A New Satellite Will Watch the Western Drought from Space
The launch of a small satellite wont fix the the drought in the American Westnow entering its fourth yearand it wont change the fact that January was the driest month in recorded California history. But the Soil Moisture Active Passive mission might at least tell scientists and farmers something new about that drought, and maybe how much worse itll get.
Winds and mechanical issues delayed the SMAP launch for two days, but on Saturday morning a Delta II rocketed it from Vandenberg Air Force Base to about 400 miles above the planet. After three months of commissioningwhen ground control makes sure all the instruments are workingSMAP will spend three years taking the most accurate readings ever of soil moisture around the world. Thats right: It will measure how wet the dirt is. From space.
For understanding water on Earth getting a good handle on dampness is crucial. SMAP can see through atmospheric moisture, plants, and a couple of inches of dirt to measure wetness over an area of about 3.5 square miles. Damp soil, it turns out, emits subtle microwave signalsthe wetter the dirt, the weaker the signal. SMAP can see those, and it also fires microwave pulses at the ground (dampness affects how they bounce back) for more accuracy. What sets SMAP apart from other satellites is its 20-foot-wide rotating antenna, big enough to pick up more subtle signals for better resolution.
The data will feed computer models that forecast weather, climate, and agricultural production, says John Bolten, a hydrologist at NASAs Goddard Space Flight Center. Even better, says Bolten, its really a game-changer for drought assessment. For the first time, researchers will have direct measurements of soil moisture from around the world, enabling computer models to be more accurate in their forecasts. Having SMAP observations every two days, well have a global picture of soil moisture, Bolten says. Well be able to steer our forecast toward reality.
http://www.wired.com/2015/01/new-satellite-will-watch-western-drought-space/