Present Local weather Mannequin Simulations Overestimate Future Sea Stage Rise – Watts Up With That?
From Phys.org
from Utrecht University, Faculty of Natural Sciences at Utrecht University
Photo credit: CC0 Public Domain
The melting rate of the Antarctic ice sheet is mainly controlled by the rise in sea temperatures around the Antarctic. With the help of a new, higher-resolution climate model simulation, scientists from the University of Utrecht found a much slower rise in sea temperature compared to current simulations with a coarser resolution. As a result, the projected sea level rise in 100 years is about 25% lower than expected from the current simulations. These results are published today in the journal Science Advances.
Estimates for future sea level rise are based on a large ensemble of climate model simulations. The results of these simulations help to understand future climate change and its effects on sea level. Climate researchers are constantly striving to improve these models, for example by using a much higher spatial resolution that takes into account more details. “High-resolution simulations can determine the ocean circulation much more precisely,” says Prof. Henk Dijkstra. Together with his doctorate, the candidate René van Westen has investigated ocean currents in high-resolution climate model simulations in recent years.
Ocean vortex
The new high-resolution model takes into account ocean vortex processes. A vortex is a large (10-200 km) swirling and turbulent feature in the ocean circulation that contributes to the transport of heat and salt. Adding ocean eddies to the simulation results in a more realistic representation of ocean temperatures around Antarctica, which is critical to determining the mass loss of the Antarctic ice sheet. “The Antarctic ice sheet is surrounded by ice shelves that reduce the flow of land ice into the ocean,” explains Van Westen. “Higher sea temperatures in Antarctica increase the melting of these ice shelves, which accelerates the land ice into the ocean and consequently leads to a greater rise in sea levels.
Comparison of the new high-resolution model (left) with the previously used low-resolution model (right). Photo credit: Utrecht University
The current climate model simulations, in which the eddies of the ocean are not taken into account, assume that sea temperatures in Antarctica rise under the influence of climate change. The new high-resolution simulation shows a completely different behavior and some regions near the Antarctic are even cooling down under climate change. “These regions seem to be more resilient in the face of climate change,” says Van Westen. Dijkstra adds: “You get a very different temperature response due to ocean vortex effects.”
Full article here.
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