Global Ocean Chlorophyll-a anomalies
'''DEFINITION'''
The global annual chlorophyll anomaly is computed by subtracting a reference climatology (1997-2014) from the annual chlorophyll mean, on a pixel-by-pixel basis and in log10 space. Both the annual mean and the climatology are computed employing ESA Ocean Colour Climate Change Initiative (ESA OC-CCI, Sathyendranath et al., 2018a) global products (i.e. using the standard OC-CCI chlorophyll algorithms, OCI) as distributed by CMEMS.
'''CONTEXT'''
Phytoplankton – and chlorophyll concentration as a proxy for phytoplankton – respond rapidly to changes in their physical environment. Some of those changes are seasonal and are determined by light and nutrient availability (Racault et al., 2012). By comparing annual mean values to a climatology, we effectively remove the seasonal signal, while retaining information on potential events during the year. Chlorophyll anomalies can be correlated to climate indexes in particular regions, such as the ENSO index in the equatorial Pacific (Behrenfeld et al. 2006; Racault et al., 2012) and the IOD index in the Indian Ocean (Brewin et al., 2012). It is important to study chlorophyll anomalies in consonance with sea surface temperature and sea level anomalies, as increases in chlorophyll are generally consistent with decreases in SST and sea level anomalies, suggesting an increase in mixing and vertical nutrient transport (von Schuckmann et al., 2016).
'''CMEMS KEY FINDINGS'''
The average global chlorophyll anomaly 2019 is -0.02 log10(mg m-3), with a maximum value of 1.7 log10(mg m-3) and a minimum value of -3.2 log10(mg m-3). That is to say that, in average, the annual 2019 mean value is slightly lower (96%) than the 1997-2014 climatological value. The positive signals reported in 2016 and 2017 (Sathyendranath et al., 2018b) in the southern Pacific Ocean could still be observed in the 2019 map, while the significant negative anomalies in the tropical waters of the northern Pacific Ocean were also detected to a lesser extent. Areas showing a change of anomaly sign from 2019 include the southern coast of Japan (no anomaly to positive) and the tropical Atlantic (anomalies close to zero for 2019). A marked increase in chlorophyll concentration was observed during 2019 in the Great Australian Bight, while negative anomalies became stronger in the Guatemala Basin and the region south of the Gulf of Guinea and, with values of chlorophyll reaching as low as 30% of the climatological value (anomaly < -0.5 log10(mg m-3)). The persistent positive anomalies in the higher latitudes of the North Atlantic (> 40°) match the cooling observed in the 2018 and previous years SST anomaly maps.
Simple
- Title
-
Global Ocean Chlorophyll-a anomalies
- Alternate title
-
GLOBAL_OMI_HEALTH_OceanColour_anomalies
- Date (Creation)
- 2018-02-12
- Edition
-
3.4
- Edition date
- 2018-02-12
- Citation identifier
- 1c5fe986-1cd7-4c56-aeff-7bba0b4ff554
- Abstract
-
'''DEFINITION'''
The global annual chlorophyll anomaly is computed by subtracting a reference climatology (1997-2014) from the annual chlorophyll mean, on a pixel-by-pixel basis and in log10 space. Both the annual mean and the climatology are computed employing ESA Ocean Colour Climate Change Initiative (ESA OC-CCI, Sathyendranath et al., 2018a) global products (i.e. using the standard OC-CCI chlorophyll algorithms, OCI) as distributed by CMEMS.
'''CONTEXT'''
Phytoplankton – and chlorophyll concentration as a proxy for phytoplankton – respond rapidly to changes in their physical environment. Some of those changes are seasonal and are determined by light and nutrient availability (Racault et al., 2012). By comparing annual mean values to a climatology, we effectively remove the seasonal signal, while retaining information on potential events during the year. Chlorophyll anomalies can be correlated to climate indexes in particular regions, such as the ENSO index in the equatorial Pacific (Behrenfeld et al. 2006; Racault et al., 2012) and the IOD index in the Indian Ocean (Brewin et al., 2012). It is important to study chlorophyll anomalies in consonance with sea surface temperature and sea level anomalies, as increases in chlorophyll are generally consistent with decreases in SST and sea level anomalies, suggesting an increase in mixing and vertical nutrient transport (von Schuckmann et al., 2016).
'''CMEMS KEY FINDINGS'''
The average global chlorophyll anomaly 2019 is -0.02 log10(mg m-3), with a maximum value of 1.7 log10(mg m-3) and a minimum value of -3.2 log10(mg m-3). That is to say that, in average, the annual 2019 mean value is slightly lower (96%) than the 1997-2014 climatological value. The positive signals reported in 2016 and 2017 (Sathyendranath et al., 2018b) in the southern Pacific Ocean could still be observed in the 2019 map, while the significant negative anomalies in the tropical waters of the northern Pacific Ocean were also detected to a lesser extent. Areas showing a change of anomaly sign from 2019 include the southern coast of Japan (no anomaly to positive) and the tropical Atlantic (anomalies close to zero for 2019). A marked increase in chlorophyll concentration was observed during 2019 in the Great Australian Bight, while negative anomalies became stronger in the Guatemala Basin and the region south of the Gulf of Guinea and, with values of chlorophyll reaching as low as 30% of the climatological value (anomaly < -0.5 log10(mg m-3)). The persistent positive anomalies in the higher latitudes of the North Atlantic (> 40°) match the cooling observed in the 2018 and previous years SST anomaly maps.
- Credit
-
E.U. Copernicus Marine Service Information
- Point of contact
-
Organisation name Individual name Electronic mail address Role OC-CNR-ROMA-IT
Rosalia SANTOLERI
Production center OC-PML-PLYMOUTH-UK
Silvia PARDO
Product manager OC-CNR-ROMA-IT
CMEMS-DU
Local service desk OC-PML-PLYMOUTH-UK
Ben TAYLOR
Production Unit MOI-OMI-SERVICE
MOI-OMI-SERVICE
Dissemination Unit
- Maintenance and update frequency
- Annually
- Other
-
P0M0D0H/P0M0D0H
- Maintenance note
-
N/A
-
GEMET - INSPIRE themes, version 1.0
- Use limitation
-
See Copernicus Marine Environment Monitoring Service Data commitments and licence at: http://marine.copernicus.eu/web/27-service-commitments-and-licence.php
- Access constraints
- Other restrictions
- Use constraints
- License
- Other legal constraints
-
No limitations on public access
- Aggregate Datasetindentifier
- 9cc3262c-fee9-4ff4-be11-806480b4a4be
- Association Type
- Cross reference
- Initiative Type
- Document
- Title
-
Brewin, RJW., et al., 2012. The influence of the Indian ocean dipole on inter annual variations in phytoplankton size structure as revealed by earth observation. Deep Sea Res Part II 77–80:117–127
- Date (Creation)
- 2019-05-08
- Association Type
- Cross reference
- Initiative Type
- Reference
- Title
-
Racault MF, Le Quere C, Buitenhuis E, Sathyendranath S, Platt T. 2012. Phytoplankton phenology in the global ocean. Ecol Indicators 14(1): 152–163.
- Date (Creation)
- 2019-05-08
- Association Type
- Cross reference
- Initiative Type
- Reference
- Title
-
Sathyendranath, S., et al., 2018a. ESA Ocean Colour Climate Change Initiative (Ocean_Colour_cci): Version 3.1. Technical Report Centre for Environmental Data Analysis. doi:10.5285/9c334fbe6d424a708cf3c4cf0c6a53f5.
- Date (Creation)
- 2019-05-08
- Association Type
- Cross reference
- Initiative Type
- Reference
- Title
-
Sathyendranath, S., Pardo, S., Benincasa, M., Brando, V. E., Brewin, R. J.W., Mélin, F., Santoleri, R., 2018b, 1.5. Essential Variables: Ocean Colour in Copernicus Marine Service Ocean State Report - Issue 2, Journal of Operational Oceanography, 11:sup1, 1-142, doi: 10.1080/1755876X.2018.1489208
- Date (Creation)
- 2019-05-08
- Association Type
- Cross reference
- Initiative Type
- Reference
- Title
-
von Schuckmann, K., et al., (2016) The Copernicus Marine Environment Monitoring Service Ocean State Report, Journal of Operational Oceanography, 9:sup2, s235-s320, doi: 10.1080/1755876X.2016.1273446
- Date (Creation)
- 2019-05-08
- Association Type
- Cross reference
- Initiative Type
- Reference
- Language
-
eng
- Topic category
-
- Oceans
- Description
-
bounding box
))
- Begin date
- 1901-01-01
- End date
- 1901-01-01
Vertical extent
- Minimum value
- 0
- Maximum value
- 0.0
Vertical CRS
- Supplemental Information
-
display priority: 99999
- Reference system identifier
- EPSG / WGS 84 (EPSG:4326)
- Number of dimensions
- 2
- Dimension name
- Row
- Resolution
- 1 km
- Dimension name
- Column
- Resolution
- 1 km
- Cell geometry
- Area
- Transformation parameter availability
- Distribution format
-
Name Version NetCDF-4
Classic model
Distributor
- Hierarchy level
- Series
Conformance result
- Title
-
COMMISSION REGULATION (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services
- Date (Publication)
- 2010-12-08
- Explanation
-
See the referenced specification
- Statement
-
The myOcean products depends on other products for production or validation. The detailed list of dependencies is given in ISO19115's aggregationInfo (ISO19139 Xpath = "gmd:MD_Metadata/gmd:identificationInfo/gmd:aggregationInfo[./gmd:MD_AggregateInformation/gmd:initiativeType/gmd:DS_InitiativeTypeCode/@codeListValue='upstream-validation' or 'upstream-production']")
- Attribute description
- observation
- Content type
- Physical measurement
- Descriptor
-
vertical level number: 1
- Included with dataset
- Feature types
- Grid
Metadata
- File identifier
- 953eac68-6e35-4b8e-b60e-b26f63fbb1c6
- Metadata language
- English
- Character set
- UTF8
- Hierarchy level
- Series
- Hierarchy level name
-
Copernicus Marine Service product specification
- Date stamp
- 2021-07-19T09:42:29
- Metadata standard name
-
ISO 19139, MyOcean profile
- Metadata standard version
-
0.2
- Metadata author
-
Organisation name Individual name Electronic mail address Role CMEMS
Local service desk
accessData
Overviews
)))