Cold, symmetric, and cryptic

Researchers aim a barrage of sensors at nature’s most enduring heiroglyphs.

SNOWFLAKES have intrigued many for centuries, but it has been an especially befuddling ride for remote sensing scientists. Aiming a microwave radiometer at a rainstorm gives them streams of beautiful data. Pointing it at a snowstorm sends the instrument into conniptions. “Scientists have the technology to study rain from space, but we’re forty years behind for snow,” said Gail Skofronick-Jackson, who studies remote sensing of snowfall. “Raindrops are spherical when small, or shaped like burger buns when large.” This simplicity allows satellites to recognize raindrops from 200 miles away. “Snow is trickier to detect because, as you know, it has so many shapes,” she said.

Skofronick-Jackson and about a hundred other scientists in the NASA Global Precipitation Mission Cold-season Precipitation Experiment (GCPEx) are using instruments that can, among other things, tell the difference between raindrops and snowflakes. If they succeed, the Global Precipitation Measurement satellite mission will use GCPEx data to measure snowfall worldwide, bringing crucial data to meteorologists, freshwater resource managers, and climate researchers. The big hurdle, however, is teaching it how to see snow.

Originally published in Sensing Our Planet: NASA Earth Science Research Features. Read the full story here.