A satellite that monitors daily soil moisture changes around the world could improve short- and long-term weather forecasts.
NASA expects to launch the Hydros satellite in 2010 and plans to feed the data it collects into models used by meteorologists to predict the weather.
Bob Cormier, meteorologist with Environment Canada, said current weather forecasting models do not include daily soil moisture figures, only soil moisture readings that are collected periodically.
That information is critical because soil moisture affects weather, he said.
Soil moisture change is part of the global water cycle and is the result of rain, evaporation and snow melt. The soil surface interaction is similar to the ocean surface atmospheric interactions that cause the El Nino and La Nina weather phenomena.
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Cormier said underestimating the amount means underestimating the amount of moisture available for weather systems development. Overestimating can affect temperature calculations.
“It could make the difference between forecasting a garden variety thunderstorm and severe thunderstorm,” Cormier said.
Using real time data in the computer simulations would contribute to accuracy, said Cormier.
“The better data you can put into models, the more accurate picture you get in the end,” he said.
For farmers, that means better one- and two-day forecasts but also improved seasonal forecasts.
Tom Jackson of the Agricultural Research Service’s hydrology and remote sensing laboratory in Maryland said farmers could use the information to make decisions on planting, irrigating and fertilizing, municipalities could use it to manage reservoirs and flooding and homeowners could use it to decide when to water their lawns.
He is engaged in experiments to verify that information received from orbiting satellites matches soil moisture readings taken at ground level.
Rapid evaporation of soil moisture in the atmosphere is often not taken into account and sudden changes in soil moisture over vast areas can be important in determining whether it rains or not, he said.
“They drive the atmospheric circulation that spawns storms,” he said.
Jackson hopes the Hydros’s data can be used with other satellites and sources to improve global forecasting.
