Modeling of the Coastal Boundary Layer and Pollutant Transport in New England

Angevine, W. M.; Tjernström, Michael; Žagar, Mark

doi:10.1175/jam2333.1

Cited by 35 publications

(38 citation statements)

References 29 publications

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“…Bosveld and Beyrich 2004). Such results have important implications for dispersion calculations in the stably stratified boundary layer (Angevine et al 2006). The directional shear in the lowest layers of the atmosphere is often also underestimated in models, which is important for plume spread (e.g.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Model Results for the Turning of the Wind and Related Momentum Fluxes in the Stable Boundary Layer

Svensson

Holtslag

2009

Boundary-Layer Meteorol

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The turning of wind with height and the related cross-isobaric (ageostrophic) flow in the thermally stable stratified boundary layer is analysed from a variety of model results acquired in the first Global Energy and Water Cycle Experiment (GEWEX) Atmospheric Boundary Layer Study (GABLS1). From the governing equations in this particular simple case it becomes clear that the cross-isobaric flow is solely determined by the surface turbulent stress in the direction of the geostrophic wind for the quasi-steady state conditions under consideration. Most models indeed seem to approach this relationship but for very different absolute values. Because turbulence closures used in operational models typically tend to give too deep a boundary layer, the integrated total cross-isobaric mass flux is up to three times that given by research numerical models and large-eddy simulation. In addition, the angle between the surface and the geostrophic wind is typically too low, which has important implications for the representation of the larger-scale flow. It appears that some models provide inconsistent results for the surface angle and the momentum flux profile, and when the results from these models are removed from the analysis, the remaining ten models do show a unique relationship between the boundary-layer depth and the surface angle, consistent with the theory given. The present results also imply that it is beneficial to locate the first model level rather close to the surface for a proper representation of the turning of wind with height in the stable boundary layer.

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Section: Introductionmentioning

confidence: 99%

Analysis of Model Results for the Turning of the Wind and Related Momentum Fluxes in the Stable Boundary Layer

Svensson

Holtslag

2009

Boundary-Layer Meteorol

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“…Daum et al, 1996;Angevine et al, 1996Angevine et al, , 2004. Angevine et al (2006) examined meteorological characteristics and associated transport processes over the northeastern US using a three-dimensional meteorological model in which the New York City and Boston emissions were considered as tracers. They also attributed model-measurement discrepancies and the difficulty of simulating stable boundary layers to atmospheric boundary layer (ABL) processes.…”

Section: Introductionmentioning

confidence: 99%

Modeling ozone plumes observed downwind of New York City over the North Atlantic Ocean during the ICARTT field campaign

et al. 2011

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Abstract. Transport and chemical transformation of welldefined New York City (NYC) urban plumes over the North Atlantic Ocean were studied using aircraft measurements collected on 20-21 July 2004 during the ICARTT (International Consortium for Atmospheric Research on Transport and Transformation) field campaign and WRF-Chem (Weather Research and Forecasting-Chemistry) model simulations. The strong NYC urban plumes were characterized by carbon monoxide (CO) mixing ratios of 350-400 parts per billion by volume (ppbv) and ozone (O 3 ) levels of about 100 ppbv near New York City on 20 July in the WP-3D in-situ and DC-3 lidar aircraft measurements. On 21 July, the two aircraft captured strong urban plumes with about 350 ppbv CO and over 150 ppbv O 3 (∼160 ppbv maximum) about 600 km downwind of NYC over the North Atlantic Ocean. The measured urban plumes extended vertically up to about 2 km near New York City, but shrank to 1-1.5 km over the stable marine boundary layer (MBL) over the North Atlantic Ocean. The WRF-Chem model reproduced ozone formation processes, chemical characteristics, and meteorology of the measured urban plumes near New York City (20 July) and in the far downwind region over the North Atlantic Ocean (21 July). The quasi-Lagrangian analysis of transport and chemical transformation of the simulated NYC urban plumes using WRF-Chem results showed that the pollutants can be efficiently transported in (isentropic) layers in the lower atmosphere (<2-3 km) over the Correspondence to: S.-H. Lee (nihil93@snu.ac.kr) North Atlantic Ocean while maintaining a dynamic vertical decoupling by cessation of turbulence in the stable MBL. The O 3 mixing ratio in the NYC urban plumes remained at 80-90 ppbv during nocturnal transport over the stable MBL, then grew to over 100 ppbv by daytime oxidation of nitrogen oxides (NO x = NO + NO 2 ) with mixing ratios on the order of 1 ppbv. Efficient transport of reactive nitrogen species (NO y ), specifically nitric acid (HNO 3 ), was confirmed through the comparison of the CO/NO y ratio in photochemically fresh and aged NYC plumes, implying the possibility of long-range transport of O 3 over the stable MBL over the North Atlantic Ocean in association with NO x regeneration mechanism. The impact of chemical initial and boundary conditions (IC/BCs) on modelled O 3 urban plumes was investigated in terms of the background O 3 level and the vertical structure of the urban plumes. Simulations with dynamic ("time-variant") chemical IC/BCs enhanced the O 3 level by 2-12 ppbv on average in the atmospheric layer below 3 km, showing better agreement with the observed NYC plumes and biomass-burning plumes than the simulation with prescribed static IC/BCs. The simulation including MOZART-4 chemical IC/BCs and Alaskan/Canadian wildfire emissions compared better to the observed O 3 profiles in the upper atmospheric layer (>∼3 km) than models that only accounted for North American anthropogenic/biogenic and wildfire contributions to background ozone. The comparison between models and observat...

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“…1. Advective processes include transport by the warm and cold conveyor belts associated with frontal systems [ Kowol‐Santen et al , 2001; Donnell et al , 2001; Esler et al , 2003; Agustí‐Panareda et al , 2005], sea breeze circulations and coastal outflow [ Lu and Turco , 1994; Leon et al , 2001; Angevine et al , 2006; Verma et al , 2006] and mountain venting [ Lu and Turco , 1994; Baltensperger et al , 1997; Seibert et al , 1998; Kossmann et al , 1999].…”

Section: Introductionmentioning

confidence: 99%

A case study of boundary layer ventilation by convection and coastal processes

Dacre¹,

Gray²,

Belcher³

2007

J. Geophys. Res.

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[1] It is often assumed that ventilation of the atmospheric boundary layer is weak in the absence of fronts, but is this always true? In this paper we investigate the processes responsible for ventilation of the atmospheric boundary layer during a nonfrontal day that occurred on 9 May 2005 using the UK Met Office Unified Model. Pollution sources are represented by the constant emission of a passive tracer everywhere over land. The ventilation processes observed include shallow convection, turbulent mixing followed by large-scale ascent, a sea breeze circulation and coastal outflow. Vertical distributions of tracer are validated qualitatively with AMPEP (Aircraft Measurement of chemical Processing Export fluxes of Pollutants over the UK) CO aircraft measurements and are shown to agree impressively well. Budget calculations of tracers are performed in order to determine the relative importance of these ventilation processes. Coastal outflow and the sea breeze circulation were found to ventilate 26% of the boundary layer tracer by sunset of which 2% was above 2 km. A combination of coastal outflow, the sea breeze circulation, turbulent mixing and large-scale ascent ventilated 46% of the boundary layer tracer, of which 10% was above 2 km. Finally, coastal outflow, the sea breeze circulation, turbulent mixing, large-scale ascent and shallow convection together ventilated 52% of the tracer into the free troposphere, of which 26% was above 2 km. Hence this study shows that significant ventilation of the boundary layer can occur in the absence of fronts (and thus during high-pressure events). Turbulent mixing and convection processes can double the amount of pollution ventilated from the boundary layer.

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Modeling of the Coastal Boundary Layer and Pollutant Transport in New England

Cited by 35 publications

References 29 publications

Analysis of Model Results for the Turning of the Wind and Related Momentum Fluxes in the Stable Boundary Layer

Analysis of Model Results for the Turning of the Wind and Related Momentum Fluxes in the Stable Boundary Layer

Modeling ozone plumes observed downwind of New York City over the North Atlantic Ocean during the ICARTT field campaign

A case study of boundary layer ventilation by convection and coastal processes

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