For the InstructorThese student materials complement the Coastal Processes, Hazards and Society Instructor Materials. If you would like your students to have access to the student materials, we suggest you either point them at the Student Version which omits the framing pages with information designed for faculty (and this box). Or you can download these pages in several formats that you can include in your course website or local Learning Managment System. Learn more about using, modifying, and sharing InTeGrate teaching materials.
Measuring Sea Level
How is sea level measured?
The white pipe contains the water level detection equipment. The apparatus on the dock provides solar power, data storage capability, and telemetry instrumentation which sends the data in real time to the GOES Satellite which then sends the data via Wallops Island Virginia (Command and Data Acquisition Center) to USGS data systems where it is made available to scientists worldwide.<div class="img-credit">Credit: http://nj.usgs.gov/publications/FS/fs-048-03/
Sea level is often measured locally by tide gauges (and averaged over tidal cycles) that detect high and low points in a given period of time. Local tide gauges are especially useful for people who work or recreate in coastal areas and need to know what the water level ranges will be. These data points are also important for detecting water levels during storms and other events as well as in long-term investigation of relative water level change (rise or fall). Tide levels are also measured by floating buoys, as well - which are being used to detect Tsunami waves.
Later on in this module, we will be working with individual tide gauge records for more insight, but geoscientists often work to integrate data collected by individual tide gauge stations with other sites over large areas in order to look at trends that are distinct from the tides. For more information on this, feel free to look at the NOAA Ocean Climate Observation Program link: http://www.oco.noaa.gov/tideGauges.html
Sea level can also be measured by satellite. These measurements utilize multi-beam methods that are very precise and can measure changes in elevations of the earth's surface. These methods have shown that water bodies are not flat, but are incredibly dynamic and have high and low spots due to geography, and other factors.
NODC (National Oceanographic Data Center) Jason-2 Satellite is one of several missions designed to investigate the surface of the ocean including wave heights, sea level rise, and other phenomena. http://www.nodc.noaa.gov/SatelliteData/Jason2/