Wave forcing of the quasi-biennial oscillation in the Max Planck Institute Earth System Model

This study investigates the resolved wave forcing of the quasi-biennial oscillation (QBO) in the Max Planck Institute Earth System Model truncated at T63 with 95 vertical levels. The model, which parameterizes unresolved gravity waves, internally generates a QBO. The resolved waves contribute up to 50% and 30% to the total wave forcing (resolved plus parameterized) of the QBO westerly and easterly jet, respectively, mostly owing to waves with zonal wavenumbers lower than 20 and frequencies lower than 0.5 cpd. At higher frequencies and wavenumbers, the model underestimates the strength of the tropospheric wave sources when compared to Tropical Rainfall Measuring Mission (TRMM) observations and applies strong horizontal diffusion, which explains the shortage of wave momentum at these scales (relative to recent studies based on high-resolution models). The study further relates the vertical structure of equatorial Kelvin waves, which contribute most to the transport and deposition of westerly wave momentum, to their radiative dissipation and compares the role of longwave radiation and horizontal diffusion in the dissipation of the resolved waves in general. The Kelvin waves adjust their vertical wavelength according to their intrinsic phase speed and are efficiently damped by longwave radiation within westerly flow, where the vertical wavelength strongly decreases. Waves with zonal wavenumbers larger than 10, however, are mostly damped by horizontal diffusion. The latitudinal distribution of the resolved wave forcing reflects the latitudinal structure of the waves and is asymmetric with respect to the equator. © 2014 American Meteorological Society

Seasonal aspects of the quasi-biennial oscillation in the Max Planck Institute Earth System Model and ERA-40

This study investigates seasonal modulations of the quasi-biennial oscillation (QBO) of the tropical stratosphere. For this purpose, the Max Planck Institute Earth System Model (MPI-ESM), which internally generates a realistic QBO compared to the ERA-40 data set, is employed. The modeled QBO is forced with resolved and parametrized waves. At 5 hPa, the seasonal distribution of the onset of QBO westerly jets clusters in spring and fall due to the coupling of the QBO and the semiannual oscillation. This seasonal clustering of the westerly jets extends throughout the stratosphere, shifting to later months with increasing pressure. QBO westerly jets starting in the upper stratosphere in fall propagate to the middle stratosphere more slowly than westerly jets starting in spring. This is attributed to seasonal modulations of the QBO forcing and enhanced wave filtering by the QBO westerly jet in the lower stratosphere in fall and winter compared to spring and summer. The observed stalling of the QBO easterly jet in the lower stratosphere and the accompanied prolonged persistence of the QBO westerly jet in the vicinity of the tropopause are attributed equally to seasonal variations of the resolved and parameterized wave forcing and the advective forcing

The influence of the spectral truncation on the simulation of waves in the tropical stratosphere

Convectively triggered waves are the main driver of the tropical stratospheric circulation. In atmospheric models, the model’s resolution limits the length of the simulated wave spectrum. In this study, the authorscompare the tropical tropospheric wave sources, their projection on the wave field in the lower stratosphere, and the circumstances of their upward propagation in the atmospheric model ECHAM6 with three spectral truncations of T63, T127, and T255. The model internally generates the quasi biennial oscillation (QBO),which dominates the variability in the tropical stratosphere. This analysis focuses on two opposite phases of the QBO to account for the influence of the background wind field on the wave filtering. It is shown that, compared to the high-resolution model versions, the T63 version has less convective variability and less wave momentum in the lower stratosphere at wavenumbers larger than 20, well below the version’s truncation limit.In the low-resolution version, the upward propagation of the waves is further hindered by the highly active (relative to the high-resolution versions) horizontal diffusion scheme. However, even in the T255version of ECHAM6, the convective variability is too small compared to TRMM observations at periods shorter than 2 days and wavelengths shorter than 1000 km. Hence, to model a realistic tropical waveactivity, the convective parameterization of the model has to improve to increase the day-to-day precipitation variability

A decade of energy and mass balance investigations on the glacier Kongsvegen, Svalbard

Kongsvegen is an Arctic glacier located in northwest Spitzbergen. We use meteorological observations made near the average equilibrium line of Kongsvegen during the decade 2001 to 2010 to drive a glacier energy and mass balance model. Average daily and seasonal cycles are analyzed over the course of a full decade, as well as the interannual variations of the meteorological parameters and of the mass and energy balance components. The calculated average of net radiation is close to zero and the sensible heat flux is the most important and continuous source of energy at the surface. The latent heat flux is a weak source of energy as well. The resultant flux constellation yields a surplus of energy accumulating throughout the decade (9.5 W m-2) and fosters a negative specific surface mass balance throughout the investigated decade (-1.8 m w. eq.). The most significant mass loss occurred during the middle of the decade (2004 until 2006), with positive surface mass balances observed afterward when significant amounts of superimposed ice were formed. This development is well correlated to the total surface mass balance of the glacier. Application of monthly temperature and precipitation perturbations corroborates earlier studies indicating a high sensitivity of the mass balance to energy fluxes depending on temperature conditions during summer. Key PointsEvaluation of a decadal meteorological record of an Arctic glacierUse of SOMARS, validation of results, investigations of climate sensitiviyAnnual, monthly, daily consideration ©2012. American Geophysical Union. All Rights Reserved

Urban eddy covariance measurements reveal significant missing NOx emissions in Central Europe

Nitrogen oxide (NOx) pollution is emerging as a primary environmental concern across Europe. While some large European metropolitan areas are already in breach of EU safety limits for NO2, this phenomenon does not seem to be only restricted to large industrialized areas anymore. Many smaller scale populated agglomerations including their surrounding rural areas are seeing frequent NO2 concentration violations. The question of a quantitative understanding of different NOx emission sources is therefore of immanent relevance for climate and air chemistry models as well as air pollution management and health. Here we report simultaneous eddy covariance flux measurements of NOx, CO2, CO and non methane volatile organic compound tracers in a city that might be considered representative for Central Europe and the greater Alpine region. Our data show that NOx fluxes are largely at variance with modelled emission projections, suggesting an appreciable underestimation of the traffic related atmospheric NOx input in Europe, comparable to the weekend-weekday effect, which locally changes ozone production rates by 40%

Study protocol of cost-effectiveness and cost-utility of a biopsychosocial multidisciplinary intervention in the evolution of non-specific sub-acute low back pain in the working population: cluster randomised trial.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Low back pain (LBP), with high incidence and prevalence rate, is one of the most common reasons to consult the health system and is responsible for a significant amount of sick leave, leading to high health and social costs. The objective of the study is to assess the cost-effectiveness and cost-utility analysis of a multidisciplinary biopsychosocial educational group intervention (MBEGI) of non-specific sub-acute LBP in comparison with the usual care in the working population recruited in primary healthcare centres. Methods/design: The study design is a cost-effectiveness and cost-utility analysis of a MBEGI in comparison with the usual care of non-specific sub-acute LBP.Measures on effectiveness and costs of both interventions will be obtained from a cluster randomised controlled clinical trial carried out in 38 Catalan primary health care centres, enrolling 932 patients between 18 and 65 years old with a diagnosis of non-specific sub-acute LBP. Effectiveness measures are: pharmaceutical treatments, work sick leave (% and duration in days), Roland Morris disability, McGill pain intensity, Fear Avoidance Beliefs (FAB) and Golberg Questionnaires. Utility measures will be calculated from the SF-12. The analysis will be performed from a social perspective. The temporal horizon is at 3 months (change to chronic LBP) and 12 months (evaluate the outcomes at long term. Assessment of outcomes will be blinded and will follow the intention-to-treat principle. Discussion: We hope to demonstrate the cost-effectiveness and cost-utility of MBEGI, see an improvement in the patients' quality of life, achieve a reduction in the duration of episodes and the chronicity of non-specific low back pain, and be able to report a decrease in the social costs. If the intervention is cost-effectiveness and cost-utility, it could be applied to Primary Health Care Centres. Trial registration: ISRCTN: ISRCTN5871969

New insights into orthostatic hypotension in multiple system atrophy: a European multicentre cohort study

Objectives: Orthostatic hypotension (OH) is a key feature of multiple system atrophy (MSA), a fatal progressive neurodegenerative disorder associated with autonomic failure, parkinsonism and ataxia. This study aims (1) to determine the clinical spectrum of OH in a large European cohort of patients with MSA and (2) to investigate whether a prolonged postural challenge increases the sensitivity to detect OH in MSA. Methods: Assessment of OH during a 10 min orthostatic test in 349 patients with MSA from seven centres of the European MSA-Study Group (age: 63.6±8.8 years; disease duration: 4.2±2.6 years). Assessment of a possible relationship between OH and MSA subtype (P with predominant parkinsonism or C with predominant cerebellar ataxia), Unified MSA Rating Scale (UMSARS) scores and drug intake. Results: 187 patients (54%) had moderate (>20 mm Hg (systolic blood pressure (SBP)) and/or >10 mm Hg (diastolic blood pressure (DBP)) or severe OH (>30 mm Hg (SBP) and/or >15 mm Hg (DBP)) within 3 min and 250 patients (72%) within 10 min. OH magnitude was significantly associated with disease severity (UMSARS I, II and IV), orthostatic symptoms (UMSARS I) and supine hypertension. OH severity was not associated with MSA subtype. Drug intake did not differ according to OH magnitude except for antihypertensive drugs being less frequently, and antihypotensive drugs more frequently, prescribed in severe OH. Conclusions: This is the largest study of OH in patients with MSA. Our data suggest that the sensitivity to pick up OH increases substantially by a prolonged 10 min orthostatic challenge. These results will help to improve OH management and the design of future clinical trials.Fil: Pavy Le Traon, Anne. University Hospital of Toulouse; Francia. Inserm; FranciaFil: Piedvache, A.. Université Paul Sabatier; FranciaFil: Pérez Lloret, Santiago. University Hospital of Toulouse; Francia. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Instituto de Investigaciones Biomédicas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; ArgentinaFil: Calandra Buonara, G.. Università di Bologna; Italia. Istituto delle Scienze Neurologiche di Bologna; ItaliaFil: Cochen De Cock, V.. University Hospital of Toulouse; Francia. University of Montpellier; FranciaFil: Colosimo, C.. Sapienza Università di Roma; ItaliaFil: Cortelli, P.. Università di Bologna; Italia. Istituto delle Scienze Neurologiche di Bologna; ItaliaFil: Debs, R.. University Hospital of Toulouse; FranciaFil: Duerr, S.. Universidad de Innsbruck; AustriaFil: Fanciulli, A.. Universidad de Innsbruck; AustriaFil: Foubert Samier, A.. Centre Hospitalier Universitaire de Bordeaux; Francia. Universite de Bordeaux; FranciaFil: Gerdelat, Angela. University Hospital of Toulouse; FranciaFil: Gurevich, T.. Tel-Aviv University; IsraelFil: Krismer, F.. Universidad de Innsbruck; AustriaFil: Poewe, W.. Universidad de Innsbruck; AustriaFil: Tison, Francois. Universite de Bordeaux; Francia. Centre Hospitalier Universitaire de Bordeaux; FranciaFil: Tranchant, C.. University Hospital Hautepierre; FranciaFil: Wenning, G.. Universidad de Innsbruck; AustriaFil: Meissner, Wassilios G.. Universite de Bordeaux; Francia. Centre Hospitalier Universitaire de Bordeaux; FranciaFil: Rascol, Olivier. University Hospital of Toulouse; Franci

A new method for measuring torsional deformity in scoliosis

<p>Abstract</p> <p>Background</p> <p>The importance of spinal rotational and torsional deformity in the etiology and the management of scoliosis are well-recognized. For measuring the posterior spinal component rotation, Ho's method was reported to be reliable. However, there is no practical method to measure the anterior spinal component rotation. Moreover, there is also no method to quantify the spinal torsional deformity in scoliosis. The goal of this study is to characterize scoliosis and its deformity to hypothesize the etiology and the development of scoliosis, and to establish a new method for the measurement of the vertebral body rotation and spinal torsional deformity in scoliosis using CT scans.</p> <p>Methods</p> <p>Pre-operative CT scans of 25 non-congenital scoliosis patients were recruited and the apical vertebral rotation was measured by a newly developed method and Ho's method. Ho's method adopts the laminae as the rotational landmark. For a new method to measure the apical vertebral rotation, the posterior point just beneath each pedicle was used as a landmark. For quantifying the spinal torsional deformity angle, the rotational angle difference between the two methods was calculated.</p> <p>Results</p> <p>Intraobserver and interobserver reliability analyses showed both methods to be reliable. Apical vertebral rotation revealed 13.9 ± 6.8 (mean ± standard deviation) degrees by the new method and 7.9 ± 6.3 by Ho's method. Right spinal rotation was assigned a positive value. The discrepancy of rotation (6.1 ± 3.9 degrees), meaning that the anterior component rotated more than the posterior component, was considered to express the spinal torsional deformity to the convex side.</p> <p>Conclusions</p> <p>We have developed an easy, reliable and practical method to measure the rotation of the spinal anterior component using a CT scan. Furthermore, we quantified the spinal torsional deformity to the convex side in scoliosis by comparing the rotation between the anterior and posterior components.</p