Richard L. Crout

U.S. IOOS Program Office Quality Assurance of Real-Time Ocean Data Project

The Quality Assurance of Real-Time Ocean Data (QARTOD) Project is an activity of the U.S. Integrated Ocean Observing System (IOOS) Program Office designed to establish and document the minimum quality control and quality assurance procedures a non-federal Regional Information Coordination Entity must perform to meet certification criteria. Regional entities like the Gulf of Mexico Coastal Ocean Observing System Regional Association, and others, expect to benefit from certification by gaining federal protection from civil liability associated with dissemination and use of IOOS data and by becoming eligible to compete for future funding opportunities which may require certification. More importantly, these procedures will help ensure that only valid qualified data are inserted into and redistributed by the national data system.

National Data Buoy Center transition of the Tropical Atmosphere Ocean (TAO) program

The National Oceanic and Atmospheric Administrations (NOAAs) National Data Buoy Center (NDBC) operates and maintains 55 Tropical Atmosphere Ocean (TAO) buoys in the equatorial Pacific Ocean from 9°N latitude to 8°S latitude and 95°W longitude to 165°E longitude. The TAO array was developed after the need was determined following the 1982–1983 El Niño event, which had evaded detection by the science community until well into its maturity. NOAAs Office of Oceanic and Atmospheric Research (OAR) Pacific Marine Environmental Laboratory (PMEL) is an interdisciplinary organization whose focal point is collecting open ocean data for monitoring and predicting purposes. PMELs TAO project was created with help from NOAAs Equatorial Pacific Ocean Climate Studies (EPOCS) program to enhance the understanding and prediction of El Niño and La Niña events. PMEL completed the TAO array in December of 1994 and in 2005, PMEL began transitioning the TAO array (55 TAO buoys and four Acoustic Doppler Current Profilers (ADCPs)) to NDBC, first in data management and quality control (QC) and later in next-generation creation and implementation of buoys.

The Great Coastal Gale of 2007 from Coastal Storms Program Buoy 46089

During the first three days of December 2007, a series of powerful coastal storms and an associated wave approached the coasts of Washington, Oregon, and British Columbia in rapid succession. The winter storms pummeled the states with a maximum 220 kilometers per hour gust along the coast and generated the first-ever hurricane warning in the Pacific Northwest by the National Weather Service. The Coastal Storms Program of the National Oceanic and Atmospheric Administration had the National Data Buoy Center deploy a three meter discuss buoy 150 kilometers west of Tillamook, OR to monitor just this type of storm. The buoy was moored in 2200 meters of water in 2005. Although two other buoys closer to the coast were torn from their moorings, the CSP Tillamook buoy remained on station and reported wind speed and direction, barometric pressure, air temperature, waves, and currents throughout the storms. Water temperature and a redundant wind sensor failed during 3 December. The redundant wind sensor failed as the winds approached 23 m/s. The buoy survived storm generated significant wave heights that exceeded 14 meters and remained on station and reporting until the buoy was recovered in February 2008. Upon recovery, it was discovered that the wind fin that orients the buoy into the wind was bent against the buoy structure, resulting in stress fractures in the metal at several locations. Waves and currents continued to be measured and transmitted during and after the storm. The data are presented in an effort to determine the impact of waves and buoy motion on current profile data.

Preliminary results of comparisons between Tropical Atmosphere Ocean (TAO) oceanographic refresh and Legacy sensors

As part of the transition of the Tropical Atmosphere Ocean (TAO) program, NOAAs National Data Buoy Center (NDBC) is testing commercial off-the-shelf (COTS) components to replace obsolescent sensors. The ldquorefreshrdquo of TAO will also include changing to a transmission system that allows hourly receipt of high-resolution data, and incorporating a new payload. Six refresh buoys will be deployed within 10 kilometers of existing TAO buoys. Meteorological and ocean sensors will be compared in order to verify that the refresh system replicates the data provided by the ldquolegacyrdquo TAO system. Two refresh buoys have already been deployed along the TAO 140degW line at 9degN and 2degS. . An analysis of the first three months of oceanographic data from these two buoys is presented and discussed. The temperature sensors were compared in a laboratory setting and the results were very good. While the ocean temperatures from the refresh buoys are reported at ten minutes intervals every hour via the Iridium satellite constellation, the legacy buoys report ten minute data over Service ARGOS as the polar satellites pass the buoys. At the 2degS,140degW site, eight of the ten ocean temperature sensors reported data that is statistically equivalent to the legacy buoy temperatures. The other two refresh temperature sensors at 20 and 80 meter depths failed to report. Five of the ten ocean temperature sensors at the 9degN, 140degW site reported statistically equivalent data. Data from two of the legacy TAO sensors were failed by TAO analysts prior to deployment of the TAO program. Comparison of the other three temperature sensors yielded results that were not statistically equivalent. The region between 40 and 120 meters depth is characterized by a sharp temperature gradient. The environment may be responsible for the variability between the sensors in this region. Following recovery of the legacy and refresh buoys during fall 2008, the 10 minute data from the temperature sensors will be downloaded and NDBC and the NOAAs Pacific Marine Environmental Laboratory will perform an in-depth analysis.

National Data Buoy Center (NDBC) Processing, Display, and Observation of Near-Bottom Currents Acquired by Oil and Gas Companies in the Northern Gulf of Mexico

Under a Notice to Lessees (NTL No. 2005-G05) issued by the Minerals Management Service in April 2005, oil companies operating in the northern Gulf of Mexico in waters deeper than 400 meters are required to collect current profile data to a depth of 1000 meters. These data provide estimates of strong ocean currents, which may affect extreme loads, structural failure, and daily operations on the oil platforms and drilling rigs. Real-time data from near the surface to 1000 meters are reported every 20 minutes to the National Data Buoy Center (NDBC) and displayed on their public website. The oil and gas companies must also measure near- bottom currents at sites deeper than 1100 meters and recover and report these data at least every six months. These delayed-mode data are the subject of this effort. NDBC began accepting real-time current profile data in April 2005 and implemented real-time quality control of the data in March 2006 [1]. In August 2006, NDBC received four files containing the near-bottom, delayed-mode data. The data were processed through the same quality control algorithms and stored along with previously processed near-surface data. Since that time eighty-four additional data sets have been received and processed through the quality control algorithms at NDBC. Tables of these data with quality control flags and current velocity plots with depth are available to the general public on the NDBC website. One of the first delayed-mode data sets was collected from the Na Kika platform, approximately 100 kilometers south-east of the Mississippi River delta, during the active Hurricane season of 2005. The data from August 2005 showed greater than 0.30 cm/s currents at depths greater than 1900 meters to the right of the path of Hurricane Katrina. The currents rotated clockwise in the bottom waters at a period less than 24 hours and decayed over a period of nearly ten days. Although Hurricane Rita passed 360 kilometers to the southwest of the Na Kika platform in late September 2005, the bottom waters were impacted by the passage. The currents were not as strong as those related to Hurricane Katrina, but they were noticeable and lasted for several days. There are no near-surface data sets to corroborate these data because the platforms were evacuated due to the hurricanes. These results indicate a basin-wide response to these two strong hurricanes.

Mobile Bay response to a strong autumn cold front passage

Mobile Bay is a shallow embayment in Alabama bordering the northern Gulf of Mexico. A cold front passage during October 2000 decreased air temperatures from 27/spl deg/C to 9/spl deg/C and was accompanied by winds from the north in excess of 16 m/s. The winds generated a significant water level decrease throughout Mobile Bay over a three-day period. Water level decreases occurred in the northern end of Mobile Bay (0.73 m), at the southern end of the bay (0.27 m), and on the Gulf of Mexico shelf (0.30 m). Winds from four meteorological stations and water levels from six tide stations were low pass filtered. The low frequency response of water level to the winds accompanying the cold front passage was analyzed. The amount of water level change in the bay was related to the location of the tide station. Correlations between the water level and northerly component of the wind were high and the correlations between the individual water level stations indicate that the water was transported southward over 12 hours. The analysis is consistent with a sustained northerly wind blowing down the axis of Mobile Bay and lowering water level at all locations within the bay. The water exits through the Mobile Bay Ship Channel and flows across the inner shelf. Satellite-derived sea surface temperatures show the plume moving southwestward over a six-day period.

Complexity of near-bottom ocean currents in the northern Gulf of Mexico from a sea-bed ADCP

The oceanography of the northern Gulf of Mexico is complex. The Loop Current dominates the eastern half of the Gulf and a-periodically shed anti-cyclonic Loop Eddies that move into the western Gulf of Mexico. Wind-generated inertial waves move throughout the water column, carrying surface energy to depth. Stronger inertial currents associated with storm events, including cold front passages. Energy from tropical cyclone winds has been shown to impact near-bottom currents in water nearly two kilometers deep. Topographic Rossby Waves (TRWs), apparently generated by interactions associated with Loop Current and Loop Eddy processes, travel through the northern Gulf of Mexico and accelerate near-bottom currents. Current profile data from a bottom-mounted acoustic Doppler current profiler (ADCP) at 1300 meters depth in Green Canyon Block 645, south of the Atchafalaya Bay in Louisiana, are analyzed to investigate these phenomena. The seabed mounted 75 kHz ADCP was installed in June 2005 in response to a Notice to Lessees by the Bureau of Ocean Energy Management to collect data to insure the safety of drilling and production platforms. The innovative design, supplying power and recovering data from the ADCP via a tether, allows almost continuous receipt of data. The 75 kHz ADCP collects data in 20 meter bins to 500 meters above the ocean bottom at 20 minute intervals. As with all current profile data required by the NTL, the data are transmitted to the National Data Buoy Center (NDBC) where they are quality controlled and transmitted to the worlds numerical prediction centers. Copies of the raw binary data and the quality controlled data are maintained at NDBC. Statistical and spectral analysis indicates a complex current structure temporally and vertically. Yearly averaged currents are approximately 5 cm/s from May 2005 through May 2010. At 1200 meters, the yearly averaged data range between 3.8 and 5.0 cm/s. The spectral analysis indicates that energy at 1000 and 1200 meter depths are dominated by processes near the inertial frequency (26.08 hours) and in the 17-20 day band that is related to Topographic Rossby Waves (TRWs). At 1000 meters, the energy in the two bands is approximately equal. Energy in the TRW frequency band exceeds that in the inertial frequency band at 1200 meters depth. Although the inertial currents are obvious in the data record, they weaken with depth. Individual time series are investigated to determine the impact of Loop Current Eddies and Gulf of Mexico hurricanes Katrina, Rita, Gustav, and Ike. Periodic currents at approximately 20-day intervals are obvious in the time series data following Loop Eddy generation. A common Loop Eddy path following eddy shedding is near the Green Canyon 645 site. Time series records show intense near-bottom currents. The highest speed currents at this location, exceeding 35 cm/s are associated with the passage of nearby Loop Eddies. Hurricanes also pass near the Green Canyon site and the near bottom currents respond on a delayed basis.

Ocean data integration: Successes and lessons learned from the bleeding edge

NOAAs Center for Operational Oceanographic Products and Services (CO-OPS), National Data Buoy Center (NDBC) and the U.S. Integrated Ocean Observing System (IOOS®) Program Office have collaborated for several years on a major data integration project to increase interoperability between data providers and the user community. The ultimate goal of the collaboration was to better serve the information needs of researchers, scientists, operational managers, and the public. In this CWP, we provide some background on the motivation and justification for why CO-OPS and NDBC participated in this effort and elaborate on some of the experiences of these two Federal partners during that project. We enumerate a series of general outcomes of the project and identify lessons learned by CO-OPS, NDBC, and the larger IOOS data management community. Finally, we provide suggestions for community wide expansion of select data integration technologies, where they fit in a larger Data Management and Communications (DMAC) architecture and comments on the unique roles of CO-OPS and NDBC as essential elements of the observational and data management infrastructure of the Integrated Ocean Observing System.

Internal wave signatures in the Tropical Atmosphere Ocean array from paired moorings

In order to replace obsolescent sensors in the Tropical Atmosphere Ocean (TAO) array and comply with the Ten Climate Principles, twenty-nine TAO Refresh buoys were deployed near paired TAO Legacy buoys for approximately one year each. At the end of each deployment, a statistical comparison of the daily averaged data was conducted for each pair of sensors. The results are summarized elsewhere. The subsurface ocean temperature sensor comparisons provided some unexpected results. While the average ocean temperature differences within the mixed-layer and at depth were nearly identical, average temperature differences in the thermocline were higher than expected and not within the statistical accuracy of the sensors. A comparison of the variability of the paired ocean temperature sensors and the amount of drift that occurred during each deployment led to the conclusion that the TAO Refresh sensors were reporting the same oceanographic phenomena as the TAO Legacy sensors. Closer examination of the high resolution (10-minute interval) ocean temperature data within the thermocline exhibited internal wavelike signatures. At some locations within the water column, the temperature at a single depth changes 10 Kelvins over a period of 10 minutes. Although this is an extreme example, it indicates the difficulty in comparing the data from sensors on moorings which were generally less than 5 kilometers apart. The internal wavelike signatures range from small to greater than 100 meter amplitudes. Attempts to apply a phase shift to the data to compensate for the movement of these features were unsuccessful, suggesting that the internal wave signatures were arriving from different directions at various times. These phenomena are prevalent throughout the TAO array.

Use of existing current profiling assets in the Gulf of Mexico to support the Deepwater Horizon response

The explosion and collapse of the Deepwater Horizon drilling rig in Mississippi Canyon Block 252 (MC-252) in the Gulf of Mexico in mid-April 2010 began the largest release of oil into the environment in US history. From 23 April, when the first oil sheen was noted on the surface, until 15 July, when the well was capped, oil flowed at varying rates from 1500 meters below the surface. Because of the high rate of flow and the use of dispersants, a cloud of oil and gas droplets was trapped between 1000 and 1300 meters depth. As the cloud was moved away by ambient currents, new oil and gas was added to the cloud.