NERC/STFC and NASA
The High Resolution Dynamics Limb Sounder (HIRDLS) is an international joint
development project between the USA and UK; this instrument is flying on the Earth
Observing System (EOS) Aura Mission Spacecraft. Aura's four instruments (including
HIRDLS) study the atmosphere's chemistry and dynamics. Aura's measurements will
enable us to investigate questions about ozone trends, air quality changes and their
linkage to climate change. The Aura mission was successfully launched on 15 July
2004 and has a design life of six years.
The research
HIRDLS is a multi-channel limb-viewing infrared radiometer for high resolution
monitoring of upper tropospheric, stratospheric, and mesospheric temperature, trace
chemicals, and geopotential height gradients. It measures temperatures and atmospheric
composition, including ozone, water vapour and aerosol particulate in the upper
layers of the atmosphere to understand processes affecting climate change. These
measurements are an unprecedented high spatial resolution, and are starting to reveal
processes, such as as the distributions of gravity waves, that are virtually unobservable
by other satellite instruments.
The collaboration
NERC invested £19.5 million to develop the HIRDLS instrument in collaboration
with NASA. The UK team, funded through the UK NERC, consists of groups from: STFC
Rutherford Appleton Laboratory, Space Science Department, with subcontractor EADS
Astrium UK (formerly MMS); University of Oxford, Department of Atmospheric and Oceanic
Physics, with subcontractor Selex (formerly GEC Marconi, and BAe Systems); and the
University of Reading, Department of Cybernetics, Infrared Multilayer Laboratory
and their subcontractors.
The USA team, funded by the US NASA, is led by Dr John Gille, the US Principal
Investigator, from the University of Colorado and the National Center for Atmospheric
Research in Boulder, and the hardware phase was managed by NASA Goddard Space Flight
Center.
John Gille and John Barnett, the joint Principal Investigator for HIRDLS - based
at the University of Oxford, had to overcome an added problem when it transpired
that a piece of protective film had torn free during launch and lodged over the
instrument’s only optical beam, reducing visibility to just 20 per cent. When they
were unable to clear the obstruction, the team painstakingly developed new algorithms
to maximise the data retrieved from HIRDLS. Now, even with 80 per cent of the beam
still blacked out, the instrument can collect data from nearly the entire world
in one day.
Quotation: John Barnett explained the importance of the study. "HIRDLS
will give us a much better picture of what is happening in the upper atmosphere.
Computer models of the atmosphere show features that we are incapable of observing
at present. We need to understand in more detail how the atmosphere works and whether
these models are right or need changing, because we rely on them for predictions
of climate change." John adds "We have been working on HIRDLS with our US colleagues
for 15 years and it has been a great experience. The keen, dedicated members of
the team are all prepared to do that little bit more than they need to make the
project a success."
Contacts:
UK Project Manager:
Dr Brian
Kerridge, STFC Rutherford Appleton Laboratory.
HIRDLS joint Principal Investigator:
Dr John
Barnett, University of Oxford.
Links:
HIRDLS on the NASA AURA website
NERC news release (9 June 2004)