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The Antarctic Tropospheric Chemistry Investigation (ANTCI) was carried out from late November to December 2003 with both extended ground-based and tethered balloon studies at Amundsen Scott Station, South Pole. ANTCI 2003 was the first of two Antarctic field studies with the primary goal of further exploring the active photochemistry of the South Pole region that was first identified in the previous Investigation of Sulfur Chemistry in the Antarctic Troposphere (ISCAT) program. Since ISCAT was fully ground-based, ANTCI 2003 goals included expanding chemical studies both vertically upward to investigate mixing and horizontally to better understand large-scale plateau NOx production and transport. Thus, in addition to ground-based experiments at South Pole, Twin Otter aircraft sampling took place out to hundreds of kilometers in several directions from the South Pole. These were designed to specifically address the issue of how representative past South Pole chemical measurements are of the surrounding high plateau region. The Twin Otter was also used to make transects along the coast both north and south of McMurdo Station. The present paper summarizes the overall setting and results of this investigation and highlights the many new findings that were obtained. © 2007 Elsevier Ltd. All rights reserved.

The first airborne measurements of nitric oxide (NO) on the Antarctic plateau have demonstrated that the previously reported elevated levels of this species extend well beyond the immediate vicinity of South Pole. Although the current database is still relatively weak and critical laboratory experiments are still needed, the findings here suggest that the chemical uniqueness of the plateau may be substantially greater than first reported. For example, South Pole ground-based findings have provided new evidence showing that the dominant process driving the release of nitrogen from the snowpack during the spring/summer season (post-depositional loss) is photochemical in nature with evaporative processes playing a lesser role. There is also new evidence suggesting that nitrogen, in the form of nitrate, may undergo multiple recycling within a given photochemical season. Speculation here is that this may be a unique property of the plateau and much related to its having persistent cold temperatures even during summer. These conditions promote the efficient adsorption of molecules like HNO3 (and very likely HO2NO2) onto snow-pack surface ice where we have hypothesized enhanced photochemical processing can occur, leading to the efficient release of NOx to the atmosphere. In addition, to these process-oriented tentative conclusions, the findings from the airborne studies, in conjunction with modeling exercises suggest a new paradigm for the plateau atmosphere. The near-surface atmosphere over this massive region can be viewed as serving as much more than a temporary reservoir or holding tank for imported chemical species. It defines an immense atmospheric chemical reactor which is capable of modifying the chemical characteristics of select atmospheric constituents. This reactor has most likely been in place over geological time, and may have led to the chemical modulation of some trace species now found in ice cores. Reactive nitrogen has played a critical role in both establishing and in maintaining this reactor. © 2007 Elsevier Ltd. All rights reserved.

Volatile organic compounds (VOCs) were measured at the South Pole (SP) from late Austral spring to mid-summer 2000 as part of the Investigation of Sulfur Chemistry in the Antarctic Troposphere Program (ISCAT-2000). This paper focuses on VOCs that are directly emitted from the ocean, specifically dimethyl sulfide (DMS), methyl nitrate (CH3ONO2), methyl iodide (CH 3I) and bromoform (CHBr3). A partial seasonal cycle of these gases was also recorded during the year following ISCAT-2000. During the summer, the SP periodically receives relatively fresh marine air containing short-lived oceanic trace gases, such as DMS (τ≈1 day). However, DMS was not detected at the SP until January even though DMS emissions from the Southern Ocean typically start peaking in November and elevated levels of other ocean-derived VOCs, including CH3ONO2 and CHBr 3, were observed in mid-November. We speculate that in November and December most of the DMS is oxidized before it reaches the SP: a strong correlation between CH3ONO2 and methane sulfonate (MSA), an oxidation product of DMS, supports this hypothesis. Based on a limited number of samples taken over the course of one year, CH3ONO2 apparently accumulates to a quasi-steady-state level over the SP in winter, most likely due to continuing emissions of the compound coupled with a lower rate of photochemical destruction. Oceanic emissions were concluded to be the dominant source of alkyl nitrates at the SP; this is in sharp contrast to northern high latitudes where total alkyl nitrate mixing ratios are dominated by urban sources. © 2004 Elsevier Ltd. All rights reserved.

Observations over the tropical Pacific during the Pacific Exploratory Mission (PEM)-Tropics B experiment (March-April 1999) are analyzed. Concentrations of CO and long-lived nonmethane hydrocarbons in the region are significantly enhanced due to transport of pollutants from northern industrial continents. This pollutant import also enhances moderately O3 concentrations but not NOx concentrations. It therefore tends to depress OH concentrations over the tropical Pacific. These effects contrast to the large enhancements of O3 and NOx concentrations and the moderate increase of OH concentrations due to biomass burning outflow during the PEM-Tropics A experiment (September-October 1996). Observed CH3I concentrations, as in PEM-Tropics A, indicate that convective mass outflux in the middle and upper troposphere is largely independent of altitude over the tropical Pacific. Constraining a one-dimensiohal model with CH3I observations yields a 10-day timescale for convective turnover of the free troposphere, a factor of 2 faster than during PEM-Tropics A. Model simulated HO2, CH2O, H2O2, and CH3OOH concentrations are generally in agreement with observations. However, simulated OH concentrations are lower (∼25%) than observations above 6 km. Whereas models tend to overestimate previous field measurements, simulated HNO3 concentrations during PEM-Tropics B are too low (a factor of 2-4 below 6 km) compared to observations. Budget analyses indicate that chemical production of O3 accounts for only 50% of chemical loss; significant transport of O3 into the region appears to take place within the tropics. Convective transport of CH3OOH enhances the production of HOx and O3 in the upper troposphere, but this effect is offset by HOx loss due to the scavenging of H2O2. Convective transport and scavenging of reactive nitrogen species imply a necessary source of 0.4-1 Tg yr-1 of NOx in the free troposphere (above 4 km) over the tropics. A large fraction of the source could be from marine lightning. Oxidation of DMS transported by convection from the boundary layer could explain the observed free tropospheric SO2 concentrations over the tropical Pacific. This source of DMS due to convection, however, would imply in the model free tropospheric concentrations much higher than observed. The model overestimate cannot be reconciled using recent kinetics measurements of the DMS-OH adduct reaction at low pressures and temperatures and may reflect enhanced OH oxidation of DMS during convection. Copyright 2001 by the American Geophysical Union.

This paper reports results of NASA's Chemical Instrumentation and Test Evaluation (CITE 3) during which airborne measurements for carbonyl sulfide (COS), hydrogen sulfide (H2S), and carbon disulfide (CS2) were intercompared. Instrumentation included a gas chromatograph using flame photometric detection (COS, H2S, and CS2), a gas chromatograph using mass spectrometric detection (COS and CS2), a gas chromatograph using fluorination and subsequent SF6 detection via electron capture (COS and CS2), and the Natusch technique (H2S). The measurements were made over the Atlantic Ocean east of North and South America during flights from NASA's Wallops Flight Center, Virginia, and Natal, Brazil, in August/September 1989. Most of the intercomparisons for H2S and CS2 were at mixing ratios 25 pptv, the instruments agreed on average to about 15%. At mixing ratios

This paper reports results from NASA's Chemical Instrumentation and Test Evaluation (CITE 3) during which airborne measurements of dimethyl sulfide (DMS) from six instruments were intercompared. Represented by the six instruments are three fundamentally different detection principles (flame photometric, mass spectrometric, and electron capture after fluorination); three collection/preconcentration methods (cryogenic, gold wool absorption, and polymer absorbent); and three types of oxidant scrubbers (solid phase alkaline, aqueous reactor, and cotton). The measurements were made over the Atlantic Ocean in August/September 1989 during flights from NASA's Wallops Flight Center, Virginia, and Natal, Brazil. The majority of the intercomparisons are at DMS mixing ratios

This paper reviews an emerging experimental literature that uses laboratory methods to both identify causes of the 2007–2009 financial crisis, and to assess the effectiveness of policies implemented in response. Papers reviewed include experiments conducted to evaluate central bank and Treasury responses to the crisis, experiments that study the consequences of interconnectedness between financial firms on financial system stability, and experiments conducted to evaluate policies intended to more effectively regulate specific types of financial institutions. Laboratory methods are ideally suited to investigating the consequences of untested policies in new environmental circumstances – just the situation provoked by the crisis. The continually evolving structure of the financial system suggests an expanded future role for laboratory methods in this area. [ABSTRACT FROM AUTHOR]

We report an experiment that assesses the effects of alterations in production conditions and product durability on market power in Bertrand-Edgeworth duopolies. Static equilibrium analysis predicts that advance (rather than 'to demand') production raises prices, but does not affect profits. The further addition of a simple inventory option causes prices to fall and seller earnings to increase. Contrary to these predictions, we observe similar prices in baseline and advance production treatments, but lower profits given advance production. An inventory option reduces both prices and earnings. Results are driven by the treatments' effects on sellers' capacities to tacitly collude. (JEL C9, D4, L4), I. INTRODUCTION Bertrand-Edgeworth games are an important part of any industrial organization economist's toolkit. The unilateral market power created by capacity constraints represents one of economists' primary methods for modeling [...]

This paper reports an experiment conducted to evaluate a 'near-continuous' variant of the posted offer trading institution, where the number of periods in a market session is increased by reducing sharply each period's maximum length. Experimental results suggest that although decisions in time-truncated periods are not equivalent to periods' of longer duration, extensive repetition improves considerably the drawing power of equilibrium predictions in some challenging environments. Nevertheless, significant deviations remain in the near-continuous framework. We also observe that the extra data collected in the near-continuous framework allow new insights into price convergence and signaling. (JEL C92, L12, L11), I. INTRODUCTION Posted offer markets occupy a central place in the laboratory investigation of market behavior. The posting of price decisions by sellers to consumers on a take-it-or-leave-it basis parallels [...]

A study examines market performance and mergers in differentiated product oligopoly.

Experimental results on the viability of antitrust logit model to examine anticompetitive issues in horizontal merges in differentiated-product markets are presented.

Experimental methods are used to examine the existence and detectability of collusion in environments that exhibit critical parallels to procurement auctions. We find that given the opportunity sellers often raise prices considerably Moreover, noncollusive Nash equilibrium predictions are insufficient to dismiss 'suspicious' behavior as innocuous: in an environment where identical prices are predicted in a noncollusive Nash equilibrium, common prices are observed only when sellers communicate. In a second environment designed to parallel construction procurement contracting, market rotations are observed both with and without collusion, but collusion can often be detected from the pattern of losing bids. (JEL L4, 09), Bart J. Wilson (*) I. INTRODUCTION Questioning the value of efforts to enforce federal anticonspiracy laws raises spirited debate among antitrust economists. Although everyone recognizes the welfare costs of successful [...]

An experimental analysis shows that nonstationarities affect call markets positively. Aspects of demand or supply conditions that are repeatitive and systematic results to reduction of transaction costs and more accurate determination of equilibrium price movement cause. Nonstationarities are shown to have a more desirable effect on the performance of call markets than double auctions.

I. INTRODUCTION One of the seminal developments leading to the information economics revolution in the 1970s and 19c0s was Diamond's [1971] theoretical result that, in the absence of publicly posted [...]

The influence of systematic supply and/or demand nonstationaries on market performance and dynamic adjustment paths was investigated. The results showed that the ability of markets to track the competitive equilibrium was heavily affected by the trading institution and the source of the nonstationary. Posted-offer markets were not very efficient in tracking the competitive equilibrium price.