SALIENT FEATURES OF INDIAN DEEP SEA INSTRUMENTED BUOY NETWORK IN THE BAY OF BENGAL.
by
R. Venkatesan, Arul Muthiah, Simi Mathew and V. R. Shamji, National Institute of Ocean Technology, India

The Bay of Bengal a semi-enclosed sea which plays a foremost role in predicting the monsoon system over the Asian region with its highly stratified waters and the reversal of winds and current with the march of each season. The high concentration of heat in the surface layer along with favorable atmospheric component always favor development of more than three to four low pressure systems in this region every year. The high river discharge in the northern bay makes it a region of low saline water especially during the southwest monsoon season and the advection of these water mass along with the prevailing current makes the water in the bay highly stratified. India has also joined the elite group of nations which has buoy systems for studying the underwater scenarios like PIRATA in the Atlantic, TAO/TRITON in the Pacific which is very crucial for real time observation and for assimilation of data into model for better prediction. The Ocean Moored Network for the Northern Indian Ocean (OMNI) is an initiative by the Ministry of Earth Sciences, Government of India to collect oceanographic data with special emphasis on subsurface measurement of temperature, conductivity and current. Considering the scientific importance of these data sets at present there are six OMNI and six RAMA buoys in the Bay of Bengal in addition to the existing Met-Ocean buoys which was operational since 1997. The OMNI buoy network came into operational with the deployment of two buoy systems BD13 and BD14 at 86E, 11N and 85E, 8N respectively during October, 2010 in the Bay of Bengal. The time series data with high temporal resolution is the highlight of moored buoy program in the Indian Ocean which is very crucial for the Asian monsoon prediction. In order to understand the factor which is more pre-dominant in interfering the data transmission from the buoy system a detailed study of the telemetry data obtained from two buoys each of RAMA and OMNI were studied for a period of 517 days, during November, 2010 to March, 2012. The OMNI buoys BD13 and BD14 had to face three to four cases of vandalism during this period. Both RAMA and OMNI buoy has subsurface sensors; especially Conductivity-Temperature sensor at discrete depth which can also store data internally. A comparison has been done between the average transmitted data per deployment for all the six RAMA buoys as well as OMNI buoys in the northern Bay of Bengal for a period of ten months, June, 2011 to March, 2012. Further Indian buoy system are equipped with wave sensors with three each at OMNI and Met Ocean buoy locations in the Bay of Bengal. The OMNI buoys are also equipped with pyrgeometer and pyranometers for measuring the downward long wave radiation and solar irradiance respectively which is very crucial for the heat budget studies. There are enormous rain gauges over land for measuring the rainfall data but such measurement over ocean is very sparse. All the six OMNI buoys are equipped with rain gauge to measure the quantity of rain occurred over the Bay of Bengal. Special care has been taken to include the high peaks in the data especially associated with cyclonic storm and heavy spells during southwest monsoon period with the hourly data record. It is planned to expand the network of moored buoy system in the Arabian Sea with the deployment of five OMNI buoys by the end of 2012. Piracy is another challenge faced which is partly overcome with help of armed guards. These OMNI buoy systems have overcome technological challenge to transmit data hourly through INMARSAT. The data reception centre is upgraded with servers and other redundancy facility. This paper describes these unique features in detail.

THE USE OF TSUNAMETER OBSERVATIONS WITHIN THE AUSTRALIAN TSUNAMI WARNING SYSTEM
by
Diana Greenslade, Centre for Australian Weather and Climate Research, Bureau of Meteorology, Australia
Peter Coburn, National Meteorological and Oceanographic Centre, Bureau of Meteorology, Australia
Brian Ingham, Observations and Engineering Branch, Bureau of Meteorology, Australia

The Bureau of Meteorology currently owns and operates 9 tsunameters which are deployed in the oceans around Australia, with 6 of them forming a core network. Real-time observations from these tsunameters are displayed within the Joint Australian Tsunami Warning Centre (JATWC) at the Bureau, sent to the World Meteorological Organisation’s Global Telecommunications System (GTS) and provided to the U.S. National Data Buoy Center (NDBC). The primary use of the data within the JATWC is for confirmation of the existence of a tsunami. When a potentially tsunamigenic earthquake occurs duty staff look for tsunami wave signals in the tsunameter data, assess whether the observed tsunami matches that predicted from the numerical model-based forecast system and use that information in framing the tsunami warnings they issue.

The tsunameter observations are also used for research and development in support of the JATWC. This has predominantly been for post-event verification and scenario selection for event-based inundation studies. A recent tsunami hazard assessment study for New South Wales demonstrated that coastal sea-level can be reproduced more accurately for those historical events for which tsunameter data exists (e.g. Japan 2011, Chile 2010, New Zealand 2009) than for events for which no tsunameter data exists (e.g. Chile 1960, Solomon Is. 2007).

Work is currently underway to develop an operational system to objectively assimilate the tsunameter data in order to provide improved real-time tsunami forecasts and warnings. An overview of the proposed system will be presented.

UPDATE ON INDIAN OCEAN OBSERVING SYSTEM (INDOOS)
by
Sidney Thurston, NOAA, Climate Program Office, USA

Partnerships for New GEOSS Applications (PANGEA) www.jcomm.info/pangea-concept in the Indian Ocean Region are underway to help build sustainable capacity for ocean observations and their societal applications. Fremantle Australia is the ideal Venue to highlight how PANGEA Partnerships have been successful towards implementing the IOGOOS/CLIVAR Indian Ocean Observing System (IndOOS) Research Moored Array for African-Asian-Australian Monsoon Analysis and Prediction (RAMA) www.pmel.noaa.gov/tao/rama/ and other in-situ ocean-climate observations. For the past five years PANGEA Partners have been convening in-country, practical, socio-economic applications training for Regional decision-makers, policy and budget administrators, scientists, end-users and other stakeholders, so that RAMA is now over two-thirds completed. By building on and complementing existing capacity building programs, a sustainable capacity for the region is being achieved through the increases in both near real-time in-situ ocean observational data and information as well as demonstrating the more effective applications of, and access to, these existing and new data. This presentation will provide an updated brief on NOAA’s ongoing collaboration with India, Indonesia, Japan, the Agulhas-Somali Current Large Marine Ecosystem (ASCLME, nine East African Nations) Program and now with Australia and emerging Partnership with China; highlights of the DBCP’s Third In-Region Capacity Building Workshop for the Western Indian Ocean www.jcomm.info/wio-dbcp3 in Mombasa Kenya; and near-term opportunities to expand the PANGEA concept beyond the Indian Ocean for Data Buoy & potentially future Glider implementation and training.

EVALUATION OF MINIMET DRIFTING BUOY WTIH SONIC WIND SENSOR FOR ARCTIC WEATHER MONITORING APPLICATION
by
Chris Marshall - Manager of Marine Networks for Environment Canada

In-situ measurements of weather and oceanographic parameters in the Arctic are very expensive, due to significant logistical costs to deploy and maintain equipment. As part of a broader project to expand marine weather observations in the Arctic Basin, Environment Canada has completed an in-field evaluation of two MINIMET manufactured by Pacific Gyre. The buoys were equipped with sonic anemometers, and the purpose of the evaluation was to examine the relative accuracy of the wind measurements taken from the buoys, along with their performance in a harsh winter environment. The two buoys were deployed in Gimili, Manitoba, Canada, collocated with a Environment Canada Reference Climate Station (RCS). Likely the furthest from an Ocean a drifting buoy has even been deployed!) The hourly observations from the MINIMET buoys (one directly at ground level, and a second at 2.5 m) were compared to wind and pressure measurement from the RCS. The initial results are promising, and suggest that MINIMET buoy, or a buoy with similar configuration may provide a low-cost option for obtaining in-situ wind speed and direction observations in the Arctic

PROGRESS IN REFRESHING THE TROPICAL OCEAN ATMOSPHERE ARRAY
by
Richard L. Crout, PhD, Lex LeBlanc, Karen Girssom, Dawn Petraitis, and Landry Bernard
NOAA National Weather Service, National Data Buoy Center, Stennis Space Center, MS, USA

In order to replace obsolescent sensors in the TAO array and comply with the Ten Climate principles, twenty-nine TAO Refresh buoys were deployed near paired TAO Legacy buoys during the period 2008-2012. At the end of each deployment, a statistical comparison of the daily averaged data was conducted for each of the sensors. The meteorological comparisons were successful and while ocean temperature differences in the surface mixed-layer and at depth were nearly identical, temperature differences in the thermocline were higher than expected and not within the statistical accuracy of the sensors. Closer examination of the high-resolution (10-minute interval) ocean temperature data within the thermocline layer indicates that internal waves are responsible for the differences. The standard deviations for the two systems are the same indicating that the sensors are recording the same phenomena. Additionally, analysis of pre- and post-calibration of the 266 returned temperature drift indicates that the average sensor drift is less than 0.001oC per year.
As of 1 August 2012, twenty-four operational Refresh buoys (representing 44% of the array) have been deployed in the TAO Array. The Refresh buoys are reporting six 10-minute data points every hour to the National Data Buoy Center through the Iridium Satellite system. Hourly data are transmitted to the Global Telecommunications System and delivered to worldwide numerical weather and ocean prediction centers.

LONG TERM AUTONOMOUS OCEAN REMOTE SENSING UTILIZING THE WAVE GLIDER
by
Jamie Griffith, Liquid Robotics; Matt Cosad, Liquid Robotics, USA

Rising costs of ship time and increasing budgetary restrictions make installation and maintenance of fixed, mid-ocean buoys a logistical and financial challenge. The cost associated with launch, recovery, and maintenance has resulted in a limited number of deployed buoys, restricting data on mid-oceanic conditions. To address these challenges, Liquid Robotics (LRI) has developed the Wave Glider, an autonomous, mobile remote sensing solution. This system utilizes wave energy for propulsion allowing for long duration deployments of up to one year while providing real-time data on meteorological and oceanographic conditions. In November 2011, LRI deployed four Wave Gliders on a mission to cross the Pacific Ocean (the PacX) from San Francisco to Australia (two vehicles) or Japan (two vehicles) while transmitting data on weather conditions, wave profiles, sea surface temperatures, and biological conditions (fluorometry) in real-time. This report evaluates the vehicle’s ability to operate as an ocean going data platform by comparing data from the onboard weather sensors with two moored buoys, NDBC 46092 in Monterey Bay and NDBC 51000 200 nmi northeast of Maui. The report also analyzes data transmitted from all four vehicles as they passed directly through a tropical storm 580 nmi northeast of Hawaii.

The route traveled from San Francisco to Australia directed all four vehicles past the two aforementioned NOAA buoys. Upon arriving at a buoy, gliders continuously circled for a period of two days at a distance of three to eight nautical miles to build a comparative dataset. Data from both platforms were streamed in near real time enabling mid-mission evaluation of the performance of sensors. Overall, results varied from a <0.5% difference in barometric pressure between buoy NDBC 46092 and the gliders to high disagreement in wind speed and direction. While comparisons to moored buoy data can provide valuable insight into the relative accuracy of each platform, differences in agreement on variables such as wind speed and direction were attributed to micro-spatial variability in oceanic conditions. Also, disagreements in sea surface temperature were attributed to the buoys reporting the hull temperature of the mooring and not a true in-situ water temperature.

In addition to data collected for comparison between existing moored buoys, all four PacX vehicles collected data from directly within a tropical storm off the coast of Hawaii. Starting on February 5th, 2012, the vehicles measured sustained winds of 40 knots for 4 days with gusts up to 80 knots at the height of the storm. The vehicles also measured sustained wave heights of 7m along with a barometric pressure drop to a low of 985 mbar. A pressure between 965 and 979 mbar is comparable to that of a category two hurricane while the measured wind speeds fall within the range of a tropical storm on the SSHS. The wind data from the vehicles compares favorably to satellite imagery from the ASCAT satellite data of the same storm but with much higher spatial resolution.

In conclusion, the Pacific crossing has provided solid evidence that the Wave Glider as deployed would provide a suitable and highly efficient platform for the observation of sea surface and lower atmospheric conditions over extended sampling periods. The system could be used to quickly and efficiently increase the operational density of ocean observations without the need for expensive deployment and recovery vessels. In future studies, data from the PacX will be compared with additional satellite and oceanic data sources to provide ground truthing of collected oceanographic data. In addition, two Wave Gliders will be deployed from Puerto Rico to monitor storm conditions from directly within a hurricane.

WAVE MEASUREMENT EVALUATION AND TESTING PHASE II
by
Robert Jensen, USACE Engineer Research and Development Center, USA
Val Swail, Environment Canada
Tyler Hesser
Boram Lee, WMO Secretariat

The JCOMM Expert Team on Wind Waves and Storm Surges (ETWS) is presently carrying out a Pilot Project (www.jcomm.info/WET) for the Data Buoy Cooperation Panel to address potential biases in in-situ wave measurements from buoys. Previous comparisons with satellite altimeter data suggest that there may be significant biases between operational buoy networks operated by different national agencies, even with the same platforms. Biases are a serious concern in climatology, especially in computation of trends, but are also relevant for example in wave forecast verification, comparisons of wave model performance and regional statistics.

This presentation will describe the results from various components of the wave measurement testing and evaluation program being carried out in various regions, based on the “First-5” inter-comparison methodology. The presentation will describe results from continuation of the first two Pilot Project co-deployments, on the east and west coasts of Canada. A Datawell Directional Waverider was located beside an operational Canadian 3m discus buoy and an operational 6m NOMAD; TriAxys wave sensors were also located on both operational buoys. Results from three additional testing configurations from other partners will be included.

OVERVIEW OF EMERGING UNMANNED SYSTEMS TECHNOLOGIES FOR MARINE MONITORING
by
Walt McCall, NOAA National Data Buoy Center, USA
(presentation made by Richard Crout during the workshop)

The Unmanned Systems groups of Autonomus Underwater Vehicles (AUV) and Autonomus Surface Vehicles (ASV) have increased their reliability and endurance over the past decade leading to potential for higher density observations in the world's oceans at a lower cost. This has lead to multiple groups developing operational observatories with the goal of increasing the spatial resolution in the Global Ocean Observing System (GOOS) while maintaining a cost effective program.
This presentation will provide a general overview of unmanned systems capable of longer endurance (> 2 weeks), their abilities and limitations, Infrastructure requirements, operational considerations, and discuss the potential for global operations.

REMOVING SPURIOUS LOW-FREQUENCY VARIABILITY IN DRIFTER VELOCITIES
by
R. Lumpkin, NOAA Atlantic Oceanographic and Meteorological Laboratory, USA
S. Grodsky, University of Maryland, USA
L. Centurioni, Scripps Institution of Oceanography, USA
M.-H. Rio, Collecte Localisation Satellites (CLS), France
J. Carton, University of Maryland, USA
Dongkyu Lee, Pusan National University, Republic of Korea

Drogue presence has historically been determined from submergence or tether strain records. However, recent studies have revealed that a significant fraction of drifters believed to be drogued have actually lost their drogues, a problem which peaked in the mid-2000s before the majority of drifters in the global array switched from submergence to tether strain sensors. In this study, a methodology is applied to the data to automatically reanalyze drogue presence based on anomalous downwind ageostrophic motion. Results indicate that the downwind slip of undrogued drifters is approximately 50% higher than previously believed.
The reanalyzed results no longer exhibit dramatic and spurious interannual variations seen in the original data. These results, along with information from submergence/tether strain and transmission frequency variations, have been used to conduct a systematic manual reevaluation of drogue presence for the drifters in the post-1992 data set.

ANALYSIS OF Argos 3 VIABILITY FOR BUOY PLATFORMS
by
L. Braasch, C. McCall, L. Centurioni
CASPO, Scripps Institution of Oceanography, La Jolla, California, USA

Since the introduction of Argos 3 technology, comparable satellite communication technologies have emerged as a solution for buoy platforms. Here, we report the implications of data throughput, power consumption, and impact on the scientific community in transitioning to an Argos 3 PMT system. Using an in-house developed microcontroller and buoy platform, six systems were configured as SVP drifters (SST, battery voltage, and strain gauge) in a controlled environment. Each system was powered by a 2.5 amp-hour AA cell battery pack until depletion to compare Argos 2 PTT (A2), Argos 3 PMT (A3) and Iridium Short Burst Data (SBD) technologies. Statistics were collected regarding system longevity, data throughput and latency. It has been determined that sacrifices are incurred transitioning to A3. Power consumption of an A3 system is reduced while increasing data throughput in comparison to an A2 system. However, A3 will have reduced power savings with the deployment of additional A3 satellites. Under the current design, A3 cannot achieve near real-time data delivery. The A3 system requires modifications to meet the functional requirements of the end user. It is recommended that changes be made to the A3 system prior to widespread implementation into buoy platforms.

INCREASING OF EFFECTIVENESS AND RELIABILITY OF DATA FROM DRIFTING BUOYS
by
Motyzhev S., Lunev E., Tolstosheev A.
Marine Hydrophysical Institute NASU / Marlin-Yug Ltd., 2, Kapitanskaya St., Sevastopol, 99011, Ukraine

For a few last years Marine Hydrophysical Institute NAS of Ukraine and Marlin-Yug Ltd company in coordination with the DBCP Pilot Projects have been focusing its efforts to increase an effectiveness and reliability of data from the WOCE type drifting buoys. The goal of study was more different data, better timeliness, longer lifetime, higher space-temporal resolution of measurements, even if very rough weather conditions take place during full lifetime of drifters. The following results were achieved. Argos-2 drifters with continuous mode for transmitting can keep tracking capabilities for 6 years and longer. Argos-3 drifters show good results in operation. Iridium drifters can have 2-year lifetime with hourly GPS fixes and near 3-year without GPS. Continuity of hourly samples and GPS fixes for Iridium/GPS buoys takes place under rough weather conditions. SVP-B drifters retain air pressure samples with accuracy better than 1.0 hPa for 3 years at least in the rough South Ocean. Iridium/GPS temperature-profiling drifters provide effective lifetime near one year. Iridium/GPS temperature-profiling drifter to be deployed on ice was developed. Some efforts have been made to keep the drogue attached during full lifetime of drifter. Micro buoys with parachute deployments were developed for the marine and ice applications. These results could be the reference points to keep the certainty of drifter data with necessary quality of samples and locations and without increasing of costs to support density of global drifter observations

DRIFTER LIFETIMES BY MANUFACTURER AND BUOY TYPE
by
Mayra Pazos, NOAA Atlantic Oceanographic and Meteorological Laboratory, USA

The transmission lifetimes of drifters are examined for each of the major manufacturers since 2005, quantified two ways: median half-life and number of drifters dead within 90 days of deployment.
Lifetimes are also examined by buoy type (SVP vs. SVPB). Particular emphasis is placed on drifters deployed during the most recent year, where problems diagnosed include high power consumption by Pacific Gyre and Clearwater PMT-bearing drifters operating in PTT mode

DROGUE EVALUATION AND ANALYSIS
by
Shaun Dolk, NOAA Atlantic Oceanographic and Meteorological Laboratory, USA

Using recently enhanced drogue detection methods, the Global Drifter Program's drogue database was reanalyzed. As a result of this reanalysis, drogue lifetimes from each manufacturer will be examined, including the transition from large drogue to the current mini drogue design.

EVALUATING THE IMPACT ON NWP OF SEA LEVEL ATMOSPHERIC PRESSURE DATA OVER THE OCEAN FROM DRIFTING BOYS
by
L.R. Centurioni, Scripps Institution of Oceanography, La Jolla, California, USA
R. F. Lumpkin, NOAA Atlantic Oceanographic and Meteorological Laboratory, USA

The Global Drifter Program (GDP, http://www.aoml.noaa.gov/phod/dac/index.php) maintains an ocean-observing network of approximately 1250 Lagrangian drifters that, through the Argos and Iridium satellite systems, returns data of meteo-marine variables including near-surface ocean currents, sea surface temperature (SST), sea surface salinity (SSS), sea-level atmospheric pressure (SLP), sea-level winds (SLW) and subsurface temperature (Tz). The drifters are an ideal platform to make global SLP measurements. The SLP sensor fitted on the drifters (SVPB hereinafter) is the Honeywell HPB. Each year the GDP upgrades 290 drifters with barometers and an additional 190 drifters are upgraded by the GDP every other year. Another 180 drifters per year are upgraded by meteorological agencies members of the DBCP.
We present the results of several studies performed by NASA, ECMW, MeteoFrance and the UKMO with the goal to quantify the impact of SLP data from the existing SVPB network on NWP. We will show how SLP data from drifters improve substantially the forecast skill of a variety of models, and have the highest impact per observation of all surface pressure observations. Drifters’ SLP data, which are more accurate than the SLP derived from GPSRO, are very important to anchor the surface pressure field. We will also discuss plans to improve our understanding of the impact of drifters’ SLP on NWP, for example, by introducing new metrics, running more OSEs, studying specific cyclogenesis episodes when the drifter data make a particularly significant impact.

INFLUENCE OF WARM SST ANOMALIES FORMED IN THE EASTERN PACIFIC SUBDUCTION ZONE ON RECENT EL NIÑO EVENTS
by
Dongkyu Lee and Luca Centurioni
Scripps Institution of Oceanography, La Jolla, California, USA

Anomalous April-June warm surface water in the eastern Pacific convergence zone (the Great Pacific Garbage Patch) subducts and depresses the thermocline as a single waveform. This waveform propagates towards the equator much more quickly (reaching the equator in 1.5-2.5 years) than the normal transit time (5-10 years) of the meridional overturning cell. The movements of the sea surface temperature (SST) anomalies that occurred before the 1997 and 2009 El Niños can be clearly traced to the area south of 20ºN using the altimeter sea level signals. Upon arriving near the Pacific equator, these warm water anomalies can contribute to the formation of the El Niño by lowering the depth of the thermocline. The time required for a subducted SST anomaly to ‘drift’ 3000 km to the equator depends upon its initial location and on the distribution of the SST anomalies near the western coast of North America. The initial warm SST anomaly that extended southward along Baja and was observed before the El Niños of 1982 and 1997 took 12 months to reach the equator. Longer drift times of 24 months were indicated for the 1972, 1986, 1993, 2003, 2006 and 2009 events. The thermocline depressions that “drift” towards the equator in the eastern Pacific are shown to be a major energy source for the onset of the El Niño in the central and eastern Pacific. This study presents a theory that could expand our understanding of the onset mechanism of the El Niño episode. For observing the propagating thermocline depression, a wave glider equipped with CTD is being developed.

THE SOUTHERN OCEAN TIME SERIES MOORED OBSERVATORY: A TECHNICAL AND SCIENTIFIC REVIEW
by
Eric W. Schulz, Bureau of Meteorology, CAWCR, Australia
Tom. W. Trull, CSIRO, CAWCR, ACE-CRC, UTas, Australia
Simon Josey, NOCS, Australia

The Southern Ocean Time Series is an OceanSITES observing program dedicated to understanding the role of the Southern Ocean in the global climate system by quantifying the flux of carbon, heat, mass and momentum between the ocean and atmosphere. The Southern Ocean covers 77 million km2 - 22% of the world’s ocean, of which more than half is contained in the Sub-Antarctic zone, north of the westerly wind maximum and the Antarctic Circumpolar Current. Here, subduction occurs over vast areas, driving water mass formation and trapping carbon and heat in the ocean interior. This region is inhospitable and rarely visited, leading to a paucity of observations. The observing program commenced in the late 1990’s with sediment trap moorings as part of the Antarctic CRC and was enhanced significantly in 2009 with the addition of moorings to sample air-sea fluxes and the bio-geo-chemical properties in the surface waters.

Here we present the mooring program and provide some examples of results from the observations and applications including numerical weather prediction model validation.

USING AN ARGOS PMT IN A DRIFTING BUOY
by
Andy Sybrandy, Pacific Gyre, Inc., USA
Bill Woodward, Collecte Localisation Satellites (CLS) America, USA
Michel Guigue, Collecte Localisation Satellites (CLS), France

The Argos PMT (Platform Messaging Transceiver) offers additional technical features beyond the traditional PTT that are of benefit to ocean platforms such as drifting buoys. The Global Drifter Program is currently integrating the PMT in a large percentage of their new buoys. This presentation outlines the features of the PMT that are beneficial and how they can be applied towards improving the technical performance of the drifters.