Magellan started mapping the planet Venus on September 15, 1990, and after one cycle (one Venus day or 243 Earth days) had mapped 84% of the planet's surface. This returned an image data volume greater than all past planetary missions combined. Spacecraft problems were experienced in flight. Changes in operational procedures and reprogramming of onboard computers minimized the amount of mapping data lost. Magellan data processing is the largest planetary image‐processing challenge to date. Compilation of global maps of tectonic and volcanic features, as well as impact craters and related phenomena and surface processes related to wind, weathering, and mass wasting, has begun. The Magellan project is now in an extended mission phase, with plans for additional cycles out to 1995. The Magellan project will fill in mapping gaps, obtain a global gravity data set between mid‐September 1992 and May 1993, acquire images at different view angles, and look for changes on the surface from one cycle to another caused by surface activity such as volcanism, faulting, or wind activity.
Aquarius is a new satellite mission concept to study the impact of the global water cycle on the ocean, including the response of the ocean to buoyancy forcing and the subsequent feedback of the ocean on the climate. The measurement objective of Aquarius is sea surface salinity, which reflects the concentration of freshwater at the ocean surface. Salinity affects the dielectric constant of sea water and, consequently, the radiometric emission of the sea surface to space. Rudimentary space observations with an L-band radiometer were first made from Skylab in the mid-70s and numerous aircraft missions of increasing quality and improved technology have been conducted since then. Technology is now available to carry out a global mission, which includes both an accurate L band (1.413 Ghz) radiometer and radar system in space and a global array of in situ observations for calibration and validation, in order to address key NASA Earth Science Enterprise questions about the global cycling of water and the response of the ocean circulation to climate change. The key scientific objectives of Aquarius examine the cycling of water at the ocean's surface, the response of the ocean circulation to buoyancy forcing, and the impact of buoyancy forcing on the ocean's thermal feedback to the climate. Global surface salinity will also improve our ability to model the surface solubility chemistry needed to estimate the air-sea exchange of CO2. In order to meet these science objectives, the NASA Salinity Sea Ice Working Group over the past three years has concluded that the mission measurement goals should be better than 0.2 practical salinity units (psu) accuracy, 100 km resolution, and weekly to revisits. The Aquarius mission proposes to meet these measurement requirements through a real aperture dual-polarized L band radiometer and radar system. This system can achieve the less than 0.1 K radiometric temperature measurement accuracy that is required. A 3 m antenna at approx. 600km altitude in a sun-synchronous orbit and 300 km swath can provide the desired 100 km resolution global coverage every week. Within this decade, it may be possible to combine satellite sea surface salinity measurements with ongoing satellite observations of temperature, surface height, air-sea fluxes; vertical profiles of temperature and salinity from the Argo program; and modern ocean/atmosphere modeling and data assimilation tools, in order to finally address the complex influence of buoyancy on the ocean circulation and climate.
This paper highlights a few of the education and outreach products on harmful algal blooms (HABs) that have been developed at Bigelow Laboratory for Ocean Sciences, a non-profit organisation dedicated to marine biological research and education. The 'Toxic & Harmful Algal Blooms' web page (www.bigelow.org/hab) provides information about blooms, where they occur in US waters, foodweb effects, how toxins affect humans, and causative species. The 'Special topics' section features freshwater blooms, ocean colour, detection methods and research on South African HABs. This online resource is augmented by educational activities (www.bigelow.org/edhab) that allow teachers to use the topic of HABs as a vehicle to investigate the role that algae play in our environment. The multimedia CD-ROM, 'Phytopia: Discovery of the Marine Ecosystem', is a data-rich resource with tutorials, interactive tools, high-quality graphics and movie clips designed for users of various skill and interest levels. 'Phytopia' enables those without appropriate equipment or data to investigate the microscopic marine ecosystem. Since its release in May 2003, over 6 100 copies have been requested from users in 61 countries for formal and informal education and research.
Magellan images of Alpha Regio reveal previously undetected structures and details of the morphology of this region of complex ridged terrain. We examine the complex ridged terrain of Alpha Regio, using morphology and crosscutting relationships between structures to derive a sequence of tectonic events. Structures include broad (∼10–20 km wide) linear and arcuate ridges, fine‐scale (<3 km wide) ridges, linear disruption zones (LDZs) up to several kilometers wide, and numerous grabens (∼5 km wide) and associated scarps and troughs. Based on their morphology, we interpret the broad and fine‐scale ridges as compressional structures, possibly folds. LDZs appear to be due to small amounts of lateral shear which most commonly disrupts the older ridge fabric. Graben and associated structures are interpreted as extensional features. They crosscut ridges and LDZs and thus appear to be the youngest structures in Alpha Regio. This sequence of events and information on the orientation of these various structures are compared to the predictions of two models for the formation of complex ridged terrain (and highlands on Venus in general): a hotspot model and a coldspot model. The presence of compressional features along and parallel to the margins of Alpha Regio and the lack of any high‐elevation ring of extensional features are more consistent with a coldspot or roughly axisymmetric mantle downwelling. Mantle downwelling appears to be the most likely mode of formation of the upland of Alpha Regio and is likely to be important in other highland regions, such as Ovda and Thetis regiones, which are also dominated by complex ridged terrain.
Abstract The next decade will usher in significant changes in ocean observational infrastructure and how students engage with marine sciences content. Faced with the challenge of helping undergraduate students make sense of very complicated marine systems, a computer sciences-based organizational structure (i.e., ontology) has been employed to characterize the Ocean Observatories Initiative (OOI). Five interlinked vocabularies that include terms, descriptions, and images define the overall system from high-level science themes to specialized data products. Given the importance of visual representations in learning, particularly for novices, an associated interactive tool called the “Vocabulary Navigator” has been developed. Created in tandem, the design of the vocabularies and their visualizer is based on principles related to the needs of the target audience such as placing information in a broader context and promoting self-directed discovery. Overall, this effort has resulted in not only innovative online resources for learning about the OOI but also, perhaps more importantly, valuable “lessons learned” and transferable software that could be used by other marine technology endeavors.
FACING PAGE.All photos, except as noted, courtesy of Eric Lindstrom.Abbreviations are defined in Box 1. Middle set of photos, starting at the top left, proceeding clockwise and spiraling inward: (1) SEA-POL radome installed on R/V Revelle for cruise 2. Also visible are the laser for the CFT in front of radome and the radiometer for the ROSR to the right.(2) Janet Sprintall (pointing) and some members of her group watching a display during a CTD cast on Revelle cruise 1. (3) Two yellow Seagliders in the foreground and a neutrally buoyant float in the background before deployment on Revelle cruise 1. (4) Two gray and white PICO moorings on the aft deck of Revelle, one about to be deployed.( 5) A radiosonde about to be launched.( 6) A front view of the SSP secured on deck.(7) The LA. (8) A Wave Glider being deployed from Revelle.(8) Flotation for the central mooring being prepared for deployment on the aft deck of Revelle.(9) A nighttime view of some of the meteorological instrumentation on the bow of Revelle (photo courtesy of Julian Schanze).(10) The central mooring.FIGURE 4. The data exploration tool links to many posts in the SPURS-2 blog,
The Ocean Observatories Initiative (OOI) promises to reshape the way ocean science is conducted by providing ocean researchers with access to near real-time data, the ability to control/configure sensors and mobile assets, high-bandwidth infrastructure for images, powerful cyberinfrastructure, and data visualization and modeling tools to conduct their research. Recent advances in the delivery of web-based education, and the use of visualization technology in educational contexts, have led to the development of on-line platforms for instruction that engage students in active scientific inquiry by collecting and analyzing real world data. The OOI Education and Public Engagement (EPE) Implementing Organization will leverage these technologies for ocean education. EPE will construct a series of software tools and a web-based social network that leverages the OOI Cyberinfrastructure to support engagement of a wide range of users. These tools will enable educators and developers to enhance their undergraduate education programs and engage free choice learners using real-time and streaming data provided by the OOI. EPE will enable a new approach to oceanography research, where scientists, students and the public can explore and research the ocean in real-time from their classrooms, offices, dorm rooms, and even their homes. The face of an oceanographer will be expanded well beyond the professor at sea to to a student at home viewing and analyzing exactly the same data at exactly the same time. In addition to the OOI EPE Implementing Organization (IO), there are additional IOs supporting the OOI construction (Figure 1): Regional Scale Nodes (RSN): RSN will deploy sensors to study Hydrate Ridge, an area of massive sub-seafloor gashydrate deposits, and Axial Seamount, an active submarine volcano. Coastal and Global Scale Nodes (CGSN): CGSN will deploy a global array of moorings and underwater gliders to provide sustained, but adaptable, access to complex coastal and global systems. Cyberinfrastructure (CI): The CI will provide a common operating infrastructure connecting and coordinating the operations of the marine components with the OOI scientific and educational pursuits. Program Management Office (PMO): The OOI program is funded by the National Science Foundation (NSF) and managed by the OOI PMO, located at the Consortium for Ocean Leadership (COL) offices in Washington, D.C.
