Baroclinic, Kelvin and inertia-gravity waves in the barostrat instability experiment

International audienceThe differentially heated rotating annulus is a laboratory experiment historically designed for modelling large-scale features of the mid-latitude atmosphere. In the present study, we investigate a modified version of the classic baroclinic experiment in which a juxtaposition of convective and motionless stratified layers is created by introducing a vertical salt stratification. The thermal convective motions are suppressed in a central region at mid-depth of the rotating tank, therefore double-diffusive convection rolls can develop only in thin layers located at top and bottom, where the salt stratification is weakest. For high enough rotation rates, the baroclinic instability destabilises the flow in the top and the bottom shallow convective layers, generating cyclonic and anticyclonic eddies separated by the stable stratified layer. Thanks to this alternation of layers resembling the convective and radiative layers of stars, the planetary's atmospheric troposphere and stratosphere or turbulent layers at the sea surface above stratified waters, this new laboratory setup is of interest for both astrophysics and geophysical sciences. More specifically, it allows to study the exchange of momentum and energy between the layers, primarly by the propagation of internal gravity waves (IGW). PIV velocity maps are used to describe the wavy flow pattern at different heights. Using a co-rotating laser and camera, the wave field is well resolved and different wave types can be found: baroclinic waves, Kelvin, and Poincaré type waves. The signature of small-scale IGW can also be observed attached to the baroclinic jet. The baroclinic waves occur at the thin convectively active layer at the surface and the bottom of the tank, though decoupled they show different manifestation of nonlinear interactions. The inertial Kelvin and Poincaré waves seem to be mechanically forced. The small-scale wave trains attached to the meandering jet point to an imbalance of the large-scale flow. For the first time, the simultaneous occurrence of differentwave types is reported in detail for a differentially heated rotating annulus experiment

The Jervell and Lange-Nielsen syndrome; atrial pacing combined with ß-blocker therapy, a favorable approach in young high-risk patients with long QT syndrome?

BackgroundPatients with Jervell and Lange-Nielsen syndrome (JLNS) exhibit severe phenotypes that are characterized by congenital deafness, very long QT intervals, and high risk of life-threatening arrhythmias. Current treatment strategies include high doses of beta-blocker medication, left cardiac sympathetic denervation, and ICD placement, which is challenging in young children.ObjectiveThe purpose of this study was to evaluate the safety and effect of pacing in addition to beta-blocker treatment in children with JLNS.MethodsAll genetically confirmed patients with JLNS born since 1999 in Norway were included in the study. Data on history of long QT syndrome–related symptoms, QT interval, and beta-blocker and pacemaker treatment were recorded.ResultsA total of 9 patients with QT intervals ranging from 510 to 660 ms were identified. Eight patients developed long QT syndrome–related symptoms, and 1 patient died before diagnosis. The survivors received beta-blocker medication. Seven patients also received a pacemaker; 1 had a ventricular lead and 6 had atrial leads. The patient with the ventricular lead died during follow-up. The 6 patients with atrial leads survived without events at a mean follow-up of 6.9 years after pacemaker implantation. Two patients received prophylactic upgrade to a 2-chamber ICD.ConclusionNo arrhythmic events occurred in 6 very young JLNS patients who received atrial pacing in combination with increased doses of beta-blockers during 7-year follow-up. If confirmed in additional patients, this treatment strategy may prevent life-threatening arrhythmias in this high-risk patient group and may act as a bridge to insertion of a 2-chamber ICD when left cardiac sympathetic denervation is not available

Skill and added value of the MiKlip regional decadal prediction system for temperature over Europe

In recent years, several decadal prediction systems have been developed to provide multi-year predictions of the climate for the next 5–10 years. On the global scale, high decadal predictability has been identified for the North Atlantic sector, often extending over Europe. The first full regional hindcast ensemble, derived from dynamical downscaling, was produced within the German MiKlip project (‘decadal predictions’). The ensemble features annual starting dates from 1960 to 2017, with 10 decadal hindcasts per starting year. The global component of the prediction system uses the MPI-ESM-LR and the downscaling is performed with the regional climate model COSMO-CLM (CCLM). The present study focusses on a range of aspects dealing with the skill and added value of regional decadal temperature predictions over Europe. The results substantiate the added value of the regional hindcasts compared to the forcing global model as well as to un-initialized simulations. The results show that the hindcasts are skilful both for annual and seasonal means, and that the scores are comparable for different observational reference data sets. The predictive skill increases from earlier to more recent start-years. A recalibration of the simulation data generally improves the skill further, which can also be transferred to more user-relevant variables and extreme values like daily maximum temperatures and heating degree-days. These results provide evidence of the potential for the regional climate predictions to provide valuable climate information on the decadal time-scale to users

The urban land use in the COSMO-CLM model: A comparison of three parameterizations for Berlin

The regional non-hydrostatic climate model COSMO-CLM is increasingly being used on fine spatial scales of 1–5 km. Such applications require a detailed differentiation between the parameterization for natural and urban land uses. Since 2010, three parameterizations for urban land use have been incorporated into COSMO-CLM. These parameterizations vary in their complexity, required city parameters and their computational cost. We perform model simulations with the COSMO-CLM coupled to these three parameterizations for urban land in the same model domain of Berlin on a 1-km grid and compare results with available temperature observations. While all models capture the urban heat island, they differ in spatial detail, magnitude and the diurnal variation

La production biologique de porcs en Europe - Gestion de la santé des porcs dans les élevages de production

Les éleveurs de porcs biologiques ont développé en Europe différents systèmes de logement qui dépendent de la disponibilité des terres, des caractéristiques du sol et du climat, des traditions et des schémas de certification. Ce guide décrit les principaux systèmes de logement des porcs biologiques. Il compare les avantages et les inconvénients de chacun et donne des recommandations aux éleveurs pour mieux agir sur la santé des animaux

Yield Assessment of Off-grid PV Systems in Nigeria

Off-grid PV systems are providing critical access to energy services for millions of people throughout the globe. However, optimum sizing of these PV systems still poses a challenge, as inadequate system sizing could result in low system reliability and/or high cost of electricity generated. This paper presents a hybrid method of sizing off-grid PV systems for undefined electricity consumption. It then compares this sizing with off-grid PV systems installed in Nigeria - ranked the most populous electricity-deficit country in the world. The yields of the installed off-grid PV systems are also simulated for four major cities in Nigeria. Results show that for the over 1.5MWp of off-grid PV systems installed in the country, there is a potential 1.11 – 3.04 MWh of unutilised surplus electricity, which can supply 2hours of green electricity to at least 2,000 Tier-2 households during peak demand in the dry hot season. Thus, our hybrid model provides design and operational insight to off-grid PV system optimizatio

The Fluvial and Water-Rich History of Northern Xanthe Terra: A Reference for the ExoMars Landing Site

We produced a geomorphological map of a study area in northern Xanthe Terra, which shares several characteristics with the ExoMars Rover landing site

The Deep Sea and Sub-Seafloor Frontier

The deep sea and its sub-seafloor contain a vast reservoir of physical, mineral and biological resources that are rapidly coming into the window of exploitation. Assessing the opportunities and the risks involved requires a serious commitment to excellent deep sea research. There are numerous areas in this field in which Europe has cutting-edge technological potential. These include drilling and monitoring technology in the field of renewable energies such as geothermal, offshore wind and seafloor resources. Scientific ocean drilling will continue to play a valuable role, for example in the exploration of resource opportunities, in obtaining estimates for ecosystem and Earth climate sensitivity, or in improving understanding about the controlling factors governing processes and recurrence intervals of submarine geohazards. In Europe, there is also the scientific expertise needed to define a framework for policymakers for environmental protection measures and to carry out ecological impact assessments before, during and after commercial exploitation. Taking up these societal challenges will strengthen European scientific and educational networks and promote the development of world-class technology and industrial leadership.Published3.7. Dinamica del clima e dell'oceano4.6. Oceanografia operativa per la valutazione dei rischi in aree marineope