29 June 2011

Defunding of NOAA Weather Satellites Means Goodbye To the 7-Day Forecast.

Posted by Dan Satterfield

TV viewers in America are used to seeing the 7- day forecast on the nightly weather report and the accuracy is actually as good for 7 days as it was for three back in 1980. If the polar orbiting satellite program is defunded ( as now proposed by Congress) then forecast accuracy will likely go backwards.

That means a five-day forecast instead of seven and even those five will not be as good as they were. This isn’t just idle talk, the model data proves it. I wrote a post on this several months ago, and below is that post again with some updates. Apparently, one congressman told NOAA to turn on the Weather Channel to get the data (where do you think they get it from!). I cannot fathom how someone so scientifically illiterate gets to be elected to Congress.

Here is the post again:

I rarely pay much attention to federal budget issues, but this issue is on my turf. Having worked around TV-news folks for 31 years, I’m rarely surprised by politics or politicians! You tend to get rather jaded because you end up seeing a lot of crazy things, day in and day out!

That said, this is one I really could not believe. It seems the House of Representatives proposed budget includes no replacement for the NOAA polar orbiting weather satellites. The orbiters up there now are not likely to last much longer, and I suspect the average person has no idea of just how critical they are to the forecasts made each day by private meteorologists like me (and the folks at the National Weather Service and Environment Canada) etc.

Winds aloft measured by satellites are crucial for good forecasts. Satellite data is used to initialize numerical weather models world wide. Especially over oceans. This image from CIMMS shows upper winds around TS Arlene on Wed. 29 June,2011.

First of all, these satellites are not the images you see on most TV weather-casts, they are at a much lower (870 km) altitude and actually have a much better view of storm systems. Most importantly, they have instruments that allow the temperatures and winds in the atmosphere to be measured over wide areas, including the oceans, where very few weather observations exist. Modern forecasting relies very heavily on numerical weather prediction models that simulate the atmosphere out to about 10 days and you must give these models as accurate an initial condition as possible.

In other words, GIGO: garbage in=garbage out.

The number of weather balloon launches each day are nowhere near close enough to give an accurate initial state of the atmosphere, and satellite data is used to analyze the state of the atmosphere at many different levels. This data is automatically included in each model run, and many universities and atmospheric research centers run their own models using the initial conditions produced by NOAA’s National Center for Environmental Prediction (NCEP).

It’s actually pretty easy to show what the loss of these satellites will do to forecasts. Just go back and run the models without the satellite data and compare the difference between the model runs with the data AND with what actually happened!

NOAA has done just that.

If you are thinking that NOAA will just have to get by with those rawinsonde balloons, you should know that under the current proposed funding, they may have to cut the number of rawinsondes as well. You won’t need to worry about the weather for your trip to Paris though, the European Centre for Medium Range Forecasting (ECMWF) runs what is possibly the most accurate weather model in the world.