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  • C-CORE 1.11 Sea level

 

 Sea level

Challenge ID

C-CORE_OFF1.11

Title

Sea level

Challenge originator:

 

General Description

 

What data/products do you use?

Historical sea level heights are available in the form of remotely-sensed satellite observations via DEOS-RADS.

Near real-time sea level heights are also available in the form of remotely-sensed satellite observations of sea heights from NOAA (STAR) and DEOS-RADS.

Global Sea Level mean based on satellite observations:

When do you use this kind of dataset?

Sea levels data sets area used to assess the most likely interval of the sea surface in the area of interest. The data is crucial where there are chances of strong storm surges, large variations of tidal height, but also where wave heights are likely to add to the sea level. The data are used to qualify and quantify the means and extremes of sea heights. Air gap analysis for jack-up rigs and fixed platforms, seismic survey (to calibrate data), mooring analysis are some uses.

What are your actual limitations and do you have a work around? 

The primary limitation of historical and near real-time sea level heights is that the remotely-sensed satellite observations are not continuous. Modelled data of tidal level and pressure effects are used instead, but wind induced effects are not well represented. Hence these are estimated based on wind data, but are not as accurate as measurements.

(Also, improved measurements of sea level heights - high frequency, high resolution - will improve modelling of currents.)

Needs and expectations on EO data

EO is used for this today and probably the best source offshore. However resolution could be better.

Specific need: Hourly time series of observed sea heights, ideally ≥ 19 years.

Challenge classification

 

Pre license

1

Exp.

3

Dev.

4

Prod.

4

Decom.

3

Geographic context/ restrictions

Applies to all six areas of interest.

Seasonality: Applies to all seasons.

Topographic classification / Offshore classification

Ocean

Activity impacted/concerned

 

Technology Urgency

Short term (2-5 years)

Information requirements

 

Update frequency

Multiple times per day from polar-orbiting satellites. Sufficient.

Temporal resolution

At least daily.

Available:
Remotely-sensed satellite observation: sub-daily to less frequently

Spatial resolution

50-10 km.
Available: Remotely-sensed satellite observation: varies based on platform scanning swath size and other parameters

Data quality

The selected sources in this document are selected because they are known to have sufficient quality (after some work arounds and adaptations). In general separate indepth verification studies has to be made for each source planned to be used for analysis, and the analysis has to be repeated for each geographical area (since sources might be of sufficient quality in one area but not another).

Data Coverage and extent

Regional

Example format

text

Timeliness

Daily, weekly or monthly is sufficient.

Existing standards

Paragraph 11.1 of HSE OTR 2001/010 states: Metocean parameters are
required describing wave or sea state heights, wave lengths, periods and direction, current speed and directions, sea level and (if they are likely to cause significant stress ranges) wind speeds.

Paragraph 3.15 of ISO 19901-1:2005(E) states: The Mean Sea Level (MSL) is the arithmetic mean of all sea levels measured at hourly intervals over a long period, ideally 19 years.

Paragraph 6.7 of NORSOK-N-003e2 states: Characteristic values of individual environmental actions are defined by annual exceedance probabilities. (Note: The sea level thresholds are shown in Table 4 beneath Paragraph 6.7.)

 

 

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