Researchers predict seasonal sea level rises

Polynesia, Micronesia and Melanesia are the three largest island groups in the Pacific. The islands often protrude only a few meters from the world's largest ocean and they are all threatened by sea level rise. Researchers have now found a way to make life on these islands more predictable.

An island in French Polynesia

"I am at Matthew Widlansky and I am a researcher at the University of Hawaii at the sea level center in Honolulu, and I study the sea level changes in the tropical pacific islands."

Matthew Widlansky from the University of Hawaii in Honolulu is studying how the sea level rise around the islands of the tropical Pacific is predicting.

"We know from observations by means of measuring instruments and satellite images that the water masses in the Pacific are slowly spinning back and forth, so if a wave hits the islands, this results in minor flooding that last for some time, or the contrary happens and parts of the coral reefs Fall dry and die. "

At present, these seasonal sea-level fluctuations in the Pacific are not causing any major damage. The water rises and falls again after some time. But just as in all other seas, the underlying sea level in the Pacific is continually rising as a result of climate change. The combination of rising water and seasonal fluctuations could therefore lead to ever more and ever stronger floods in the future.

"If you have a chance to predict these fluctuations of the sea level, even if they only last for a few months and then the water sinks again, the island communities can adjust to prepare for the next flood event."

Together with colleagues from Australia and New Zealand, Matthew Widlansky has therefore combined several global climate models with weather and ocean data, with water temperatures and ocean currents.

"This is how our computer simulation can determine the sea level at different locations in the ocean, we start the simulation with the current conditions, and as the ocean reacts much slower than the atmosphere, we can make more prognosis than a simple weather report Reliable data, where we can predict the water levels of the next six months. "

The sea-level forecasts by Matthew Widlansky are freely available on the Internet and are used by numerous residents.

"I live in Honolulu and here we have just a period with slightly increased water levels, 15 to 20 cm more than normal, which does not sound like much, but the coasts of the Hawaiian Islands are surrounded by coral reefs that slow the wave energy The waves can roll over the reefs unobstructed and hit the beaches with greater force.Some coastal hotels have used our forecasts and prepared for them by sheltering the lower floors with sandbags. "

In a next step, Matthew Widlansky and his colleagues want to offer their forecasts also for other world regions.