• Canada
• 2013 close

Variations in sea level have a great environmental impact. They modulate coastal deposition, erosion and morphology, regulate heat and salt fluxes in estuaries, bays and ground waters, and control the dynamics of coastal ecosystems. Sea level variability has importance for coastal navigation, the building of coastal infrastructure, and the management of waste. The challenges of measuring, understanding and predicting sea level variations take particular relevance within the backdrop of global sea level rise, which might lead to the displacement of hundreds of millions of people by the end of this century. Sea level measurement relies primarily on the use of coastal tide gauges and satellite altimetry. Tide gauges provide sea levels at fine time resolutions (up to one second), but collect data only in coastal areas, and are irregularly distributed, with large gaps in the southern hemisphere and at high latitudes. Satellite altimetry, in contrast, has poor time resolution (ten days or longer), but provides near global coverage at moderate spatial resolutions (10-to-100 kilometres). Altimetric sea level products are problematic near the coast for reasons such as uncertainties in applying sea state bias corrections, errors in coastal tidal models, and large geoid gradients. The complicated shoreline geometry means that the raw altimeter data have to either undergo special transformations to provide more reliable measurements of sea level or be rejected. Developments in GPS measurements from buoys are now making it possible to determine sea surface heights with accuracy comparable to that of altimetry. In combination with coastal tide gauges, GPS buoys could be used as the nodes of a global sea level monitoring network extending beyond the coast. However, GPS buoys have several downsides. They are difficult and expensive to deploy, maintain, and recover, and, like conventional tide gauges, provide time series only at individual points in the ocean. This proposal focuses on the development of a unique system that overcomes these shortcomings. We propose a technology-led project to integrate Global Navigation Satellite Systems (GNSS i.e. encompassing GPS, GLONASS and, possibly, Galileo) technology with a state-of-the-art, unmanned surface vehicle: a Wave Glider. The glider farms the ocean wave field for propulsion, uses solar power to run on board equipment, and uses satellite communications for remote navigation and data transmission. A Wave Glider equipped with a high-accuracy GNSS receiver and data logger is effectively a fully autonomous, mobile, floating tide gauge. Missions and routes can be preprogrammed as well as changed remotely. Because the glider can be launched and retrieved from land or from a small boat, the costs associated with deployment, maintenance and recovery of the GNSS Wave Glider are comparatively small. GNSS Wave Glider technology promises a level of versatility well beyond that of existing ways of measuring sea levels. Potential applications of a GNSS Wave Glider include: 1) measurement of mean sea level and monitoring of sea level variations worldwide, 2) linking of offshore and onshore vertical datums, 3) calibration of satellite altimetry, notably in support of current efforts to reinterpret existing altimetric data near the coast, but also in remote and difficult to access areas, 4) determination of regional geoid variations, 5) ocean model improvement. The main thrust of this project is to integrate a state-of-the-art, geodetic-grade GNSS receiver and logging system with a Wave Glider recently acquired by NOC to create a mobile and autonomous GNSS-based tide gauge. By the end of the project, a demonstrator GNSS Wave Glider will be available for use by NOC and the UK marine community. The system performance will be validated against tide gauge data. Further tests will involve the use of the GNSS Wave Glider to calibrate sea surface heights and significant wave heights from Cryosat-2.

Northern sea ice levels are at an historical and millennial low, and nowhere are the effects of contemporary climate change more pronounced and destructive than in the Arctic. The Western Arctic rim of North America is considered the climate change "miners canary", with temperatures increasing at twice the global average. In the Yukon-Kuskokwim Delta (Y-K Delta), Western Alaska, the indigenous Yup'ik Eskimos are facing life-altering decisions in an uncertain future, as rising temperatures, melting permafrost and coastal erosion threaten traditional subsistence lifeways, livelihoods and settlements - the Yup'ik face becoming "the world's first climate change refugees" (The Guardian 2008). For the Yup'ik, however - whose relationship to the total environment is central to their worldview - coping with global climate change entails far more than adapting to new physical and ecological conditions. This is reflected in the holistic incorporation of both natural and social phenomena embodied in the use of the Yup'ik word ella, (variably translating as "weather", "world", "universe", "awareness"), which is understood in intensely social as well as physical terms. Ella reflects the relationship Yup'ik society has with the natural world. As changing environmental conditions jeopardise traditional subsistence practices in the Arctic, their deep-rooted dependency and social connection to the land is also threatened - further severing their ecological ties and compromising their cultural adaptive capacity that has defined Yup'ik community and identity for thousands of years. Rapid climatic change is by no means a uniquely modern phenomenon and the indigenous cultures of this region have faced such life-changing situations before. In fact, Western Alaska has experienced pronounced climatic variations within the last millennia, with the forebears of the Yup'ik being similarly challenged by regime shifts that would have influenced the availability of important subsistence resources, much the same as their descendants face today. The ELLA project will use both the products and processes of archaeological research to understand how Yup'ik Eskimos adapted to rapid climate change in the late prehistoric past (AD 1350-1700), and to inform and empower descendant Yup'ik communities struggling with contemporary global warming today. Taking full advantage of the spectacular but critically endangered archaeological resource now emerging from melting permafrost along the Bering Sea coast, this community-based project will illuminate the adaptive capacity of the precontact Yup'ik; build sustainable frameworks for the documenting of local sites under threat; and reinforce Yup'ik cultural resilience by providing new contexts for encountering and documenting their past.

Efficient air traffic management depends on reliable communications between aircraft and the air traffic control centres. However there is a lack of ground infrastructure in the Arctic to support communications via the standard VHF links (and over the Arctic Ocean such links are impossible) and communication via geostationary satellites is not possible above about 82 degrees latitude because of the curvature of the Earth. Thus for the high latitude flights it is necessary to use high frequency (HF) radio for communication. HF radio relies on reflections from the ionosphere to achieve long distance communication round the curve of the Earth. Unfortunately the high latitude ionosphere is affected by space weather disturbances that can disrupt communications. These disturbances originate with events on the Sun such as solar flares and coronal mass ejections that send out particles that are guided by the Earth's magnetic field into the regions around the poles. During such events HF radio communication can be severely disrupted and aircraft are forced to use longer low latitude routes with consequent increased flight time, fuel consumption and cost. Often, the necessity to land and refuel for these longer routes further increases the fuel consumption. The work described in this proposal cannot prevent the space weather disturbances and their effects on radio communication, but by developing a detailed understanding of the phenomena and using this to provide space weather information services the disruption to flight operations can be minimised. The occurrence of ionospheric disturbances and disruption of radio communication follows the 11-year cycle in solar activity. During the last peak in solar activity a number of events caused disruption of trans-Atlantic air routes. Disruptions to radio communications in recent years have been less frequent as we were at the low phase of the solar cycle. However, in the next few years there will be an upswing in solar activity that will produce a consequent increase in radio communications problems. The increased use of trans-polar routes and the requirement to handle greater traffic density on trans-Atlantic routes both mean that maintaining reliable high latitude communications will be even more important in the future.