Down the Lines: US Army Communications in Europe, 1942-45

The incredible complexity of the Second World War continues to fire the imagination of the public and historians, alike. However, historians have largely ignored the immense importance of communications within the respective campaigns. This thesis will begin to redress this oversight by showing the role of military communications within the United States Army in Europe during World War II. In the wake of the war, the United States Army’s Center of Military History commissioned a large series of histories detailing the conduct of the US Army during the war. Interestingly, there were three entire books devoted to the Technical Services; specifically, the Signal Corps. In the decades after, the Center of Military History has continued to provide examination of the signal services, with a branch history of the Signal Corps published in 1994. Despite this profound endorsement, the academic community has not seen fit to give this subject its due diligence. Modern histories of World War II make very little mention of the difficulties of communication, if any mention is made at all. Even amateur efforts have been spotty and sometimes slipshod. Using a variety of modern texts, period works, and primary research at the National Archives, this thesis will use a narrowing lens approach to showing the multifaceted dimensions of military communications. From lessons learned in the Pacific and the Mediterranean, the organization and implementation of cohesive communications allowed command and control to function. By the commencement of Operation Cobra in July of 1944, the US Army had the most complete and flexible communications organization on the planet. The success of this organization can be seen most clearly during the German Winter Offensive of 1944-45, known as the Battle of the Bulge, when despite the rapid penetration of Allied battle-lines, at no time was communications cutoff between Northern and Southern forces

A database and tool for boundary conditions for regional air quality modeling: description and evaluation

Transported air pollutants receive increasing attention as regulations tighten and global concentrations increase. The need to represent international transport in regional air quality assessments requires improved representation of boundary concentrations. Currently available observations are too sparse vertically to provide boundary information, particularly for ozone precursors, but global simulations can be used to generate spatially and temporally varying lateral boundary conditions (LBC). This study presents a public database of global simulations designed and evaluated for use as LBC for air quality models (AQMs). The database covers the contiguous United States (CONUS) for the years 2001–2010 and contains hourly varying concentrations of ozone, aerosols, and their precursors. The database is complemented by a tool for configuring the global results as inputs to regional scale models (e.g., Community Multiscale Air Quality or Comprehensive Air quality Model with extensions). This study also presents an example application based on the CONUS domain, which is evaluated against satellite retrieved ozone and carbon monoxide vertical profiles. The results show performance is largely within uncertainty estimates for ozone from the Ozone Monitoring Instrument and carbon monoxide from the Measurements Of Pollution In The Troposphere (MOPITT), but there were some notable biases compared with Tropospheric Emission Spectrometer (TES) ozone. Compared with TES, our ozone predictions are high-biased in the upper troposphere, particularly in the south during January. This publication documents the global simulation database, the tool for conversion to LBC, and the evaluation of concentrations on the boundaries. This documentation is intended to support applications that require representation of long-range transport of air pollutants

Editor\u27s Corner - New Assistant Editors

It is a special pleasure to introduce two new assistant editors in the physical sciences. Chemistry and physics articles have not been abundant in recent issues and both editors are particularly interested in locating articles of practical value to classroom teachers. As each of the new editors states in his editorial, many readers have excellent ideas for classroom activities. Some of these activities may not be totally new but have a new approach which will prove helpful to other teachers. The entire editorial staff is eager to aid you in preparing articles for publication. Contact one of the editors to help you share your ideas with the profession

A comparison of atmospheric composition using the Carbon Bond and Regional Atmospheric Chemistry Mechanisms

We incorporate the recently developed Regional Atmospheric Chemistry Mechanism (version 2, RACM2) into the Community Multiscale Air Quality modeling system for comparison with the existing 2005 Carbon Bond mechanism with updated toluene chemistry (CB05TU). Compared to CB05TU, RACM2 enhances the domain-wide monthly mean hydroxyl radical concentrations by 46% and nitric acid by 26%. However, it reduces hydrogen peroxide by 2%, peroxyacetic acid by 94%, methyl hydrogen peroxide by 19%, peroxyacetyl nitrate by 40%, and organic nitrate by 41%. RACM2 enhances ozone compared to CB05TU at all ambient levels. Although it exhibited greater overestimates at lower observed concentrations, it displayed an improved performance at higher observed concentrations. The RACM2 ozone predictions are also supported by increased ozone production efficiency that agrees better with observations. Compared to CB05TU, RACM2 enhances the domain-wide monthly mean sulfate by 10%, nitrate by 6%, ammonium by 10%, anthropogenic secondary organic aerosols by 42%, biogenic secondary organic aerosols by 5%, and in-cloud secondary organic aerosols by 7%. Increased inorganic and organic aerosols with RACM2 agree better with observed data. Any air pollution control strategies developed using the two mechanisms do not differ appreciably

Understanding the impact of recent advances in isoprene photooxidation on simulations of regional air quality

The CMAQ (Community Multiscale Air Quality) us model in combination with observations for INTEX-NA/ICARTT (Intercontinental Chemical Transport Experiment–North America/International Consortium for Atmospheric Research on Transport and Transformation) 2004 are used to evaluate recent advances in isoprene oxidation chemistry and provide constraints on isoprene nitrate yields, isoprene nitrate lifetimes, and NO_x recycling rates. We incorporate recent advances in isoprene oxidation chemistry into the SAPRC-07 chemical mechanism within the US EPA (United States Environmental Protection Agency) CMAQ model. The results show improved model performance for a range of species compared against aircraft observations from the INTEX-NA/ICARTT 2004 field campaign. We further investigate the key processes in isoprene nitrate chemistry and evaluate the impact of uncertainties in the isoprene nitrate yield, NO_x (NO_x = NO + NO_2) recycling efficiency, dry deposition velocity, and RO_2 + HO_2 reaction rates. We focus our examination on the southeastern United States, which is impacted by both abundant isoprene emissions and high levels of anthropogenic pollutants. We find that NO_x concentrations increase by 4–9% as a result of reduced removal by isoprene nitrate chemistry. O3 increases by 2 ppbv as a result of changes in NO_x. OH concentrations increase by 30%, which can be primarily attributed to greater HO_x production. We find that the model can capture observed total alkyl and multifunctional nitrates (∑ANs) and their relationship with O_3 by assuming either an isoprene nitrate yield of 6% and daytime lifetime of 6 hours or a yield of 12% and lifetime of 4 h. Uncertainties in the isoprene nitrates can impact ozone production by 10% and OH concentrations by 6%. The uncertainties in NO_x recycling efficiency appear to have larger effects than uncertainties in isoprene nitrate yield and dry deposition velocity. Further progress depends on improved understanding of isoprene oxidation pathways, the rate of NOx recycling from isoprene nitrates, and the fate of the secondary, tertiary, and further oxidation products of isoprene

Evaluation of simulated photochemical partitioning of oxidized nitrogen in the upper troposphere

Regional and global chemical transport models underpredict NOx (NO + NO2) in the upper troposphere where it is a precursor to the greenhouse gas ozone. The NOx bias has been shown in model evaluations using aircraft data (Singh et al., 2007) and total column NO2 (molecules cm−2) from satellite observations (Napelenok et al., 2008). The causes of NOx underpredictions have yet to be fully understood due to the interconnected nature of simulated emission, transport, and chemistry processes. Recent observation-based studies, in the upper troposphere, identify chemical rate coefficients as a potential source of error (Olson et al., 2006; Ren et al., 2008). Since typical chemistry evaluation techniques are not available for upper tropospheric conditions, this study develops an evaluation platform from in situ observations, stochastic convection, and deterministic chemistry. We derive a stochastic convection model and optimize it using two simulated datasets of time since convection, one based on meteorology, and the other on chemistry. The chemistry surrogate for time since convection is calculated using seven different chemical mechanisms, all of which predict shorter time since convection than our meteorological analysis. We evaluate chemical simulations by inter-comparison and by pairing results with observations based on NOx:HNO3, a photochemical aging indicator. Inter-comparison reveals individual chemical mechanism biases and recommended updates. Evaluation against observations shows that all chemical mechanisms overpredict NOx removal relative to long-lived methanol and carbon monoxide. All chemical mechanisms underpredict observed NOx by at least 30%, and further evaluation is necessary to refine simulation sensitivities to initial conditions and chemical rate uncertainties

Evaluation of simulated photochemical partitioning of oxidized nitrogen in the upper troposphere

Regional and global chemical transport models underpredict NO<sub>x</sub> (NO + NO<sub>2</sub>) in the upper troposphere where it is a precursor to the greenhouse gas ozone. The NO<sub>x</sub> bias has been shown in model evaluations using aircraft data (Singh et al., 2007) and total column NO<sub>2</sub> (molecules cm<sup>−2</sup>) from satellite observations (Napelenok et al., 2008). The causes of NO<sub>x</sub> underpredictions have yet to be fully understood due to the interconnected nature of simulated emission, transport, and chemistry processes. Recent observation-based studies, in the upper troposphere, identify chemical rate coefficients as a potential source of error (Olson et al., 2006; Ren et al., 2008). Since typical chemistry evaluation techniques are not available for upper tropospheric conditions, this study develops an evaluation platform from in situ observations, stochastic convection, and deterministic chemistry. We derive a stochastic convection model and optimize it using two simulated datasets of time since convection, one based on meteorology, and the other on chemistry. The chemistry surrogate for time since convection is calculated using seven different chemical mechanisms, all of which predict shorter time since convection than our meteorological analysis. We evaluate chemical simulations by inter-comparison and by pairing results with observations based on NO<sub>x</sub>:HNO<sub>3</sub>, a photochemical aging indicator. Inter-comparison reveals individual chemical mechanism biases and recommended updates. Evaluation against observations shows that all chemical mechanisms overpredict NO<sub>x</sub> removal relative to long-lived methanol and carbon monoxide. All chemical mechanisms underpredict observed NO<sub>x</sub> by at least 30%, and further evaluation is necessary to refine simulation sensitivities to initial conditions and chemical rate uncertainties

Evaluation of simulated photochemical partitioning of oxidized nitrogen in the upper troposphere

Regional and global chemical transport models underpredict NO<sub>x</sub> (NO + NO<sub>2</sub>) in the upper troposphere where it is a precursor to the greenhouse gas ozone. The NO<sub>x</sub> bias has been shown in model evaluations using aircraft data (Singh et al., 2007) and total column NO<sub>2</sub> (molecules cm<sup>−2</sup>) from satellite observations (Napelenok et al., 2008). The causes of NO<sub>x</sub> underpredictions have yet to be fully understood due to the interconnected nature of simulated emission, transport, and chemistry processes. Recent observation-based studies, in the upper troposphere, identify chemical rate coefficients as a potential source of error (Olson et al., 2006; Ren et al., 2008). Since typical chemistry evaluation techniques are not available for upper tropospheric conditions, this study develops an evaluation platform from in situ observations, stochastic convection, and deterministic chemistry. We derive a stochastic convection model and optimize it using two simulated datasets of time since convection, one based on meteorology, and the other on chemistry. The chemistry surrogate for time since convection is calculated using seven different chemical mechanisms, all of which predict shorter time since convection than our meteorological analysis. We evaluate chemical simulations by inter-comparison and by pairing results with observations based on NO<sub>x</sub>:HNO<sub>3</sub>, a photochemical aging indicator. Inter-comparison reveals individual chemical mechanism biases and recommended updates. Evaluation against observations shows that all chemical mechanisms overpredict NO<sub>x</sub> removal relative to long-lived methanol and carbon monoxide. All chemical mechanisms underpredict observed NO<sub>x</sub> by at least 30%, and further evaluation is necessary to refine simulation sensitivities to initial conditions and chemical rate uncertainties