Magnetic Quenching of Turbulent Diffusivity: Reconciling Mixing-length Theory Estimates with Kinematic Dynamo Models of the Solar Cycle

The turbulent magnetic diffusivity in the solar convection zone is one of the most poorly constrained ingredients of mean-field dynamo models. This lack of constraint has previously led to controversy regarding the most appropriate set of parameters, as different assumptions on the value of turbulent diffusivity lead to radically different solar cycle predictions. Typically, the dynamo community uses double step diffusivity profiles characterized by low values of diffusivity in the bulk of the convection zone. However, these low diffusivity values are not consistent with theoretical estimates based on mixing-length theory -- which suggest much higher values for turbulent diffusivity. To make matters worse, kinematic dynamo simulations cannot yield sustainable magnetic cycles using these theoretical estimates. In this work we show that magnetic cycles become viable if we combine the theoretically estimated diffusivity profile with magnetic quenching of the diffusivity. Furthermore, we find that the main features of this solution can be reproduced by a dynamo simulation using a prescribed (kinematic) diffusivity profile that is based on the spatiotemporal geometric-average of the dynamically quenched diffusivity. Here, we provide an analytic fit to the dynamically quenched diffusivity profile, which can be used in kinematic dynamo simulations. Having successfully reconciled the mixing-length theory estimated diffusivity profile with kinematic dynamo models, we argue that they remain a viable tool for understanding the solar magnetic cycle.Comment: Submitted to ApJ

Satisfacción de necesidades de habitabilidad en procesos de reasentamientos urbanos: El caso de Ciudad Victoria en Guayaquil

En el Ecuador, la relación entre producción de barrios populares y enfoques psicoambientales de estudio ha sido muy poco explorada. Esta preocupación ha sido abordada por la línea de investigación en psicología ambiental comunitaria del Grupo de Investigaciones Psicosociales de la Carrera de Psicología de la Universidad Politécnica Salesiana. Sostenemos la necesidad de producir conocimientos relativos a la satisfacción de necesidades de habitabilidad y los factores que se asocian a la producción social del hábitat y de la ciudad. Las y los lectores de este trabajo podrán profundizar sobre las dimensiones psicosociales que median las relaciones humanas con sus entornos construidos. En efecto, se presenta el análisis de los factores psicosociales que inciden en la satisfacción de necesidades de habitabilidad de 32 familias de la primera etapa de relocalización que se dio en Ciudad Victoria en Guayaquil. Desde una perspectiva cualitativa de investigación se establece un modelo analítico que relaciona los conflictos entre actores institucionales y las familias beneficiarias, desde la comprensión de la experiencia vivida a nivel personal, relacional y colectivo. Este estudio adquiere relevancia en el sentido de documentar un complejo proceso de reasentamiento en vista de generar aprendizajes para mejorar los modelos de gestión pública en la producción de barrios populares

Polar Field Puzzle: Solutions from Flux-Transport Dynamo and Surface Transport Models

Polar fields in solar cycle 23 were about 50% weaker than those in cycle 22. The only theoretical models which have addressed this puzzle are surface transport models and flux-transport dynamo models. Comparing polar fields obtained from numerical simulations using surface flux transport models and flux-transport dynamo models, we show that both classes of models can explain the polar field features within the scope of the physics included in the respective models. In both models, how polar fields change as a result of changes in meridional circulation depends on the details of meridional circulation profile used. Using physical reasoning and schematics as well as numerical solutions from a flux-transport dynamo model, we demonstrate that polar fields are determined mostly by the strength of surface poloidal source provided by the decay of tilted, bipolar active regions. Profile of meridional flow with latitude and its changes with time have much less effect in flux-transport dynamo models than in surface transport models.Comment: ApJ (accepted

Using the Dipolar and Quadrupolar Moments to Improve Solar-Cycle Predictions Based on the Polar Magnetic Fields

The solar cycle and its associated magnetic activity are the main drivers behind changes in the interplanetary environment and Earth's upper atmosphere (commonly referred to as space weather and climate). In recent years there has been an effort to develop accurate solar cycle predictions, leading to nearly a hundred widely spread predictions for the amplitude of solar cycle 24. Here we show that cycle predictions can be made more accurate if performed separately for each hemisphere, taking advantage of information about both the dipolar and quadrupolar moments of the solar magnetic field during minimum

The Carbon Content of Austrian Trade Flows in the European and International Trade Context

In this study CO2 emissions embodied in Austrian international trade are quantified employing a 66-region input output model of multidirectional trade. We find that Austria’s final demand CO2 responsibilities on a global scale are 38% higher than conventional statistics report (110 Mt-CO2 versus 79 Mt-CO2 in 2004). For each unit of Austrian final demand, currently two thirds of the thus triggered CO2 emissions occur outside Austrian borders. We then develop a 19-region computable general equilibrium model of Austria and its major trading partners and world regions to find that future Austrian climate policy can achieve the EU 20-20 emission reduction targets, but that its carbon trade balance would worsen considerably. Both unilateral EU and internationally coordinated climate policies affect Austrian international trade stronger than its domestic production.Multi-regional Input-Output Analysis, Multi-regional Computable General Equilibrium, Embodied emissions, Consumption-based principle, Carbon Leakage, Carbon dioxide, Unilateral Climate Policy

Las bases materiales del sector exportador chileno : un análisis input-output

El objetivo principal de este estudio ha sido reatribuir los materiales que extrajo la economía chilena en el año 1996 de acuerdo a la demanda final extranjera. Para ello se utilizó una metodología input-output (IO). En 1996 la economía chilena requirió 500 millones de toneladas de inputs de materiales directos (IMD). Los resultados encontrados indican que el sector exportador de Chile, que representó el 38% del PIB en 1996, demandó en total 399 millones de toneladas (80%) de los IMD que ingresaron a la economía. La industria del cobre en particular fue responsable de 316 de las 399 millones de toneladas de IMD. Estos resultados indican que si bien el sector externo de la economía chilena ha sido el motor del crecimiento económico, es necesario remarcar también que éste utilizó el 80% de los IMD que ingresaron en la economía. Sin duda, ésta es sólo una de las cargas ambientales asociadas a las exportaciones chilenas intensivas en recursos naturales.This study aims to reattribute the materials that were used by Chilean economy in 1996 according to its foreign final demand. An input-output (IO) methodology has been applied. In 1996 the Chilean economy requested 500 million tons of direct material inputs (DMI). The results showed that the exporting sector of Chile, which represented 38% of the GDP in 1996, used a total of 399 million tons of the DMI incorporated into the economy. The foreign final demand of copper commodity was responsible for 316 of the 399 million tons of DMI. These findings indicated that if the external sector of Chilean economy was a motor of economic growth, we needed to highlight the fact that it represented 80% of direct material flow that was used by the economy. Without doubt, these are only a few of the environmental load associated to the intense exportation of natural resources in Chile

Memorias de San Isidro

Memorias de San Isidro es un proyecto que consistió en la realización de una serie de entrevistas y la interacción y participación de la cotidianidad en la vereda San Isidro, Puerto Caldas, Pereira, como un insumo para elaborar una pieza audio visual y un Libro Arte, que recogen parte de la historia de esta zona; esto, en un momento en el que líderes comunitarios del sector, buscan fortalecer los lazos de identidad que permitirán generar espacios de organización y lucha, aprovechando el Arte como un medio importante para entretejer las memorias vivas de cada individuo y conectarlas en procesos amplios

Las bases materiales del sector exportador chileno: un análisis input-output

El objetivo principal de este estudio ha sido reatribuir los materiales que extrajo la economía chilena en el año 1996 de acuerdo a la demanda final extranjera. Para ello se utilizó una metodología input-output (IO). En 1996 la economía chilena requirió 500 millones de toneladas de inputs de materiales directos (IMD). Los resultados encontrados indican que el sector exportador de Chile, que representó el 38% del PIB en 1996, demandó en total 399 millones de toneladas (80%) de los IMD que ingresaron a la economía. La industria del cobre en particular fue responsable de 316 de las 399 millones de toneladas de IMD. Estos resultados indican que si bien el sector externo de la economía chilena ha sido el motor del crecimiento económico, es necesario remarcar también que éste utilizó el 80% de los IMD que ingresaron en la economía. Sin duda, ésta es sólo una de las cargas ambientales asociadas a las exportaciones chilenas intensivas en recursos naturales.Contabilidad y análisis de flujos de materiales, metodología insumo-producto, comercio internacional, Chile, recursos naturales

How many active regions are necessary to predict the solar dipole moment?

We test recent claims that the polar field at the end of Cycle 23 was weakened by a small number of large, abnormally oriented regions, and investigate what this means for solar cycle prediction. We isolate the contribution of individual regions from magnetograms for Cycles 21, 22 and 23 using a 2D surface flux transport model, and find that although the top ~10% of contributors tend to define sudden large variations in the axial dipole moment, the cumulative contribution of many weaker regions cannot be ignored. In order to recreate the axial dipole moment to a reasonable degree, many more regions are required in Cycle 23 than in Cycles 21 and 22 when ordered by contribution. We suggest that the negative contribution of the most significant regions of Cycle 23 could indeed be a cause of the weak polar field at the following cycle minimum and the low-amplitude Cycle 24. We also examine the relationship between a region's axial dipole moment contribution and its emergence latitude, flux, and initial axial dipole moment. We find that once the initial dipole moment of a given region has been measured, we can predict the long-term dipole moment contribution using emergence latitude alone.Comment: 15 pages, 10 figures, accepted for publication in Ap