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心如止水是什么意思
Abstract
In their pioneering work, Leighton and Murray argued that the Mars atmosphere, which at present is 95% carbon dioxide, is controlled by vapor equilibrium with a much larger polar reservoir of solid carbon dioxide. Here we argue that the polar reservoir is small and cannot function as a long-term buffer to the more massive atmosphere. Our work is based on modeling of the circular depressions commonly found on the south polar cap. We argue that a carbon dioxide ice layer about 8 meters thick is being etched away to reveal water ice underneath. This is consistent with thermal infrared data from the Mars Odyssey mission.
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REFERENCES AND NOTES
1
Leighton R. B., Murray B. C., Science 153, 136 (1966).
2
Murray B. C., Malin M. C., Science 182, 437 (1973).
3
Kieffer H. H., J. Geophys. Res. 84, 8263 (1979).
4
___, Chase S. C., Martin T. Z., Miner E. D., Palluconi F. D., Science 194, 1341 (1976).
5
Farmer C. B., Davies D. W., LaPorte D. D., Science 194, 1339 (1976).
6
P. B. James, H. H. Kieffer, D. A. Paige, in Mars, H. H. Kieffer et al., Eds. (Univ. of Arizona Press, Tucson, AZ, 1992), pp. 934–968.
7
P. C. Thomas, S. W. Squyres, K. E. Herkenhoff, A. Howard, B. C. Murray, in Mars, H. H. Kiefferet al., Eds. (Univ. of Arizona Press, Tucson, AZ, 1992), pp. 767–795.
8
Ingersoll A. P., J. Geophys. Res. 79, 3403 (1974).
9
Wood S. E., Paige D. A., Icarus 99, 1 (1992).
10
Barker E. S., Schorn R. A., Woszczyk A., Tull R. G., Little S. J., Science 170, 1308 (1970).
11
Durham W. B., Kirby S. H., Stern L. A., Geophys. Res. Lett. 26, 3493 (1999).
12
Nye J. F., Durham W. B., Schenk P. M., Moore J. M., Icarus 144, 449 (2000).
13
Smith D. E., et al., Science 284, 1495 (1999).
14
Schenk P. M., Moore J. M., J. Geophys. Res. 105, 24529 (2000).
15
Malin M. C., et al., J. Geophys. Res. 97, 7699 (1992).
16
Thomas P. C., et al., Nature 404, 161 (2000).
17
Malin M. C., Edgett K. S., J. Geophys. Res. 106, 23429 (2001).
18
Malin M. C., Caplinger M. A., Davis S. D., Science 294, 2146 (2001).
19
We used a matrix inversion approach (“radiosity”) to calculate all orders of scattering. By assuming circular symmetry, we only have to keep track of annular bands. All surfaces are assumed to be Lambert scatterers. The time step is 1° of Ls, which is ～2 days. We verified the model against the analytic solution for spherical bowl-shaped craters.
20
Vasavada A. R., Paige D. A., Wood S. E., Icarus 141, 179 (1999).
21
Ingersoll A. P., Svitek T., Murray B. C., Icarus 100, 40 (1992).
22
We experimented with depressions embedded in pure (clean at all depths) CO2 ice and found them to be self-erasing. Depressions in dirty CO2 ice with no resistant substrate grew indefinitely as shallow bowls, which are not observed on the residual cap. Initial size and shape had no effect on long-term behavior in all cases. Albedo and thickness of the dirty CO2 ice slab ranged from 0.4 to 0.65 and from 4 to 20 m, respectively. H2O ice albedos were set to the same value as those of the CO2 directly above it (that is, the bottom of the dirty slab).
23
P. R. Christensen et al., J. Geophys. Res. 97, 7719, (1992).
24
P. R. Christensen et al., in preparation.
25
We thank O. Aharonson, A. Albee, B. Murray, N. Schorghofer, and two anonymous reviewers for helpful comments and NASA's Mars Data Analysis Program and Mars Global Surveyor project for financial support.
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Published In
Science
Volume 299 | Issue 5609
14 February 2003
14 February 2003
Submission history
Received: 5 November 2002
Accepted: 23 December 2002
Published in print: 14 February 2003
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- Andrew P. Ingersoll
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