Matches in SemOpenAlex for { <https://semopenalex.org/work/W2143264080> ?p ?o ?g. }
- W2143264080 endingPage "563" @default.
- W2143264080 startingPage "549" @default.
- W2143264080 abstract "SUMMARYWe investigate the thermal and chemical buoyancy forces that drive convection in the Earth's liquid outer core and derive a radial buoyancy profile that can be used in geodynamo models. We assume the core is well mixed, adiabatic and cools as a result of mantle convection. The buoyancy profile is developed for a Boussinesq fluid and incorporates secular cooling, latent heat release at the inner core boundary, radiogenic heating, the effect of the adiabat, and compositional buoyancy due to inner core freezing. Surprisingly, these complex effects can be modelled accurately by a simple combination of bottom heating and near-uniform heat sinks, which is implemented using a cotemperature formulation that converts compositional effects into effective thermal effects. The relative importance of internal and bottom heating is then defined by just two parameters, the cooling rate at the core–mantle boundary (CMB) and the uniform rate of internal radiogenic heat production, both of which can be obtained from core evolution calculations. We vary these parameters in geodynamo models and compare basic features of the generated fields with the geomagnetic field; in this manner we link core evolution models, geodynamo simulations and geomagnetic observations.We consider three end-member scenarios for core evolution: (1) rapid cooling and a young inner core; (2) moderate cooling and neutral stability at the CMB; (3) slow cooling and enough radiogenic heating to allow the inner core to be 3.5 Gyr old. We find that compositional buoyancy dominates thermal buoyancy everywhere except near the CMB, even with large amounts of radiogenic heating, and buoyancy forces are far larger at depth than higher up. Reducing the cooling rate and increasing radiogenic heating reduces the drop in the superadiabatic gradient between the inner and outer boundaries: for rapid cooling the drop is by a factor 50; for slow cooling it is a factor of 5. We demonstrate the effects of these different buoyancy profiles in numerical simulations as a function of the Rayleigh number. At low Rayleigh number the internal velocity and magnetic fields vary between the core evolution scenarios, but these differences do not affect the surface field. Significant differences in the surface field emerge when the Rayleigh number is sufficiently large. For rapid cooling we find dipolar magnetic fields in the time average that reverse and are dominated by large-scale features at high latitudes. Moderate cooling results in magnetic fields that are stable and dominantly dipolar. Slow cooling produces multipolar magnetic fields that reverse very frequently. This preliminary study suggests that the generated fields are sufficiently different that geodynamo simulations together with geomagnetic observations could be used to discriminate between different core evolution scenarios." @default.
- W2143264080 created "2016-06-24" @default.
- W2143264080 creator A5034791711 @default.
- W2143264080 creator A5088178438 @default.
- W2143264080 date "2011-09-28" @default.
- W2143264080 modified "2023-09-26" @default.
- W2143264080 title "A buoyancy profile for the Earth's core" @default.
- W2143264080 cites W1522608183 @default.
- W2143264080 cites W1853813265 @default.
- W2143264080 cites W1963512158 @default.
- W2143264080 cites W1968281042 @default.
- W2143264080 cites W1970855385 @default.
- W2143264080 cites W1989696873 @default.
- W2143264080 cites W1994976007 @default.
- W2143264080 cites W2006214166 @default.
- W2143264080 cites W2010802074 @default.
- W2143264080 cites W2013159332 @default.
- W2143264080 cites W2026436988 @default.
- W2143264080 cites W2039149596 @default.
- W2143264080 cites W2041763366 @default.
- W2143264080 cites W2042296555 @default.
- W2143264080 cites W2049923710 @default.
- W2143264080 cites W2051724188 @default.
- W2143264080 cites W2054924949 @default.
- W2143264080 cites W2060175453 @default.
- W2143264080 cites W2064202365 @default.
- W2143264080 cites W2064426841 @default.
- W2143264080 cites W2072292670 @default.
- W2143264080 cites W2074852243 @default.
- W2143264080 cites W2080962756 @default.
- W2143264080 cites W2083734642 @default.
- W2143264080 cites W2084123972 @default.
- W2143264080 cites W2085581605 @default.
- W2143264080 cites W2095570883 @default.
- W2143264080 cites W2104482280 @default.
- W2143264080 cites W2106186106 @default.
- W2143264080 cites W2114164194 @default.
- W2143264080 cites W2128521752 @default.
- W2143264080 cites W2130786258 @default.
- W2143264080 cites W2132626212 @default.
- W2143264080 cites W2136144064 @default.
- W2143264080 cites W2137054842 @default.
- W2143264080 cites W2139341184 @default.
- W2143264080 cites W2140845958 @default.
- W2143264080 cites W2142113316 @default.
- W2143264080 cites W2145970211 @default.
- W2143264080 cites W2156653410 @default.
- W2143264080 cites W2166992439 @default.
- W2143264080 cites W2168137993 @default.
- W2143264080 cites W2170001576 @default.
- W2143264080 cites W2996842158 @default.
- W2143264080 cites W4237871081 @default.
- W2143264080 cites W4243632982 @default.
- W2143264080 doi "https://doi.org/10.1111/j.1365-246x.2011.05144.x" @default.
- W2143264080 hasPublicationYear "2011" @default.
- W2143264080 type Work @default.
- W2143264080 sameAs 2143264080 @default.
- W2143264080 citedByCount "27" @default.
- W2143264080 countsByYear W21432640802012 @default.
- W2143264080 countsByYear W21432640802013 @default.
- W2143264080 countsByYear W21432640802014 @default.
- W2143264080 countsByYear W21432640802015 @default.
- W2143264080 countsByYear W21432640802018 @default.
- W2143264080 countsByYear W21432640802019 @default.
- W2143264080 countsByYear W21432640802020 @default.
- W2143264080 countsByYear W21432640802021 @default.
- W2143264080 countsByYear W21432640802022 @default.
- W2143264080 countsByYear W21432640802023 @default.
- W2143264080 crossrefType "journal-article" @default.
- W2143264080 hasAuthorship W2143264080A5034791711 @default.
- W2143264080 hasAuthorship W2143264080A5088178438 @default.
- W2143264080 hasBestOaLocation W21432640801 @default.
- W2143264080 hasConcept C120665830 @default.
- W2143264080 hasConcept C121332964 @default.
- W2143264080 hasConcept C127313418 @default.
- W2143264080 hasConcept C1276947 @default.
- W2143264080 hasConcept C2164484 @default.
- W2143264080 hasConcept C26148502 @default.
- W2143264080 hasConcept C538625479 @default.
- W2143264080 hasConcept C57879066 @default.
- W2143264080 hasConcept C72782756 @default.
- W2143264080 hasConcept C8058405 @default.
- W2143264080 hasConceptScore W2143264080C120665830 @default.
- W2143264080 hasConceptScore W2143264080C121332964 @default.
- W2143264080 hasConceptScore W2143264080C127313418 @default.
- W2143264080 hasConceptScore W2143264080C1276947 @default.
- W2143264080 hasConceptScore W2143264080C2164484 @default.
- W2143264080 hasConceptScore W2143264080C26148502 @default.
- W2143264080 hasConceptScore W2143264080C538625479 @default.
- W2143264080 hasConceptScore W2143264080C57879066 @default.
- W2143264080 hasConceptScore W2143264080C72782756 @default.
- W2143264080 hasConceptScore W2143264080C8058405 @default.
- W2143264080 hasIssue "2" @default.
- W2143264080 hasLocation W21432640801 @default.
- W2143264080 hasLocation W21432640802 @default.
- W2143264080 hasOpenAccess W2143264080 @default.
- W2143264080 hasPrimaryLocation W21432640801 @default.
- W2143264080 hasRelatedWork W1963512158 @default.