Wave Sensor Technologies, St Petersburg, Florida, March 7-9, 2007: workshop proceedings

The Alliance for Coastal Technologies (ACT) convened a workshop on "Wave Sensor Technologies" in St. Petersburg, Florida on March 7-9, 2007, hosted by the University of South Florida (USF) College of Marine Science, an ACT partner institution. The primary objectives of this workshop were to: 1) define the present state of wave measurement technologies, 2) identify the major impediments to their advancement, and 3) make strategic recommendations for future development and on the necessary steps to integrate wave measurement sensors into operational coastal ocean observing systems. The participants were from various sectors, including research scientists, technology developers and industry providers, and technology users, such as operational coastal managers and coastal decision makers. Waves consistently are ranked as a critical variable for numerous coastal issues, from maritime transportation to beach erosion to habitat restoration. For the purposes of this workshop, the participants focused on measuring "wind waves" (i.e., waves on the water surface, generated by the wind, restored by gravity and existing between approximately 3 and 30-second periods), although it was recognized that a wide range of both forced and free waves exist on and in the oceans. Also, whereas the workshop put emphasis on the nearshore coastal component of wave measurements, the participants also stressed the importance of open ocean surface waves measurement. Wave sensor technologies that are presently available for both environments include bottom-mounted pressure gauges, surface following buoys, wave staffs, acoustic Doppler current profilers, and shore-based remote sensing radar instruments. One of the recurring themes of workshop discussions was the dichotomous nature of wave data users. The two separate groups, open ocean wave data users and the nearshore/coastal wave data users, have different requirements. Generally, the user requirements increase both in spatial/temporal resolution and precision as one moves closer to shore. Most ocean going mariners are adequately satisfied with measurements of wave period and height and a wave general direction. However, most coastal and nearshore users require at least the first five Fourier parameters ("First 5"): wave energy and the first four directional Fourier coefficients. Furthermore, wave research scientists would like sensors capable of providing measurements beyond the first four Fourier coefficients. It was debated whether or not high precision wave observations in one location can take the place of a less precise measurement at a different location. This could be accomplished by advancing wave models and using wave models to extend data to nearby areas. However, the consensus was that models are no substitution for in situ wave data.[PDF contains 26 pages]

Enabling Sensor* Interoperability, Portland, Maine, October 16-18 2006: workshop proceedings

The ACT workshop "Enabling Sensor Interoperability" addressed the need for protocols at the hardware, firmware, and higher levels in order to attain instrument interoperability within and between ocean observing systems. For the purpose of the workshop, participants spoke in tern of "instruments" rather than "sensors," defining an instrument as a device that contains one or more sensors or actuators and can convert signals from analog to digital. An increase in the abundance, variety, and complexity of instruments and observing systems suggests that effective standards would greatly improve "plug-and-work" capabilities. However, there are few standards or standards bodies that currently address instrument interoperability and configuration. Instrument interoperability issues span the length and breadth of these systems, from the measurement to the end user, including middleware services. There are three major components of instrument interoperability including physical, communication, and application/control layers. Participants identified the essential issues, current obstacles, and enabling technologies and standards, then came up with a series of short and long term solutions. The top three recommended actions, deemed achievable within 6 months of the release of this report are: A list of recommendations for enabling instrument interoperability should be put together and distributed to instrument developers. A recommendation for funding sources to achieve instrument interoperability should be drafted. Funding should be provided (for example through NOPP or an IOOS request for proposals) to develop and demonstrate instrument interoperability technologies involving instrument manufacturers, observing system operators, and cyberinfrastructure groups. Program managers should be identified and made to understand that milestones for achieving instrument interoperability include a) selection of a methodology for uniquely identifying an instrument, b) development of a common protocol for automatic instrument discovery, c) agreement on uniform methods for measurements, d) enablement of end user controlled power cycling, and e) implementation of a registry component for IDS and attributes. The top three recommended actions, deemed achievable within S years of the release of this report are: An ocean observing interoperability standards body should be established that addresses standards for a) metadata, b) commands, c) protocols, d) processes, e) exclusivity, and f) naming authorities.[PDF contains 48 pages]

Seabed Sensor Technology, Savannah, Georgia, February 1-3, 2006: workshop proceedings

Future coastal management practices require that a holistic, ecosystem management approach be adopted. Coastal ecosystems, however, present a variety of specific and unique challenges relative to open ocean systems. In particular, interactions with the seabed significantly influence the coastal ecosystem. Observing technologies must be developed and employed to incorporate seafloor interactions, processes and habitat diversity into research and management activities. An ACT Workshop on Seabed Sensor Technology was held February 1-3, 2006 in Savannah, Georgia, to summarize the current state of sensor technologies applicable to examining and monitoring the coastal seabed, including the near-bed benthic boundary layer and surface sediment layer. Workshop participants were specifically charged to identify current sensors in use, recommend improvements to these systems and to identify areas for future development and activities that would advance the use of sensor technology in the observation, monitoring and management of the coastal benthic environment. (pdf contains 23 pages)

Adjustment of ocean color sensor calibration through multi-band statistics

The band-by-band vicarious calibration of on-orbit satellite ocean color instruments, such as SeaWiFS and MODIS, using ground-based measurements has significant residual uncertainties. This paper applies spectral shape and population statistics to tune the calibration of the blue bands against each other to allow examination of the interband calibration and potentially provide an analysis of calibration trends. This adjustment does not require simultaneous matches of ground and satellite observations. The method demonstrates the spectral stability of the SeaWiFS calibration and identifies a drift in the MODIS instrument onboard Aqua that falls within its current calibration uncertainties.