Title

[ARCHIVE] South Atlantic Subtropical Gyre Area Oligotrophic time series and trend from Observations Reprocessing

Alternate title

GLOBAL_OMI_HEALTH_OceanColour_oligo_sag_area_mean

Date (Creation)

2019-11-28

Edition

3.4

Edition date

2019-11-28

Citation identifier

a78600a4-a280-47b5-8ddd-0dc8b5e9c9d9

Abstract

'''This product has been archived'''

For operationnal and online products, please visit https://marine.copernicus.eu

'''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 South Altantic gyre area for the 1997 Sept – 2020 December period was positive, with a 0.09% increase in area relative to 2000-01-01 values. Note that this trend is lower than the 0.13% rate for the 1997-2019 trend (though within the uncertainties associated with the two estimates) and is statistically significant (p<0.05).

During the 1997 Sept – 2020 December period, the trend in chlorophyll concentration was positive (0.35% year-1) relative to 2000-01-01 values. This is a significant increase from the trend of 0.02% year-1 for the 1997-2019 period.

Note: The key findings will be updated annually in November, in line with OMI evolutions.

'''DOI (product):'''

https://doi.org/10.48670/moi-00228

Credit

E.U. Copernicus Marine Service Information

Point of contact

Organisation name	Individual name	Electronic mail address	Role
OC-CNR-ROMA-IT	Rosalia SANTOLERI	rosalia.santoleri@cnr.it	Production center
OC-PML-PLYMOUTH-UK	Silvia PARDO	bac@pml.ac.uk	Product manager
OC-CNR-ROMA-IT	CMEMS-DU	gsdk@isac.cnr.it	Local service desk
OC-PML-PLYMOUTH-UK	Ben CALTON	cmems@pml.ac.uk	Production Unit
MOI-OMI-SERVICE	MOI-OMI-SERVICE	omi.service@mercator-ocean.fr	Dissemination Unit

Maintenance and update frequency

Annually

Other

P0M0D0H/P0M0D0H

Maintenance note

N/A

GEMET - INSPIRE themes, version 1.0

• Oceanographic geographical features

Discipline

• satellite-observation

Climate and Forecast Standard Names

• area_type_oligotropic_gyre
• mass_concentration_of_chlorophyll_in_seawater_for_averaged_mean

Temporal scale

• multi-year

Area of benefit

• coastal-marine-environment
• marine-resources
• weather-climate-and-seasonal-forecasting
• marine-safety

Reference Geographical Areas

• global-ocean

Processing level

• Level 4

Model assimilation

• Not Applicable

Mission Atlantic - Resources

• Data

Mission Atlantic - Data type (DMP)

• Modelling data

Mission Atlantic - BODC Parameters

• /Cross-discipline/Rate measurements

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

Title

Aiken J, Brewin RJW, Dufois F, Polimene L, Hardman-Mountford NJ, Jackson T, Loveday B, Hoya SM, Dall’Olmo G, Stephens J, et al. 2016. A synthesis of the environmental response of the North and South Atlantic sub-tropical gyres during two decades of AMT. Prog Oceanogr. doi:10.1016/j.pocean.2016.08.004.

Date (Creation)

2019-05-08

Association Type

Cross reference

Initiative Type

Reference

Title

McClain CR, Signorini SR, Christian JR 2004. Subtropical gyre variability observed by ocean-color satellites. Deep Sea Res Part II Top Stud Oceanogr. 51:281–301. doi:10.1016/j.dsr2.2003.08.002.

Date (Creation)

2019-05-08

Association Type

Cross reference

Initiative Type

Reference

Title

Polovina JJ, Howell EA, Abecassis M 2008. Ocean’s least productive waters are expanding. Geophys Res Lett. 35:270. doi:10.1029/2007GL031745.

Date (Creation)

2019-05-08

Association Type

Cross reference

Initiative Type

Reference

Title

Sathyendranath S, Pardo S, Brewin RJW. 2018. Oligotrophic gyres. In: Copernicus Marine Service Ocean State Report, Issue 2, Journal of Operational Oceanography, 11:sup1, s13–s16, DOI: 10.1080/1755876X.2018.1489208

Date (Creation)

2019-05-08

Association Type

Cross reference

Initiative Type

Reference

Title

Signorini SR, Franz BA, McClain CR 2015. Chlorophyll variability in the oligotrophic gyres: mechanisms, seasonality and trends. Front Mar Sci. 2. doi:10.3389/fmars.2015.00001.

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

b5daa4b6-1487-4883-99be-da2a9911e708

Association Type

Cross reference

Initiative Type

Document

Language

eng

Topic category

• Oceans

Description

bounding box

Begin date

1901-01-01

End date

1901-01-01

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

Distribution format

Name	Version
NetCDF-4	Classic model

Hierarchy level

Series

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

97c598b8-efbe-42ac-b3de-e5e58ccd33a3

Metadata language

English

Character set

UTF8

Hierarchy level

Series

Hierarchy level name

Copernicus Marine Service product specification

Date stamp

2022-11-28T15:24:43.377Z

Metadata standard name

ISO 19139, MyOcean profile

Metadata standard version

0.2

Metadata author

Organisation name	Individual name	Electronic mail address	Role
CMEMS		servicedesk.cmems@mercator-ocean.eu	Local service desk