Franklin Fact Archive
January, 2000
February, 2000
March, 2000
April, 2000
May, 2000
June, 2000
July, 2000
August, 2000
September, 2000
October, 2000
November, 2000
December, 2000
January, 2001
February, 2001
Back to Franklin Facts homepage.
Back to TV12
|
TUESDAY FEBRUARY 13 - SENSITIVITY OF DOPPLER TO SNOW INTENSITY
When you think about the many ways that
Doppler Radar has revolutionized meteorology,
right at the top of the list is better detection of potential tornado-producing
thunderstorms. But Doppler Radar has been a revolution in other ways too, one
of which gets a lot of use this time of year. That's the ability to tell the
difference between
various intensities of snow, something older radars couldn't
do very well, if at all.
Radar works by sending out pulses of radiation. When that radiation strikes
raindrops or snowflakes, some of it is reflected back to a receiver. In
general, the more radiation that comes back, the heavier the rain or snow.
Snow is harder to detect with radar than rain because snowflakes actually
have a
lot of holes in them. So it's easier for the
radar beam to go right
through a snowflake without reflecting back.
But Doppler radar is extremely sensitive, even to relatively small amounts of
reflected radiation. So it can actually differentiate
bands of heavier snow
within larger areas of lighter snow. And this can help meteorologists tell
you with more detail where the heaviest snow is falling in a storm.
|