise noted by data qualifiers, these data meet all quality standards relative to their original purpose. It is the user's responsibility to validate these data consistent with their intended purpose. Data is provided on the condition that neither GLNPO nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information. GLNPO, USEPA, and the US Government provide no warranty, nor accept any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data.
2. Any presentation or publication of this information should include an acknowledgement of USEPA GLNPO by stating "information for this work was provided in part by USEPA GLNPO's Monitoring Program." When possible, references to the specific dataset should also be included.
Lake Superior
Between 2015 and 2020 the average concentration levels of chlorophyll a in Lake Superior were significantly higher than the long term median of all chlorophyll ɑ concentration levels between 1998 and 2020.
The time series shows monthly averages of satellite-derived surface chlorophyll concentration estimates by year
Data Interpretation:
Time series: This time series shows the average concentration levels of chlorophyll ɑ for Lake Superior. During the last five years there has been no significant trend and values have remained within the 10th and 90th percentiles of all observed data in the time series.
Gauge: The gauge value of 87 indicates that between 2015 and 2020 the average concentration levels of chlorophyll a in Lake Superior were significantly higher than the long term median of all chlorophyll ɑ concentration levels between 1998 and 2020.
Description of Indicator
The U.S. Environmental Protection Agency (U.S. EPA) Great Lakes National Program Office (GLNPO) makes estimates of surface chlorophyll-a concentrations derived from satellite observations of the surface waters of the Great Lakes. These data are used to supplement data collected during GLNPO’s in-situ Great Lakes monitoring programs. The satellite-derived estimates reported here are based on a band-ratio retrieval algorithm developed using GLNPO monitoring data (Lesht et al. 2013; 2016) applied to data from the Sea-viewing Wide Field-of-view (SeaWiFS, 1998–2007) and Moderate resolution imaging spectroradiometer (MODIS, 2002–present) ocean color sensors. Source data are extracted from NASA Level-L2 image files at each GLNPO station location. This workbook contains the monthly averages of satellite-derived surface chlorophyll concentration estimates in this lake by year for the period 1998-present. By contouring the month/year averages in this file this analysis is intended to illustrate long-term trends in surface chlorophyll concentrations with temporal detail not possible using the twice-a-year regular monitoring data.
Lake Superior Description
Lake Superior is the second largest lake in the world by surface area, and is the largest and deepest of the five Great Lakes. Lake Superior reaches depths up to 406 m or 1,333 ft. Extending through Canada and the United States, about 444,000 US residents and 229,000 Canadian residents live along the shores of Lake Superior. Lake Superior flows into Lake Huron through the St. Marys River.
Data Background and Caveats
Data obtained from NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Ocean Biology Processing Group; (2014): Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Ocean Color Data, NASA OB.DAAC. doi: 10.5067/ORBVIEW-2/SEASWIFS_OC.2014.0 and Moderate-resolution imaging spectroradiometer (MODIS) Ocean Color Data; 2018 Reprocessing. NASA OB.DAAC. doi: 10.5067/AQUA/MODIS/L2/OC/2018. Accessed on various dates.
Source data are extracted from daily NASA Level-L2 image files. Pixels in a 5x5 pixel box surrounding each station location are examined and the average, standard deviation, and number of valid pixels within the box are calculated for each daily image. The daily images are sorted by month and for each month those daily station averages for which there are 19 or more valid pixels (of the 25) and for which the standard deviation is less than 0.5*max_allowable_value (lake/basin dependent) and for which the mean + standard deviation is less than 1.1*max_allowable_value and for which the mean - one standard deviation is greater than zero are averaged to provide the monthly average for that station. Then the monthly values for the stations are averaged to produce the lake average.
1. Data have been subjected to GLNPO’s quality assurance procedures, and approved by the GLNPO program technical lead and database manager. GLNPO contractors and grantees are responsible for verifying their data before submitting it to GLNPO. Once received by GLNPO, the data are evaluated for completeness, accuracy, transcription errors, and compliance with quality documentation requirements. Unless otherwise noted by data qualifiers, these data meet all quality standards relative to their original purpose. It is the user's responsibility to validate these data consistent with their intended purpose. Data is provided on the condition that neither GLNPO nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information. GLNPO, USEPA, and the US Government provide no warranty, nor accept any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data.
2. Any presentation or publication of this information should include an acknowledgement of USEPA GLNPO by stating "information for this work was provided in part by USEPA GLNPO's Monitoring Program." When possible, references to the specific dataset should also be included.
Alaska
During the last five years there has been a significant increasing trend while values have remained within the 10th and 90th percentiles of all observed data in the time series.
This time series shows the average concentration levels of chlorophyll a for Alaska. During the last five years there has been a significant increasing trend while values have remained within the 10th and 90th percentiles of all observed data in the time series.
Indicator and source information:
Chlorophyll-a concentration values for this indicator were obtained using data from the European Spatial Agency (ESA) that is a validated, error-characterized, Essential Climate Variable (ECV) and climate data record (CDR) from satellite observations specifically developed for climate studies. The dataset (v56.0) is created by bandshifting the reflectances values from SeaWiFS, MODIS and VIIRS to MERIS wavebands if necessary, and SeaWiFS and MODIS were corrected for inter-sensor bias when compared with MERIS in the 2003-2007 period. VIIRS and OLCI were also corrected to MERIS levels, via a two-stage process comparing against the MODIS-corrected-to-MERIS-levels (2012-2013 for VIIRS and 2016-2019 for OLCI).
Source: https://climate.esa.int/en/projects/ocean-colour/key-documents/
https://docs.pml.space/share/s/fzNSPb4aQaSDvO7xBNOCIw
Annual means for each LME were calculated from the average of the 12 monthly means in that year on a pixel by pixel basis. Then for each year, the median average was taken spatially to yield one value per year per LME. The overall “National Annual Mean” mean was calculated as the average of all LME annual means. See the Data Background section for more details.
Data background and limitations:
Satellite chlorophyll a data was extracted for each LME from the ESA OC-CCI v6.0 product. These 4 km mapped, monthly composited data were - averaged over each year to produce pixel by pixel annual composites, then the spatial median was calculated for each LME, resulting in one value per year per LME. This technique was used for each LME from North America and Hawaii. The overall “National Annual Mean” was calculated as the average of all the LME annual means. Phytoplankton concentrations are highly variable (spatially and temporally), largely driven by changing oceanographic conditions and seasonal variability.
The northern section of the Alaska region (northern Chukchi and Beaufort Sea), have no to very low data coverage for part of year, so this likely biases the absolute values for the whole region. This does not likely affect the trend.
Resources
European Space Agency Ocean Colour
This project focuses on the Ocean Colour ECV encompassing water-leaving radiance in the visible domain, derived chlorophyll and inherent optical properties and utilises data archives from Copernicus, ESA, NASA and NOAA.
Satellite Data Products | NOAA CoastWatch & OceanWatch
Guide to satellite data products hosted by the NOAA Coastwatch and Oceanwatch websites.
MODIS Aqua NIR-SWIR Ocean Color Chlorophyll Concentration: Daily - OSPO
The MODIS/Aqua NIR-SWIR ocean color products are derived by using the shortwave infrared (SWIR)-based atmospheric correction algorithm developed by the NOAA/NESDIS Center for Satellite Applications and Research (STAR). The products include chlorophyll concentration, remote sensing reflectance at 667 nm, water attenuation coefficient at 490 nm over 12 CoastWatch Regions-of-Interest, i.e., Northeast (NE), Southeast (SE), Gulf of Mexico (GOM), Caribbean (CB), West Coast (WC), Alaska (AK), East Tropical Pacific (EP), Equatorial Atlantic (EA), Great Lakes (GL), Hawaii (HI), North Atlantic (NA), and Pacific Basin (PB).
MODIS / Aqua NASA L2gen NIR Ocean Color Chlorophyll Concentration (Chl-a): Daily - OSPO
The MODIS/Terra ocean color products are derived by using the NASA L2gen SeaDAS codes based on Near-Infrared (NIR) atmospheric correction algorithm. The products include chlorophyll concentration and remote sensing reflectance at 667 nm over 2 CoastWatch Regions-of-Interest, i.e., Gulf of Mexico (GOM) and Hawaii (HI).
NCEI Ocean Color Archive
This site contains an overview of the NOAA archive services being provided for Level 2 (L2) and Level 3 (L3) ocean color (OC) products generated by the NOAA CoastWatch/OceanWatch Program (a.k.a CoastWatch). CoastWatch is an operational NOAA program that processes near real-time satellite data and makes it available to a variety of users in order to manage U.S. coastal resources and understand climate variability. CoastWatch currently produces near real-time ocean color products from multiple platforms.
PSL Real-time Satellite Products
Real-time data products hosted by NOAA's Physical Sciences Laboratory
NASA Ocean Color
NASA's OceanColor Web is supported by the Ocean Biology Processing Group (OBPG) at NASA's Goddard Space Flight Center. Our responsibilities include the collection, processing, calibration, validation, archive and distribution of ocean-related products from a large number of operational, satellite-based remote-sensing missions providing ocean color, sea surface temperature and sea surface salinity data to the international research community since 1996.
MODIS Chlorophyll-a Concentration
This algorithm returns the near-surface concentration of chlorophyll-a (chlor_a) in mg m-3, calculated using an empirical relationship derived from in situ measurements of chlor_a and blue-to-green band ratios of in situ remote sensing reflectances (Rrs). Implementation is contingent on the availability three or more sensor bands spanning the 440 - 570 nm spectral regime. The algorithm is applicable to all current ocean color sensors. The chlor_a product is included as part of the standard Level-2 OC product suite and the Level-3 CHL product suite.
Phytoplankton Monitoring Network (PMN)
The National Phytoplankton Monitoring Network (PMN) is a community-based network of volunteers monitoring marine phytoplankton and harmful algal blooms (HABs). PMN recognizes the interrelationships between humans and coastal ecosystems while providing volunteer citizen scientists with meaningful opportunities for hands-on science engagement. The PMN enhances the Nation’s ability to respond to and manage the growing threat posed by HABs by collecting important data for species composition and distribution in coastal waters and creating working relationships between volunteers and professional marine biotoxin researchers.
Ocean - Oceanic Climate Variables
This page describes some of the 50 Essential Climate Variables identified by the Global Climate Observing System (GCOS) for worldwide monitoring. Panels of experts at GCOS helped identify which climate observations should be made on an ongoing basis, and agreed upon principles and guidelines for the best ways to make them.
GOOS Essential Ocean Variables
The ocean environment is vast, remote, and harsh, and the cost involved in its observation are high. There is a need to avoid duplication of efforts, across observing platforms and networks, and to adopt common standards for data collection and dissemination to maximize the utility of data. To address these concerns, the Framework is designed to approach ocean observations with a focus on Essential Ocean Variables, ensuring assessments that cut across platforms and recommend the best, most cost effective plan to provide an optimal global view for each EOV.
GOOS-EOV-Ocean-Colour
The Essential Ocean Variable Sheet and Criteria for ocean colour
IOOS Core Variables
The 34 IOOS Core Variables: Ocean observing measurements required to detect and predict changes in the ocean
Gulf of Mexico Harmful Algal Bloom Forecast
In the Gulf of Mexico, some harmful algal blooms are caused by the rapid growth of the microscopic algae species Karenia brevis (commonly called red tide). Red tide can cause respiratory illness and eye irritation in humans. It can also kill marine life. Blooms are often patchy, so impacts vary by beach and throughout the day.
NOAA monitors conditions daily and issues twice-weekly forecasts for red tide blooms in the Gulf of Mexico and East Coast of Florida. You can find up-to-date information on where a bloom is located and a 3–4 day forecast for potential respiratory irritation by selecting a region below. This information may help you find an unaffected beach if you are visiting the coast
The Global Plankton Database
COPEPOD's global plankton database component provides plankton and ecosystem researchers with an integrated data set of quality-reviewed, globally distributed plankton abundance, biomass and composition data. Its visual, interactive interface is designed to help the user see exactly what data are currently available and then download them in a variety of usable formats and compilations. In addition to data distribution maps, COPEPOD offers a variety of text and graphical content summaries and searching options.
NCCOS Harmful Algal Bloom Forecasting
Our HAB forecasts alert coastal managers to blooms before they cause serious damage. Short-term (once or twice weekly) forecasts identify which blooms are potentially harmful, where they are, how big they are, and where they're likely headed. Longer-term, seasonal forecasts predict the severity of HABs for the bloom season in a particular region. Early warning provides health officials, environmental managers and water treatment facility operators information to focus their testing to guide beach and shellfish bed closures or water treatment in a more appropriate timeframe. They also allow the seafood and tourism industries to minimize impacts.
