Editing Significant wave height

<!-- SIGNAL_EARTH_INFOBOX_START -->
{| class="wikitable" style="float:right; clear:right; margin:0 0 1em 1em; width:320px;"
|+ SIGNAL Earth Structured Data
|-
! Object type
| Damage Signal
|-
! SIGNAL Earth ID
| DS-00773
|-
! Observable type
| Significant wave height
|-
! Unit
| unitless / index or declared physical unit (Provisional unit carried from Step 2 DS-to-OT cleanup review; requires later OT curation if source-specific units diverge.)
|-
! Temporal structure
| —
|-
! Monitoring backbone
| —
|}
<!-- SIGNAL_EARTH_INFOBOX_END -->

is a key oceanographic parameter representing the average height of the highest one-third of waves observed over a given time period. It serves as a canonical measure of ocean wave energy and is critical for understanding coastal processes such as inundation, erosion, and ecological stress on shorelines. This parameter is widely used in marine navigation, coastal engineering, and environmental monitoring to assess wave conditions and their potential impacts.

The significance of wave height extends beyond immediate coastal effects; it influences sediment transport, coastal morphology, and habitat conditions for marine and shoreline ecosystems. Understanding variations in significant wave height contributes to risk assessment for coastal infrastructure and informs scientific studies of ocean-atmosphere interactions.

Within the broader context of ocean physical change, significant wave height integrates information about wind forcing, ocean currents, and bathymetry. It is a fundamental observable in oceanography and is monitored globally through a combination of satellite, in situ, and model-based methods.

== Geographic / System Context ==
Significant wave height is a global oceanographic phenomenon not limited to any specific geographic region. It is relevant across all ocean basins and coastal zones, where wave dynamics interact with local bathymetry and atmospheric conditions. Coastal areas, in particular, experience variations in wave height that influence shoreline morphology and ecological habitats. The parameter is applicable to open ocean environments as well as nearshore zones, making it a versatile indicator of ocean surface conditions worldwide.

== Monitoring and Measurement ==
Monitoring of significant wave height is conducted using a variety of observational platforms and methodologies. Satellite altimetry provides broad spatial coverage by measuring sea surface height variations, enabling estimation of wave heights over large ocean areas. In situ measurements from wave buoys and coastal radar systems offer localized, high-resolution data essential for validating satellite observations and calibrating models. Numerical wave models assimilate observational data to produce reanalyses and forecasts of wave conditions. Institutions such as the U.S. Geological Survey, the U.S. Army Corps of Engineers Coastal and Hydraulics Laboratory, and international agencies contribute to the collection and dissemination of wave height data.

Within the SIGNAL system, significant wave height is treated as a defined environmental signal whose boundaries and measurement conventions are described below.

== Signal Definition ==
Significant wave height is defined as the average height of the highest one-third of ocean surface waves over a specified time interval. It quantifies the canonical state of ocean wave energy and surface roughness relevant to coastal inundation, erosion, and shoreline ecological stress. The measurement is expressed in physical units of length, typically meters, or as a unitless index depending on the data source and processing method.

== Boundary Conditions ==
Boundary inclusions encompass all ocean surface waves contributing to the upper one-third of wave heights within the temporal and spatial sampling window. This includes swell and locally generated wind waves influencing coastal and open ocean environments. Boundary exclusions omit wave phenomena outside the defined temporal averaging period, wave heights below the threshold for the highest one-third classification, and non-wave surface disturbances such as tides or currents. The signal does not include wave energy dissipation processes or subsurface wave interactions.

== Aggregation Semantics ==
Geographic aggregation of significant wave height data typically involves spatial averaging over defined ocean grid cells or coastal segments to characterize regional wave climates. Temporal aggregation may range from hourly to monthly averages depending on monitoring objectives and data resolution. Cross-signal aggregation involves integrating significant wave height with related environmental signals such as coastal erosion extent, flood inundation extent, extreme wind intensity, and mangrove area extent to assess compound coastal hazard dynamics and ecosystem responses. Aggregation practices must consider the heterogeneity of wave conditions and the scales of coastal processes.

== Observational Status ==
Significant wave height is actively monitored through a combination of satellite altimetry, in situ buoy networks, and numerical wave models. Long-term global datasets spanning multiple decades provide calibrated wave height records essential for climate and coastal studies. Ongoing efforts focus on improving measurement accuracy in coastal zones where complex bathymetry and wave interactions challenge observational methods. Future SIGNAL releases may incorporate enhanced temporal resolution, improved coastal data assimilation, and integration with related environmental signals to support comprehensive coastal hazard assessments.

== Related Signals ==
* Coastal erosion extent
* Coastal flood inundation extent
* Extreme wind intensity
* Mangrove area extent

== Key People ==
* Agustinus Ribal
* Ian R. Young
* Ben Timmermans
* Andrew G. P. Shaw
* Christine Gommenginger

<!-- SIGNAL_EARTH_PEOPLE_START -->
== Key Associated People ==
* '''Ian R. Young''' — University of Melbourne [Source author; High]
* '''Agustinus Ribal''' — University of Melbourne [Supporting contributor; High]

Inclusion reflects material contribution to the scientific understanding of this damage signal; it does not imply review, endorsement, or affiliation with SIGNAL Earth.
<!-- SIGNAL_EARTH_PEOPLE_END -->

<!-- SIGNAL_EARTH_SOURCES_START -->
== Sources ==
* [https://www.nature.com/articles/s41597-019-0083-9 33 years of globally calibrated wave height and wind speed data based on altimeter observations] — Scientific Data, 2019. DOI: 10.1038/s41597-019-0083-9. [Dataset; Supporting; High]
* [https://www.nature.com/articles/s41597-022-01459-3 A global ensemble of ocean wave climate statistics from contemporary wave reanalysis and hindcasts] — Scientific Data, 2022. DOI: 10.1038/s41597-022-01459-3. [Dataset; Supporting; High]
<!-- SIGNAL_EARTH_SOURCES_END -->