Improved prediction of extreme weather

In 2017, there was a flood in Ouagadougou, Burkina Faso. Credits: Fowe Tazen / Gnenakantanhan Coulibaly

Although mostly small, mapping the effects of extreme rainfall events to global climate models poses significant challenges. Computer models used to simulate global climate, such as the Intergovernmental Panel on Climate Change (IPCC) report, typically have a grid resolution of approximately 100×100 kilometers.

“Most clouds, swirls of air, and mountains are less than 100 km, so they are not completely” visible “in many climate models. This also means that thunderstorms and their associated extreme rainfall cannot be simulated in a realistic way. The principle is comparable to high pressure. -And low-definition television: In HD you can see all the leaves on the soccer field, but older televisions may just recognize the ball, “said Dr. Cornelia Crane, Department of Atmospheric and Climate Sciences. Explains. “The increased computing power has finally made it possible to make the first high-resolution climate predictions that can” see “the storm. Using Sahel’s high-resolution forecasts as an example, we have devised a way to put together the best climate forecasts. The world of climate modeling and observed data provides improved estimates of the expected intensity of future extreme rainfall events. The results of the study were recently published in the journal Environmental research letter A collaboration between researchers at the University of Insbrook and the UK Center for Ecology and Literature (UKCEH). Reliable information on future extreme weather events is critical to areas such as urban development, water and energy infrastructure, flood resilience and sustainable agricultural practices. “This is especially relevant for areas that are extremely vulnerable to extreme weather events, such as West Africa,” says Klein.

Model and observation

Using the Sahel as an example, the team uses a statistics-based method that combines the projection of a high-resolution model of the Met Office for the African continent with a number of commonly used global climate models and observations. I devised it. data. These “observation data” include information on cloud formation and rainfall intensity from satellite data, as well as humidity and wind measurements. These factors are essential to the occurrence of heavy thunderstorms, but can only be captured and predicted accordingly using high resolution data. “Our results show that extreme weather events in Sahel at the end of this century could result in up to 25% higher rainfall per hour than currently predicted by traditional climate models. It shows that, “explains atmospheric scientists. “Observation data and high-resolution climate models have given us an idea of ​​how thunderstorm rainfall intensity responds to changes in humidity and wind atmosphere. Then, using this knowledge, we can predict. Extreme changes in atmospheric changes from many traditional climate models. Changes in rainfall. The important thing here is to consider large-scale atmospheric changes in traditional climate models to be at least plausible. “We can’t say about extreme rainfall.” “Our calculations show a better risk for future extreme rainfall by deriving more realistic process-based rainfall changes for many climate simulations.” You can create a rating. ”

Extreme Weather: More Accurate Forecasts in Changing Climates

For more information:
Cornelia Klein et al, Combining CMIP data with regional convection tolerance models and observations, predicting extreme rainfall under climate change, Environmental research letter (2021). DOI: 10.1088 / 1748-9326 / ac26f1

Provided by Universität Innsbruck

Quote: Improved extreme rainfall forecasts obtained from // on October 22, 2021 (October 22, 2021)

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Improved prediction of extreme weather

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