The Persistent Cold-Air Pool Study

Lareau, Neil P.; Crosman, Erik T.; Whiteman, C. David; Horel, John D.; Hoch, Sebastian W.; Brown, William O.; Horst, Thomas

doi:10.1175/bams-d-11-00255.1

Cited by 186 publications

(209 citation statements)

References 29 publications

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“…Cold-pool-type inversion layers, occurring within basins and valleys in the western US, have been studied extensively (Banta and Cotton, 1981;Clements et al, 2003;Lareau et al, 2013). Such valley cold pools (VCP) are identified when a radiosonde indicates the presence of an inversion below the maximum crest height of the surrounding mountains, and average wind speeds beneath the inversion top that are less than 5 m s −1 (Reeves and Stensrud, 2009).…”

Section: R Ahmadov Et Al: Understanding High Wintertime Ozone Pollumentioning

confidence: 99%

Understanding high wintertime ozone pollution events in an oil- and natural gas-producing region of the western US

et al. 2015

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Abstract. Recent increases in oil and natural gas (NG) production throughout the western US have come with scientific and public interest in emission rates, air quality and climate impacts related to this industry. This study uses a regionalscale air quality model (WRF-Chem) to simulate high ozone (O 3 ) episodes during the winter of 2013 over the Uinta Basin (UB) in northeastern Utah, which is densely populated by thousands of oil and NG wells. The high-resolution meteorological simulations are able qualitatively to reproduce the wintertime cold pool conditions that occurred in 2013, allowing the model to reproduce the observed multi-day buildup of atmospheric pollutants and the accompanying rapid photochemical ozone formation in the UB.Two different emission scenarios for the oil and NG sector were employed in this study. The first emission scenario (bottom-up) was based on the US Environmental Protection Agency (EPA) National Emission Inventory (NEI) (2011, version 1) for the oil and NG sector for the UB. The second emission scenario (top-down) was based on estimates of methane (CH 4 ) emissions derived from in situ aircraft measurements and a regression analysis for multiple species relative to CH 4 concentration measurements in the UB. Evaluation of the model results shows greater underestimates of CH 4 and other volatile organic compounds (VOCs) in the simulation with the NEI-2011 inventory than in the case when the top-down emission scenario was used. Unlike VOCs, the NEI-2011 inventory significantly overestimates the emissions of nitrogen oxides (NO x ), while the topdown emission scenario results in a moderate negative bias. The model simulation using the top-down emission case captures the buildup and afternoon peaks observed during high O 3 episodes. In contrast, the simulation using the bottomup inventory is not able to reproduce any of the observed high O 3 concentrations in the UB. Simple emission reduction scenarios show that O 3 production is VOC sensitive and NO x insensitive within the UB. The model results show a disproportionate contribution of aromatic VOCs to O 3 formation relative to all other VOC emissions. The model analysis reveals that the major factors driving high wintertime O 3 in the UB are shallow boundary layers with light winds, high emissions of VOCs from oil and NG operations compared to NO x emissions, enhancement of photolysis fluxes and reduction of O 3 loss from deposition due to snow cover.

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Section: R Ahmadov Et Al: Understanding High Wintertime Ozone Pollumentioning

confidence: 99%

Understanding high wintertime ozone pollution events in an oil- and natural gas-producing region of the western US

et al. 2015

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“…Most of these works have in common that the background circulation reduces the relevance of the local effects (Crosman and Horel, 2010). For coastal mountain cities there is, however, also the possibility of an interaction between local circulations such as local breezes and cold air pools (Holmer et al, 1999;Lareau et al, 2013). These local circulations can be either dominating the local circulation forced by the largescale flow or interacting with it.…”

Section: Observational Perspective On Air Pollution In Coastal Citiesmentioning

confidence: 99%

“…Interactions within the cold air pools can be further complicated by other local dynamic effects, such as breeze-like circulations (e.g. Lareau et al, 2013) or up-and down-slope winds (Fernando, 2010). This complexity challenges numerical weather prediction (NWP) models, which often cannot properly resolve and hence predict air pollution episodes, in particular those developing during the periods with strong stable stratification in the lower atmosphere and mountainous terrain (e.g.…”

mentioning

confidence: 99%

Sensitivity of local air quality to the interplay between small- and large-scale circulations: a large-eddy simulation study

Wolf¹,

Esau²,

Reuder

2017

Atmos. Chem. Phys.

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Abstract. Street-level urban air pollution is a challenging concern for modern urban societies. Pollution dispersion models assume that the concentrations decrease monotonically with raising wind speed. This convenient assumption breaks down when applied to flows with local recirculations such as those found in topographically complex coastal areas. This study looks at a practically important and sufficiently common case of air pollution in a coastal valley city. Here, the observed concentrations are determined by the interaction between large-scale topographically forced and local-scale breeze-like recirculations.Analysis of a long observational dataset in Bergen, Norway, revealed that the most extreme cases of recurring wintertime air pollution episodes were accompanied by increased large-scale wind speeds above the valley. Contrary to the theoretical assumption and intuitive expectations, the maximum NO 2 concentrations were not found for the lowest 10 m ERA-Interim wind speeds but in situations with wind speeds of 3 m s −1 . To explain this phenomenon, we investigated empirical relationships between the large-scale forcing and the local wind and air quality parameters. We conducted 16 large-eddy simulation (LES) experiments with the Parallelised Large-Eddy Simulation Model (PALM) for atmospheric and oceanic flows. The LES accounted for the realistic relief and coastal configuration as well as for the large-scale forcing and local surface condition heterogeneity in Bergen. They revealed that emerging local breeze-like circulations strongly enhance the urban ventilation and dispersion of the air pollutants in situations with weak largescale winds. Slightly stronger large-scale winds, however, can counteract these local recirculations, leading to enhanced surface air stagnation.Furthermore, this study looks at the concrete impact of the relative configuration of warmer water bodies in the city and the major transport corridor. We found that a relatively small local water body acted as a barrier for the horizontal transport of air pollutants from the largest street in the valley and along the valley bottom, transporting them vertically instead and hence diluting them. We found that the stable stratification accumulates the street-level pollution from the transport corridor in shallow air pockets near the surface. The polluted air pockets are transported by the local recirculations to other less polluted areas with only slow dilution. This combination of relatively long distance and complex transport paths together with weak dispersion is not sufficiently resolved in classical air pollution models. The findings have important implications for the air quality predictions over urban areas. Any prediction not resolving these, or similar local dynamic features, might not be able to correctly simulate the dispersion of pollutants in cities.

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“…Therefore, the impact of a cold wave on air quality depends on the type of cold wave it is. The first type tends to advect in well-mixed upwind air conditions (e.g., Lee et al, 2012b), while the second type allows local air pollution to accumulate (e.g., Lareau et al, 2013).…”

Section: Cold Waves and Snowmentioning

confidence: 99%

Changes in weather and climate extremes: State of knowledge relevant to air and water quality in the United States

Peterson

Karl

Kossin

et al. 2013

Journal of the Air & Waste Management Association

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Air and water quality are impacted by extreme weather and climate events on time scales ranging from minutes to many months. This review paper discusses the state of knowledge of how and why extreme events are changing and are projected to change in the future. These events include heat waves, cold waves, floods, droughts, hurricanes, strong extratropical cyclones such as nor'easters, heavy rain, and major snowfalls. Some of these events, such as heat waves, are projected to increase, while others, with cold waves being a good example, will decrease in intensity in our warming world. Each extreme's impact on air or water quality can be complex and can even vary over the course of the event.Implications: Because extreme weather and climate events impact air and water quality, understanding how the various extremes are changing and are projected to change in the future has ramifications on air and water quality management.

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The Persistent Cold-Air Pool Study

Cited by 186 publications

References 29 publications

Understanding high wintertime ozone pollution events in an oil- and natural gas-producing region of the western US

Understanding high wintertime ozone pollution events in an oil- and natural gas-producing region of the western US

Sensitivity of local air quality to the interplay between small- and large-scale circulations: a large-eddy simulation study

Changes in weather and climate extremes: State of knowledge relevant to air and water quality in the United States

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