Research
Sensing the weather
Research into improving weather measurement and
forecasting has led to the formation of a new interdisciplinary research
centre.
The Centre for Remote Sensing and Environentrics brings together
expertise in the Departments of Electronic Systems Engineering, Biological
Sciences and Mathematics.
Remote sensing is typically about using radio, infrared, and light wave
observations to gauge - efficiently - at a distance what is going on or
above the earth’s surface. Much of this is satellite based, but
ground-based observations using tools such as radars and lidars are also
important.
Research at Essex has focussed mainly on atmospheric, including radar
observations of severe weather, by the remote sensing and propagation
group, and aerosols, by the aerosol group. However, funding bodies are
increasingly concerned with benefits to end users, such as meteorological
services and hydrologists and in these areas there is a need to improve
short term weather measurement and forecasting.
By its nature remote sensing typically involves indirect measurements,
and depends on the modelling of the wave propagation and scattering that
connect the atmospheric phenomena with the observations. These are the
kinds of problem on which research at Essex has largely concentrated –
information is often gleaned by detecting subtle changes in the way waves
propagate and scatter, which arise from changes in shapes and sizes of
particles such as raindrops or ice crystals.
Increasingly, trends in this subject area are towards fusion of
information from a variety of sources, each of which may contribute
something to the interpretation or measurement of some phenomenon. For
example, aerosol concentrations affect nucleation of cloud droplets which
lead to the initiation of precipitation, which might in turn be observed
by radar.
Bringing broadband to homes
In January 2002 Wyvern reported on the world record
achieved by researchers in the Department of Electronic Systems
Engineering who succeeded in sending the largest ever amount of computer
data over a single multimode optical fibre.
Since that date, the research team, led by Dr Stuart Walker, have
improved the performance of multimode fibres with polarisation techniques,
demonstrated a complete optical network using polarisation and wavelength,
and presented their work at international conferences. All of the current
work aims to improve access to broadband internet and therefore make
browsing at home more accessible and faster.
Broadband to the home is a well-known service available to computer
users, but it is still not an economically viable method of data
transmission for both user and vendor. The main obstacle is what is known
as 'the last mile,' the last mile to the home which is prohibitively
expensive. Recently, Dr Walker's group have been looking at an alternative
approach to solely using fibre optics in the last mile, by integrating
radio and optical technologies. Group members Sandra Dudley and Terry
Quinlan are currently using self-pulsating two-section lasers and
utilising their locking properties for data capture. They have combined
this work with homemade aerials which out-perform commercial counterparts
and successfully demonstrated a working system.
Also in the printed July edition of Wyvern:
