Wolfgang A. Müller

Multiyear Prediction of Monthly Mean Atlantic Meridional Overturning Circulation at 26.5°N

Stable Flow Whole-ocean deep circulation in the Atlantic, the Atlantic Meridional Overturning Circulation (AMOC), transports great quantities of heat from low latitudes to higher ones, which, for example, helps to warm Europes climate. Matei et al. (p. 76) describe a modeling technique that allows AMOC strength to be predicted for up to 4 years in advance and suggests that AMOC should remain stable until at least 2014. The strength of an ocean current that transports heat to Europe can be predicted up to 4 years in advance. Attempts to predict changes in Atlantic Meridional Overturning Circulation (AMOC) have yielded little success to date. Here, we demonstrate predictability for monthly mean AMOC strength at 26.5°N for up to 4 years in advance. This AMOC predictive skill arises predominantly from the basin-wide upper-mid-ocean geostrophic transport, which in turn can be predicted because we have skill in predicting the upper-ocean zonal density difference. Ensemble forecasts initialized between January 2008 and January 2011 indicate a stable AMOC at 26.5°N until at least 2014, despite a brief wind-induced weakening in 2010. Because AMOC influences many aspects of climate, our results establish AMOC as an important potential carrier of climate predictability.

Interleukin-6 and acute-phase protein concentrations in surgical intensive care unit patients: diagnostic signs in nosocomial infection.

ObjectiveTo determine the value of serum concentrations of interleukin-6 (IL-6), C-reactive protein, and glycosylation of α-acid glycoprotein as tools for diagnosing nosocomial infection in surgical intensive care unit (ICU) patients. DesignProspective, consecutive entry study of patients with an anticipated stay of at least 24 hrs in a surgical ICU. SettingUniversity hospital, a major provider of acute surgical care. PatientsOne hundred four consecutive patients admitted to the surgical ICU between March and June 1990. MeasurementsConcentrations of IL-6, C-reactive protein, and glycosylation of α1-acid glycoprotein were measured on days 1 and 6 after ICU admission. Clinical evaluation for infection was performed daily in a blinded fashion, i.e., without knowing the results of the acute-phase parameters. Main ResultsOn day 6 after surgery or trauma, nosocomial infection could be ascertained in 13 cases. The clinical parameter-of fever >38°C had a sensitivity of 54% and a specificity of 90% to demonstrate nosocomial infection. Infected patients showed increased concentrations of IL-6 (p < .001), C-reactive protein (p < .001), and increased reactivity of α1-acid glycoprotein to concanavalin A (p < .001) compared with patients without infections. By choosing appropriate cutoff values, IL-6 determinations had the highest specificity (97%), and C-reactive protein values had the highest sensitivity (85%) for diagnosing nosocomial infections. In uninfected patients, 81% of the IL-6 values, but only 29% of the C-reactive protein values, were back to the normal range on day 6 after injury. ConclusionDue to the rapid normalization after trauma, a single measurement of the serum IL-6 concentration may be useful to support or refute the clinical suspicion of nosocomial infection. (Crit Care Med 1993; 21:1175–1180)

A Debiased Ranked Probability Skill Score to Evaluate Probabilistic Ensemble Forecasts with Small Ensemble Sizes

Abstract The ranked probability skill score (RPSS) is a widely used measure to quantify the skill of ensemble forecasts. The underlying score is defined by the quadratic norm and is comparable to the mean squared error (mse) but it is applied in probability space. It is sensitive to the shape and the shift of the predicted probability distributions. However, the RPSS shows a negative bias for ensemble systems with small ensemble size, as recently shown. Here, two strategies are explored to tackle this flaw of the RPSS. First, the RPSS is examined for different norms L (RPSSL). It is shown that the RPSSL=1 based on the absolute rather than the squared difference between forecasted and observed cumulative probability distribution is unbiased; RPSSL defined with higher-order norms show a negative bias. However, the RPSSL=1 is not strictly proper in a statistical sense. A second approach is then investigated, which is based on the quadratic norm but with sampling errors in climatological probabilities conside...

Predictability of the mid-latitude Atlantic meridional overturning circulation in a multi-model system

Assessing the skill of the Atlantic meridional overturning circulation (AMOC) in decadal hindcasts (i.e. retrospective predictions) is hampered by a lack of observations for verification. Models are therefore needed to reconstruct the historical AMOC variability. Here we show that ten recent oceanic syntheses provide a common signal of AMOC variability at 45°N, with an increase from the 1960s to the mid-1990s and a decrease thereafter although they disagree on the exact magnitude. This signal correlates with observed key processes such as the North Atlantic Oscillation, sub-polar gyre strength, Atlantic sea surface temperature dipole, and Labrador Sea convection that are thought to be related to the AMOC. Furthermore, we find potential predictability of the mid-latitude AMOC for the first 3–6 year means when we validate decadal hindcasts for the past 50 years against the multi-model signal. However, this predictability is not found in models driven only by external radiative changes, demonstrating the need for initialization of decadal climate predictions.

Predictability of the quasi‐biennial oscillation and its northern winter teleconnection on seasonal to decadal timescales

The predictability of the quasi-biennial oscillation (QBO) is examined in initialized climate forecasts extending out to lead times of years. We use initialized retrospective predictions made with coupled ocean-atmosphere climate models that have an internally generated QBO. We demonstrate predictability of the QBO extending more than 3 years into the future, well beyond timescales normally associated with internal atmospheric processes. Correlation scores with observational analyses exceed 0.7 at a lead time of 12 months. We also examine the variation of predictability with season and QBO phase and find that skill is lowest in winter. An assessment of perfect predictability suggests that higher skill may be achievable through improved initialization and climate modeling of the QBO, although this may depend on the realism of gravity wave source parameterizations in the models. Finally, we show that skilful prediction of the QBO itself does not guarantee predictability of the extratropical winter teleconnection that is important for surface winter climate prediction.

Glycosylation of α1-acid glycoprotein in relation to duration of disease in acute and chronic infection and inflammation

Abstract Microheterogeneity of acute phase proteins frequently differs in acute and chronic types of inflammation. However, it is unknown whether these changes depend on the duration of the inflammation in a given disease. We therefore investigated the microheterogeneity of α 1 -acid glycoprotein (AGP) in sera from patients with acute and chronic bacterial infection in comparison to rheumatoid arthritis and ankylosing spondylitis. In acute bacterial infection Con A-reactivity of AGP was significantly elevated. By contrast, AGP in chronic bacterial infection showed the same glycosylation pattern as rheumatoid arthritis and ankylosing spondylitis being characterized by a decreased reactivity to Con A. Serial measurements in individual patients with bacterial infections showed a transition from the initially elevated to decreased reactivity to Con A as the disease became chronic.

TNF-α gene polymorphism does not affect the clinical and radiological outcome of rheumatoid arthritis

Abstract The present study was undertaken in order to investigate the relationship between tumor necrosis factor-α (TNF-α) gene polymorphism and the radiological progression of rheumatoid arthritis (RA) within the first 3-years of the disease.Sixty-eight RA patients (59 women and nine men) were observed for 3-years. TNF-α polymorphism analysis was performed in all patients. Radiographs of the hands were taken at the onset of study and after 3-years of follow-up. Radiographs were assessed according to the Larsen index (damage score and progression of damage score). We did not observe any correlation between TNF gene polymorphism and damage score or progression of damage score. The obtained data suggests that TNF-308 polymorphism cannot serve as an indicator of the disease course in RA patients.

Seasonal predictability over Europe arising from El Niño and stratospheric variability in the MPI-ESM seasonal prediction system

AbstractPredictability on seasonal time scales over the North Atlantic–Europe region is assessed using a seasonal prediction system based on an initialized version of the Max Planck Institute Earth System Model (MPI-ESM). For this region, two of the dominant predictors on seasonal time scales are El Nino–Southern Oscillation (ENSO) and sudden stratospheric warming (SSW) events. Multiple studies have shown a potential for improved North Atlantic predictability for either predictor. Their respective influences are however difficult to disentangle, since the stratosphere is itself impacted by ENSO. Both El Nino and SSW events correspond to a negative signature of the North Atlantic Oscillation (NAO), which has a major influence on European weather.This study explores the impact on Europe by separating the stratospheric pathway of the El Nino teleconnection. In the seasonal prediction system, the evolution of El Nino events is well captured for lead times of up to 6 months, and stratospheric variability is re...

Elektrophysiologische und elektronenmikroskopische Untersuchungen an der Riechschleimhaut des Jacobsonschen Organs von Eidechsen (Lacerta)

Summary1.Electro-olfactograms have been recorded from the nasal mucosa as well as from the mucosa of the vomero-nasal organ in lizards (Lacerta). The potentials from both organs show the typical characteristics of electro-olfactograms recorded from the nasal mucosa in other vertebrates. The form of the positive responses evoked by stimulation with methanol in the vomero-nasal organ is highly variable.2.The receptors in the vomero-nasal organ differ from those of the nasal mucosa in lacking cilia and even centrioles. The perikarya have a very uniform structure. Their axons, about 0.17 μ in diameter are bundled together into groups of 7 to more than 100 by mesaxons.

Decadal climate predictions for the period 1901–2010 with a coupled climate model

An ensemble of yearly initialized decadal predictions is performed with the Max Planck Institute Earth System Model to examine the forecast skill for the period from 1901 to 2010. Compared to the more recent period (1960 to present day), the extended period leads to an enlargement of regions with significant anomaly correlation coefficients (ACC) for predicted surface temperatures. This arises from an increased contribution of the trend, which is also found in the uninitialized runs. Additionally, in the North Atlantic decadal variability plays a larger role over the extended period, with detrended time series showing higher ACC for the extended compared to the short period. Furthermore, in contrast to the uninitialized simulations, the initialized predictions capture the North Atlantic warming events during the 1920s and 1990s, together with some of the surface climate impacts including warm European summer temperatures and a northward shift of Atlantic tropical rainfall.