Ex-world war II radar is directed
towards weather system
The combatant nation
if World War II developed radar to detect enemy airplanes. They also noticed
that they were picking up signals from raindrops, hailstone, and snowflakes.
After the War these signals were used for weather Forecasting. From 1948
weather radar was carried on aircraft to help the crew detect potentially
hazardous Cumulonimbus cloud system. Next generation radar which is also known
as NEXRAD is an network of 159 high resolution Doppler weather radar operate by
national weather service
Weather radar Station Transmit a directional, narrow beam of
pulsed microwaves up towards the cloud, using the antenna that rotates and
scans the sky. These microwaves typically have wavelength of 1-10 cm , these
length being about ten times the size of the raindrops ,snowflakes , hailstone
they are aiming to detect .the falling particle scatter the microwaves and a
returns pulse is then picked up back at the radar station
Five things are measured. The time taken for the pulse to
travel to and from scattering body gives the distance to precipitation the Doppler
shift of the return pulse gives the direction and speed in which the cloud is
moving .variability in the Doppler signals can indicate the turbulence of the
rain drops and thus gives clues as to whether thunderstorm or even tornadoes
might develop. The strength of the return pulse is function of the amounts of
rain in the specific cloud and the shape of the return pulse distinguishes
between Snow Hail, rain. To get a complete 3D moving weather picture, together
with cloud height, requires an interlinked series of weather radar dotted over
the land .meteorological weather radar usually provide complete radar rain
picture every half hour.
Doppler was invented by Christian
Johann Doppler, a physicist, from Austria in 1842 he studied at Vienna and
became professor of physics .he worked out his idea using sound waves
No comments:
Post a Comment