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  • Author or Editor: A. L. Lazrus x
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A. L. Lazrus and B. W. Gandrud

Abstract

Stratospheric nitric acid vapor was collected by sorption on cellulose filters impregnated with dibutoxy-ethylpthalate. The sampling was conducted by both stratospheric aircraft and balloons from 53S to 65N up to altitudes of 37 km. Results indicate concentrations increase with higher latitudes. The most concentrated layer extends from about 20 to 27 km in polar regions, and higher at lower latitudes. The present data indicate a seasonal variation in concentration. Stratospheric nitrate does not appear to be appreciably associated with stratospheric aerosol. The observed concentrations are in reasonable agreement with theoretically computed profiles. The transport rate of stratospheric nitric acid into the troposphere balances the computed production rate of stratosphere nitric oxide from nitrous oxide.

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A. L. Lazrus, B. Gandrud, and R. D. Cadle

Abstract

Evidence is presented indicating that nitrate present in stratospheric filtration samples represents adsorbed nitric acid vapor. The concentrations observed are comparable to those found by solar infrared spectrometry. Concentrations increase with altitude up to 28 km. Concentrations in the Southern Hemisphere are similar to those in the Northern.

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Philip L. Haggenson, Allan L. Lazrus, Ying-Hwa Kuo, and Ginger A. Caldwell

Abstract

Field data collected during APEX (Acid Precipitation Experiment) are used in combination with an isentropic trajectory model to analyze the relationship between acid precipitation and three-dimensional transport associated with cyclonic storms. Data are presented which indicate that high acidity in precipitation is often associated with slow transport speed and elevated SO2 concentrations in the dry air feeding into the precipitating regions. Conversely, low acidity is usually related to rapid transit, descending motion, and transport above the atmospheric boundary layer. The results also show that precipitation in the cold sector of a cyclone (in advance of the surface warm front) is often more acidic than that in other sectors of the storm. Four case studies are included to detail some of these meteorological effects.

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R. D. Cadle, F. E. Grahek, B. W. Gandrud, and A. L. Lazrus

Abstract

The relative efficiencies of impactors of the type used by Junge and co-workers for collecting stratosphere sulfate particles and of filters used in these laboratories have been determined by flying these collecting devices on the same aircraft in the stratosphere. The impactors have less than 20% of the efficiency of the filters for total sulfate. At most, a small percentage of the stratospheric sulfate was present as the ammonium salt. At least about half of the ammonium ion found on the impactors could have resulted from reaction of the collected samples with ammonia in tropospheric air.

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R. D. Cadle, R. Bleck, J. P. Shedlovsky, I. H. Blifford, Jan Rosinski, and A. L. Lazrus

Abstract

An extensive series of experiments is being undertaken to determine the concentrations and transport of trace atmospheric constituents in the stratosphere and troposphere in the vicinity of jet streams during tropopause “folding” episodes. The first experiments were undertaken in March and April 1968 and the results are described and discussed. Both propeller-driven aircraft and U. S. Air Force jet aircraft were used, supplemented by ozonesonde and lidar measurements. Trace constituents investigated included ozone, sulfates, various cations, freezing nuclei, aerosol particles in general, and radioactive nuclides. A high, positive correlation was observed between the intensity of radioactivity and the sulfate concentrations. Relative concentrations were consistent with transport of air from the troposphere to the stratosphere on the anticyclonic side of the jet stream. Concentrations of freezing nuclei were on the average much lower but much more uniform in the stratosphere than in the troposphere.

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Rebecca E. Morss, Julie L. Demuth, Heather Lazrus, Leysia Palen, C. Michael Barton, Christopher A. Davis, Chris Snyder, Olga V. Wilhelmi, Kenneth M. Anderson, David A. Ahijevych, Jennings Anderson, Melissa Bica, Kathryn R. Fossell, Jennifer Henderson, Marina Kogan, Kevin Stowe, and Joshua Watts

Abstract

During the last few decades, scientific capabilities for understanding and predicting weather and climate risks have advanced rapidly. At the same time, technological advances, such as the Internet, mobile devices, and social media, are transforming how people exchange and interact with information. In this modern information environment, risk communication, interpretation, and decision-making are rapidly evolving processes that intersect across space, time, and society. Instead of a linear or iterative process in which individual members of the public assess and respond to distinct pieces of weather forecast or warning information, this article conceives of weather prediction, communication, and decision-making as an interconnected dynamic system. In this expanded framework, information and uncertainty evolve in conjunction with people’s risk perceptions, vulnerabilities, and decisions as a hazardous weather threat approaches; these processes are intertwined with evolving social interactions in the physical and digital worlds. Along with the framework, the article presents two interdisciplinary research approaches for advancing the understanding of this complex system and the processes within it: analysis of social media streams and computational natural–human system modeling. Examples from ongoing research are used to demonstrate these approaches and illustrate the types of new insights they can reveal. This expanded perspective together with research approaches, such as those introduced, can help researchers and practitioners understand and improve the creation and communication of information in atmospheric science and other fields.

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