Mechanisms for tropical upwelling in the stratosphere

The dynamics of the tropical upwelling branch of the stratospheric Brewer–Dobson circulation are examined, with a particular focus on the role of the middle-atmosphere Hadley circulation. Upwelling is examined in terms of both the diabatic circulation and Lagrangian trajectories using a zonally symmetric balance model. The behavior of the wave-driven circulation in the presence of angular momentum redistribution by the Hadley circulation is also considered. The results of the zonally symmetric model are compared with fields from a middle-atmosphere GCM. It is found that the Hadley circulation makes a significant contribution to annual mean tropical upwelling at the upwelling maximum in the vicinity of the stratopause, and can account for most of the annual mean upwelling seen in the GCM. In the mid- to lower stratosphere, the role of the Hadley circulation is much weaker and wave drag appears to be required to explain the observed upwelling, although the Hadley circulation makes a nonnegligible contribution to the annual cycle of the upwelling. Subtropical wave drag can produce annual mean upwelling through a nonlinear mechanism; viscosity is not required. However, the magnitude of the observed upwelling suggests that wave drag must penetrate quite close to the equator.

Breaking the impasse: towards a new regime for international climate governance

The reality of the current international order makes it imperative that a just and effective climate regime balance the historical responsibility of developed countries with the increasing absolute emissions from many developing nations. In this short outlook article, key pillars are proposed for a new international climate architecture that envisions replacing the current annex system with two new annexes –Annex α, for countries with high current emissions and historically high emissions, and Annex β, for countries with high current emissions and historically low emissions. Countries in both annexes would implement legally binding targets under this framework. Additionally, this proposal includes tweaks and revisions to funding and technology transfer mechanisms to correct for weaknesses and inequities under the current Kyoto architecture. The proposed framework stems from a belief that a top-down, international approach to climate policy remains the most effective for ensuring environmental integrity. Given the slow rate of institutional learning, reforming and improving the current system is held as a more efficient course of action than abandoning the progress already achieved. It is argued that the proposed framework effectively accommodates key equity, environmental integrity and political feasibility concerns.

Increasing Autumn drought over Southern China associated with ENSO regime shift

In the two most recent decades, more frequent drought struck southern China during autumn, causing an unprecedented water crisis. We found that the increasing autumn drought is largely attributed to an ENSO regime shift. Compared to traditional eastern-Pacific (EP) El Niño, central-Pacific (CP) El Niño events have occurred more frequently, with maximum sea surface temperature anomalies located near the dateline. Southern China usually experiences precipitation surplus during the autumn of EP El Niño years, while the CP El Niño tends to produce precipitation deficits. Since the CP El Niño has occurred more frequently while EP El Niño has become less common after the early 1990s, there has been a significant increase in the frequency of autumn drought. This has implications for increasing precipitation shortages over southern China in a warming world, in which CP El Niño events have been suggested to become more common.

Ionospheric ion upwelling in the wake of flux transfer events at the dayside magnetopause

The effects of flux transfer events (FTE) on the dayside auroral ionosphere are studied, using a simple twin-vortex model of induced ionospheric plasma flow. It is shown that the predicted and observed velocities of these flows are sufficient to drive nonthermal plasma in the F region, not only within the newly opened flux tube of the FTE, but also on the closed, or "old" open, field lines around it. In fact, with the expected poleward neutral wind, the plasma is more highly nonthermal on the flanks of, but outside, the open flux tube: EISCAT observations indicate that plasma is indeed driven into nonthermal distributions in these regions. The nonthermal plasma is thereby subject to additional upforce due to the resulting ion temperature anisotropy and transient expansion due to Joule heating and also to ion accelerations associated with the FTE field aligned current system. Any upflows produced on closed field lines in the vicinity of the FTE are effectively bunched-up in the "wake" of the FTE. Observations from the AMPTE-UKS satellite at the magnetopause reveal ion upflows of energy ∼100 eV flowing out from the ionosphere on closed field lines which are only found in the wake of the FTE. Such flows are also only found shortly after two, out of all the FTEs observed by AMPTE-UKS. The outflow from the ionosphere is two orders of magnitude greater than predicted for the "classical" polar wind. It is shown that such ionospheric ion flows are only expected in association with FTEs on the magnetopause which are well removed from the sub-solar point-either towards dusk or, as in the UKS example discussed here, towards dawn. It is suggested that such ionospheric ions will only be observed if the center of the FTE open flux tube passes very close to the satellite. Consequently, we conclude the ion upflows presented here are probably driven by the second of two possible source FTEs and are observed at the satellite with a lag after the FTE which is less than their time-of-flight.

Upwelling O+ ion source characteristics

Recent observations from the Dynamics Explorer 1 (DE-1) spacecraft have shown that the dayside auroral zone is an important source of very low-energy superthermal O^+ ions for the polar magnetosphere. When observed at 2000- to 5000-km altitude, the core of the O^+ distribution exhibits transverse heating to energies on the order of 10 eV, significant upward heat flux, and subsonic upward flow at significant flux levels exceeding 10^8 cm^{-2}s^{-1}. The term "upwelling ions" has been adopted to label these flows, which stand out in sharp contrast to the light ion polar wind flows observed in the same altitude range in the polar cap and subauroral magnetosphere. We have chosen a typical upwelling ion event for detailed study, correlating retarding ion mass spectrometer observations of the low-energy plasma with energetic ion observations and local electromagnetic field observations. The upwelling ion signature is colocated with the magnetospheric cleft as marked by precipitating energetic magnetosheath ions. The apparent ionospheric heating is clearly linked with the magnetic field signatures of strong field-aligned currents in the vicinity of the dayside polar cap boundary. Electric field and ion plasma measurements indicate that a very strong and localized convection channel or jet exists coincident with the other signatures of this event. These observations indicate that transverse ion heating to temperatures on the order of 10^5 K in the 2000- to 5000-km ionosphere is an important factor in producing heavy ion outflows into the polar magnetosphere. This result contrasts with recent suggestions that electron heating to temperatures of order 10^4 K is the most important parameter with regard to O^+ outflow.

A regime-dependent parametrization of subgrid-scale cloud water content variability

The subgrid-scale spatial variability in cloud water content can be described by a parameter f called the fractional standard deviation. This is equal to the standard deviation of the cloud water content divided by the mean. This parameter is an input to schemes that calculate the impact of subgrid-scale cloud inhomogeneity on gridbox-mean radiative fluxes and microphysical process rates. A new regime-dependent parametrization of the spatial variability of cloud water content is derived from CloudSat observations of ice clouds. In addition to the dependencies on horizontal and vertical resolution and cloud fraction included in previous parametrizations, the new parametrization includes an explicit dependence on cloud type. The new parametrization is then implemented in the Global Atmosphere 6 (GA6) configuration of the Met Office Unified Model and used to model the effects of subgrid variability of both ice and liquid water content on radiative fluxes and autoconversion and accretion rates in three 20-year atmosphere-only climate simulations. These simulations show the impact of the new regime-dependent parametrization on diagnostic radiation calculations, interactive radiation calculations and both interactive radiation calculations and in a new warm microphysics scheme. The control simulation uses a globally constant f value of 0.75 to model the effect of cloud water content variability on radiative fluxes. The use of the new regime-dependent parametrization in the model results in a global mean which is higher than the control's fixed value and a global distribution of f which is closer to CloudSat observations. When the new regime-dependent parametrization is used in radiative transfer calculations only, the magnitudes of short-wave and long-wave top of atmosphere cloud radiative forcing are reduced, increasing the existing global mean biases in the control. When also applied in a new warm microphysics scheme, the short-wave global mean bias is reduced.

La monarquia francesa y los financieros en el Antiguo Régimen. El ejemplo de los traitants durante la Guerra de los Nueve Años, 1689-1697 = The French Monarchy and the financiers during the Old Regime. The case of the traitants during the Nine Years War, 1689-1697

This article explores the relationship between the Crown, the French society and the king's financiers. It starts with a brief review of the discourses on the financiers and a survey of the work done by historians. Further to a description of the various groups of financiers, it analyses the nature of the contracts passed between the king and the traitants to pay for the Nine Years War, as well as the latter’s activities and profits. The article argues that the government supervised effectively the traitants and that, given the constraints of the Old Regime, these financiers provided essential services, but too costly to be sustainable.

A new regime of carbon counting: the practices and politics of accounting for everyday carbon through C02e

Inspired by the commercial desires of global brands and retailers to access the lucrative green consumer market, carbon is increasingly being counted and made knowable at the mundane sites of everyday production and consumption, from the carbon footprint of a plastic kitchen fork to that of an online bank account. Despite the challenges of counting and making commensurable the global warming impact of a myriad of biophysical and societal activities, this desire to communicate a product or service's carbon footprint has sparked complicated carbon calculative practices and enrolled actors at literally every node of multi-scaled and vastly complex global supply chains. Against this landscape, this paper critically analyzes the counting practices that create the ‘e’ in ‘CO2e’. It is shown that, central to these practices are a series of tools, models and databases which, in building upon previous work (Eden, 2012 and Star and Griesemer, 1989) we conceptualize here as ‘boundary objects’. By enrolling everyday actors from farmers to consumers, these objects abstract and stabilize greenhouse gas emissions from their messy material and social contexts into units of CO2e which can then be translated along a product's supply chain, thereby establishing a new currency of ‘everyday supply chain carbon’. However, in making all greenhouse gas-related practices commensurable and in enrolling and stabilizing the transfer of information between multiple actors these objects oversee a process of simplification reliant upon, and subject to, a multiplicity of approximations, assumptions, errors, discrepancies and/or omissions. Further the outcomes of these tools are subject to the politicized and commercial agendas of the worlds they attempt to link, with each boundary actor inscribing different meanings to a product's carbon footprint in accordance with their specific subjectivities, commercial desires and epistemic framings. It is therefore shown that how a boundary object transforms greenhouse gas emissions into units of CO2e, is the outcome of distinct ideologies regarding ‘what’ a product's carbon footprint is and how it should be made legible. These politicized decisions, in turn, inform specific reduction activities and ultimately advance distinct, specific and increasingly durable transition pathways to a low carbon society.

Climate justice and the international regime: before, during and after Paris

With a focus on key themes and debates, this article aims to illustrate and assess how the interaction between justice and politics has shaped the international regime and defined the nature of the international agreement that was signed in COP21 Paris. The work demonstrates that despite the rise of neo-conservatism and self-interested power politics, questions of global distributive justice remain a central aspect of the international politics of climate change. However, while it is relatively easy to demonstrate that international climate politics is not beyond the reach of moral contestations, the assessment of exactly how much impact justice has on climate policies and the broader normative structures of the climate governance regime remains a very difficult task. As the world digests the Paris Agreement, it is vital that the current state of justice issues within the international climate change regime is comprehensively understood by scholars of climate justice and by academics and practitioners, not least because how these intractable issues of justice are dealt with (or not) will be a crucial factor in determining the effectiveness of the emerging climate regime.

THE CO-INFLUENCE OF THE SEA BREEZE AND THE COASTAL UPWELLING AT CABO FRIO: A NUMERICAL INVESTIGATION USING COUPLED MODELS

A coupled atmospheric-oceanic model was used to investigate whether there is a positive feedback between the coastal upwelling and the sea breeze at Cabo Frio - RJ (Brazil). Two experiments were performed to ascertain the influence of the sea breeze on the coastal upwelling: the first one used the coupled model forced with synoptic NE winds of 8 m s(-1) and the sign of the sea breeze circulation was set by the atmospheric model; the second experiment used only the oceanic model with constant 8 m s(-1) NE winds. Then, to study the influence of the coastal upwelling on the sea breeze, two more experiments were performed: one using a coastal upwelling representative SST initial field and the other one using a constant and homogeneous SST field of 26 degrees C. Finally, two more experiments were conducted to verify the influence of the topography and the spatial distribution of the sea surface temperature on the previous results. The results showed that the sea breeze can intensify the coastal upwelling, but the coastal upwelling does not intensify the sea breeze circulation, suggesting that there is no positive feedback between these two phenomena at Cabo Frio.

Melting Regime of the Anionic Phospholipid DMPG: New Lamellar Phase and Porous Bilayer Model

Aqueous dispersions of the anionic phospholipid dimyristoyl phosphatidylglycerol (DMPG) at pH above the apparent pK of DMPG and concentrations in the interval 70-300 mM have been investigated by small (SAXS) and wide-angle X-ray scattering, differential scanning calorimetry, and polarized optical microscopy. The order. disorder transition of the hydrocarbon chains occurs along an interval of about 10 degrees C (between T(m)(on) similar to 20 degrees C and T(m)(off) similar to 30 degrees C). Such melting regime was previously characterized at lower concentrations, up to 70 mM DMPG, when sample transparency was correlated with the presence of pores across the bilayer. At higher concentrations considered here, the melting regime persists but is not transparent. Defined SAXS peaks appear and a new lamellar phase L(p) with pores is proposed to exist above 70 mM DMPG, starting at similar to 23 degrees C (similar to 3 degrees C above T(m)(on)) and losing correlation after T(m)(off). A new model for describing the X-ray scattering of bilayers with pores, presented here, is able to explain the broad band attributed to in-plane correlation between pores. The majority of cell membranes have a net negative charge, and the opening of pores across the membrane tuned by ionic strength, temperature, and lipid composition is likely to have biological relevance.

PL spectroscopy of Fermi electrons in regime of the quantum Hall effect

The influence of the interlayer coupling on formation of the quantized Hall phase at the filling factor v = 2 was studied in the multilayer GaAs/AlGaAs heterostructures The disorder broaden Gaussian photoluminescence line due to the localized electrons was found in the quantized Hall phase of the isolated multi-quantum well structure On the other hand. the quantized Hall phase of the weakly-coupled multilayers emitted an asymmetrical line similar to that one observed in the metallic electron systems. We demonstrated that the observed asymmetry indicates a formation of the Fermi Surface in the quantized Hall phase of the multilayer electron system due to the interlayer peicolation. A sharp decrease of the single-particle scattering time associated with the extended states oil the Fermi surface was observed at the filling factor v = 2. (C) 2009 Elsevier B.V All rights reserved

The mass media destabilizes the cultural homogenous regime in Axelrod`s model

An important feature of Axelrod`s model for culture dissemination or social influence is the emergence of many multicultural absorbing states, despite the fact that the local rules that specify the agents interactions are explicitly designed to decrease the cultural differences between agents. Here we re-examine the problem of introducing an external, global interaction-the mass media-in the rules of Axelrod`s model: in addition to their nearest neighbors, each agent has a certain probability p to interact with a virtual neighbor whose cultural features are fixed from the outset. Most surprisingly, this apparently homogenizing effect actually increases the cultural diversity of the population. We show that, contrary to previous claims in the literature, even a vanishingly small value of p is sufficient to destabilize the homogeneous regime for very large lattice sizes.