Platforms are workspaces to accommodate staff scientists and large equipment at the study site and serve as field laboratories, in addition to collecting the types of data provided by unmanned moorings. The data collected at moorings and platforms give scientists the information they need to pursue some of the most pressing scientific and environmental questions of the twenty-first century. Staffed platforms allow scientists to collect biological specimens, sea water, and sediment samples, to observe marine organisms, to conduct diving expeditions, and to deploy to manned and unmanned submersible vehicles. Instruments installed on drifting platforms measure oceanographic, atmospheric, and biological data along the path of an ocean current.
Ocean and climate observing systems can be installed on new vessels or retrofitted to existing ships. Typical sensor configurations provide information on a variety of environmental and oceanographic variables. Bridge crew can view the environmental information in real time, while various telemetry choices are offered if the data also needs to be sent to a remote location. Crews are trained on how to take ocean observations while at sea and also to calibrate sensors used aboard ships. The ships record and transmit oceanographic and meteorological observations such as air pressure, air temperature, sea surface temperature (SST), wind and sea state. Observations are recorded by officers onboard and are immediately sent to a data centers.
A typical buoy can measure, (but is not limited to), wind speed and direction, atmospheric pressure, air temperature, relative humidity, water temperature, currents, waves, oil, pH, dissolved oxygen, and other water quality parameters. Raw data is processed and can be logged on board the buoy and then transmitted via radio, cellular, or satellite telemetry to the end user. Buoys provide the dual function of an automated ocean and climate station, plus navigational aid. Deployments can be in a variety of locations, from calm, shallow waterways to 4,900m depth in open oceans. All buoys are powered by solar panels and rechargeable batteries.
Argo Floats, Sub-Surface Drifters
Argo is an observation system for the Earth’s oceans that provides real-time data for use in climate, weather, oceanographic and fisheries research. Argo consists of a large collection of small, drifting oceanic robotic probes deployed worldwide. The probes float as deep as 2 km. Once every 10 days, the probes surface, measuring conductivity and temperature profiles to the surface. From these, salinity and density can be calculated. The data are transmitted to scientists on shore via satellite. The data collected are freely available to everyone, without restrictions. The initial project goal was to deploy 3,000 probes, completed in November 2007.
Remotely Operated Vehicles (ROVs)
ROVs range from very small units with a few cubic feet of volume, to large units the size of an automobile. ROV technology has benefited from recent advances in many different fields, including increased computational capabilities, fiber optics, robotic miniaturization, and video. ROVs are designed for gathering detailed information within a relatively small area during missions that last a few hours.
The main types of instruments in ROVs are video cameras supported by light systems that provide real-time images to operators in the support vessel. In addition to video cameras, ROVs frequently carry other instruments, such as still cameras; sonar; devices for collection of biological, chemical, and geological samples; and manipulators to conduct underwater work. Most of the new ROVs have modular designs that permit the interchange of instruments according to mission requirements and the payload capabilities of each system. In general, smaller systems are designed for shallow-water operations and are more limited in the size and number of instruments they can carry. Deep-water systems tend to be larger because they require larger motors to enable them to overcome the increase in tether drag and weight. Larger systems have greater payload capacity and can accommodate diverse sets of instrumentation.
Autonomous Underwater Vehicles (AUVs)
AUVs are the next big advance in tools for oceanography and national defense for several compelling reasons. AUVs can work 24/7 in conditions that keep research vessels at the dock. They provide a three-dimensional view of the water column more rapidly and less costly (by a factor of 8 to 10) as compared to ship-based surveys. They can bring sensors like side scan sonar close to the sea floor to produce superior data. And they can react to observations they make on the fly, investigate fast-changing features in the ocean, provide real-time data to ocean observing systems and their predictive models, and mitigate threats to our national security while protecting the environment.
Research Satellites: Even though remote sensing has proven to be a powerful tool, NASA has just 10 satellite missions in operation dedicated to ocean research (Table 4-13). At least two of these missions may not continue beyond FY2003. Two new research satellites are expected to be launched by 2006. Some ocean remote-sensing research activities are actually conducted using data from sensors aboard operational satellites, including recent advances in the use of GPS signals to infer sea state and wind speed. A few research missions rely on international partnerships either for instrumentation or spacecraft platform. In addition, the United States relies on European satellites (ERS-1 and ERS-2); a Japanese satellite (JERS-1), and a Canadian satellite (RADARSAT-1) for Synthetic Aperture Radar data.
Operational Satellites: The National Academy of Science defined operational satellites as those that routinely and reliably generate services and products with specific accuracy, periodicity, and format, and that make their product available to a variety of users including public, private, and academic sectors. In the United States, NOAA has primary responsibility for operational satellites for ocean and coastal activities. DoD and USGS also have some ocean and coastal operational satellite capabilities.
To provide wider and more frequent data coverage of the ocean regions, scientists employ satellites that circle Earth above the atmosphere several times a day. Various satellites and measuring instruments provide the ocean surface data you will use in your investigations. They collect the following data that help scientists track ocean surface currents and their potential impact on weather and climate:
NOAA, NASA, DoD, NSF and DOE own and operate most of the aircraft used for ocean and coastal research, exploration, and monitoring activities. The DOI Office of Aircraft Services manages aircraft use and contracting to support its natural resources mission, including research and monitoring of coastal assets. Data from DOI’s MMS indicate that MMS leases 1 fixedwing aircraft for 59 days a year to conduct bowhead whale surveys, and leases16 helicopters for 365 days a year to conduct oil and gas platform inspections.
Some states own or operate aircraft for assessment, management, and protection of natural resources including coastal and ocean areas, but information on these assets was not available. The private sector provides aircraft contracting services to federal and state agencies in support of ocean and coastal activities. Most of these commercial aircraft are not included in this report because they are not considered facilities dedicated to the direct support of ocean and coastal activities. An exception is the US LTA 138S airship owned by US-LTA Corporation. This aircraft is included because of its unique design. This non-rigid, 160-foot airship provides a slow-moving platform that has been used to conduct detailed vertical and horizontal profiling of the marine boundary layer.
Aircraft that support ocean and coastal activities frequently serve as platforms for atmospheric research and monitoring purposes. The multidisciplinary use of aircraft tends to ameliorate their relatively high acquisition and maintenance costs.
Unmanned Aerial Vehicles (UAVs)
A significant advantage provided by UAV over piloted aircraft is the extended mission time, which in some current systems can exceed 24 hours of continuous flying. The sensors installed in aircraft depend on the aircraft payload capabilities, operational limitation, and mission requirements. Missions can range from a visual survey for marine biota to high-altitude remote-sensing measurements.
Autonomous Unmanned Aerial Vehicles (AUAVs): Lightweight (AUAVs) and their miniaturized instruments are an effective and inexpensive means of simultaneously sampling clouds in polluted environments from within and from all sides. They serve as additions to our oceanic and atmospheric measurement capability for one of the major issues in climate change science.
Then starting in the late 90s, scientists got their hands on a new tool called high frequency (HF) radar. These instruments map surface currents in wide swaths of coastal waters up to 200 km off shore, 24 hours a day, and in all weather conditions. Researchers began installing HF radar stations along the East, West, and Gulf coasts, and today the network continues to expand. Developers of these systems hope that someday soon, anybody who is interested will be able to look up information on currents and waves as easily as they can look up information on the weather.
The HF radar is well established as a powerful tool for sea current measurements up to a range of about 30 km. It operates in the MHz frequency band corresponding to a radar wavelength in the range of 10 to 300m. The Doppler shift of the first order Bragg lines of the radar echo is used to derive sea current estimates in very much the same way as for the dual frequency microwave radar. Two radar installations are normally required, looking at the same patch of the sea surface from different angles.
Most drilling platforms are too expensive for publicly funded scientific studies, but they are common equipment in the petroleum industry. Oil platforms over major petroleum reservoirs may house hundreds of staff members who live and work on the rig for weeks or months at a time. The petroleum industry also maintains smaller, unmanned platforms that house oil and gas pumps once an offshore field is established.