• Catalogue PIGMA
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Global Ocean, extreme and mean significant wave height trends from satellite observations - seasonal trends

'''DEFINITION'''

Significant wave height (SWH), expressed in metres, is the average height of the highest one-third of waves. This OMI provides time series of seasonal mean and extreme SWH values in three oceanic regions as well as their trends from 2002 to 2020, computed from the reprocessed global L4 SWH product (WAVE_GLO_PHY_SWH_L4_MY_014_007). The extreme SWH is defined as the 95th percentile of the daily maximum of SWH over the chosen period and region. The 95th percentile represents the value below which 95% of the data points fall, indicating higher wave heights than usual. The mean and the 95th percentile of SWH are calculated for two seasons of the year to take into account the seasonal variability of waves (January, February, and March, and July, August, and September) and are in m while the trends are in cm/yr.

'''CONTEXT'''

Grasping the nature of global ocean surface waves, their variability, and their long-term interannual shifts is essential for climate research and diverse oceanic and coastal applications. The sixth IPCC Assessment Report underscores the significant role waves play in extreme sea level events (Mentaschi et al., 2017), flooding (Storlazzi et al., 2018), and coastal erosion (Barnard et al., 2017). Additionally, waves impact ocean circulation and mediate interactions between air and sea (Donelan et al., 1997) as well as sea-ice interactions (Thomas et al., 2019). Studying these long-term and interannual changes demands precise time series data spanning several decades. Until now, such records have been available only from global model reanalyses or localised in situ observations. While buoy data are valuable, they offer limited local insights and are especially scarce in the southern hemisphere. In contrast, altimeters deliver global, high-quality measurements of significant wave heights (SWH) (Gommenginger et al., 2002). The growing satellite record of SWH now facilitates more extensive global and long-term analyses. By using SWH data from a multi-mission altimetric product from 2002 to 2020, we can calculate global mean SWH and extreme SWH and evaluate their trends.

'''KEY FINDINGS'''

Over the period from 2002 to 2020, positive trends in both Significant Wave Height (SWH) and extreme SWH are mostly found in the southern hemisphere. The 95th percentile of wave heights (q95), increases more rapidly than the average values, indicating that extreme waves are growing faster than the average wave height. In the North Atlantic, SWH has increased in summertime (July August September) and decreased during the wintertime: the trend for the 95th percentile SWH is decreasing by 2.1 ± 3.3 cm/year, while the mean SWH shows a decreasing trend of 2.2 ± 1.76 cm/year. In the south of Australia, in boreal winter, the 95th percentile SWH is increasing at a rate of 2.6 ± 1.5 cm/year (a), with the mean SWH increasing by 0.7 ± 0.64 cm/year (b). Finally, in the Antarctic Circumpolar Current, also in boreal winter, the 95th percentile SWH trend is 3.2 ± 2.15 cm/year (a) and the mean SWH trend is 1.4 ± 0.82 cm/year (b). This variation highlights that waves evolve differently across different basins and seasons, illustrating the complex and region-specific nature of wave height trends. A full discussion regarding this OMI can be found in A. Laloue et al. (2024).

'''DOI (product):'''

https://doi.org/10.48670/mds-00352

Simple

Alternate title
OMI_EXTREME_SEASTATE_GLOBAL_swh_mean_and_P95_obs
Date (Creation)
2024-11-26
Edition
3.4
Edition date
2024-11-26
Identifier
a78600a4-a280-47b5-8ddd-0dc8b5e9c9d9
Credit
E.U. Copernicus Marine Service Information
Resource provider
  WAVE-CLS-TOULOUSE-FR -
Maintenance and update frequency
Unknown
Other
P0M0D0H/P0M0D0H
Maintenance note
N/A
GEMET - INSPIRE themes, version 1.0
  • Oceanographic geographical features
Discipline
  • satellite-observation
Climate and Forecast Standard Names
  • sea_surface_wave_significant_height_seasonal_mean
  • sea_surface_wave_significant_height_seasonal_95percentile
  • sea_surface_wave_significant_height_mean_trend
  • sea_surface_wave_significant_height_95percentile_trend
  • sea_surface_significant_height_seasonal_number_of_observations
  • sea_surface_significant_height
  • sea_surface_significant_height_trend_uncertainty_95percentile
  • sea_surface_significant_height_trend_uncertainty_mean
Temporal scale
  • multi-year
Area of benefit
  • weather-climate-and-seasonal-forecasting
  • coastal-marine-environment
  • marine-safety
  • marine-resources
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 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
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
3880057d-d1ad-4fd9-b93a-e0cf3fbb7084
Association Type
Cross reference
Initiative Type
document
Aggregate Datasetindentifier
31a1122d-e74c-420a-a586-ff33cd1115ee
Association Type
Cross reference
Initiative Type
document
Aggregate Datasetindentifier
94dfa859-f336-463d-a175-1679b80961c0
Association Type
Cross reference
Initiative Type
document
Metadata language
eng
Topic category
  • Oceans
Description
bounding box
N
S
E
W
thumbnail


Begin date
2001-11-15

Vertical extent

Vertical CRS
  • urn:ogc:def:crs:EPSG:5714
Supplemental Information
display priority: 53800
Codespace
EPSG
Number of dimensions
2
Dimension name
Row
Dimension name
Column
Cell geometry
Area
Transformation parameter availability
No
Distribution format
  • NetCDF-4 ( )

Distributor

OnLine resource
omi_extreme_seastate_global_swh_mean_and_p95_obs ( WWW:STAC )

For accessing native data and Analysis-ready Cloud-optimized data services, consult this STAC metadata endpoint

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
timeseries
File identifier
fd526e1b-b581-40b4-b1a8-45278a9a4dd2 XML
Metadata language
English
Character set
UTF8
Hierarchy level
Series
Hierarchy level name
Copernicus Marine Service product specification
Date stamp
2025-04-28T13:11:09.739557Z
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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