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Constraints on Uranus's haze structure, formation and transport

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Constraints on Uranus's haze structure, formation and transport. / Toledo, Daniel; Irwin, Patrick G.J.; Rannou, Pascal; Teanby, Nicholas A.; Simon, Amy A.; Wong, Michael H.; Orton, Glenn S.

In: Icarus, Vol. 333, 15.11.2019, p. 1-11.

Research output: Contribution to journalArticle

Harvard

Toledo, D, Irwin, PGJ, Rannou, P, Teanby, NA, Simon, AA, Wong, MH & Orton, GS 2019, 'Constraints on Uranus's haze structure, formation and transport', Icarus, vol. 333, pp. 1-11. https://doi.org/10.1016/j.icarus.2019.05.018

APA

Toledo, D., Irwin, P. G. J., Rannou, P., Teanby, N. A., Simon, A. A., Wong, M. H., & Orton, G. S. (2019). Constraints on Uranus's haze structure, formation and transport. Icarus, 333, 1-11. https://doi.org/10.1016/j.icarus.2019.05.018

Vancouver

Toledo D, Irwin PGJ, Rannou P, Teanby NA, Simon AA, Wong MH et al. Constraints on Uranus's haze structure, formation and transport. Icarus. 2019 Nov 15;333:1-11. https://doi.org/10.1016/j.icarus.2019.05.018

Author

Toledo, Daniel ; Irwin, Patrick G.J. ; Rannou, Pascal ; Teanby, Nicholas A. ; Simon, Amy A. ; Wong, Michael H. ; Orton, Glenn S. / Constraints on Uranus's haze structure, formation and transport. In: Icarus. 2019 ; Vol. 333. pp. 1-11.

Bibtex

@article{0fed90897a144e45a1e0c2230590133a,
title = "Constraints on Uranus's haze structure, formation and transport",
abstract = "Microphysical simulations have been performed to constrain the formation and structure of haze in Uranus's atmosphere. These simulations were coupled to a radiative-transfer code to fit observations performed by the SINFONI Integral Field Unit Spectrometer on the Very Large Telescope (VLT)and by the Wide Field Camera 3 (WFC3)of the Hubble Space Telescope (HST)in 2014. Our simulations yield an effective radius of ∼0.2 μm for the haze particles in the tropopause and a density of ∼2.9 particles per cm 3. Our simulations also provide an estimate for the haze production rate in the stratosphere of between ∼3.10 −16 and 3.10 −15 kg m −2 s −1, about 100 times smaller than that found in Titan's atmosphere (e.g. Rannou et al., 2004). This range of values is very similar to that derived by Pollack et al. (1987)from Voyager-2 observations in 1986, suggesting microphysical timescales greater than the elapsed time between these observations (28 years, or 1/3 of a Uranian year). This result is in agreement with analyses performed with our microphysical model that show timescales for haze particles to grow and settle out to be >∼30 years at pressure levels >0.1 bar. However, these timescales are too big to explain the observed variations in the haze structure over Uranus's northern hemisphere after 2007 equinox (e.g. de Pater et al., 2015). This indicates that dynamics may be the main factor controlling the spatial and temporal distribution of the haze over the poles. A meridional stratospheric transport of haze particles with winds velocities >∼0.025 m s −1 would result in dynamics timescales shorter than 30 years and thus may explain the observed variations in the haze structure.",
keywords = "Haze microphysics, Radiative transfer, Uranus",
author = "Daniel Toledo and Irwin, {Patrick G.J.} and Pascal Rannou and Teanby, {Nicholas A.} and Simon, {Amy A.} and Wong, {Michael H.} and Orton, {Glenn S.}",
year = "2019",
month = "11",
day = "15",
doi = "10.1016/j.icarus.2019.05.018",
language = "English",
volume = "333",
pages = "1--11",
journal = "Icarus",
issn = "0019-1035",
publisher = "Academic Press",

}

RIS - suitable for import to EndNote

TY - JOUR

T1 - Constraints on Uranus's haze structure, formation and transport

AU - Toledo, Daniel

AU - Irwin, Patrick G.J.

AU - Rannou, Pascal

AU - Teanby, Nicholas A.

AU - Simon, Amy A.

AU - Wong, Michael H.

AU - Orton, Glenn S.

PY - 2019/11/15

Y1 - 2019/11/15

N2 - Microphysical simulations have been performed to constrain the formation and structure of haze in Uranus's atmosphere. These simulations were coupled to a radiative-transfer code to fit observations performed by the SINFONI Integral Field Unit Spectrometer on the Very Large Telescope (VLT)and by the Wide Field Camera 3 (WFC3)of the Hubble Space Telescope (HST)in 2014. Our simulations yield an effective radius of ∼0.2 μm for the haze particles in the tropopause and a density of ∼2.9 particles per cm 3. Our simulations also provide an estimate for the haze production rate in the stratosphere of between ∼3.10 −16 and 3.10 −15 kg m −2 s −1, about 100 times smaller than that found in Titan's atmosphere (e.g. Rannou et al., 2004). This range of values is very similar to that derived by Pollack et al. (1987)from Voyager-2 observations in 1986, suggesting microphysical timescales greater than the elapsed time between these observations (28 years, or 1/3 of a Uranian year). This result is in agreement with analyses performed with our microphysical model that show timescales for haze particles to grow and settle out to be >∼30 years at pressure levels >0.1 bar. However, these timescales are too big to explain the observed variations in the haze structure over Uranus's northern hemisphere after 2007 equinox (e.g. de Pater et al., 2015). This indicates that dynamics may be the main factor controlling the spatial and temporal distribution of the haze over the poles. A meridional stratospheric transport of haze particles with winds velocities >∼0.025 m s −1 would result in dynamics timescales shorter than 30 years and thus may explain the observed variations in the haze structure.

AB - Microphysical simulations have been performed to constrain the formation and structure of haze in Uranus's atmosphere. These simulations were coupled to a radiative-transfer code to fit observations performed by the SINFONI Integral Field Unit Spectrometer on the Very Large Telescope (VLT)and by the Wide Field Camera 3 (WFC3)of the Hubble Space Telescope (HST)in 2014. Our simulations yield an effective radius of ∼0.2 μm for the haze particles in the tropopause and a density of ∼2.9 particles per cm 3. Our simulations also provide an estimate for the haze production rate in the stratosphere of between ∼3.10 −16 and 3.10 −15 kg m −2 s −1, about 100 times smaller than that found in Titan's atmosphere (e.g. Rannou et al., 2004). This range of values is very similar to that derived by Pollack et al. (1987)from Voyager-2 observations in 1986, suggesting microphysical timescales greater than the elapsed time between these observations (28 years, or 1/3 of a Uranian year). This result is in agreement with analyses performed with our microphysical model that show timescales for haze particles to grow and settle out to be >∼30 years at pressure levels >0.1 bar. However, these timescales are too big to explain the observed variations in the haze structure over Uranus's northern hemisphere after 2007 equinox (e.g. de Pater et al., 2015). This indicates that dynamics may be the main factor controlling the spatial and temporal distribution of the haze over the poles. A meridional stratospheric transport of haze particles with winds velocities >∼0.025 m s −1 would result in dynamics timescales shorter than 30 years and thus may explain the observed variations in the haze structure.

KW - Haze microphysics

KW - Radiative transfer

KW - Uranus

UR - http://www.scopus.com/inward/record.url?scp=85066259869&partnerID=8YFLogxK

U2 - 10.1016/j.icarus.2019.05.018

DO - 10.1016/j.icarus.2019.05.018

M3 - Article

VL - 333

SP - 1

EP - 11

JO - Icarus

JF - Icarus

SN - 0019-1035

ER -