27 July 2015
Europe Doesn’t Just Have Better Roads, Faster Trains, and Nicer Airports. They Have Better Weather Satellites, and More Accurate Weather Models.
..and don’t get me started about roundabouts either, because that’s a whole other blog post!
Seriously though, our once number one position in atmospheric science is long gone, and there are few signs of that changing. Yes, we will launch a weather satellite next year that will be as good or perhaps better than Europe’s Meteosat, but they have an even better one on the drawing board,while Japan has us beat now and has plans for more as well. I want to talk about numerical weather models though, and when it comes to the weather prediction gap, the person to listen to is Univ. of Washington professor Dr. Cliff Mass.
First some background on where we are now. I spent this weekend watching some of the talks at the AMS Conference on Weather and Forecasting held in Chicago in late June. I did not make that meeting, having been at the AMS meeting on Broadcast meteorology a couple of weeks earlier, but most of the talks are online and I will link to a few here.
WHOSE IN FIRST
Ask any forecaster what the best medium range weather model is, and they will almost certainly tell you that it’s the model run in Reading, England by the European Center for Medium Range Forecasting. We just call it the ECMWF model for short. If, by chance, someone tells you otherwise, they’re wrong, and the data proves it.
Before someone says something along the lines of “It must be nice to get paid for being wrong all the time”, let me point out two things. My batting average is better than any MLB player, and I’ll gladly swap paychecks with them. Secondly, numerical models have improved amazingly over the last 20 years. A three-day model forecast today is as good as a two-day forecast from just 13 years ago. The Hurricane WRF model has improved dramatically as well (see image below from the same talk).
That said there is no doubt that Europe is ahead of us, and in spite of new more powerful supercomputers at NOAA, they will likely stay there. The reason is that early next year the ECMWF will be upgraded to a much higher resolution with even better physics. They will also upgrade their long-range ensemble forecasting as well. FYI: Long range predictions are more accurate when you run the model many times using a very slightly different starting point and then look at the solutions that are most common. A high spread can also tell you that predictability is low, and this too is valuable information. See this talk by David Richardson at ECMWF, and the images below are from that talk.
For those not familiar with the terminology, the grid size is like the number of pixels in your digital camera. Smaller grid equals better resolution. You also have vertical resolution, and the ECM model now has 137 layers starting at the surface and extending to a height that will freeze you to death about the time you die from lack of oxygen!
Models are only as good as their starting point though and this is on of the reasons the ECM is so good. The starting point it is given is very good and more realistic than the one NOAA uses. We do not know what the state of the atmosphere is over the entire globe, so we have to estimate it using the available data from surface stations, ships, weather balloons and ever more importantly satellites. They do a very good job of this at ECMWF and are planning on improving more.
The Charles Emerson Winchester Technique of Weather Prediction
The M*A*S*H character Charles Emerson Winchester had a line in one episode where he says “I do one thing at a time, I do it very well, and then I move on.” This is how the ECMWF folks approach forecasting. They have one main model, and work to make it better. Look at the distribution of computer time on NOAA’s mainframe for the different numerical models. (See below-from an image that Bill Lapenta (head of NOAA’s National Center for Env. Prediction (They run the NOAA models) showed in his talk (watch it here).
NOAA folks realize that we need to step back and take a hard look at the future, and they have a committee put together to do just that.(I’m hoping they have at least one broadcast meteorologist on it, and I’d bet they do!)
NOW THE BAD NEWS
Remember Dr. Cliff Mass I mentioned at the top of this post? He made some remarks in Chicago as well,and I hope everyone was listening, because it sure made me sit up and pay attention watching online! Look at the graph he showed. The models have not really improved much in the past 5 years. None of them. You can watch the talk by Dr. Mass here, but some of the images he showed are below:
I think he is spot on. It was Cliff Mass who first made public what we forecasters have known for a while, about the state of our atmospheric modeling, and that actually helped to get NOAA new computers. I asked him about his talk and he said “I have blogged about these issues quite a bit and I wrote a paper in BAMS (the uncoordinated giant) that deals with many of the issues. The bottom line is really straightforward: the US has fallen behind because we have divided our resources on too many models and systems. No system of coordination and combination of resources. A complacency among NWS leadership and a willingness to be third rate. But I think there are encouraging signs, like the acquisition of the new computer and the current NGGPS effort.“
The threat of Russia’s space program took us to the Moon. Here’s hoping China’s forecast system gets even better than the ECM model soon!