Increasing tornadoes or better information gathering?

John Kerry’s comment about the recent tornadoes in the southeastern USA being caused by “global warming” has caused more than a few dustups on the Internet blogs in the last couple of days.

So, from the perspective of a former TV meteorologist, I thought I’d share some of my thoughts about modern tornado statistics.

Graph from NWS/NOAA. Smaller (F1) tornadoes seem to be on the increase, but not larger ones.

I see it as simply increased reporting bias. No I’m not talking about talking heads in news stories, but rather, our ability to detect and report tornadoes has increased dramatically in the last 50 years.

There are three main reasons:

1) Our 155 strong WSR-88D NEXRAD Doppler Radar Network. This nationwide tool sees tornadoes with more regularity than the old WSR74 and WSR57 C band analog radars which used to be the mainstay of the NWS radar network. Often tornadoes that would have gone undetected and unseen before (such as in unpopulated areas) are reported with accuracy by Doppler radar. You can even download software now for your PC and get in on the action yourself. See my StormPredator program, for example.

2) Increased population density. There are more people around in places that used to be uninhabited resulting in more tornado reports where before they went unseen. It is sort of like a twist on that old saying: “If a tree falls in the forest and there’s nobody to hear it, does it make a sound?”

3) More reporting coverage. TV news and storm chasers make getting tornadoes on live TV almost as regular as watching LA car chases. Helicopters with video feeds, live vans, and just regular folks with a K-Mart video camera in the right place at the right time increase the frequency with which we see severe weather events on TV, resulting in the “feeling” that such events are on the increase.

A person from the year 1900 watching The Weather Channel today would probably think we were living in the end times.

Oddly, even with such a major increases in our reporting and news gathering ability, plus inexpensive digital cameras and camcorders in the hands of people worldwide, we have not had an increase in good photo or video evidence of UFO’s, Bigfoot, or Loch Ness.

But that’s a blog argument for another day.

Cold and Warm Bias in a Weather Station

Early on in my www.surfacestations.org project I got complaints like “why don’t you ever show a cooling bias?”. Problem was, there weren’t a lot of cold bias stations to show. Other than shading, and in one case in Washington state where the station was getting mist from a dam spillway, there just weren’t many examples. This also explains why “Eli Rabett” was never able to keep up his “cool station of the day” series that he started as a counter to my published photos (he used mine), some months ago.

Given human energy use, and artificial surfaces such as concrete, asphalt, and roofing tend to be near where many stations have been located, the bias has been predominantly warmer. Another reason the predominate bias is warm is that stations are often placed for the convenience of the observer, which means closer to human habitation.

So it was with some intrigue that I found this station yesterday, with the help of my very first volunteer, Russ Steele. The NOAA COOP station simultaneously demonstrates a cold bias and a warm bias. This is the infrared photo I took of it:

The warm bias seem obvious, but can you guess what the cold bias is?

Ok if you didn’t guess it, don’t feel bad. Infrared photos don’t show detail well.

Here is the answer: