DBCP issues for OOPC

OOPC-XII, Paris, 2-5 May 2007

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DBCP issues for OOPC

Boram Lee

IOC Secretariat for JCOMM


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• Requirement on SST Measurement

• Requirement on Wave Measurement

• Any other issue(s)


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Requirement on SST Measurement

DBCP Data Users and Technology Workshop (27-28 March 2006, Reading)

• Requirements expressed for drifter SST– Predicting AT, RH, through satellite SST and wind

– SST analysis (e.g. Reynolds) for NWP and ocean/climate modelling

– GHRSST: Resolving the SST Diurnal Cycle globally, seasonally in extreme events.

• Workshop agreed that this was feasible and asked DBCP to proceed

• DBCP-22 asked OOPC to provide detailed rationale and documentation for this requirement


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Timeliness (driven by NWP requirements)• better Argos network of local receiving stations, • use of Argos multi-satellite service, and• use of other satellite data telecommunications systems (e.g.

Iridium)

Resolution: “provide for hourly data, at the hour”

Quality • existing quality information monitoring activities and feed back

mechanisms (e.g. buoy QC guidelines)• Advertise known quality of buoy data in order to build confidence

Quantity• Increase deployments or deployment strategies in certain regions

↔ Capacity Building, Coordinate with GOOS Regional Alliance


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NWPClimate variability, predictability, ocean modeling, climate forecast

Space resolution

250x250km threshold for MSLP; all drifters with barometers; study needed on drifters escaping into tropical regions; MSLP needed in tropical regions for hurricane prediction and tracking; impact of wind (TAO) in tropical regions demonstrated

SST: 5 degreesSSS: 200kmWind: 2 degreesT profiles: 1m then 5m down to 200mSurface velocity: 600kmSea ice velocity: 200 km

Time resolution

MSLP: Hourly SST: High resolution hourly data required for diurnal cycle resolution

SST: 25 samples per weekSSS: 1 sample per 10 daysWind: 1 to 4 samples per 1 to 2 daysT profiles: Surface velocity: 1 sample per monthSea ice velocity: 1 sample per day

Timeliness <3H at main synoptic hours (global models); forecasters need timely data. NWP requirements will be sufficient for all other applications.

Quality Time of observation: 10 minutesMSLP: 0.6 hPaSST: 0.5CWind: 5m/s for tropics; quickscat needs in situ wind in rain conditions; wind 10 min. averages; turbulence: desirable e.g. gustiness W Pacific (research)

SST: 0.2CSSS: 0.1 psuWind: 0.1 to 1 m/sT profiles: Surface velocity: 2cm/sSea ice velocity: 1cm/s

Metadata Real time: Anemometer height; instrument height; measurement technique (acoustic, WOTAN, cup ...)

SST: High resolution hourly data required for diurnal cycle resolution


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Issues: “hourly data, at the hour”• Stable clock adds cost

– e.g., controller with Temp Compensated Crystal Oscillator, ±1 min/yr at 0—40ºC.

• GPS adds cost but …– provides additional location, accuracy, frequency

• Argos does not provide for real-time hourly reports

What is an “hourly” SST value? Instantaneous value at top of hour, average over surrounding 15 minutes, or 60 minutes?


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Recommendations to OOPC:• Precise statement of OOPC requirements needed to

ascertain whether/what new technological developments are required– real time requirements– clarification of the definition of hourly SST value

• sampling period• averaging period• averaging period ending on the hour or centred on the hour• timing accuracy, etc.

• advise on technical solutions (adding a temperature compensated crystal oscillator (TCXO) or using GPS)

The DBCP Evaluation Group will look at practical technical solutions in more detail and work on cost impacts once the requirements became available.


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Requirement on enhanced high-quality, long-term wave measurements

Needs for:• Ocean wave climatology and variability;• Air-sea interaction;• Assimilation into offshore wave forecast models; • Validation of wave forecast models; • Calibration / validation of satellite wave sensors.

The primary requirement: additional wave measurements • Comprising (at a minimum) significant wave height, peak

period and 1-D spectra, hourly in real-time, for assimilation into coupled atmosphere-ocean wave models for real-time forecasting activities, and subsequent verification


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Currently, the vast majority of existing wave measurements were made in the coastal margins of North America and western Europe, with a huge data void in most of the rest of the global ocean, particularly in the southern ocean and the tropics.

* Non-moored wave observations



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DBCP-22 (October 2006, La Jolla)• recommend adding wave measurements to the DBCP

Implementation Strategy;• invite buoy operators and Panel Members to increase wave

measurements, particularly from open ocean areas, in the Southern Ocean, and the tropics;

• invite the DBCP Evaluation Group to address wave measurement technology issues and to communicate with the ETWS and OOPC on user requirements;

• recommend JCOMM/OCG to address the broader issues in terms of technological development and implementation, including wave measurements from Ocean Sites, Argo, drifters, Triton/TAO/PIRATA and shipboard systems;

• urge the ETWS to work with the JCOMM OPA to put forward a more detailed set of requirements for additional high-quality wave measurements



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ETWS draft of the table:Requirements for surface wave observations http://www.jcomm-services.org/ETWS-Observation-Requirements.html

Advice/Comments ?



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What new variables might in due course be

usefully implemented on data buoys (e.g. pCO2) ?

Other Issue(s)


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DBCP status

DBCP issues for OOPC

Documents

Transcript of DBCP issues for OOPC