99 / 2023-07-30 14:25:30

Regional Sea Level Changes: From the Altimeter-era Observational Record to Future Projection

sea level,climate model,climate variability,future projections

As one of the most severe consequences of climate change, sea-level rise increases the risks to coastal environments and communities from coastal hazards such as destructive storm surge, flooding, and erosion. Sea-level changes are not expected to be spatially uniform, that is, one region may experience a very different sea level change from other regions. It is challenging to identify the local or regional anthropogenic sea level change signals, which can be easily masked by the noise of natural sea level fluctuations on various temporal and spatial scales. In this talk, I will first show the sea level observations from satellite altimeters since 1993 exhibit not only considerable interannual (2~7 yr) variations but also quasi-decadal (10~15 yr) cycles. Analysis of relatively longer sea level products confirms the robustness of such quasi-decadal cycle and also reveals a multi-decadal trend reversal around the early 1990s. Climate model simulations significantly underestimate the magnitude of these decadal-to-multidecadal sea level variations. Future projections of regional dynamic sea level changes from the latest CMIP6 models will be examined to show how these projections are affected by model systematic biases and when/where the long-term sea level change signals will emerge from the natural sea level variations.