| General Forecasting Division
Data Collection - Space Based
SATELLITE
Visible Satellite
This visible satellite image measures the sunlight reflected by the Earth’s
surface and clouds. Clouds and snow reflect a lot of light and are bright;
the oceans absorb almost all incoming light and are dark; thin or low
clouds and land have variable reflectivity’s or albedos, and are
varying shades of grey. The earth is scanned every 15minutes by the new
MSG geostationary satellite which is located over the Equator at 0 degrees
W. Images are available here at 1200 all year round, and also at 0600
and 1800 from Spring to Autumn. VISIBLE
SATELLITE IMAGE
Infra-red Image
The infra red satellite image measures the temperature or radiance of
the ground and clouds. Light shades represent low temperatures and
dark shades high temperatures. The Earth is scanned every 30 minutes
by the MSG geostationary satellite which is located over the
Equator at 0 degrees W. Images are available here at 0000, 0600, 1200
and 1800. INFRA-RED SATELLITE IMAGE
RADAR
Radar
There are currently operational radars at Dublin and Shannon Airports
and also one in Belfast. Electromagnetic pulses of wavelength 5.6cm are
sent out and the time taken for them to return is measured. They are
reflected by precipitation. A composite picture of the precipitation
over Ireland is created every 15 minutes. RADAR
IMAGE
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