Parameter Tree:
EARTH SCIENCE > SPECTRAL/ENGINEERING > PLATFORM CHARACTERISTICS > AIRSPEED/GROUND SPEED

Definition:
Airspeed is the speed on an exposed (usually airborne) object relative to the
atmosphere.
In a calm atmosphere, airspeed equals ground speed. Ground speed is the speed
of an airborne object relative to the earth's surface. It is the magnitude of
the vector sum of the object's velocity with respect to the air and the wind
velocity, or, expressed in a different manner, the algebraic sum of the
aircraft's airspeed and the wind factor.


Reference:
American Meteorological Society Glossary of Meteorology Online.
http://amsglossary.allenpress.com/glossary