• Catalogue PIGMA
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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

Alternate title
GLOBAL_OMI_HEALTH_OceanColour_anomalies
Date (Creation)
2018-02-12
Edition
3.4
Edition date
2018-02-12
Identifier
1c5fe986-1cd7-4c56-aeff-7bba0b4ff554
Credit
E.U. Copernicus Marine Service Information
Custodian
  OC-CNR-ROMA-IT - Rosalia SANTOLERI
Originator
  OC-PML-PLYMOUTH-UK - Silvia PARDO
Point of contact
  OC-CNR-ROMA-IT - CMEMS-DU
Resource provider
  OC-PML-PLYMOUTH-UK - Ben TAYLOR
Distributor
  MOI-OMI-SERVICE - MOI-OMI-SERVICE
Maintenance and update frequency
Annually
Other
P0M0D0H/P0M0D0H
Maintenance note
N/A
GEMET - INSPIRE themes, version 1.0
  • Oceanographic geographical features
Discipline
  • satellite-observation
Temporal scale
  • multi-year
Area of benefit
  • weather-climate-and-seasonal-forecasting
  • marine-resources
  • coastal-marine-environment
  • marine-safety
Reference Geographical Areas
  • global-ocean
Processing level
  • Level 4
Model assimilation
  • Not Applicable
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 constraints
No limitations on public access
Aggregate Datasetindentifier
9cc3262c-fee9-4ff4-be11-806480b4a4be
Association Type
Cross reference
Initiative Type
document
Date (Creation)
2019-05-08
Association Type
Cross reference
Initiative Type
reference
Date (Creation)
2019-05-08
Association Type
Cross reference
Initiative Type
reference
Date (Creation)
2019-05-08
Association Type
Cross reference
Initiative Type
reference
Date (Creation)
2019-05-08
Association Type
Cross reference
Initiative Type
reference
Date (Creation)
2019-05-08
Association Type
Cross reference
Initiative Type
reference
Metadata language
eng
Topic category
  • Oceans
Description
bounding box
N
S
E
W
thumbnail


Begin date
1901-01-01
End date
1901-01-01

Vertical extent

Minimum value
0
Maximum value
0.0
Vertical CRS
  • urn:ogc:def:crs:EPSG:5714
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
No
Distribution format
  • NetCDF-4 ( Classic model )

Distributor

Hierarchy level
Series

Conformance result

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
No
Feature types
Grid
File identifier
953eac68-6e35-4b8e-b60e-b26f63fbb1c6 XML
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
Point of contact
  CMEMS
http://marine.copernicus.eu/
 
 

Overviews

overview

Spatial extent

N
S
E
W
thumbnail


Keywords

GEMET - INSPIRE themes, version 1.0
Oceanographic geographical features
Model assimilation
Not Applicable

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