Sunday, May 8, 2011

Promising, and Not So Promising, Tornado Research

Yesterday's Wall Street Journal had an article about tornado research in the wake of the recent storms.

In general, I'm in favor of meteorological research because better weather forecasts and warnings have a huge benefit to cost ratio.  This research, in some cases, performs a dual role in helping better understand climate. That said, research dollars are not infinite. So, I'm going to critique the projects mentioned in the article.  Keep in mind that the goal of the taxpayer-funded public relations and lobbying arms of these government laboratories is to pry more tax money from Congress. Most of them never met a research program they didn't like, regardless of its real-world merits.

First of all, the premise of the article: "Better" warnings on April 27 in the South would have saved lives. Based on the evidence I have examined (more on that in a blog posting tomorrow), the forecasts and warnings of those storms were excellent. The loss of life was exaggerated in this case because of the extensive power failures 12 to 16 hours before the tornadoes arrived. The lack of power prevented people from receiving the warnings via TV, internet, etc. Improving warnings makes no difference if people cannot get them because the power is out.

Now, the areas where the interviewees want to perform more research, spend more money, or create new programs, in the order in which they appear in the article:

NOAA's Budget Cut This Year
I believe this was unfortunate, but it had nothing to do with the loss of life on April 27. The warnings and forecasts were excellent.

WSR-74C radar used by NWS in Topeka.
I used one of these for more than 20 years and it could survey the atmosphere for
tornado detection every 20 to 30 seconds. 
Radars That Don't Survey the Lower Atmosphere Often Enough to Detect Tornadoes
This part of the article is misleading. There is nothing inherent in the National Weather Service's radars that prevent them from surveying the lower atmosphere much more frequently. That is software and it could be changed by modifying a few lines of code if the decision was made to do it.

In fact, up until the Doppler radars were installed from 1991 to 1996, radars surveyed the lower atmosphere every 20 to 30 seconds, which is plenty often to find tornadoes. The reason they don't today is because the radars were part of a three agency program: NOAA, the Department of Defense, and the Federal Aviation Administration.  The latter two agencies wanted better coverage for aviation and, when the radars were installed, we thought they were going to be able to detect turbulence aloft. To do so, the radars spend a lot of time probing the upper atmosphere -- not very useful for detecting tornadoes. So far, turbulence detection has not worked as anticipated. I believe there are compelling reasons, in tornado situations, to ditch the lengthy "volume scans" for aviation and run the radars so they survey the lower atmosphere more often.

That said, the current generation of radars is approaching twenty years old and will need to be replaced. I'm not sold on the article's proposed solution of "phased array radars" because, at least so far, they present a picture that is more "blurry" than the existing radars. Detail is critical when trying to find tornadoes.

Something the article does not mention is "gap filling" radars. There are inexpensive current generation radars that could be put in areas where the current radar coverage is poor (northeast Missouri, for example). That would do more to save lives than phased array would at the current state of the art.

Better Computer Models and Vortex II
Needed and welcome!

Lightning Detection
There are good reasons to get better lightning data from both ground and satellite-based sensors, but it is not clear whether better tornado warnings are among them. Since at least 1955, meteorologists have been trying to figure out the link, if any, between lighting and tornadoes. While I have my ideas on the subject, they have not been tested in rigorous studies. This is worth pursuing.

Infrasonic (sound) Detection of Tornadoes
The theory is that, if a tornado made it to the ground without warning, we would "hear" the roar made by the tornado in contact with the ground so we could get a warning out for people downwind. This idea has been around since at least the 1970's. It is not needed anymore due to the fact that in 1999 meteorologists discovered the "debris ball" radar signature. This signature will be more useful with the NWS's new dual-polarization capability being installed at present in its existing radars.

A weather balloon. From top, the balloon, a parachute, and the
instrument package that measures the atmosphere.

Aircraft Weather Measurements
As noted, this is already being done and it is great if we can expand it. That said, it should never replace weather balloons. #1) An airplane might not be near the location when and where a measurement is needed. #2) The vertical measurements that can only be done by balloons are needed for climate studies.

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