NASA's Soil Moisture Active Passive (SMAP) mission launched on January 31 to measure moisture on the top few inches of soil globally will begin monitoring the frozen or thawed landscape by April-end.SMAP will monitor the landscape north of 45 degrees north latitude (about the latitude of Minneapolis) every two days.The primary mission of SMAP is to measure the amount of moisture but it also detects whether that moisture is frozen or in liquid form.SMAP's radar measurements, with "tiles" only one to three km across, will reveal far more detail than scientists now have about the freeze and thaw status of the land surface, the US space agency said in a statement.
One ecosystem where scientists would most like to understand the effects of changing freeze/thaw cycles is boreal forests - the great ring of green covering the land nearest to the North Pole.The forests of Alaska, Canada, Scandinavia and Siberia cover almost 15 percent of Earth's land surface.The Arctic is warming more quickly than lower latitudes and the way these forests respond to this rapid change could provide valuable clues about our planet's warmer future.But we know very little about how the boreal forests are changing. Millions of square miles have no roads or even villages.
"What we have now are very sparse, seasonal measurements from the ground," said John Kimball, member of the science team for NASA's SMAP mission."We do have long-term, global satellite data sets that are sensitive to freeze-thaw, but they tend to be very coarse," he added.With SMAP, this is about to change, the scientists said.For example, this spring, SMAP will spin up in time to track the spring thaw in the boreal forests with the detail scientists need.