DOI: 10.1002/2016GL069927
论文题名: The energetics and convective vigor of mixed-mode heating: Velocity scalings and implications for the tectonics of exoplanets
作者: Weller M.B. ; Lenardic A.
刊名: Geophysical Research Letters
ISSN: 0094-8597
EISSN: 1944-8328
出版年: 2016
卷: 43, 期: 18 起始页码: 9469
结束页码: 9474
语种: 英语
英文关键词: early Earth
; exoplanet
; isoviscous scaling
; mantle convection
; mixed heating
; velocity
Scopus关键词: Heating
; Planets
; Tectonics
; Velocity
; Early Earth
; Exoplanet
; Internal temperature
; isoviscous scaling
; Mantle convection
; Numerical parameters
; Relative contribution
; Scaling relationships
; Extrasolar planets
英文摘要: The discovery of large terrestrial (~1 Earth mass (Me) to < 10 Me) extrasolar planets has prompted a debate as to the likelihood of plate tectonics on these planets. Canonical models assume classic basal heating scaling relationships remain valid for mixed heating systems with an appropriate internal temperature shift. Those scalings predict a rapid increase of convective velocities (Vrms) with increasing Rayleigh numbers (Ra) and non-dimensional heating rates (Q). To test this we conduct a sweep of 3-D numerical parameter space for mixed heating convection in isoviscous spherical shells. Our results show that while Vrms increases with increasing thermal Ra, it does so at a slower rate than predicted by bottom heated scaling relationships. Further, the Vrms decreases asymptotically with increasing Q. These results show that independent of specific rheologic assumptions (e.g., viscosity formulations, water effects, and lithosphere yielding), the differing energetics of mixed and basally heated systems can explain the discrepancy between different modeling groups. High-temperature, or young, planets with a large contribution from internal heating will operate in different scaling regimes compared to cooler-temperature, or older, planets that may have a larger relative contribution from basal heating. Thus, differences in predictions as to the likelihood of plate tectonics on exoplanets may well result from different models being more appropriate to different times in the thermal evolution of a terrestrial planet (as opposed to different rheologic assumptions as has often been assumed). ©2016. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84992387609&doi=10.1002%2f2016GL069927&partnerID=40&md5=fd33821097e80136736a437fabca086d
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/9560
Appears in Collections: 科学计划与规划 气候变化与战略
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作者单位: Department of Earth Science, Rice University, Houston, TX, United States
Recommended Citation:
Weller M.B.,Lenardic A.. The energetics and convective vigor of mixed-mode heating: Velocity scalings and implications for the tectonics of exoplanets[J]. Geophysical Research Letters,2016-01-01,43(18).