• Metadata catalogue
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North Pacific Gyre Area time series and trend

'''DEFINITION'''

Oligotrophic subtropical gyres are regions of the ocean with low levels of nutrients required for phytoplankton growth and low levels of surface chlorophyll-a whose concentration can be quantified through satellite observations. The gyre boundary has been defined using a threshold value of 0.15 mg m-3 chlorophyll for the Atlantic gyres (Aiken et al. 2016), and 0.07 mg m-3 for the Pacific gyres (Polovina et al. 2008). The area inside the gyres for each month is computed using monthly chlorophyll data from which the monthly climatology is subtracted to compute anomalies. A gap filling algorithm has been utilized to account for missing data inside the gyre. Trends in the area anomaly are then calculated for the entire study period (September 1997 to December 2020).

'''CONTEXT'''

Oligotrophic gyres of the oceans have been referred to as ocean deserts (Polovina et al. 2008). They are vast, covering approximately 50% of the Earth’s surface (Aiken et al. 2016). Despite low productivity, these regions contribute significantly to global productivity due to their immense size (McClain et al. 2004). Even modest changes in their size can have large impacts on a variety of global biogeochemical cycles and on trends in chlorophyll (Signorini et al 2015). Based on satellite data, Polovina et al. (2008) showed that the areas of subtropical gyres were expanding. The Ocean State Report (Sathyendranath et al. 2018) showed that the trends had reversed in the Pacific for the time segment from January 2007 to December 2016.

'''CMEMS KEY FINDINGS'''

The trend in the North Pacific gyre area for the 1997 Sept – 2020 December period was positive, with a 2.17% increase in area relative to 2000-01-01 values. Note that this trend is slightly lower than the 2.25% reported for the 1997-2019 period (though the small difference is within the uncertainties associated with the two estimates). The trend is statistically significant (p<0.05).

During the 1997 Sept – 2020 December period, the trend in chlorophyll concentration was negative (-0.31% year-1) in the North Pacific gyre relative to 2000-01-01 values. This trend is slightly more negative than the trend of -0.25% year-1 for the 1997-2019 period, though the sign of the trend remains unchanged and is statistically significant (p<0.05).

For 2016, The Ocean State Report (Sathyendranath et al. 2018) reported a large increase in gyre area in the Pacific Ocean (both North and South Pacific gyres), probably linked with the 2016 ENSO event which saw large decreases in chlorophyll in the Pacific Ocean.

'''DOI (product):'''

https://doi.org/10.48670/moi-00227

 
Citation proposal
Rosalia SANTOLERI (OC-CNR-ROMA-IT). North Pacific Gyre Area time series and trend. https://services.mspdata.eu:/geonetwork/srv/api/records/8a59cf53-582c-444c-9245-bfa0eade56bc

Simple

Alternate title
GLOBAL_OMI_HEALTH_OceanColour_oligo_npg_area_mean
Date ( Creation )
2019-11-28
Edition
3.4
Edition date
2019-11-28
Identifier
a78600a4-a280-47b5-8ddd-0dc8b5e9c9d9
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 CALTON  

  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 ( Theme )
  • Oceanographic geographical features
Discipline ( Discipline )
  • satellite-observation
Climate and Forecast Standard Names ( parameter )
  • area_type_oligotropic_gyre , mass_concentration_of_chlorophyll_in_seawater_for_averaged_mean
Temporal scale ( temporal-scale )
  • multi-year
Area of benefit ( area-of-benefit )
  • marine-safety , marine-resources , coastal-marine-environment , weather-climate-and-seasonal-forecasting
Reference Geographical Areas ( reference-geographical-area )
  • global-ocean
Processing level ( processing-level )
  • Level 4
Model assimilation ( Theme )
  • 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
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
Aggregate Datasetindentifier
3ef35088-7164-452b-a463-2194a17b68bd
Association Type
Cross reference
Initiative Type
document
Aggregate Datasetindentifier
06f3ffff-06e0-414b-bbbb-e2d3fbe43508
Association Type
Cross reference
Initiative Type
document
Aggregate Datasetindentifier
21cb30ba-0358-4a8b-8fd2-e1a78154db81
Association Type
Cross reference
Initiative Type
document
Metadata language
eng
Topic category
  • Oceans
Description
bounding box
N
S
E
W


Vertical extent

Minimum value
0
Maximum value
0
Vertical CRS
  •   urn:ogc:def:crs:EPSG:5714
Supplemental Information
display priority: 53800
Reference system identifier
EPSG / Equirectangular
Number of dimensions
2
Dimension name
Row
Resolution
4  km
Dimension name
Column
Resolution
4  km
Cell geometry
Area
Transformation parameter availability
false
Distribution format
  • NetCDF-4 (Classic model )

Distributor

OnLine resource
global_omi_health_oligo_npg_area_mean  
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']")

Metadata

File identifier
8a59cf53-582c-444c-9245-bfa0eade56bc   XML
Metadata language
English
Character set
UTF8
Hierarchy level
Series
Hierarchy level name
Copernicus Marine Service product specification
Date stamp
2021-12-10T15:52:12
Metadata standard name
ISO 19139, MyOcean profile
Metadata standard version
0.2

  Point of contact

CMEMS  

Website
http://marine.copernicus.eu/  
 
 

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