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DATA QUALITY CONTROL Julie Thomas Coastal Data Information Program (CDIP) Scripps Institution of Oceanography CI Design Workshop 17-19 October 2007 La Jolla, CA ACT QARTOD REAL-TIME CASE STUDY INTERNATIONAL EFFORTS WMO, OceanSITES/Eurosites/IFREMER, JCOMM, …….. ALLIANCE FOR COASTAL TECHNOLOGIES ACT Wave Sensor Technologies University of South Florida, March 7-9 2007 By Bill O’Reilly Directional Wave Observations 1) The Basics 2) Remote Sensing v. In Situ : It’s all good. 3) Estimating directional wave properties. 4) Measurement accuracy and user needs. 5) A Recipe for instrument evaluation. The Basics: Estimating the Motion of a Sea Surface Particle z z dz/dx, dz/dy y x w The Big 3 v u X, Y, Z Pressure Sensors Accelerometers Tilt sensors Angular Rate Sensors Acoustic Sensors Radar Lidar In-Situ and Remotely Sensed Waves Method O(cm) X,Y,Z Accuracy Spatial Coverage Time Coverage In situ SAR,LIDAR HF, X-Band Radar In situ and remote sensing systems are complimentary, NOT redundant. XYZ TIME SERIES The Big 3: X, Y, Z Time Series Analysis The First 5: S(f),a1(f),b1(f),a2(f),b2(f) !! S Theoretical maximum level of breaking wave in a fully developed sea Each box represents the number of hourly observation – Datawell Buoy Mark II w/ hippy used as data source (standard). GPS instrument dropped out during low Frequency – causing spikes in data Instruments tend to disagree as they are interpreting sea surface differently under breaking wave conditions. Comparison between a Datawell Buoy w/ hippy and a PROTOTYPE Datawell w/ GPS. Low numbers indicate good correlations. Instruments Were co-located. Datawell w/ hippy and Datawell w/ GPS tend to agree well with wave direction. Note how both instruments reach their noise floor during long period, low energy events. GPS antenna on top of the buoy has a “natural” noise when it wobbles – a method has been devised to correct for this problem. Directional spread is where many instruments fall apart! Good indication of the quality of the instrument – demonstrates their directional noise level! QUALITY ASSURANCE OF REAL-TIME DATA QARTOD http://qartod.org QARTOD is a continuing multi-agency effort to address the Quality Assurance and Quality Control issues of the Integrated Ocean Observing System (IOOS) and broader international community. Quality Control standards have been submitted to DMAC for both waves and Currents. Ocean.US is now soliciting submissions from the Regional Associations for all standards including QA/QC. The QARTOD submissions Will be posted soon on the Ocean.US website. Parameters addressed through QARTOD: Waves, In-situ Currents, Remote Currents (HF RADAR), CTDs, Dissolved Oxygen. Collaborated with DMAC Metadata team for a one day appended workshop During QARTOD IV, June 2006. Quality Assurance (QA) – Verify that instrumentation is calibrated and tested to assure collection of the highest quality data possible. Quality Control (QC) – Analyze and verify the data stream to assure the highest quality data possible. http://qartod.org http://cdip.ucsd.edu/documents/index/product_docs/qc_summaries/waves/waves_table.php VALIDATION CASE STUDY - Real-time Buoy Data OREGON Humboldt Bay South Spit (128) CALIFORNIA Eel River Cape Mendocino (094) NDBC BUOY 46022, EEL RIVER, re-deployed this summer with 3DMG sensor. 46022 is 34 miles away from buoy 46213 (CDIP Datawell Buoy Station 094). Full spectra looks ok at first glance! Noisy directional spread Under predicts LONG PERIOD SWELL (12-33 sec) 46022 under predicts low frequency waves. Buoys are moored 34 miles apart. Part of this difference in the high frequency could be caused by local sea conditions. Comparison of the Datawell /hippy and the NDBC 46022 (Eel River Buoy) w/ 3DMG sensor . Why is directional spread important? Why do we need accurate wave measurements? The models are only as good as their input source. In Southern California, for instance, 5 degrees can make a big difference in how much energy reaches the beach. Let’s come together as an IOOS community and further validate our wave instrumentation!