Transcript The University of Toronto’s Balloon

The University of Toronto’s
Balloon-Borne Fourier
Transform Spectrometer
Debra Wunch, James R. Drummond, Clive Midwinter, Kimberly Strong
University of Toronto
Hans Fast
Meteorological Service of Canada
Atmospheric Science from Space using Fourier Transform Spectrometry
12th Workshop
Quebec City, May 18-20, 2005
Outline
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Motivation
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Instrument: The University of Toronto’s FTS
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History
Preparation for MANTRA
Results
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MANTRA high-altitude balloon campaign
FTS instruments on MANTRA
Ground-based
Balloon-based
Conclusions and Future Work
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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Motivation: MANTRA
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Middle Atmosphere Nitrogen TRend Assessment
Investigates the changing chemical balance of the mid-latitude
stratosphere, with a focus on the role of nitrogen chemistry on the
depletion of ozone.
Scientific Objectives
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Measurement of profiles of relevant chemical species
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Intercomparison between instruments using different measurement
techniques
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O3, NO, NO2, HNO3, HCl, ClONO2, N2O5, CFC-11, CFC-12, OH, H2O, N2O, CH4, Jvalues for O(1D) and NO2, aerosol, wind, pressure, temperature and humidity
FTS, grating spectrometers, radiometers and sondes
Solar occultation, emission, in situ
Validation of satellite data
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SCISAT: ACE-FTS, MAESTRO
Odin: OSIRIS, SMR
ENVISAT: SCIAMACHY, MIPAS, GOMOS
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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Motivation: MANTRA
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High-altitude balloon platform
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Float height around 40 km
He-filled balloon
Payload size around 2 m by 2 m by 2 m
Main gondola pointing system
Four campaigns: 1998, 2000, 2002,
2004 in Vanscoy, Saskatchewan (52°N,
107°W)
Launch balloons during late summer
stratospheric zonal wind turnaround
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photochemical control regime
low winds allow for longer float times
launch window is August 26 – September 5
at 52°N
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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FTS Instruments on MANTRA
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Measure most atmospheric trace gas species simultaneously
DU FTS on 1998, 2002, 2004
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PARIS FTS on 2004
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University of Denver
30 years of flight heritage
0.02 cm-1 resolution; 700-1300 cm-1 spectral range
Portable Atmospheric Research Interferometric Spectrometer, U. of Waterloo
0.02 cm-1 resolution; 750-4100 cm-1 spectral range
An ACE FTS clone built in 2003/4 as a balloon-borne validation instrument
MSC FTS on 2002, 2004
Occultation mode instruments (solar absorption through
sunrise/sunset)
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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The Role of the MSC FTS on MANTRA
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Develop a Canadian capacity for balloon-borne FTS
measurements
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Measure HCl, O3, N2O, CO2, CO, etc.
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Complement MANTRA’s science goals of measuring ozone depletion
and the molecules that contribute to the ozone budget
Ground-based and balloon-based intercomparisons
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Compare a well-understood instrument (DU) with new Canadian
instruments (MSC, PARIS)
Compare linear Michelson-type FTS with a pendulum-style FTS
(PARIS)
Compare with ground-based instruments on-site and other balloon-borne
instruments
Satellite validation
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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The MSC FTS: History
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Bomem DA2 instrument built in the 1980s
Purchased by the Meteorological Service of Canada (MSC)
Built as a ground-based instrument
Upgraded to a DA5 instrument with DA8 electronics
(including the dynamic alignment) in the mid-1990s
Obtained by the University of Toronto from the MSC in 2001
0.02 cm-1 resolution; 1200-5000 cm-1 spectral range
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InSb and MCT detectors that measure simultaneously, CaF2
beamsplitter
Flown on MANTRA 2002 and 2004
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MANTRA 2002 flight was an engineering flight
Test of temperatures and voltages
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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The MSC FTS: History
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Original Software
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Original Hardware and Electronics
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Software contained user prompts in the form of
“pop-up” boxes
Inaccessible housekeeping information
Control software embedded in hardware (bios)
Dependable dynamic alignment (compensation
for motion in moving mirror)
Large electronics box with circa 1990’s
electronics boards and power supplies
Power consumption: 140 W
Mass: 90 kg
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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Tasks in Preparation for MANTRA 2004
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Convert the MSC FTS from a ground-based
FTS into an instrument that can take groundbased and balloon-based data
Update the software and electronics
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Remove pop-up boxes
Use modern technology without compromising
performance
Address issue of accurate pointing for solar
occultation measurements
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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Preparation for MANTRA 2004
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Re-engineered control of the
dynamic alignment system
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Almost entirely new electronics
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3 boards kept (DA), 7 discarded
Replaced two control computers with
one low-power motherboard
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New power supply system
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Vicor power supplies
New data acquisition system
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USB 16-bit ADC for interferograms
USB 12-bit ADC for housekeeping
Wrote control software in
LabVIEW
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Controls DA
Includes automated scheduler
No human intervention required
Full uplink and downlink capabilities
Housekeeping
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Temperatures, voltages,
interferograms
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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Preparation for MANTRA 2004: Results
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Mass reduction
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Electronics box no longer
necessary
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Mass reduced from ~90kg to
~55kg
Power reduction
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All necessary electronics fit into
spectrometer box
Power reduced from ~140W to
~65W due to new electronic
components
Improves temperature performance
– less power means less heat
Now about half the
mass/power of the other two
FTS instruments
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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Preparation for MANTRA 2004: Pointing
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Obtained a dedicated sunseeker that tracks the sun within ±10
degrees in zenith and azimuth
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No longer dependent on main gondola pointing system
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Had flown before on other balloon campaigns
Only dependent on being pointed in general direction of sun
Would still get no data if payload rotated uncontrollably
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True for any solar-mode instrument on payload
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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MANTRA 2004
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Ground-based campaign
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5 dedicated ground-based instruments
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Brewer, grating spectrometers
~43 days of measurements
Flight on September 1st at 8:34 am
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Successful launch, followed by loss of
commanding to the payload
Pointing system overheated before sunset
Payload began rotating
Two spectra recorded on each detector
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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MSC FTS Ground-Based Data
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Good quality ground-based data
Can resolve CO, CO2, O3, CH4, N2O, HCl, H2O and
other molecules
Data acquired during almost every clear-sky
opportunity (~10 days)
Can participate in the ground-based campaign
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Can compute column amounts of O3, which every other
ground-based instrument measures
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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MSC FTS Ground-Based Data
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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MSC FTS Flight Data
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Two spectra (on each detector) during sunset on the
first MANTRA 2004 flight at ~91°
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Signal-to-noise ratio reduced
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reduced resolution attributed to rotation of payload,
temperature, poor alignment before flight?
Can resolve CO, CO2, O3, CH4, N2O, HCl, H2O
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lower SNR attributed to rotation of payload – tracker at
ends of its field of view
Resolution reduced
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acquired during rotation of payload at sunset
should be able to retrieve slant columns
No vertical profile retrievals possible
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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MSC FTS Flight Data
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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Conclusions and Future Work
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New instrument is improvement over old
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Continued work
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Lower power consumption
Lower mass
Robust software
Build “delta”-tracker with larger field of view
Improve detector alignment system
Slant column amounts from balloon data
Intercomparisons of ground-based data
Future work
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Fly FTS on MANTRA 2006 payload and get data from a
full occultation
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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Acknowledgements
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The authors wish to thank Pierre Fogal, John Olson, Tom
McElroy, Kaley Walker and the MANTRA 2002 and 2004
science teams.
Funding is provided by the Canadian Space Agency, the
Meteorological Service of Canada and NSERC.
Atmospheric Science from Space using FTS; 12th Workshop, Quebec City, May 18-20, 2005
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