The importance of wave modelling in predicting the impact of climate change on sea ice

Researchers from the University of Adelaide have developed a new theoretical model that predicts the distances ocean waves will travel to break up sea ice.

Monitoring ocean wave propagation is important for predicting how ice covering the Arctic and Antarctic oceans will respond to climate change, but current models were first developed in the 1970s and 1980s.

Dr Luke Bennett and Jordan Pitt, from the University of Adelaide’s School of Computer and Mathematical Sciences, investigated how changes in ice breakup affect wave propagation and published their findings in Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences.

“Until now, the distance over which ocean waves can break up sea ice has only been considered in terms of the gradual decrease in wave energy with distance,” Dr Bennett said.

“Our results show that large reductions can occur over short distances before an unbroken ice sheet begins to collapse, and that this additional consideration may change the interpretation of field observations.”

When waves reach frozen areas on the ocean’s surface, they can break up the ice cover into separate chunks called ice floes, which can be washed away and melt quickly.

“At the same time, because of the ice cover, the waves lose strength over distance, so breaking only occurs over a limited distance,” Dr Bennett said.

“We see changes in the way waves move through the sea ice before and after the ice breaks up, but these changes are very difficult to measure in harsh polar oceans.”

“We used mathematical models to understand the changes and were able to quantify the local changes that occur where the ice sheet begins, as well as the changes that occur over long distances.”

Dr Bennett said the findings could inform how wave and sea ice interactions are treated in numerical models used to study climate.

“The main goal of this research field is to predict the distance at which ocean waves will break up sea ice,” he said.

“The long-term goal is to advance numerical climate model predictions of the future of global sea ice.

“In the short term, we aim to combine models of the effect of ice on waves with models of ice breakup by waves to predict the extent of ice breakup.”