The plasma environment extending from the solar surface through interplanetary
space to the outermost reaches of the Earth’s atmosphere and magnetic
field is dynamic, often disturbed, and capable of harming humans and damaging
manmade systems. Disturbances in this environment have been identified as
space weather disturbances. At the present time there is growing interest in
monitoring and predicting space weather disturbances. In this paper we present
some of the difficulties involved in achieving this goal by comparing the
processes that drive tropospheric-weather systems with those that drive
space-weather systems in the upper atmosphere and ionosphere. The former are
driven by pressure gradients which result from processes that heat and cool
the atmosphere. The latter are driven by electric fields that result from
interactions between the streams of ionised gases emerging from the Sun (solar
wind) and the Earth’s magnetosphere. Although the dimensions of the
Earth’s magnetosphere are vastly greater than those of tropospheric
weather systems, the global space-weather response to changes in the solar
wind is much more rapid than the response of tropospheric-weather systems to
changing conditions. We shall demonstrate the rapid evolution of space-weather
systems in the upper atmosphere through measurements with a global network of
radars known as SuperDARN. We shall also describe how the SuperDARN network is
evolving, including a newly funded Australian component known as the Tasman
International Geospace Environmental Radar (TIGER).
Space Weather, SuperDARN and the Tasmanian Tiger
