Search results for "Pau"

Le “brigand lusitanien” reconsidéré. Analyse du problème de la terre chez Appien

2015

The study of the “Lusitanian robbery” led to an important research since the late nineteenth century.Nevertheless, and despite a gradual shift in modern historiography towards a more nuanced approachto the origin of the phenomenon, the problem of land still remains a central concern of many historiansand archaeologists. From a close discussion of the main passages of Livy, Diodorus and Appian especiallyrelating to the relationship that some have sought to establish between lack and / or poverty ofthe land and development of robbery among the Lusitanians, it gives a review of the socio-economicinterpretation.

Teollisen internetin hyödyntäminen toiminnanohjauksessa

2016

Teollinen internet on ollut informaatioteknologiatutkimuksen yksi ajankohtaisimmista aiheista. Yritysmaailmassa asiakkaat sekä toimittajat ovat todella kiinnostuneita teollisen internetin mahdollisuuksista. Teollista internetiä onkin pidetty mahdollisena seuraavana digitaalisena vallankumouksena. Palvelujen toiminnanohjauksessa ja yleisesti toiminnanohjauksessa on tapahtunut viimeisimpinä vuosina vain vähäisiä muutoksia, mutta nyt teollisen internetin odotetaan mullistavan jopa perinteiset toiminnanohjauksenjärjestelmät ja -prosessit. Yritykset niin teollisen internetin että toiminnanohjauksen alueilla ovat todella kiinnostuneita näiden kahden palasen yhdistämisestä ja sen tuomista mahdolli…

Cosmological bounds on neutrino statistics

2018

We consider the phenomenological implications of the violation of the Pauli exclusion principle for neutrinos, focusing on cosmological observables such as the spectrum of Cosmic Microwave Background anisotropies, Baryon Acoustic Oscillations and the primordial abundances of light elements. Neutrinos that behave (at least partly) as bosonic particles have a modified equilibrium distribution function that implies a different influence on the evolution of the Universe that, in the case of massive neutrinos, can not be simply parametrized by a change in the effective number of neutrinos. Our results show that, despite the precision of the available cosmological data, only very weak bounds can …

Dynamics in the extratropical tropopause region: A case of transition between dynamically active and passive tracer advection?

2005

It is argued that certain aspects of tracer patterns and related stirring by the flow in the extratropical tropopause region can be understood in terms of a transition between dynamically active and passive tracer advection, called ‘active-to-passive tracer transition’. In the framework of surface quasi-geostrophic dynamics, a specific initial-value problem is defined and investigated. It features a gradual transition between the two paradigms of tracer advection and allows a clear interpretation thanks to the idealized nature of the model setup. Physical reasoning and anecdotal evidence from previous studies suggest that, at least in specific cases, this interpretation is relevant for the …

2020

Abstract. The vertical distribution and seasonal variation of water vapour volume mixing ratio (H2O VMR), of relative humidity with respect to ice (RHice) and particularly of regions with ice-supersaturated air masses (ISSRs) in the extratropical upper troposphere and lowermost stratosphere are investigated at northern mid-latitudes over the eastern North American, North Atlantic and European regions for the period 1995 to 2010. Observation data originate from regular and continuous long-term measurements on board instrumented passenger aircraft in the framework of the European research programme MOZAIC (1994–2010), which continues as the European research infrastructure IAGOS (from 2011). …

Analysis of a jet stream induced gravity wave associated with an observed ice cloud over Greenland

2004

International audience; A polar stratospheric ice cloud (PSC type II) was observed by airborne lidar above Greenland on 14 January 2000. It was the unique observation of an ice cloud over Greenland during the SOLVE/THESEO 2000 campaign. Mesoscale simulations with the hydrostatic HRM model are presented which, in contrast to global analyses, are capable to produce a vertically propagating gravity wave that induces the low temperatures at the level of the PSC afforded for the ice formation. The simulated minimum temperature is ~8 K below the driving analyses and ~4.5 K below the frost point, exactly coinciding with the location of the observed ice cloud. Despite the high elevations of the Gre…

2019

Abstract. The evolution of the tropopause inversion layer (TIL) during cyclogenesis in the North Atlantic storm track is investigated using operational meteorological analysis data (Integrated Forecast System from the European Centre for Medium-Range Weather Forecasts). For this a total of 130 cyclones have been analysed during the months August through October between 2010 and 2014 over the North Atlantic. Their paths of migration along with associated flow features in the upper troposphere and lower stratosphere (UTLS) have been tracked based on the mean sea level pressure field. Subsets of the 130 cyclones have been used for composite analysis using minimum sea level pressure to filter t…

A convolution of observational and model data to estimate age of air spectra in the northern hemispheric lower stratosphere

2020

Abstract. Derivation of mean age of air (AoA) and age spectra from atmospheric measurements remains a challenge and often requires data from atmospheric models. This study tries to minimize the direct influence of model data and presents an extension and application of a previously established inversion method to derive age spectra from mixing ratios of long- and short-lived trace gases. For a precise description of cross-tropopause transport processes, the inverse method is extended to incorporate air entrainment into the stratosphere across the tropical and extratropical tropopause. We first use simulations with the Chemical Lagrangian Model of the Stratosphere (CLaMS) to provide a genera…

Evidence of small-scale quasi-isentropic mixing in ridges of extratropical baroclinic waves

2019

Abstract. Stratosphere–troposphere exchange within extratropical cyclones provides the potential for anthropogenic and natural surface emissions to rapidly reach the stratosphere as well as for ozone from the stratosphere to penetrate deep into the troposphere, even down into the boundary layer. The efficiency of this process directly influences the surface climate, the chemistry in the stratosphere, the chemical composition of the extratropical transition layer, and surface pollution levels. Here, we present evidence for a mixing process within extratropical cyclones which has gained only a small amount of attention so far and which fosters the transport of tropospheric air masses into the…

The tropopause inversion layer in baroclinic life-cycle experiments: the role of diabatic processes

2016

Abstract. Recent studies on the formation of a quasi-permanent layer of enhanced static stability above the thermal tropopause revealed the contributions of dynamical and radiative processes. Dry dynamics leads to the evolution of a tropopause inversion layer (TIL), which is, however, too weak compared to observations and thus diabatic contributions are required. In this study we aim to assess the importance of diabatic processes in the understanding of TIL formation at midlatitudes. The non-hydrostatic model COSMO (COnsortium for Small-scale MOdelling) is applied in an idealized midlatitude channel configuration to simulate baroclinic life cycles. The effect of individual diabatic processe…