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32 results on '"Moffet, R."'

1. Aerosol–Ice Formation Closure : A Southern Great Plains Field Campaign

Author

Knopf, D. A., Barry, K. R., Brubaker, T. A., Jahl, L. G., Jankowski, K. A., Li, J., Lu, Y., Monroe, L. W., Moore, K. A., Rivera-Adorno, F. A., Sauceda, K. A., Shi, Y., Tomlin, J. M., Vepuri, H. S. K., Wang, P., Lata, N. N., Levin, E. J. T., Creamean, J. M., Hill, T. C. J., China, S., Alpert, P. A., Moffet, R. C., Hiranuma, N., Sullivan, R. C., Fridlind, A. M., West, M., Riemer, N., Laskin, A., DeMott, P. J., and Liu, X.

Published
2021

2. Microscopic Characterization of Carbonaceous Aerosol Particle Aging in the Outflow from Mexico City

Author

Moffet, R. C.

Subjects
Environmental sciences, aerosols, STXM, scanning transmission X-ray microscopy, soot, MILAGRO, particles, NEXAFS
Abstract

This study was part of the Megacities Initiative: Local and Global Research Observations (MILAGRO) field campaign conducted in Mexico City Metropolitan Area during spring 2006. The physical and chemical transformations of particles aged in the outflow from Mexico City were investigated for the transport event of 22 March 2006. A detailed chemical analysis of individual particles was performed using a combination of complementary microscopy and micro-spectroscopy techniques. The applied techniques included scanning transmission X-ray microscopy (STXM) coupled with near edge X-ray absorption fine structure spectroscopy (NEXAFS) and computer controlled scanning electron microscopy with an energy dispersive X-ray analyzer (CCSEM/EDX). As the aerosol plume evolves from the city center, the organic mass per particle increases and the fraction of carbon-carbon double bonds (associated with elemental carbon) decreases. Organic functional groups enhanced with particle age include: carboxylic acids, alkyl groups, and oxygen bonded alkyl groups. At the city center (T0) the most prevalent aerosol type contained inorganic species (composed of sulfur, nitrogen, oxygen, and potassium) coated with organic material. At the T1 and T2 sites, located northeast of T0 (~;;29 km and ~;;65 km, respectively), the fraction of homogenously mixed organic particles increased in both size and number. These observations illustrate the evolution of the physical mixing state and organic bonding in individual particles in a photochemically active environment.

Published
2009

5. Microscopic characterization of carbonaceous aerosol particle aging in the outflow from Mexico City

Author

Moffet, R. C., Henn, T. R., Tivanski, A. V., Hopkins, R. J., Desyaterik, Y., Kilcoyne, A. L. D., Tyliszczak, T., Fast, J., Barnard, J., Shutthanandan, V., Cliff, S. S., Perry, K. D., Alexander Laskin, and Gilles, M. K.

Subjects
lcsh:Chemistry, lcsh:QD1-999, lcsh:Physics, lcsh:QC1-999
Abstract

This study was part of the Megacities Initiative: Local and Global Research Observations (MILAGRO) field campaign conducted in Mexico City Metropolitan Area during spring 2006. The physical and chemical transformations of particles aged in the outflow from Mexico City were investigated for the transport event of 22 March 2006. A detailed chemical analysis of individual particles was performed using a combination of complementary microscopy and micro-spectroscopy techniques. The applied techniques included scanning transmission X-ray microscopy (STXM) coupled with near edge X-ray absorption fine structure spectroscopy (NEXAFS) and computer controlled scanning electron microscopy with an energy dispersive X-ray analyzer (CCSEM/EDX). As the aerosol plume evolves from the city center, the organic mass per particle increases and the fraction of carbon-carbon double bonds (associated with elemental carbon) decreases. Organic functional groups enhanced with particle age include: carboxylic acids, alkyl groups, and oxygen bonded alkyl groups. At the city center (T0) the most prevalent aerosol type contained inorganic species (composed of sulfur, nitrogen, oxygen, and potassium) coated with organic material. At the T1 and T2 sites, located northeast of T0 (~29 km and ~65 km, respectively), the fraction of homogenously mixed organic particles increased in both size and number. These observations illustrate the evolution of the physical mixing state and organic bonding in individual particles in a photochemically active environment.

Published
2010

11. Comparison of Canadian air quality forecast models with tropospheric ozone profile measurements above midlatitude North American during the IONS/ICARTT campaign: Evidence for stratospheric input

Author

Tarasick, David W., Moran, M. D., Thompson, Anne M., Carey-Smith, T., Rochon, Y., Bouchet, V. S., Gong, W., Makar, P. A., Stroud, C., Ménard, S., Crevier, L. P., Cousineau, S., Pudykiewicz, J. A., Kallaur, A., Moffet, R., Ménard, R., Robichaud, A., Cooper, Owen R., Oltmans, Samuel J., Witte, Jacquelyn C., Forbes, Gerry, Johnson, B. J., Merrill, J., Moody, J. L., Morris, G., Newchurch, Michael J., Schmidlin, F. J., Joseph, Everette, Tarasick, David W., Moran, M. D., Thompson, Anne M., Carey-Smith, T., Rochon, Y., Bouchet, V. S., Gong, W., Makar, P. A., Stroud, C., Ménard, S., Crevier, L. P., Cousineau, S., Pudykiewicz, J. A., Kallaur, A., Moffet, R., Ménard, R., Robichaud, A., Cooper, Owen R., Oltmans, Samuel J., Witte, Jacquelyn C., Forbes, Gerry, Johnson, B. J., Merrill, J., Moody, J. L., Morris, G., Newchurch, Michael J., Schmidlin, F. J., and Joseph, Everette

Abstract

During July and August, 2004, balloon-borne ozonesondes were released daily at 12 sites in the eastern USA and Canada, producing the largest single set of free tropospheric ozone measurements ever compiled for this region. At the same time, a number of air quality forecast models were run daily as part of a larger field experiment. In this paper, we compare these ozonesonde profiles with predicted ozone profiles from several versions of two of these forecast models, the Environment Canada CHRONOS and AURAMS models. We find that the models show considerable skill at predicting ozone in the planetary boundary layer and immediately above. Individual station biases are variable, but often small. Standard deviations of observation-forecast differences are large, however. Ozone variability in the models is somewhat higher than observed. Most strikingly, none of the model versions is able to reproduce the typical tropospheric ozone profile of increasing mixing ratio with altitude. Results from a sensitivity test suggest that the form of the ozone lateral boundary condition used by all model versions contributes significantly to the large ozone underpredictions in the middle and upper troposphere. The discrepancy could be reduced further by adding a downward flux of ozone from the model lid and by accounting for in situ production of ozone from lightning-generated NOx.

Published
2007

12. Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES)

Author

Zaveri, R. A., primary, Shaw, W. J., additional, Cziczo, D. J., additional, Schmid, B., additional, Ferrare, R. A., additional, Alexander, M. L., additional, Alexandrov, M., additional, Alvarez, R. J., additional, Arnott, W. P., additional, Atkinson, D. B., additional, Baidar, S., additional, Banta, R. M., additional, Barnard, J. C., additional, Beranek, J., additional, Berg, L. K., additional, Brechtel, F., additional, Brewer, W. A., additional, Cahill, J. F., additional, Cairns, B., additional, Cappa, C. D., additional, Chand, D., additional, China, S., additional, Comstock, J. M., additional, Dubey, M. K., additional, Easter, R. C., additional, Erickson, M. H., additional, Fast, J. D., additional, Floerchinger, C., additional, Flowers, B. A., additional, Fortner, E., additional, Gaffney, J. S., additional, Gilles, M. K., additional, Gorkowski, K., additional, Gustafson, W. I., additional, Gyawali, M., additional, Hair, J., additional, Hardesty, R. M., additional, Harworth, J. W., additional, Herndon, S., additional, Hiranuma, N., additional, Hostetler, C., additional, Hubbe, J. M., additional, Jayne, J. T., additional, Jeong, H., additional, Jobson, B. T., additional, Kassianov, E. I., additional, Kleinman, L. I., additional, Kluzek, C., additional, Knighton, B., additional, Kolesar, K. R., additional, Kuang, C., additional, Kubátová, A., additional, Langford, A. O., additional, Laskin, A., additional, Laulainen, N., additional, Marchbanks, R. D., additional, Mazzoleni, C., additional, Mei, F., additional, Moffet, R. C., additional, Nelson, D., additional, Obland, M. D., additional, Oetjen, H., additional, Onasch, T. B., additional, Ortega, I., additional, Ottaviani, M., additional, Pekour, M., additional, Prather, K. A., additional, Radney, J. G., additional, Rogers, R. R., additional, Sandberg, S. P., additional, Sedlacek, A., additional, Senff, C. J., additional, Senum, G., additional, Setyan, A., additional, Shilling, J. E., additional, Shrivastava, M., additional, Song, C., additional, Springston, S. R., additional, Subramanian, R., additional, Suski, K., additional, Tomlinson, J., additional, Volkamer, R., additional, Wallace, H. W., additional, Wang, J., additional, Weickmann, A. M., additional, Worsnop, D. R., additional, Yu, X.-Y., additional, Zelenyuk, A., additional, and Zhang, Q., additional

Published
2012
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14. Microscopic characterization of carbonaceous aerosol particle aging in the outflow from Mexico City

Author

Moffet, R. C., primary, Henn, T. R., additional, Tivanski, A. V., additional, Hopkins, R. J., additional, Desyaterik, Y., additional, Kilcoyne, A. L. D., additional, Tyliszczak, T., additional, Fast, J., additional, Barnard, J., additional, Shutthanandan, V., additional, Cliff, S. S., additional, Perry, K. D., additional, Laskin, A., additional, and Gilles, M. K., additional

Published
2009
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16. Comparison of Canadian air quality forecast models with tropospheric ozone profile measurements above midlatitude North America during the IONS/ICARTT campaign: Evidence for stratospheric input

Author

Tarasick, D. W., primary, Moran, M. D., additional, Thompson, A. M., additional, Carey‐Smith, T., additional, Rochon, Y., additional, Bouchet, V. S., additional, Gong, W., additional, Makar, P. A., additional, Stroud, C., additional, Ménard, S., additional, Crevier, L.‐P., additional, Cousineau, S., additional, Pudykiewicz, J. A., additional, Kallaur, A., additional, Moffet, R., additional, Ménard, R., additional, Robichaud, A., additional, Cooper, O. R., additional, Oltmans, S. J., additional, Witte, J. C., additional, Forbes, G., additional, Johnson, B. J., additional, Merrill, J., additional, Moody, J. L., additional, Morris, G., additional, Newchurch, M. J., additional, Schmidlin, F. J., additional, and Joseph, E., additional

Published
2007
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20. Assessment of an ensemble of seven real‐time ozone forecasts over eastern North America during the summer of 2004

Author

McKeen, S., primary, Wilczak, J., additional, Grell, G., additional, Djalalova, I., additional, Peckham, S., additional, Hsie, E.‐Y., additional, Gong, W., additional, Bouchet, V., additional, Menard, S., additional, Moffet, R., additional, McHenry, J., additional, McQueen, J., additional, Tang, Y., additional, Carmichael, G. R., additional, Pagowski, M., additional, Chan, A., additional, Dye, T., additional, Frost, G., additional, Lee, P., additional, and Mathur, R., additional

Published
2005
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21. A simple method to improve ensemble‐based ozone forecasts

Author

Pagowski, M., primary, Grell, G. A., additional, McKeen, S. A., additional, Dévényi, D., additional, Wilczak, J. M., additional, Bouchet, V., additional, Gong, W., additional, McHenry, J., additional, Peckham, S., additional, McQueen, J., additional, Moffet, R., additional, and Tang, Y., additional

Published
2005
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22. Real-Time Regional Air Quality Modelling in Support of the ICARTT 2004 Campaign.

Author

Borrego, Carlos, Norman, Ann-Lise, Bouchet, V. S., Ménard, S., Gaudreault, S., Cousineau, S., Moffet, R., Crevier, L. -P., Gong, W., Makar, P. A., Moran, M. D., and Pabla, B.

Abstract

During the summer of 2004, the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) coordinated the largest field study related to air quality so far. Over 500 scientists from 5 different countries, 11 planes, 1 ship, 2 satellites and numerous ground sites were involved in characterizing the emissions of particulate matter (PM), ozone and their precursors, their chemical transformations, and their removal during transport to and over the North Atlantic and into Europe. The study was organized around three main objectives: characterizing the regional air quality in eastern North America; assessing the export of smog related air pollution from eastern North America and its evolution as it travels towards Europe; and assessing the possible effects of the PM associated with the smog on our climate. [ABSTRACT FROM AUTHOR]

Published
2006
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26. Measurement of ambient aerosols in northern Mexico City by single particle mass spectrometry

Author

Moffet, R. C., Foy, B., Molina, L. T., Molina, M. J., and Kimberly Prather

Subjects
lcsh:Chemistry, lcsh:QD1-999, lcsh:Physics, lcsh:QC1-999
Abstract

Continuous ambient measurements with aerosol time-of-flight mass spectrometry (ATOFMS) were made in an industrial/residential section in the northern part of Mexico City as part of the Mexico City Metropolitan Area-2006 campaign (MCMA-2006). Results are presented for the period of 15–27 March 2006. The submicron size mode contained both fresh and aged biomass burning, aged organic carbon (OC) mixed with nitrate and sulfate, elemental carbon (EC), nitrogen-organic carbon, industrial metal, and inorganic NaK inorganic particles. Overall, biomass burning and aged OC particle types comprised 40% and 31%, respectively, of the submicron mode. In contrast, the supermicron mode was dominated by inorganic NaK particle types (42%) which represented a mixture of dry lake bed dust and industrial NaK emissions mixed with soot. Additionally, aluminosilicate dust, transition metals, OC, and biomass burning contributed to the supermicron particles. Early morning periods (2–6 a.m.) showed high fractions of inorganic particles from industrial sources in the northeast, composed of internal mixtures of Pb, Zn, EC and Cl, representing up to 73% of the particles in the 0.2–3μm size range. A unique nitrogen-containing organic carbon (NOC) particle type, peaking in the early morning hours, was hypothesized to be amines from local industrial emissions based on the time series profile and back trajectory analysis. A strong dependence on wind speed and direction was observed in the single particle types that were present during different times of the day. The early morning (3:30–10 a.m.) showed the greatest contributions from industrial emissions. During mid to late mornings (7–11 a.m.), weak northerly winds were observed along with the most highly aged particles. Stronger winds from the south picked up in the late morning (after 11 a.m.), resulting in a decrease in the concentrations of the major aged particle types and an increase in the number fraction of fresh biomass particles. The highest wind speeds were correlated with the highest number fraction of fresh biomass particles (up to 76% of the submicron number fraction) when winds were coming directly from fires that were located south and southeast of the city based on MODIS fire count data. This study provides a unique clock of hourly changes in single particle mixing state and sources as a function of meteorology in Mexico City. These new findings indicate that biomass burning and industrial emissions can make significant contributions to primary particle loadings in Mexico City that are strongly coupled with local meteorology.

29. Evaluation of several PM2.5forecast models using data collected during the ICARTT/NEAQS 2004 field study

Author

McKeen, S., Chung, S. H., Wilczak, J., Grell, G., Djalalova, I., Peckham, S., Gong, W., Bouchet, V., Moffet, R., Tang, Y., Carmichael, G. R., Mathur, R., and Yu, S.

Abstract

Real‐time forecasts of PM2.5aerosol mass from seven air quality forecast models (AQFMs) are statistically evaluated against observations collected in the northeastern United States and southeastern Canada from two surface networks and aircraft data during the summer of 2004 International Consortium for Atmospheric Research on Transport and Transformation (ICARTT)/New England Air Quality Study (NEAQS) field campaign. The AIRNOW surface network is used to evaluate PM2.5aerosol mass, the U.S. EPA STN network is used for PM2.5aerosol composition comparisons, and aerosol size distribution and composition measured from the NOAA P‐3 aircraft are also compared. Statistics based on midday 8‐hour averages, as well as 24‐hour averages are evaluated against the AIRNOW surface network. When the 8‐hour average PM2.5statistics are compared against equivalent ozone statistics for each model, the analysis shows that PM2.5forecasts possess nearly equivalent correlation, less bias, and better skill relative to the corresponding ozone forecasts. An analysis of the diurnal variability shows that most models do not reproduce the observed diurnal cycle at urban and suburban monitor locations, particularly during the nighttime to early morning transition. While observations show median rural PM2.5levels similar to urban and suburban values, the models display noticeably smaller rural/urban PM2.5ratios. The ensemble PM2.5forecast, created by combining six separate forecasts with equal weighting, is also evaluated and shown to yield the best possible forecast in terms of the statistical measures considered. The comparisons of PM2.5composition with NOAA P‐3 aircraft data reveals two important features: (1) The organic component of PM2.5is significantly underpredicted by all the AQFMs and (2) those models that include aqueous phase oxidation of SO2to sulfate in clouds overpredict sulfate levels while those AQFMs that do not include this transformation mechanism underpredict sulfate. Errors in PM2.5ammonium levels tend to correlate directly with errors in sulfate. Comparisons of PM2.5composition with the U.S. EPA STN network for three of the AQFMs show that sulfate biases are consistently lower at the surface than aloft. Recommendations for further research and analysis to help improve PM2.5forecasts are also provided.

Published
2007
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