The major events and results to date of the ongoing program of measuring stratospheric composition by the technique of far-infrared Fourier-transform spectroscopy from a balloon-borne platform are reviewed. The highlights of this period were the two balloon flight campaigns which were performed at Palestine, Texas, both of which produced large amounts of scientifically useful data

Chance, Kelly V.

Traub, Wesley A.

English

NASA Technical Reports Server

MEASUREMENT OF H02 AND OTHER TRACE GASES IN THE STRATOSPHERE
USING A HIGH RESOLUTION FAR-INFRARED SPECTROMETER AT 28 KM
NASA GRANT NSC 5175
Semiannual Status Report Nos. 20, 21, and 22
For the period 1 January 1987 to 30 June 1988
Principal Investigators
Wesley A. Traub
Kelly V. Chance
June 1988
Prepared for
National Aeronautics and Space Administration
Greenbelt, Maryland 20771
Smithsonian Institution
Astrophysical Observatory
Cambridge, Massachusetts 02138
The Smithsonian Astrophysical Observatory
is a member of the
Harvard-Smithsonian Center for Astrophysics
The NASA Technical Officer for this grant is Dr. Igor J. Eberstein, Code
616, Atmospheric Chemistry and Dynamics Branch, Goddard Space Flight
Center, Greenbelt, Maryland 20771
JNASA-CR-1804QO): M E A S U R E M E N T OF H02 AND
OTHER TRACE GASES IN THE STRATOSPHERE USING
A HIGH RESOLUTION FAB-ZSFBABED SPECTBOHETEB
AT 28 KM Semiannual Status Report, 1 Jan. /
1987 - 30-Jun.v19.88 (Smithsonian G3/45
N88-26737
Unclas;
014.8173
https://ntrs.nasa.gov/search.jsp?R=19880017353 2020-03-20T05:31:19+00:00Z
1. Personnel Working on this Grant During this Reporting Period
Dr. Wesley A. Traub (Principal Investigator)
Dr. Kelly V. Chance (Principal Investigator)
Dr. Stephen C. Wofsy (Co-Investigator)
Dr. David G. Johnson (Physicist)
Mr. Amit Ghosh (Programmer Analyst)
Both Dr. Johnson and Mr. Ghosh joined this program during the cur-
rent reporting period, and both are working full time on the grant.
Dr. Johnson recently earned his Ph.D. in physics from Princeton Univer-
sity, doing a precision measurement of the cosmic background radiation
from a balloon platform. Mr.Ghosh earned an M.S. in astrophysics from
Moscow State University and an M.S. in physics from the University of
New Hampshire.
2. Status Summary
This status report reviews the major events and results to date of
our ongoing program of measuring stratospheric composition by the
technique of far-infrared Fourier-transform spectroscopy from a balloon-
borne platform. The report cpvers an 18 month period, of which the
first 9 months has already been discussed in some detail in the History
section of our September 1987 grant renewal request. The highlights of
this period were the two balloon flight campaigns which we carried out
at Palestine, Texas, both of which produced large amounts of scientifi-
cally useful data. Since these were the first two flights of our newly-
built second-generation far-infrared spectrometer (FIRS-2), we are of
course exceptionally pleased with the success of these flights, and the
large amounts of scientifically productive data which have been gener-
ated.
3. Instrumentation
During approximately the first eight months of this reporting
period, we completed and fully tested the FIRS-2 instrument, including
the Fourier transform spectrometer, the telescope and single-axis plat-
form stabilized pointing system, and the flight electronics. For the
first flight, our ground support electronics (GSE) was very limited in
the sense that we had no independent data recording capability, and had
to rely entirely on the National Scientific Balloon Facility (NSBF) for
data capture. Fortunately, just prior to the second flight, we were
able to enhance our GSE by the addition of a new 386-based computer and
optical disk storage system, which has now been fully integrated with
the instrument. This work, which was done in the remarkably short time
of a few weeks, was completely successful, and has for the first time
given us the ability to take data, record it on either a hard disk or on
the optical disk, send it via an Ethernet line to either our own Mic-
rovax (when at the SAO) or the NSBF Microvax (when in Palestine), trans-
Page 2
form the data on the spot, and then display any desired section of
spectrum or interferogram for quick-look analysis. This rapid turn-
around capability has completely changed the way we work, and has been
extremely helpful in giving us the ability to diagnose the quality of
data within a few minutes of the time it is obtained.
For the first flight, the completed and tested instrument was ship-
ped to the Jet Propulsion Laboratory (JPL) and integrated mechanically
and electrically with a JPL-built balloon gondola in August 1987. Fol-
lowing this integration, which went very smoothly, the instrument and
gondola were shipped together to Palestine, Texas.
4. Field Measurements
The first balloon flight of the FIRS-2 instrument took place on
October 4, 1987. The launch was at 10:30 am, local time. Spectra were
taken during ascent, from 11:35 am to 12:49 pm, followed by float
spectra from 12:56 pm until 8:32 pm. The flight was terminated early
.(unfortunately, before the sunset transition) because the float winds
took the package to the edge of the termination zone surrounding the
Houston area. However, 9 hours of useful stratospheric spectra were
obtained, and are currently being analyzed. Figure 1 shows four
spectral segments from a single 3-minute scan obtained during this
flight, at an elevation angle of -2.32 degrees. (As is explained later
in this report, we are still working on the software to properly do the
phase correction of these spectra.) The OH lines in these spectra stand
out beautifully both from the interference of nearby water (and other)
lines, as well as from the background noise.
Of the four independent detectors which we have in the dewar,
measuring in parallel four separate spectral bands, only three were
functioning properly during this flight, since after the balloon reached
stratospheric altitudes, it became apparent that preamplifier number 2
had become very noisy; later analysis suggested that this unexpected
condition resulted from the dramatically reduced background load seen by
the detector in flight, coupled with a bias setting which had been op-
timized for a high (lab) background, which is our normal practice, but
which in the case of this particular detector seems not to have worked.
The instrument was recovered intact, and returned to our lab at the SAO.
There we discovered that the dewar had suffered extensive internal
damage during the truck ride immediately after recovery; this damage
required re-welding of the helium vessel support neck, and a second
round of optical realignment. At this time we also found that the
polished metal support plate for the Mylar beamsplitter was sufficiently
, warped that we decided to quickly replace it with a glass ring. We also
solved a few electronic problems in the flight hardware at this time.
The instrument was shipped back to Palestine in April 1988.
The second flight of the FIRS-2 instrument was our most successful
balloon flight to date. We flew again on the same JPL gondola. The
launch was on May 12, 1988 at 9:42 am. We obtained spectra on ascent
from 11:04 am until 12:39 pm. Limb-scanning sequences of spectra were
taken at float altitude from 12:44 pm until 5:30 'am, May 13, when the
liquid helium in the detector dewar was exhausted. This period repre-
3x10
2x10
10D
140 140.5 141 141.5 142
October 1987 : single -2.32 spectrum
2x10
1.5x10
10°
5x10*
0 -
I I t
177 177.5 178 178.5 179
October 1987 : single -2.32 spectrum
1.5x10
10°
5x10
152 152.5 153 153.5 154
October 1987 : single -2.32 spectrum
1.5x10 -.
5x10 -
188 188.5 189 189.5 190
October 1987 : single -2.32 spectrum
Figure 1. Four spectral segments from the FIRS-2 October 1987 flight,
showing OH emission lines standing out clearly from both their neighbors
as well as the' noise.
Page 3
sents most of the diurnal cycle, including the full sunset transition.
The complete FIRS-2 system performed flawlessly for this entire time.
The flight was terminated shortly after noon on May 13, and was
recovered with no damage to the gondola or instruments. We obtained 17
hours of continuous and virtually perfect stratospheric data during this
flight, surpassing the 13 hours of float data which we gathered during
our last flight with the FIRS-1 instrument during the BIC-2 campaign in
June 1983.
Figure 2 shows a sum of 8 spectra taken with one of the far in-
frared detectors; this detector receives the short-wavelength output of
a metal-mesh diplexer and is useful from about 110 to 190 cm-1. The
spectrum shown here is a sum of spectra taken at an elevation angle of -
2.32 degrees, corresponding to a 34 km tangent height. The general
quality of the spectra is excellent, as seen from the signal to noise
and the clean separation of lines. Our phase correction algorithm for
these high resolution spectra has not yet been completed (poor phase
correction of the spectra can most easily be seen from 134 to 146 cm-l),
but we expect to have have it completed shortly.
Figure 3 shows some detailed sections of the spectrum in Figure 2,
and a comparison with spectra taken with the original FIRS instrument
during the BIC-2 campaign under similar pointing conditions and with
roughly the same integration time (24 minutes). The figure contains
emission lines from OH, H20, HDO, vibrationally excited H20, 03, atomic
oxygen, HC1, and HF. The benefit of the eight times increase in resolu-
tion of FIRS-2 is obvious in the separation of atmospheric lines.
5 . Data Analysis
We have substantially improved and extended our far infrared
spectral database, in preparation for the analysis of spectra from the
FIRS-2 instrument. The database now includes spectral parameters from
the 1986 AFGL HITRAN line listing, the 1984 Jet Propulsion Laboratory
Submillimeter line listing, high resolution tunable far infrared mea-
surements performed at the National Bureau of Standards, as well as from
spectroscopic calculations we performed at SAO. Our database currently
includes lines of: H20 (including isotopes and hot bands), OH, H02, and
H202; 03P, 02 (including isotopes), and 03 (including isotopes and hot
bands); HF, HC1, HBr, and HOC1; CO, and N02.
There has, of course, been an extensive effort put into computer
programs and systems work on both our existing Microvax and our new 386-
based computer. The original programs which we had for FIRS-1 have been
upgraded for FIRS-2 from 2 channels to 4 channels, and each of these has
gone from about 8 K samples to about 64 K samples per spectral scan.
New graphics capabilities have been implemented, and many new data-han-
dling programs have been written to process and display both our
housekeeping as well as science data.
At the moment, we are temporarily being held back from fully ex-
ploiting our rich data base because of an aspect of the interferograms
which has heretofor been not fully manifested. In particular, we find
that when we do the Fourier transform which takes the recorded inter-
14-JUN-88 14:55:30
109 110 111 113 113 114 115 116 117 118 119 120, 121 122 123 124 125 126 127 128 129 130
I i i i i I i i i i I i i i i I < i i i I i i i i I i i i r:
129 130 131 138 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150
1E5 -
50000 -
149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170
169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190
Detector 1: sum of 8 -2.32* spectra (34 km tangent height)
Figure 2. The raw spectrum from FIRS-2 detector 1, from 110 to 190
wavenumbers, summed over 8 individual scans. The detector and filter
response , have not yet been removed. Phase errors can be seen in the • - •
non-symmetric shapes of lines in the second panel.
16-JUN-88 17i06i26
2E5 -
1.5E5 -
1E5 -
60000 -
140.25 140.3 140.35 140.4 140.45 140.5 140.55 140.6 140.65 140.7 140.75
Hay 1988 OH: sum of 6 -2.32* spectra. BIC-2 sum Is dashed line.
80000
50000
40000
30000
20000
10000
60000
50000
40000
30000
20000
10000
165.6 165.65 165.7 165.75 165.8 165.85 165.9 165.95 166 166.05 166.1
Hay 1988 HC1: sum of 8 -2.32* spectra. BIC-2 sum Is dashed line.
163.75 1S3.8 163.85 163.9 163.95 164 184.05 184.1 164.15 164.3 184.35
May 1988 HF: sum of 8 -2.32* spectra. BIC-2 sum Is dashed line.
50000
40000
30000
20000
10000
158 158.05 158.1 158.15 158.2 158.25 158.3 158.35 158.4 158.45 158.5
Hay 1988 0 P: sum of 8 -2.32* spectra. BIC-2 sum Is dashed line.
Figure 3. Four spectral segments selected from the FIRS-2 data in Fig-
ure 2, shown as a solid line. The dashed overlay line is an eyeball-
scaled spectrum from our FIRS-1 measurements during the 1983 BIC-2 cam-
paign, under roughly comparable conditions.
Page 4
ferogram and turns it into a spectrum, we end up with a composite
spectrum, in the sense that the low-level instrumental emission back-
ground spectrum appears with a complex phase angle which in general
differs from that of the atmospheric spectrum, by an amount which varies
across the spectrum, andwhich ranges in magnitude up to. about 60 degrees
or so. In order to properly treat the data, we are now in the midst of
an extensive program designed to allow us to essentially subtract a
complex background spectrum from each scan, rather than the conceptually
much simpler process which we had previously employed of subtracting a
real (i.e., in-phase) background. The mathematical treatment which we
are pursuing is expected to be fully successful, but until we actually
complete the process and test it fully, we will have to hold in abeyance
our next step, which is to derive concentration profiles from the exist-
ing limb-scan data. We are currently making good progress in this di-
rection, and expect to have the phase-correction algorithms well in hand
by the end of this summer, if not sooner.
6. Publications
Design of a Single-Axis Platform for Balloon-Borne Remote Sensing, L.M.
Coyle, G. Aurilio, G.U. Nystrom, J. -Bortz, B.C. Nagy, K.V. Chance,
and W.A. Traub, Review of Scientific Instruments 57, 2512 (1986).
Performance of a Single-Axis Platform for Balloon-Borne Remote Sensing,
W.A. Traub, K.V. Chance, and L.M. Coyle, Review of Scientific Instru-
ments 57, 2519 (1986) .
Evidence for Stratospheric Hydrogen Peroxide, K. V. Chance and W. A.
Traub, Journal of Geophysical Research 92, 3061 (1987).
Atomic Oxygen in the Lower Thermosphere, F.J. Lin, K.V. Chance, and
W.A. Traub, Journal of Geophysical Research 92, 4325 (1987).
Ozone Measurements During the Balloon Intercomparison Campaign, D. Rob-
bins, J. Waters, P. Zimmerman, R. Jarnot, J. Hardy, H. Pickett, S.
Pollitt, W. A. Traub, K. Chance, N. Louisnard, W. Evans, and J.
Kerr, to appear in Journal of Atmospheric Chemistry (1988).
Intercomparison of Measurements of Stratospheric Hydrogen Fluoride, W.
G. Mankin, M. T. Coffey, K. V. Chance, W. A. Traub, B. Carli, A.
Bonetti, I. G. Nolt, R. Zander, D. W. Johnson, G. Stokes, C. B.
Farmer, and R. K. Seals, to appear in Journal of Atmospheric Chemistry
(1988).
Intercomparison of Stratospheric Water Vapor Profiles Obtained During
the Balloon Intercomparison Campaign, D. G. Murcray, A. Goldman, J.
Rosters, R. Zander, W. Evans, N. Louisnard, C. Alamichel, M. Ban-
gham, S. Pollitt, B. Carli, B. Dinelli, S. Piccioli, A. Volboni, W.
A. Traub, and K. Chance, to appear in Journal of Atmospheric Chemistry
(1988).
Balloon Intercomparison Campaign: Results of Remote Sensing Measure-
ments of HC1, C. B. Farmer, B. Carli, A. Bonetti, M. Carlotti, B.
M. Dinelli, H. Fast, N. Louisnard, C. Alamichel, W. Mankin, M.
Page 5
Coffey, I. G. Nolt, D. G. Murcray, A. Goldman, G. Stokes, D.
Johnson, VL Traub, K. Chance, R. Zander, L. Delbouille, and G.
Roland, to appear in Journal of Atmospheric Chemistry (1988).


Measurement of HO2 and other trace gases in the stratosphere using a high resolution far-infrared spectrometer at 28 KM

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