Share this article

print logo


Don Paul: Private models on the move

That headline may not sound like a Don Paul article. I shall revert to my stodgier self and explain.

With all the talk about the accuracy of the American model of storm tracking versus the European model, in Irma’s case a private sector model was the best performer. Panasonic, yes, the electronics company, has developed a powerful global computer model which outperformed both the European (ECMWF-European Center for Medium Range Weather Forecasting) and the American GFS (Global Forecast System) for track forecast accuracy. This isn’t the first such case. Panasonic meteorologists, modelers, and statisticians monitor every run of their model for accuracy just as the National Weather Service and the European Center do the same with their models.

Private sector models still depend on a vast store of government-gathered data. Panasonic and a competitor, IBM, aren’t about to launch weather balloons twice a day across continents, or put up their own sophisticated weather satellites, or build a vast network of advanced Doppler radars. But Panasonic and IBM do have their own computer crunch power (you’ve heard of IBM’s Watson?) and they have the ability to pump in additional data to the GFS model to stand on its shoulders and turn out a product which often puts the NWS version to shame. Courtesy of the Washington Post, here is a quick look at track accuracy for Irma:

Panasonic pumps value-added data into the GFS which improves its physics, by broadening its information base. The most prominent example of this came from Panasonic’s purchase of a company which engineers weather instruments for jet airliners. Thousands of domestic and European airliners now gather atmospheric data from the time they take off until they land, spitting out much more realtime upper level information than twice daily balloon launches can gather. The new GOES-16 is performing spectacularly in its testing phase, but this aircraft data still fills in lots of holes in our upper air data, and enables the finished product to sometimes outscore the GFS and, often, the ECMWF. Panasonic can help pay for this by selling the data and model output. Much of the ECMWF’s monetary support comes from sale of the majority of the European output, rather than giving it all away for free.

IBM has gotten into the private sector modeling business as well and had offered to team up with the National Weather Service in replacing our GFS model with a hybrid, which was something better. For reasons not entirely understood, even after some real success with the IBM hybrid, the NWS chose not to work with them, and a number of outside experts feel that was a mistake.

Government models still have to be upgraded, since they are the underpinnings for sometimes superior private sector models. The European Center is going to replace their already superior supercomputer center in Reading, England with a new center in Italy. The U.S. is making improvements on our GFS, but we will still lag badly. As of now, the European Center runs 51 versions of the European model every 12 hours, each with slightly differing initial conditions in the atmosphere, making an ensemble of model solutions instead of just one. The American GFS runs just 21 ensemble “members”, making its ensemble inferior, most times. In longer-range forecasting out to several days, the use of ensembles has brought great improvement in verification.

The final track errors on Irma, comparing the Panasonic, GFS, and European models and ensembles look like this.

It must be remembered no model is the most accurate every time; not even the European. The average performance of the European model is, however, the best of all government models. That private sector models can add value to these very expensive government models is a good thing. All that said, for the last 18-24 hours of Irma’s movement through Florida, the GFS most accurately forecast the inland path (away from the Gulf coast) after having trailed the European model most of Irma’s lifetime. That turn to the interior is what saved Naples and Tampa Bay from a devastating storm surge. The GFS still produces valuable forecast guidance, but we’re not yet on track to match the European. Fortunately, the NWS has access to the European. There’s no nationalism allowed in the Weather Prediction Center, NWS HQ.

That’s a good thing.

There are no comments - be the first to comment