Die Klimafalle – Die gefährliche Nähe von Politik und Klimaforschung
THE ACE SATELLITE SOLAR SPECTRUM F. HASE Institut fur Meteorologie und Klimaforschung,...
16
THE ACE SATELLITE SOLAR SPECTRUM F. HASE Institut fur Meteorologie und Klimaforschung, Forschungszentrum Karlsruhe, Postfach 3640, D-76021 Karlsruhe, Germany S. D. McLEOD Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 K. A. WALKER Department of Physics, University of Toronto, Toronto, Ontario, Canada M5S 1A7 P. F. BERNATH Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK R. COLIN Spectroscopie de l’Atmosphere…, Université Libre de Bruxelles, B1050, Brussels, Belgium L. Wallace National Optical Astronomy Observatories, Tucson, AZ, 85732, USA
-
Upload
ella-richardson -
Category
Documents
-
view
214 -
download
0
Transcript of THE ACE SATELLITE SOLAR SPECTRUM F. HASE Institut fur Meteorologie und Klimaforschung,...
THE ACE SATELLITE SOLAR SPECTRUM
F. HASEInstitut fur Meteorologie und Klimaforschung, Forschungszentrum Karlsruhe, Postfach
3640, D-76021 Karlsruhe, Germany S. D. McLEOD
Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1K. A. WALKER
Department of Physics, University of Toronto, Toronto, Ontario, Canada M5S 1A7 P. F. BERNATH
Department of Chemistry, University of York, Heslington, York, YO10 5DD, UKR. COLIN
Spectroscopie de l’Atmosphere…, Université Libre de Bruxelles, B1050, Brussels, Belgium
L. WallaceNational Optical Astronomy Observatories, Tucson, AZ, 85732, USA
Introduction
• High quality solar spectra (with assignments) are useful as models in astronomical spectroscopy
• Often needed as reference spectra for atmospheric spectroscopy (e.g., to apply Beer’s law need I/I0 and I0 is a pure solar spectrum); see Hase et al. JQSRT 102, 450 (2006)
Kitt Peak Solar Spectrum
High Res. IR Solar Atlases
Nine Kitt Peak solar atlases recorded with the McMath-Pierce Fourier transform spectrometer (available at ftp://nsokp.nso.edu/pub/atlas) plus some work at Jungfraujoch
High quality spectra but telluric absorption is a problem. Solution is satellite observations.
ATMOS Mission
High resolution (0.01 cm-1) FTS covering 650-4750 cm-1 spectral region that flew on the Space Shuttle in 1985 (Spacelab-3), 1992 (ATLAS-1), 1993 (ATLAS-2) and 1994 (ATLAS-3). Used photoconductive MCT detectors and filters to improve the signal-to-noise ratio. (Good spectral coverage, but severe nonlinearity and spectra were recorded in pieces.)
ATMOS Solar Atlases1. From two days of data from 1985 Spacelab-3 mission the “ATMOS Solar
Atlas” was created. NASA publication 1989NASRP1224: A high-resolution atlas of the infrared spectrum of the Sun and Earth atmosphere from space: a compilation of ATMOS spectra of the region from 650 to 4800 cm ¹ (2.3 to ⁻16 μm) by C. B. Farmer, R. H. Norton and M. Geller (3 volumes); digital data available at ftp://nsokp.nso.edu/pub/atlas/
2. From ten days of data (about 10000 spectra; 600-4800 cm-1 in 4 filter regions) from 1994 ATLAS-3 mission at new solar “atlas” was created. See Abrams et al. Applied Optics, 35, 2747 (1996); digital data for 4 filter regions available from http://remus.jpl.nasa.gov/atmos/
ATMOS Spectra
Spacelab-3 spectrum (1985)
ATLAS-3 spectrum (1995)
Good spectra, but contain strong H2O and CO2 lines form residual gas in the instrument container on orbit and optical filters chop spectra into pieces.
3026 cm-1
3038.5 cm-1
ACE Satellite
Bernath et al. GRL, 32, L15S01 (2005)
Solar Occultation
Advantages:
•Radiance of sun gives higher S/N than emission
•Limb view gives longer path length ~500 km (lower detection limits) than nadir
•“Self-calibrating” so excellent long-term accuracy and precision
Disadvantages:
•Modest global coverage
•Samples only free troposphere
Global Distribution of Phosgene, Cl2CO
Latitude (in Degrees)
Alt
itu
de
(in
Km
)
2004-2005-2006 COCl2 Volume Mixing Ratio (in pptv)
-80 -60 -40 -20 0 20 40 60 800
5
10
15
20
25
30
35
40
0
10
20
30
40
50
60
Fu et al. GRL, 34, L17815, 2007
-10 0 10 20 30 400
5
10
15
20
25
30
Volume Mixing Ratio (in pptv)
Alt
itu
de
(in
km
)
85oS-60oS
60oS-30oS
30oS-30oN
30oN-60oN
60oN-90oNWilson et al. 1988Kindler et al. 1995
50oN-80oN
0o-90oN
0o-85oS
Cl ClC
Oװ
FTS – Spectral Range & SNR
Ryan Hughes
ACE Fourier transform spectrometer (FTS)
Range: 750 – 4400 cm-
1 (2.2 to 13 microns)
Resolution: 0.02 cm-1
Continuum SNR up to 400
ACE solar spectrum (F. Hase): 224782 spectra added, improvement over ATMOS, no telluric lines, but 0.02 cm-1 vs 0.01 cm-1 resolution (resolution largely determined by width of solar lines) and 750-4400 cm-1 vs 600-4800 cm-1.
CO, Δv=1
OH
CO Δv=2
CH, NH, OH
Mg Rydberg Emission Lines
Mg 7i 1,3I - 6h 1,3H
OH v=0 R(24)
Confusion Limit!
OH v=2-1 P1(2.5)
OH v=1-0 P1(6.5)
Every bump is an atomic or molecular line.
ATMOS Spacelab-3, 1985
ATMOS ATLAS-3, 1994
ACE, 2008
New atomic and molecular assignments (ACE linelist) by L. Wallace (NOAO); improved spectroscopic data for CH, NH and OH.
For OH, Reg Colin (ULB) finds v=4 can be improved.
Future Plans
• ACE Solar Atlas will be published with spectra (ps & pdf), digital data and revised solar linelist with assigned atomic and molecular lines.
• Less than ½ of ACE solar data used so far and mission might last for some additional years (with support from Canadian Space Agency).
• Improved analysis of CH, NH and OH.
