Detecting volcanism on Titan and Venus with microwave radiometry

Lorenz, Ralph D.; Gall, Alice Le; Janssen, M. A.

doi:10.1016/j.icarus.2015.07.023

Cited by 5 publications

(7 citation statements)

References 37 publications

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“…The current outgassing of argon (40 Ar) as measured by Cassini INMS and GCMS is the best evidence for current-day outgassing on Titan [6]; such activity may also be responsible for the present-day atmospheric CH 4 . There are features interpreted as hotspot volcanoes in the North Polar Region [27], but so far prominent hotspots have not been detected in Cassini data [28]. Titan's heat flux is just 5 mW/m 2 [29].…”

Section: Geothermalmentioning

confidence: 99%

Energy Options for Future Humans on Titan

Hendrix¹,

Yung²

2017

Astrobiol Outreach

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We review the possibilities for in situ energy resources on Titan for use by future humans, including chemical, nuclear, wind, solar, geothermal and hydropower. All of these options, with the possible exception of geothermal, represent effective sources of power. Combustion of methane (after electrolysis of the native water), in combination with another source of power such as nuclear, is a viable option; another chemical source of energy is the hydrogenation of acetylene. The large seas Kraken and Ligeia potentially represent effective sources of hydropower. Wind power, particularly at altitudes ~40 km, is expected to be productive. Despite the distance from the sun and the absorbing atmosphere, solar power is (as on Earth) an extremely efficient source of power on Titan.

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Section: Geothermalmentioning

confidence: 99%

Energy Options for Future Humans on Titan

Hendrix¹,

Yung²

2017

Astrobiol Outreach

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“…However, because the emplacement rate of these flows is not well understood, the area of a single event is ill constrained. Employing the terrestrial analog employed by Lorenz et al [9] where typical events are 75 km 2 and the thermal evolution model presented here (conservative for Venus), we find that the increased resolution of the radiometer observations planned with EnVision's VenSAR (4.5 km azimuth, 38 km range) may counteract the smaller penetration depth at 3.2 GHz (9.4 cm). The maximum temperature excess for a flow of this size remains >20 K for 40 days at 18 cm depth but not at 9 cm.…”

Section: Discussionmentioning

confidence: 62%

“…Here temperature is shown relative to the ambient temperature, ∆T B , and is calculated following the formulations of Lorenz et al [9] and Bondarenko et al [8]. The brightness temperature in a given polarization (T B,X where X=H or V) is…”

Section: Loss Tangentmentioning

confidence: 99%

“…For example, Bondarenko et al [8] calculated that even 15 year old Venusian flows can be >100 K warmer than the near surface temperature if the flow is 30 m and mafic or ultramafic. Using a similar approach, Lorenz et al [9] showed that the depending on the loss tangent of hypothetical cryovolcanic flows on Saturn's moon Titan, whose existence and composition are still a matter of debate, the duration of temperature excess at depth in the flow is on the order of days to a few years.…”

Section: Introductionmentioning

confidence: 99%

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Prospects for Detecting Volcanic Events with Microwave Radiometry

MacKenzie

Lorenz

2020

Remote Sensing

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Identifying volcanic activity on worlds with optically thick atmospheres with passive microwave radiometry has been proposed as a means of skirting the atmospheric interference that plagues near infrared observations. By probing deeper into the surface, microwave radiometers may also be sensitive to older flows and thus amenable for investigations where repeat observations are infrequent. In this investigation we explore the feasibility of this tactic using data from the Soil Moisture Active Passive (SMAP) mission in three case studies: the 2018 Kilauea eruption, the 2018 Oct-Nov eruption at Fuego, and the ongoing activity at Erta Ale in Ethiopia. We find that despite SMAP’s superior spatial resolution, observing flows that are small fractions of the observing footprint are difficult to detect—even in resampled data products. Furthermore, the absorptivity of the flow, which can be temperature dependent, can limit the depths to which SMAP is sensitive. We thus demonstrate that the lower limit of detectability at L-band (1.41 GHz) is in practice higher than expected from first principles.

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“…Bondarenko et al (2010) investigated the Magellan orbiter radiothermal emission (Pettengill et al 1992) and found that a ∼10 5 km 2 large lava flow unit in Bereghinia Planitia at 28°E 39°N shows an up to 85 K higher than expected brightness temperatures and interpret this as consistent with lava emplaced within the last few decades. Lorenz et al (2016) argue that this result is ambiguous since it could be explained by a surface emissivity that is different from that derived by Bondarenko et al (2010) from radar backscatter under assumption of a smooth lava surface. Lorenz et al (2016) furthermore point out that such a large eruption would be a very unusual event.…”

Section: Efforts At Detection Of Active Eruptionsmentioning

confidence: 79%

Resurfacing History and Volcanic Activity of Venus

et al. 2023

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Photogeologic principles can be used to suggest possible sequences of events that result in the present planetary surface. The most common method of evaluating the absolute age of a planetary surface remotely is to count the number of impact craters that have occurred after the surface formed, with the assumption that the craters occur in a spatially random fashion over time. Using additional assumptions, craters that have been partially modified by later geologic activity can be used to assess the time frames for an interpreted sequence of events. The total number of craters on Venus is low and the spatial distribution taken by itself is nearly indistinguishable from random. The overall implication is that the Venusian surface is much closer to Earth in its youthfulness than the other, smaller inner solar system bodies. There are differing interpretations of the extent to which volcanism and tectonics have modified the craters and of the regional and global sequences of geologic events. Consequently, a spectrum of global resurfacing views has emerged. These range from a planet that has evolved to have limited current volcanism and tectonics concentrated in a few zones to a planet with Earth-like levels of activity occurring everywhere at similar rates but in different ways. Analyses of the geologic record have provided observations that are challenging to reconcile with either of the endmember views. The interpretation of a global evolution with time in the nature of geologic activity relies on assumptions that have been challenged, but there are other observations of areally extensive short-lived features such as canali that are challenging to reconcile with a view of different regions evolving independently. Future data, especially high-resolution imaging and topography, can provide the details to resolve some of the issues. These different global-evolution viewpoints must tie to assessments of present-day volcanic and tectonic activity levels that can be made with the data from upcoming missions.

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Detecting volcanism on Titan and Venus with microwave radiometry

Cited by 5 publications

References 37 publications

Energy Options for Future Humans on Titan

Energy Options for Future Humans on Titan

Prospects for Detecting Volcanic Events with Microwave Radiometry

Resurfacing History and Volcanic Activity of Venus

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