Title

Global ocean acidification - mean sea water pH trend map from Multi-Observations Reprocessing

Alternate title

GLOBAL_OMI_HEALTH_carbon_ph_trend

Date (Creation)

2018-02-12

Edition

3.4

Edition date

2023-11-30

Citation identifier

0a5db440-d278-47a6-8885-b89aabb3f0b3

Abstract

'''DEFINITION'''

This ocean monitoring indicator (OMI) consists of annual mean rates of changes in surface ocean pH (yr-1) computed at 0.25°×0.25° resolution from 1985 until the last year. This indicator is derived from monthly pH time series distributed with the Copernicus Marine product MULTIOBS_GLO_BIO_CARBON_SURFACE_REP_015_008 (Chau et al., 2022a). For each grid cell, a linear least-squares regression was used to fit a linear function of pH versus time, where the slope (μ) and residual standard deviation (σ) are defined as estimates of the long-term trend and associated uncertainty. Finally, the estimates of pH associated with the highest uncertainty, i.e., σ-to-µ ratio over a threshold of 1 0%, are excluded from the global trend map (see QUID document for detailed description and method illustrations). This threshold is chosen at the 90th confidence level of all ratio values computed across the global ocean.

'''CONTEXT'''

A decrease in surface ocean pH (i.e., ocean acidification) is primarily a consequence of an increase in ocean uptake of atmospheric carbon dioxide (CO2) concentrations that have been augmented by anthropogenic emissions (Bates et al, 2014; Gattuso et al, 2015; Pérez et al, 2021). As projected in Gattuso et al (2015), “under our current rate of emissions, most marine organisms evaluated will have very high risk of impacts by 2100 and many by 2050”. Ocean acidification is thus an ongoing source of concern due to its strong influence on marine ecosystems (e.g., Doney et al., 2009; Gehlen et al., 2011; Pörtner et al. 2019). Tracking changes in yearly mean values of surface ocean pH at the global scale has become an important indicator of both ocean acidification and global change (Gehlen et al., 2020; Chau et al., 2022b). In line with a sustained establishment of ocean measuring stations and thus a rapid increase in observations of ocean pH and other carbonate variables (e.g. dissolved inorganic carbon, total alkalinity, and CO2 fugacity) since the last decades (Bakker et al., 2016; Lauvset et al., 2021), recent studies including Bates et al (2014), Lauvset et al (2015), and Pérez et al (2021) put attention on analyzing secular trends of pH and their drivers from time-series stations to ocean basins. This OMI consists of the global maps of long-term pH trends and associated 1σ-uncertainty derived from the Copernicus Marine data-based product of monthly surface water pH (Chau et al., 2022a) at 0.25°×0.25° grid cells over the global ocean.

'''CMEMS KEY FINDINGS'''

Since 1985, pH has been decreasing at a rate between -0.0008 yr-1 and -0.0022 yr-1 over most of the global ocean basins. Tropical and subtropical regions, the eastern equatorial Pacific excepted, show pH trends falling in the interquartile range of all the trend estimates (between -0.0012 yr-1 and -0.0018 yr-1). pH over the eastern equatorial Pacific decreases much faster, reaching a growth rate larger than -0.0024 yr-1. Such a high rate of change in pH is also observed over a sector south of the Indian Ocean. Part of the polar and subpolar North Atlantic and the Southern Ocean has no significant trend.

'''DOI (product):'''

https://doi.org/10.48670/moi-00277

Credit

E.U. Copernicus Marine Service Information

Point of contact

Organisation name	Individual name	Electronic mail address	Role
MULTIOBS-LSCE-GIF-FR			Production Unit

Maintenance and update frequency

Annually

Other

P0M0D0H/P0M0D0H

Maintenance note

N/A

GEMET - INSPIRE themes, version 1.0

• Oceanographic geographical features

Discipline

• in-situ-observation

Climate and Forecast Standard Names

• trend_of_surface_ocean_ph_reported_on_total_scale

Temporal scale

• multi-year

Area of benefit

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

Reference Geographical Areas

• global-ocean

Processing level

• N/A

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 legal constraints

No limitations on public access

Title

Bakker, D. C. E., Pfeil, B., Landa, C. S., Metzl, N., O'Brien, K. M., Olsen, A., Smith, K., Cosca, C., Harasawa, S., Jones, S. D., Nakaoka, S.-I. et al.: A multi-decade record of high-quality fCO2 data in version 3 of the Surface Ocean CO2 Atlas (SOCAT), Earth Syst. Sci. Data, 8, 383–413, DOI:10.5194/essd-8-383- 2016, 2016.

Date (Creation)

2019-05-08

Association Type

Cross reference

Initiative Type

Reference

Title

Bates, N. R., Astor, Y. M., Church, M. J., Currie, K., Dore, J. E., Gonzalez-Davila, M., Lorenzoni, L., Muller-Karger, F., Olafsson, J., and Magdalena Santana-Casiano, J.: A Time-Series View of Changing Surface Ocean Chemistry Due to Ocean Uptake of Anthropogenic CO2 and Ocean Acidification, Oceanography, 27, 126–141, 2014.

Date (Creation)

2019-05-08

Association Type

Cross reference

Initiative Type

Reference

Title

Chau, T. T. T., Gehlen, M., Chevallier, F. : Global Ocean Surface Carbon: MULTIOBS_GLO_BIO_CARBON_SURFACE_REP_015_008, E.U. Copernicus Marine Service Information, DOI:10.48670/moi-00047, 2022a.

Date (Creation)

2019-05-08

Association Type

Cross reference

Initiative Type

Reference

Title

Chau, T. T. T., Gehlen, M., Chevallier, F.: Global mean seawater pH (GLOBAL_OMI_HEALTH_carbon_ph_area_averaged), E.U. Copernicus Marine Service Information, DOI: 10.48670/moi-00224, 2022b.

Date (Creation)

2019-05-08

Association Type

Cross reference

Initiative Type

Reference

Title

Doney, S. C., Balch, W. M., Fabry, V. J., and Feely, R. A.: Ocean Acidification: A critical emerging problem for the ocean sciences, Oceanography, 22, 16–25, 2009.

Date (Creation)

2019-05-08

Association Type

Cross reference

Initiative Type

Reference

Title

Gattuso, J-P., Alexandre Magnan, Raphaël Billé, William WL Cheung, Ella L. Howes, Fortunat Joos, Denis Allemand et al. ""Contrasting futures for ocean and society from different anthropogenic CO2 emissions scenarios."" Science 349, no. 6243 (2015).

Date (Creation)

2019-05-08

Association Type

Cross reference

Initiative Type

Reference

Title

Gehlen, M. et al.: Biogeochemical consequences of ocean acidification and feedback to the Earth system. p. 230, in: Gattuso J.-P. & Hansson L. (Eds.), Ocean acidification. Oxford: Oxford University Press., 2011.

Date (Creation)

2019-05-08

Association Type

Cross reference

Initiative Type

Reference

Title

Gehlen M., Chau T T T., Conchon A., Denvil-Sommer A., Chevallier F., Vrac M., Mejia C. : Ocean acidification. In: Copernicus Marine Service Ocean State Report, Issue 4, Journal of Operational Oceanography, 13:sup1, s88–s91; DOI:10.1080/1755876X.2020.1785097, 2020.

Date (Creation)

2019-05-08

Association Type

Cross reference

Initiative Type

Reference

Title

Lauvset, S. K., Gruber, N., Landschützer, P., Olsen, A., and Tjiputra, J.: Trends and drivers in global surface ocean pH over the past 3 decades, Biogeosciences, 12, 1285–1298, DOI:10.5194/bg-12-1285-2015, 2015.

Date (Creation)

2019-05-08

Association Type

Cross reference

Initiative Type

Reference

Title

Lauvset, S. K., Lange, N., Tanhua, T., Bittig, H. C., Olsen, A., Kozyr, A., Álvarez, M., Becker, S., Brown, P. J., Carter, B. R., Cotrim da Cunha, L., Feely, R. A., van Heuven, S., Hoppema, M., Ishii, M., Jeansson, E., Jutterström, S., Jones, S. D., Karlsen, M. K., Lo Monaco, C., Michaelis, P., Murata, A., Pérez, F. F., Pfeil, B., Schirnick, C., Steinfeldt, R., Suzuki, T., Tilbrook, B., Velo, A., Wanninkhof, R., Woosley, R. J., and Key, R. M.: An updated version of the global interior ocean biogeochemical data product, GLODAPv2.2021, Earth Syst. Sci. Data, 13, 5565–5589, DOI:10.5194/essd-13-5565-2021, 2021.

Date (Creation)

2019-05-08

Association Type

Cross reference

Initiative Type

Reference

Title

Pörtner, H. O. et al. IPCC Special Report on the Ocean and Cryosphere in a Changing Climate (Wiley IPCC Intergovernmental Panel on Climate Change, Geneva, 2019).

Date (Creation)

2019-05-08

Association Type

Cross reference

Initiative Type

Reference

Title

Pérez FF, Olafsson J, Ólafsdóttir SR, Fontela M, Takahashi T. Contrasting drivers and trends of ocean acidification in the subarctic Atlantic. Sci Rep 11, 13991, DOI:10.1038/s41598-021-93324-3, 2021.

Date (Creation)

2019-05-08

Association Type

Cross reference

Initiative Type

Reference

Aggregate Datasetindentifier

aaac4a4d-c782-40b4-b778-f00ab32b65f4

Association Type

Cross reference

Initiative Type

Document

Aggregate Datasetindentifier

78fc6568-0dbf-4d05-a48a-3d93449cfb5b

Association Type

Cross reference

Initiative Type

Document

Aggregate Datasetindentifier

285901b7-7b08-4999-acad-5d5a6a7b054e

Association Type

Cross reference

Initiative Type

Document

Language

eng

Topic category

• Oceans

Description

bounding box

Begin date

1985-01-01

Supplemental Information

display priority: 50700

Codespace

EPSG

Number of dimensions

2

Dimension name

Row

Resolution

1  degree

Dimension name

Column

Resolution

1  degree

Cell geometry

Area

Transformation parameter availability

Distribution format

Name	Version
NetCDF-4

OnLine resource

Protocol	Linkage	Name
WWW:STAC	https://stac.marine.copernicus.eu/metadata/GLOBAL_OMI_HEALTH_carbon_ph_trend/global_omi_health_carbon_ph_trend_202303/dataset.stac.json	global_omi_health_carbon_ph_trend

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

temporal resolution: pluri-annual mean

Descriptor

vertical level number: 1

Included with dataset

Feature types

Grid

Metadata

File identifier

1be14a37-3157-4bce-919d-c40796799fd8

Metadata language

English

Character set

UTF8

Hierarchy level

Series

Hierarchy level name

Copernicus Marine Service product specification

Date stamp

2025-04-22T09:22:23.625801Z

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