Research Innovation Improves Weather Forecast Accuracy

June 29, 2012

NOAA scientists in Boulder, Colo. have helped improve the forecast system that forms the backbone of U.S. weather and climate forecasting. An upgrade to the Global Forecast System, GFS, which is run four times per day and produces forecasts up to 16 days in advance, promise to make weather and climate forecasts more accurate.

graph showing better performance of forecast model with new assimilation technique.

Comparison of 5 day forecast anomaly correlation at 500mb (higher = better) between forecasts from previous analysis system (black) and new hybrid analysis system (red) for period from August to October 2010. Credit: NCEP

On May 22, the National Centers for Environmental Prediction (NCEP) – a division of NOAA’s National Weather Service – began using a new method for assimilating the billions of pieces of atmospheric data collected daily from Earth and satellite-based systems. These data are used to describe the current state of the atmosphere, the critical first step in running any weather forecast model.

Even with billions of observations, there are gaps in our depiction of the current atmosphere and those gaps can lead to errors in forecasts. The new data assimilation technique, developed in collaboration with NOAA’s Earth System Research Laboratory (ESRL), uses ensembles or collections of forecasts to do a better job than older system at filling those gaps.

In extensive testing, the new system produced more accurate forecasts out to 16 days. It also improved hurricane track forecast accuracy, general global weather predictions and forecasts of stratospheric ozone, which affects the amount of skin-damaging radiation that hits Earth’s surface.

“This data assimilation upgrade represents the biggest improvement in U.S. weather and climate forecasting in a decade,” said Louis Uccellini, Ph.D., director of NCEP. “In the near future, we’re going to start noticing more accurate forecasts.”

The new hybrid system is the result of an intensive, three-year collaboration between scientists at NCEP, ESRL and the University of Oklahoma. Jeff Whitaker and Tom Hamill, research meteorologists in ESRL’s Physical Sciences Division, helped build, test and fine-tune the new data assimilation system.

“This is a great example of how NOAA research and operations can work together to translate cutting-edge research into improved forecasts that impact people lives,” Whitaker said.

He and his colleagues expect further system improvements over the next few years, as a result of continued collaboration between NCEP, ESRL and the academic community.

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