Statistical simulation procedures

Statistical simulation procedures utilizing Monte Carlo stratification techniqu

Barry Saltzman and the Theory of Climate

Barry Saltzman was a giant in the fields of meteorology and climate science. A leading figure in the study of weather and climate for over 40 yr, he has frequently been referred to as the father of modern climate theory. Ahead of his time in many ways, Saltzman made significant contributions to our understanding of the general circulation and spectral energetics budget of the atmosphere, as well as climate change across a wide spectrum of time scales. In his endeavor to develop a unified theory of how the climate system works, lie played a role in the development of energy balance models, statistical dynamical models, and paleoclimate dynamical models. He was a pioneer in developing meteorologically motivated dynamical systems, including the progenitor of Lorenz\u27s famous chaos model. In applying his own dynamical-systems approach to long-term climate change, he recognized the potential for using atmospheric general circulation models in a complimentary way. In 1998, he was awarded the Carl-Gustaf Rossby medal, the highest honor of the American Meteorological Society for his life-long contributions to the study of the global circulation and the evolution of the earth\u27s climate. In this paper, the authors summarize and place into perspective some of the most significant contributions that Barry Saltzman made during his long and distinguished career. This short review also serves as an introduction to the papers in this special issue of the Journal of Climate dedicated to Barry\u27s memory

Climatological features of blocking anticyclones: a study of Northern Hemisphere CCM1 model blocking events in present-day and double CO2 concentration atmospheres

http://solberg.snr.missouri.edu/gcc/Using output made with the National Center for Atmospheric Research (NCAR) Community Climate Model Version 1 (CCM1), the characteristics of blocking events over the Northern Hemisphere in a ten-year present day control simulation with a CO2 concentration of 330 ppm were compared to those in a previously analyzed observational three-year climatology. The characteristics of blocking events in a double present-day CO2 concentration simulation were then compared to those in the control simulation in order to evaluate how these characteristics might change in an increased CO2 atmosphere. The results demonstrated that in the Northern Hemisphere the CCM1 correctly simulated many characteristics of blocking events such as average annual number of occurrences, annual variations is size and intensity, and preferred formation regions. A more detailed analysis (i.e., by region and season) revealed some di¤erences between the CCM1 and observed blocking events for characteristics such as mean frequency of occurrence, intensity, size and duration. In addition, the model failed to capture adequately the occurrence of blocking events over the western Asian continent. A comparison of the double CO2 concentration run to the control showed that, in general, blocking events were more persistent and weaker, but of similar size in the increased CO2 atmosphere. Also, some statistically signiÞcant regional and seasonally dependent changes were found in the frequency of occurrence, duration, and intensity. Finally, a correlation between block size and intensity, signiÞcant at the 99% conÞdence level, was found in each climatology. This result is similar to a correlation found in the analysis of observations

Burnout and Substance Use in Collegiate Athletic Trainers

CONTEXT: The Smith Cognitive-Affective Model of Athletic Burnout suggests that athletic trainers (ATs) suffering from burnout may engage in substance use as a coping behavior. Increases in self-reported burnout symptoms are often associated with increases in heavy episodic drinking and tobacco use among various health care providers. However, this relationship has not been examined thoroughly. OBJECTIVE: To investigate the prevalence of substance use in ATs and identify relationships between symptoms of burnout and substance use among ATs. DESIGN: Cross-sectional study. SETTING: Web-based survey. PATIENTS OR OTHER PARTICIPANTS: A total of 783 certified ATs working full time in the collegiate or university setting were sampled for this study. Graduate assistant and other part-time ATs were excluded. The survey was distributed via the National Athletic Trainers\u27 Association membership directory e-mail broadcast service. MAIN OUTCOME MEASURE(S): A 100-item online questionnaire consisting of items from previously used scales was used for this study. The survey included the Maslach Burnout Inventory and questions on substance use from the Monitoring the Future study. Multiple regression analyses were performed to analyze the survey data. All independent (Maslach Burnout Inventory subscales) and dependent (use of alcohol, tobacco, and marijuana) variables were mapped to the Smith Cognitive-Affective Model of Athletic Burnout to determine which dimensions of burnout altered the odds of self-reported substance use. RESULTS: Almost half (46.3%) of participants admitted to at least 1 binge-drinking episode. However, the use of cigarettes, smokeless tobacco, marijuana, and energy drinks during the previous month was less pronounced in the sample. Emotional exhaustion (B = .008, P = .023) and personal accomplishment (B = -.016, P = .02) were significantly correlated with binge drinking. Emotional exhaustion (Exp[B] = 1.017, P \u3c .001) was also significantly positively correlated with energy-drink consumption. CONCLUSIONS: Some ATs engaged in heavy episodic drinking. Emotional exhaustion and a decreased sense of personal accomplishment were significantly correlated with this behavior

Sensitivity of Climate Models: Comparison of Simulated and Observed Patterns for Past Climates

Predicting the potential climatic effects of increased concentrations of atmospheric carbon dioxide requires the continuing development of climate models. As one index of the magnitude of past climates change, the global mean temperature increase during the past 18,000 years is similar to that predicted for carbon dioxide doubling. Simulating the climate changes of the past 18,000 years, as well as the warmer-than-present climate of 6000 years ago and the climate of the last interglacial, around 126,000 years ago, provides an excellent opportunity to test the models that are being used in global climate change research. During the past several years, we have used paleoclimatic data to test the accuracy of the NCAR CCMO (National Center for Atmospheric Research, Community Climate Model, Version 0), after changing its boundary conditions to those appropriate for past climates. We have assembled near-global paleoclimatic data sets of pollen, lake level, and marine plankton data and calibrated many of the data in terms of climatic variables. We have also developed methods that permit direct quantitative comparisons between the data and model results. Our comparisons have shown both some of the strengths and weaknesses of the model. The research so far has shown the feasibility of our methods for comparing paleoclimatic data and model results. Our research has also shown that comparing the model results with the data is an evolutionary process, because the models, the data, and the methods for comparison are continually being improved. During 1991, we have continued our studies and this Progress Report documents the results to date. During this year, we have completed new modeling experiments, compiled new data sets, made new comparisons between data and model results, and participated in workshops on paleoclimatic modeling. 37 refs

Peri‐operative cardiac arrest in children as reported to the 7th National Audit Project of the Royal College of Anaesthetists

The 7th National Audit Project of the Royal College of Anaesthetists studied peri‐operative cardiac arrest. An activity survey estimated UK paediatric anaesthesia annual caseload as 390,000 cases, 14% of the UK total. Paediatric peri‐operative cardiac arrests accounted for 104 (12%) reports giving an incidence of 3 in 10,000 anaesthetics (95%CI 2.2–3.3 per 10,000). The incidence of peri‐operative cardiac arrest was highest in neonates (27, 26%), infants (36, 35%) and children with congenital heart disease (44, 42%) and most reports were from tertiary centres (88, 85%). Frequent precipitants of cardiac arrest in non‐cardiac surgery included: severe hypoxaemia (20, 22%); bradycardia (10, 11%); and major haemorrhage (9, 8%). Cardiac tamponade and isolated severe hypotension featured prominently as causes of cardiac arrest in children undergoing cardiac surgery or cardiological procedures. Themes identified at review included: inappropriate choices and doses of anaesthetic drugs for intravenous induction; bradycardias associated with high concentrations of volatile anaesthetic agent or airway manipulation; use of atropine in the place of adrenaline; and inadequate monitoring. Overall quality of care was judged by the panel to be good in 64 (62%) cases, which compares favourably with adults (371, 52%). The study provides insight into paediatric anaesthetic practice, complications and peri‐operative cardiac arrest

Quasiparticle Density of States of Clean and Dirty s-Wave Superconductors in the Vortex State

The quasiparticle density of states (DOS) in the vortex state has been probed by specific heat measurements under magnetic fields (H) for clean and dirty s-wave superconductors, Y(Ni1-xPtx)2B2C and Nb1-xTaxSe2. We find that the quasiparticle DOS per vortex is appreciably H-dependent in the clean-limit superconductors, while it is H-independent in the dirty superconductors as expected from a conventional rigid normal electron core picture. We discuss possible origins for our observations in terms of the shrinking of the vortex core radius with increasing H.Comment: 5 pages, 4 figures, to appear in J. Phys. Soc. Jpn. Vol. 68 No.

Verifying a Computational Method for Predicting Extreme Ground Motion

Large earthquakes strike infrequently and close-in recordings are uncommon. This situation makes it difficult to predict the ground motion very close to earthquake-generating faults, if the prediction is to be based on readily available observations. A solution might be to cover the Earth with seismic instruments so that one could rely on the data from previous events to predict future shaking. However, even in the case of complete seismic data coverage for hundreds of years, there would still be one type of earthquake that would be difficult to predict: those very rare earthquakes that produce very large ground motion