January 25, 2013
Internal Waves May Get Meteorologists Off The Hook For Bad Predictions
[ Watch the Video: BYU Engineers Study How Waves Impact Weather, Atmosphere ]
redOrbit Staff & Wire Reports - Your Universe Online
While it may be easy to blame weathermen when their predictors go horribly, horribly wrong, one US researcher says that the meteorologist may not be to blame — that there are underlying scientific forces at work that can sabotage even the most well-researched forecasts.
Those forces are known as internal waves, and according to Brigham Young University (BYU) mechanical engineering professor Julie Crockett, they impact our daily weather and long-term climate without us even realizing it.
Internal waves occur both within the ocean and the atmosphere, she explained. We can´t see these “highly influential” waves, and neither can the models used by meteorologists, Crockett said, which is why their predictions can sometimes miss the mark.
“Atmospheric internal waves are waves that propagate between layers of low-density and high-density air,” the Provo, Utah-based university said in a statement. “Although hard to describe, almost everyone has seen or felt these waves. Cloud patterns made up of repeating lines are the result of internal waves, and airplane turbulence happens when internal waves run into each other and break.”
“Internal waves are difficult to capture and quantify as they propagate, deposit energy and move energy around,” Crockett added. “When forecasters don´t account for them on a small scale, then the large scale picture becomes a little bit off, and sometimes being just a bit off is enough to be completely wrong about the weather.”
One example of this phenomenon likely occurred in BYU´s home state of Utah in 2011. Meteorologists there had predicted that a tremendous winter storm was set to strike statewide just prior to Thanksgiving, the university said.
As a result, schools cancelled classes and people were sent home early in order to avoid the inclement weather — only the storm never actually happened. “Though it´s impossible to say for sure, internal waves may have been driving stronger circulations, breaking up the storm and causing it to never materialize,” BYU explained.
“When internal waves deposit their energy it can force the wind faster or slow the wind down such that it can enhance large scale weather patterns or extreme kinds of events,” added Crockett, who is attempting to model internal waves and discover how they interact with one-another or with other, related phenomena. “We are trying to get a better feel for where that wave energy is going.”
The oceanic internal waves exist between layers of low-density water and high-density water, and can affect the water´s circulation as well as weather-related phenomena such as the Jet Stream and the Gulf Stream, the researchers said. Both types of internal waves contain enough energy to cause changes to the climate.
“Crockett´s latest wave research, which appears in a recent issue of the International Journal of Geophysics, details how the relationship between large-scale and small-scale internal waves influences the altitude where wave energy is ultimately deposited,” BYU representatives explained.
“To track wave energy, Crockett and her students generate waves in a tank in her lab and study every aspect of their behavior. She and her colleagues are trying to pinpoint exactly how climate changes affect waves and how those waves then affect weather,” they added. “Based on this, Crockett can then develop a better linear wave model with both 3D and 2D modeling that will allow forecasters to improve their weather forecasting.”
Image 2 (below): BYU engineering professor Julie Crockett studies waves in the ocean and the atmosphere.