Sea level variation is a sensitive indicator of climate change because it responds both to changes in ocean temperature (where most of the excess heat from climate change is being absorbed) as well as to exchanges of water mass between the continents and the oceans (which is dominated over long time periods by the melting of ice in glaciers and ice sheets and changes in the water cycle). Therefore, the record of sea level change collected by the TOPEX/Poseidon, Jason-1, and Jason-2 satellite altimeter missions is critically important for climate change studies. However, the use of satellite altimeter data for this purpose pushes the accuracy limits of the measurements, and thus great care must be taken to monitor the performance of the instruments, investigate anomalies, improve the measurement corrections, and place the measurements in a well-defined Earth-fixed reference frame. In addition, interpreting the observed changes in sea level, identifying the causes of the changes, and eventually separating the natural and anthropogenic variations is a challenging area of research. We are carefully building a climate data record of sea level change using TOPEX/Poseidon, Jason-1, and Jason-2 altimeter data, making it publicly available (http://sealevel.colorado.edu), and then analyzing that record to better understand how our changing climate is affecting sea level. The interpretation of the record will help scientists make better predictions of future sea level change, ascertain the socio-economic impacts of sea level rise, and corroborate and improve global climate models. By the end of this investigation, a two decade, fully calibrated climate record of sea level change will be available, giving us our first opportunity to study decadal changes in sea level and their relation to climate change and other variations in the Earth system.
Building and Understanding a Climate Data Record of Sea Level Change