Mechanisms and sources of regional sea level change and variability

Past sea level changes are reconstructed from historical data based on, and analyzed jointly with, contemporary sea level observations, model simulations and projections.  Work is being based on ocean observations (tide gauge, altimetry, in-situ data and gravity anomalies), the GECCO ocean reanalysis, and numerical coupled-climate models (STORM, MILLENNIUM, CMIP5).

Approach 

Work is based on:

  1. Studies of the consistency of climate models in the representation of ocean-atmosphere energy exchanges, feedbacks, heat uptake and transports, and of their changes in the context of anthropogenic climate change;
  2. Investigations of ocean mass changes and the exchange of freshwater between the cryosphere and the ocean; and,
  3. Investigations of the impact of wind changes on ongoing and projected future sea level changes (CMIP5).

Methods

Statistical methods (including Bayesian approaches) are being used jointly with numerical simulations to reconstruct the 20th century global and regional sea level from existing data sets and ocean syntheses with advanced uncertainty measures. Decadal sea level variability during the past and throughout the next century is analyzed using CMIP5 runs. The sensitivity of results to resolution and to processes that are parameterized in low-resolution models is analyzed using output from the STORM experiment.  Predictability of sea level (regional and local scale; seasonal to decadal and longer) is investigated using model simulations and initialized model runs

Atlas of Regional Sea Level Change

Information emerging from all those investigations was assembled and completed with geodetic correction in an ‘Atlas of Regional Sea Level Change’ of the global ocean for time slices, covering decadal to centennial time scales. A first version of the atlas is available through the Integrated Climate Data Center (ICDC).