Scientists predict average late winter precipitation in western Europe for the next decade

We like to see a few bold predictions here at the Talkshop, even if they expect things to be ‘average’, but as these go out to ten years ahead we’ll add them to the (imaginary) list. The current very low solar minimum could be a wild card.

In a new study, scientists at the National Center for Atmospheric Research (NCAR) show that the average March precipitation, over the next ten years in western Europe is predictable using a novel method, says Phys.org.

The research team also issued a forecast for the coming years.

“Through the year 2027, the forecast indicates that we should expect, on average, wetter winter conditions in the UK and drier conditions in Portugal compared to the most recent ten-year averages,” said Stephen Yeager, a climate scientist at NCAR and co-author of the paper.

To make this prediction, scientists used a creative methodology that combines simulations from NCAR’s flagship climate model with statistical techniques based on observations.

Taken together, the approach—which was validated using “hindcasts” of conditions over the last century—yields a much more skillful prediction than could be made with either the model or observations alone.

“None of the methods alone could capture all the elements needed to make a prediction,” said NCAR scientist Isla Simpson, lead author of the research, appearing in the journal Nature Geoscience. “By combining multiple techniques and datasets, we were able to complete the picture.”

The predictions could be useful to resource managers and planners, including farmers and water managers, who rely on precipitation forecasts.

Filling the prediction gap

As short-term weather prediction has improved, thanks in part to increases in computing power and observational data, scientists have turned their attention to longer-term predictions, such as determining whether a particular region is likely to be unusually wet or dry over an extended period.

These long-term predictions range from seasonal to years or even decades into the future. When working on these timescales, scientists look for atmospheric circulation patterns that are tied to the ocean because the ocean changes at a much slower pace than the atmosphere.

For this new study, scientists turned to the NCAR-based Community Earth System Model (CESM). To test its use in making decadal predictions, they started the model using ocean conditions that approximate historic observations and then looked to see how well the model matched reality as it ran forward a decade at a time.

They repeated this for every year between 1954 and 2015, creating a robust test for what can and cannot be predicted on longer timescales.

Full article here.