Predicting the weather can be a risky endeavor – but NASA scientists at the National Space Science and Technology Center in Huntsville, Ala., are attempting to reduce the guesswork involved in long-term forecasting.
“We’re researching methods to predict precipitation a season or more in advance,” explained Bob Oglesby, a senior atmospheric scientist at the research center.
If successful, NASA’s prediction methods could help green industry professionals and others plan ahead for drought and flood conditions.
The key to such early predictions lies in understanding how the atmosphere interacts with the land – sometimes in a way that completely alters the expected climate of a geographic area.
“The Gulf of Mexico, for example, is what keeps the Southeast from becoming semi-arid or, in the worst-case scenario, a big desert,” Oglesby observed. “But a series of mountain ranges blocks the way. If it weren’t for the nearby gulf, the lush, green landscapes of the Southeast might more closely resemble the semi-arid landscapes of the great plains.”
Just as mountain ranges can bar moisture from an area, ridges of atmospheric pressure can act as similar barriers – blocking out moisture from dry spots. The resulting conditions are referred to as a “thermal mountain effect.”
And such conditions continue in a self- perpetuating cycle, he noted. “If an area is already experiencing drought conditions, it is more likely to continue in a drought. Similarly, if an area is experiencing extremely wet conditions, that trend is also likely to continue.”
Drought conditions can be anticipated by watching other factors – aside from the interaction of soil moisture with the atmosphere – as well. NASA has also been studying sea surface temperature variations, ocean cooling effects, north Atlantic oscillation and snow cover in surrounding regions.
Oglesby has been using computer models to replicate and predict a wide range of weather conditions, with detailed data about soil moisture, precipitation and Earth’s surface temperature. The process can be challenging, since there is a shortage of data on soil moisture – especially moisture in the lower soil layers.
But, the senior scientist anticipates better data in the future from NASA’s remote sensing technology, which gleans information using satellite or flights above certain areas.
“If someone could provide us with the state of soil moisture over a sufficiently large area, we can begin to predict its impact on precipitation over the next season or two,” Oglesby described.
The author is Assistant Editor-Internet of Lawn & Landscape magazine and can be reached at aanderson@lawnandlandscape.com.