J/ApJ/858/119 O2 laboratory atmosphere simulation experiments (Horst+, 2018)
Exploring the atmosphere of Neoproterozoic Earth: the effect of O2 on haze
formation and composition.
Horst S.M., He C., Ugelow M.S., Jellinek A.M., Pierrehumbert R.T.,
Tolbert M.A.
<Astrophys. J., 858, 119 (2018)>
=2018ApJ...858..119H 2018ApJ...858..119H
ADC_Keywords: Molecular data; Earth
Keywords: astrobiology ; Earth ; planets and satellites: atmospheres
Abstract:
Previous studies of haze formation in the atmosphere of the early
Earth have focused on N2/CO2/CH4 atmospheres. Here, we
experimentally investigate the effect of O2 on the formation and
composition of aerosols to improve our understanding of haze formation
on the Neoproterozoic Earth. We obtained in situ size, particle
density, and composition measurements of aerosol particles produced
from N2/CO2/CH4/O2 gas mixtures subjected to FUV radiation
(115-400nm) for a range of initial CO2/CH4/O2 mixing ratios
(O2 ranging from 2ppm to 0.2%). At the lowest O2 concentration
(2ppm), the addition increased particle production for all but one gas
mixture. At higher oxygen concentrations (20ppm and greater),
particles are still produced, but the addition of O2 decreases the
production rate. Both the particle size and number density decrease
with increasing O2, indicating that O2 affects particle nucleation
and growth. The particle density increases with increasing O2. The
addition of CO2 and O2 not only increases the amount of oxygen in
the aerosol, but it also increases the degree of nitrogen
incorporation. In particular, the addition of O2 results in the
formation of nitrate-bearing molecules. The fact that the presence of
oxygen-bearing molecules increases the efficiency of nitrogen fixation
has implications for the role of haze as a source of molecules
required for the origin and evolution of life. The composition changes
also likely affect the absorption and scattering behavior of these
particles but optical property measurements are required to fully
understand the implications for the effect on the planetary radiative
energy balance and climate.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 242 103 Scanning mobility particle sizer (SMPS)
measurements
table3.dat 185 120 High-resolution time-of-flight aerosol mass
spectrometer (HR-ToF-AMS) measurements
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 F6.2 nm Diam [7.3/289] Diameter midpoint
8- 14 I7 --- 120-0-0 [722/4335886] 19.7ppm CH4 (1)
16- 22 I7 --- 279-0-0 [13000/2600617] 78.8ppm CH4 (1)
24- 30 I7 --- 379-260-0 78.8ppm CH4, 260ppm CO2 (1)
32- 38 I7 --- 479-260-2 78.8ppm CH4, 260ppm CO2, 2ppm O2 (1)
40- 45 I6 --- 579-260-20 [0/182054] 78.8ppm CH4, 260ppm CO2,
20ppm O2 (1)
47- 52 I6 --- 679-260-200 [0/259214] 78.8ppm CH4, 260ppm CO2,
200ppm O2 (1)
54- 58 I5 --- 779-260-2000 [0/67033] 78.8ppm CH4, 260ppm CO2,
2000ppm O2 (1)
60- 65 I6 --- 879-394-0 78.8ppm CH4, 394ppm CO2 (1)
67- 73 I7 --- 979-394-2 78.8ppm CH4, 394ppm CO2, 2ppm O2 (1)
75- 79 I5 --- 1079-394-20 [39/55808] 78.8ppm CH4, 394ppm CO2,
20ppm O2 (1)
81- 85 I5 --- 1179-394-200 [0/52278] 78.8ppm CH4, 394ppm CO2,
200ppm O2 (1)
87- 92 I6 --- 1279-394-2000 [0/325320] 78.8ppm CH4, 394ppm CO2,
2000ppm O2 (1)
94-100 I7 --- 13118-0-0 [28917/3237940] 118ppm CH4 (1)
102-108 I7 --- 14118-260-0 118ppm CH4, 260ppm CO2 (1)
110-116 I7 --- 15118-260-2 118ppm CH4, 260ppm CO2, 2ppm O2 (1)
118-123 I6 --- 16118-260-20 118ppm CH4, 260ppm CO2, 20ppm O2 (1)
125-130 I6 --- 17118-260-200 [161/871914] 118ppm CH4, 260ppm CO2,
200ppm O2 (1)
132-137 I6 --- 18118-260-2000 [0/524338] 118ppm CH4, 260ppm CO2,
2000ppm O2 (1)
139-145 I7 --- 19118-394-0 118ppm CH4, 394ppm CO2 (1)
147-153 I7 --- 20118-394-2 118ppm CH4, 394ppm CO2, 2ppm O2 (1)
155-161 I7 --- 21118-394-20 118ppm CH4, 394ppm CO2, 20ppm O2 (1)
163-168 I6 --- 22118-394-200 [0/128965] 118ppm CH4, 394ppm CO2,
200ppm O2 (1)
170-174 I5 --- 23118-394-2000 [0/97670] 118ppm CH4, 394ppm CO2,
2000ppm O2 (1)
176-182 I7 --- 24158-0-0 [17094/2730395] 158ppm CH4 (1)
184-190 I7 --- 25158-260-0 158ppm CH4, 260ppm CO2 (1)
192-198 I7 --- 26158-260-2 158ppm CH4, 260ppm CO2, 2ppm O2 (1)
200-205 I6 --- 27158-260-20 158ppm CH4, 260ppm CO2, 20ppm O2 (1)
207-212 I6 --- 28158-260-200 [0/353555] 158ppm CH4, 260ppm CO2,
200ppm O2 (1)
214-220 I7 --- 29158-394-0 158ppm CH4, 394ppm CO2 (1)
222-228 I7 --- 30158-394-2 158ppm CH4, 394ppm CO2, 2ppm O2 (1)
230-235 I6 --- 31158-394-20 158ppm CH4, 394ppm CO2, 20ppm O2 (1)
237-242 I6 --- 32158-394-200 [20/454118] 158ppm CH4, 394ppm CO2,
200ppm O2 (1)
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Note (1): Units are [particles/cm3].
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Ratio [1/120] Mass to charge ratio
5- 11 E7.1 --- 120-0-0 [0/7.1] 19.7ppm CH4 (1)
13- 19 E7.1 --- 279-0-0 [0/70] 78.8ppm CH4 (1)
21- 28 E8.1 --- 379-260-0 [-0.0009/8.2] 78.8ppm CH4, 260ppm CO2 (1)
30- 36 E7.1 --- 479-260-2 [0/21] 78.8ppm CH4, 260ppm CO2,
2ppm O2 (1)
38- 45 E8.1 --- 579-260-20 [-1.8/8.7] 78.8ppm CH4, 260ppm CO2,
20ppm O2 (1)
47- 54 E8.1 --- 679-394-0 [-0.09/2.4] 78.8ppm CH4, 394ppm CO2 (1)
56- 63 E8.1 --- 778-394-2 [-1.4/10] 78.8ppm CH4, 394ppm CO2,
2ppm O2 (1)
65- 72 E8.1 --- 878-394-20 [-0.009/9.1] 78.8ppm CH4, 394ppm CO2,
20ppm O2 (1)
74- 80 E7.1 --- 9118-0-0 [0/190] 118ppm CH4 (1)
82- 88 E7.1 --- 10118-260-0 [0/40] 118ppm CH4, 250ppm CO2 (1)
90- 96 E7.1 --- 11118-260-2 [0/35] 118ppm CH4, 250ppm CO2,
2ppm O2 (1)
98-104 E7.1 --- 12118-260-20 [0/22] 118ppm CH4, 250ppm CO2,
20ppm O2 (1)
106-112 E7.1 --- 13118-394-0 [0/29] 118ppm CH4, 394ppm CO2 (1)
114-121 E8.1 --- 14118-394-2 [-0.2/38] 118ppm CH4, 394ppm CO2,
2ppm O2 (1)
123-129 E7.1 --- 15118-394-20 [0/12] 118ppm CH4, 394ppm CO2,
20ppm O2 (1)
131-137 E7.1 --- 16158-0-0 [0/140] 158ppm CH4 (1)
139-145 E7.1 --- 17158-260-0 [0/63] 158ppm CH4, 260ppm CO2 (1)
147-153 E7.1 --- 18158-260-2 [0/53] 158ppm CH4, 260ppm CO2,
2ppm O2 (1)
155-161 E7.1 --- 19158-260-20 [0/16] 158ppm CH4, 260ppm CO2,
20ppm O2 (1)
163-169 E7.1 --- 20158-394-0 [0/40] 158ppm CH4, 394ppm CO2 (1)
171-177 E7.1 --- 21158-394-2 [0/44] 158ppm CH4, 394ppm CO2,
2ppm O2 (1)
179-185 E7.1 --- 22158-394-20 [0/9.5] 158ppm CH4, 394ppm CO2,
20ppm O2 (1)
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Note (1): The intensity in arbitrary (but internally consistent) units.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 01-Apr-2019