The millimeter-wavelength sulfur dioxide absorption spectra measured under simulated Venus conditions

Bellotti, Amadeo; Steffes, Paul G.

doi:10.1016/j.icarus.2015.03.028

Cited by 10 publications

(5 citation statements)

References 32 publications

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“…For SO 2 and OCS, we use data for broadening by CO 2 available in HITRAN (Wilzewski et al 2016;Gordon et al 2017). Although the SO 2 broadening data are derived from a single line experiment (Chandra & Chandra 1963), the parameters in the frequencies of interest are consistent with recent laboratory results by Bellotti & Steffes (2015). The broadening values for our SO 2 lines of interest are approximately 1.8-2.0× air broadening (i.e.…”

Section: Methodsmentioning

confidence: 69%

Claimed detection of PH$_3$ in the clouds of Venus is consistent with mesospheric SO$_2$

Lincowski,

Meadows,

Crisp

et al. 2021

Preprint

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The observation of a 266.94 GHz feature in the Venus spectrum has been attributed to PH 3 in the Venus clouds, suggesting unexpected geological, chemical or even biological processes. Since both PH 3 and SO 2 are spectrally active near 266.94 GHz, the contribution to this line from SO 2 must be determined before it can be attributed, in whole or part, to PH 3 . An undetected SO 2 reference line, interpreted as an unexpectedly low SO 2 abundance, suggested that the 266.94 GHz feature could be attributed primarily to PH 3 . However, the low SO 2 and the inference that PH 3 was in the cloud deck posed an apparent contradiction. Here we use a radiative transfer model to analyze the PH 3 discovery, and explore the detectability of different vertical distributions of PH 3 and SO 2 . We find that the 266.94 GHz line does not originate in the clouds, but above 80 km in the Venus mesosphere. This level of line formation is inconsistent with chemical modeling that assumes generation of PH 3 in the Venus clouds. Given the extremely short chemical lifetime of PH 3 in the Venus mesosphere, an implausibly high source flux would be needed to maintain the observed value of 20±10 ppb. We find that typical Venus SO 2 vertical distributions and abundances fit the JCMT 266.94 GHz feature, and the resulting SO 2 reference line at 267.54 GHz would have remained undetectable in the ALMA data due to line dilution. We conclude that nominal mesospheric SO 2 is a more plausible explanation for the JCMT and ALMA data than PH 3 .

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Section: Methodsmentioning

confidence: 69%

Claimed detection of PH$_3$ in the clouds of Venus is consistent with mesospheric SO$_2$

Lincowski,

Meadows,

Crisp

et al. 2021

Preprint

Self Cite

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“…Venus is a terrestrial planet with a dense atmosphere. Assuming that the Venusian atmosphere is planar stratified and has N vertical layers, the brightness temperature (TB) measured by a spaceborne downward‐looking radiometer can be expressed as follows (Bellotti & Steffes, 2015):

TB={{\mathrm{e}}^{\left(-\sum \nolimits_{j=1}^{N}{\tau }_{j}\right)}T}_{s}{\epsilon}+{T}_{c}(1-{\epsilon}){\mathrm{e}}^{\left(-2\sum \nolimits_{j=1}^{N}{\tau }_{j}\right)}+\sum\limits _{i=1}^{N}{T}_{i}\left(1-{\mathrm{e}}^{-{\tau }_{i}}\right){\mathrm{e}}^{\left(-\sum \nolimits_{j=i+1}^{N}{\tau }_{j}\right)}+\sum\limits _{i=1}^{N}{T}_{i}(1-{\epsilon})\left(1-{\mathrm{e}}^{-{\tau }_{i}}\right){\mathrm{e}}^{\left(-\sum \nolimits_{j=1}^{i-1}{\tau }_{j}\right)}{\mathrm{e}}^{\left(-\sum \nolimits_{j=1}^{N}{\tau }_{j}\right)}

where i indicates the i th layer of the atmosphere ( i = 1 for surface), ϵ represents the surface emissivity, e denotes the natural constant, T s represents the surface physical temperature in Kelvin, T c represents the cosmic background radiation temperature (2.7 K), T i represents the physical temperature of the i th layer in Kelvin, and τ i represents the optical depth of the i th layer in Np and can be calculated as follows:

τ_{i} = \int_{s ((), z = z_{i})}^{s ...}

…”

Section: Retrieval Methodologymentioning

confidence: 99%

“…Venus is a terrestrial planet with a dense atmosphere. Assuming that the Venusian atmosphere is planar stratified and has N vertical layers, the brightness temperature (TB) measured by a spaceborne downward-looking radiometer can be expressed as follows (Bellotti & Steffes, 2015):…”

Section: Rt Modelmentioning

confidence: 99%

Frequency Channel Selection and Performance Simulation of a Microwave Radiometer for Temperature and Sulfuric Compound Profiling of the Venusian Lower Atmosphere

Zhang,

Dong,

et al. 2024

Earth and Space Science

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Exploring the Venusian lower atmosphere is crucial for studying the atmospheric circulation, surface‐atmosphere interactions, and origin and evolution of the Venusian atmosphere and climate. In this study, we investigate the theoretical capabilities of a downward‐looking passive microwave sounder placed in low Venus orbit to measure the temperature, sulfur dioxide (SO2) and gaseous sulfuric acid (H2SO4(g)) profiles. A nonlinear iterative retrieval algorithm combining a radiative transfer (RT) model and an optimal‐estimation‐based inversion algorithm is established. With the RT model adapted to the Venusian atmosphere, simulations under different atmospheric conditions are performed to optimize the selection of frequency channels. The achievable altitude coverage, vertical resolution and corresponding expected precision of the temperature, SO2 and H2SO4(g) retrievals from the multi‐channel brightness temperature measurements are quantified via retrieval simulations. The temperature can be retrieved from the surface of Venus to an altitude of ∼61 km with a precision of 1–3.5 K and a vertical resolution of 6–15 km. A precision of 10%–35% is expected for SO2 in the ∼12–64 km altitude range and with a vertical resolution of 8–19 km. H2SO4(g) can be retrieved in the ∼36–54 km altitude range with a precision of 10%–30% and a vertical resolution of 6–13 km.

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“…To extract reference flux densities, for Venus we use the model that gives brightness temperature as a function of frequency that has been discussed in [23] (see figure 38 of that paper), and which was obtained from a fit of the literature data to a power law: 𝑇 Venus B (𝜈) = 1047.1 × (𝜈/GHz) −0.25 K. This model gives Venus' brightness temperature after subtraction of the CMB monopole, so it can then be directly compared with the data, which in practice also have the CMB monopole subtracted, so it is totally absorbed by the planet disc. This model gives slightly higher temperatures than physical models in the literature [46,47]. However, we prefer to stick to this phenomenological fit as it provides a better description of the observed data.…”

Section: Planetsmentioning

confidence: 98%

LSPE-Strip on-sky calibration strategy using bright celestial sources

Génova-Santos,

Bersanelli,

Franceschet

et al. 2024

J. Inst.

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In this paper we describe the global on-sky calibration strategy of the LSPE-Strip instrument. Strip is a microwave telescope operating in the Q- and W-bands (central frequencies of 43 and 95 GHz respectively) from the Observatorio del Teide in Tenerife, with the goal to observe and characterise the polarised Galactic foreground emission, and complement the observations of the polarisation of the cosmic microwave background to be performed by the LSPE-SWIPE instrument and other similar experiments operating at higher frequencies to target the detection of the B-mode signal from the inflationary epoch of the Universe. Starting from basic assumptions on some of the instrument parameters (NET, 1/f noise knee frequency, beam properties, observing efficiency) we perform realistic simulations to study the level of accuracy that can be achieved through observations of bright celestial calibrators in the Strip footprint (sky fraction of 30%) on the determination and characterisation of the main instrument parameters: global and relative gain factors (in intensity and in polarisation), polarisation direction, polarisation efficiency, leakage from intensity to polarisation, beams, window functions and pointing model.

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The millimeter-wavelength sulfur dioxide absorption spectra measured under simulated Venus conditions

Cited by 10 publications

References 32 publications

Claimed detection of PH$_3$ in the clouds of Venus is consistent with mesospheric SO$_2$

Claimed detection of PH$_3$ in the clouds of Venus is consistent with mesospheric SO$_2$

Frequency Channel Selection and Performance Simulation of a Microwave Radiometer for Temperature and Sulfuric Compound Profiling of the Venusian Lower Atmosphere

LSPE-Strip on-sky calibration strategy using bright celestial sources

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