Tide Gauge Network

One possible comparison is between altimetry data and measurements of in situ networks. Several such networks exist over the ocean, like the tide gauges, Argo... They provide a more or less global coverage during several years, and are completely independent from altimeters, which makes the comparison interesting and allows the validation of altimetry.

Tide gauge network used for altimetry validation (CLS). Click on each icon to access to each tide gauge fact sheet.

<dfn>Tide</dfn> Gauge network

Credits CLS/Cnes/SHOM/UHSLC

The used tide gauges are the property of SHOM and LEGOS and are available on the REFMAR website (refmar.shom.fr)

	No satellite checking the criteria
	1 satellite checking the criteria
	2 satellites checking the criteria
	3 satellites checking the criteria
	at least 4 satellites checking the criteria

Cross comparison Indicators relative to the comparison between altimetry and tide gauges : for each tide gauge, the criteria defined below allow determining the relevance of an altimetric mission in the estimation of the quality of the in-situ time series.

Criteria:

correlation altimetry/tide gauge > 0.7 within 100 km around the tide gauge
rms of the differences between the altimetric and the tide gauge time series < 10 cm

Consequently, a green indicator will attest of the relevence of a tide gauge time series with the comparison to altimetry (at least 4 satellites checking the criteria). A black indicator does not indicate necessarily a bad quality of a tide gauge time series but maybe for example simply that there isn't any altimeter data recovering the temporal period of the tide gauge and thus that the tide gauge will not be used in the assessment/validation of altimetric data.