Subkilometer Numerical Weather Prediction in an Urban Coastal Area: A Case Study over the Vancouver Metropolitan Area

Leroyer, Sylvie; Bélair, Stéphane; Husain, Syed Zahid; Mailhot, Jocelyn

doi:10.1175/jamc-d-13-0202.1

Cited by 57 publications

(52 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Never the less, this result could reflect the local area's characteristics (flat terrain, situated away from the coast) confirming previous studies Valari and Menut, 2008). In regions with more complex topography or those close to the coast, the resolution of the meteorological input could have a profound effect on the simulated meteorological conditions (Leroyer et al, 2014). We note here that the refinement in the resolution of the meteorological model from 0.5 to 0.1 • may not be sufficient for the CTM to simulate noticeable concentration responses.…”

Section: Sensitivity To the Resolution Of The Meteorological Input (Esupporting

confidence: 86%

“…We note here that the refinement in the resolution of the meteorological model from 0.5 to 0.1 • may not be sufficient for the CTM to simulate noticeable concentration responses. For example Leroyer et al (2014) (see also references therein) observed that substantial changes in vertical and horizontal transport in an urban environment occurred mostly in the transition from resolutions of 2.5 to 1 km and even higher (250 m).…”

Section: Sensitivity To the Resolution Of The Meteorological Input (Ementioning

confidence: 99%

“…When the volume of these cells is large compared to the characteristic time scale of these processes, sub-grid scale errors occur such as over-dilution of emissions leading to unrealistic representation of urban-scale chemistry such as ozone titration. The resolution of meteorological modeling is another issue: Leroyer et al (2014) argue that only high-resolution meteorological modeling can correctly capture the urban heat island, also Flagg and Taylor (2011) showed that high-resolution modeling is very much dependent on the resolution of the surface layer input data.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Climate-forced air-quality modeling at the urban scale: sensitivity to model resolution, emissions and meteorology

Markakis

Valari

Perrussel³

et al. 2015

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. While previous research helped to identify and prioritize the sources of error in air-quality modeling due to anthropogenic emissions and spatial scale effects, our knowledge is limited on how these uncertainties affect climateforced air-quality assessments. Using as reference a 10-year model simulation over the greater Paris (France) area at 4 km resolution and anthropogenic emissions from a 1 km resolution bottom-up inventory, through several tests we estimate the sensitivity of modeled ozone and PM 2.5 concentrations to different potentially influential factors with a particular interest over the urban areas. These factors include the model horizontal and vertical resolution, the meteorological input from a climate model and its resolution, the use of a top-down emission inventory, the resolution of the emissions input and the post-processing coefficients used to derive the temporal, vertical and chemical split of emissions. We show that urban ozone displays moderate sensitivity to the resolution of emissions (∼ 8 %), the post-processing method (6.5 %) and the horizontal resolution of the air-quality model (∼ 5 %), while annual PM 2.5 levels are particularly sensitive to changes in their primary emissions (∼ 32 %) and the resolution of the emission inventory (∼ 24 %). The air-quality model horizontal and vertical resolution have little effect on model predictions for the specific study domain. In the case of modeled ozone concentrations, the implementation of refined input data results in a consistent decrease (from 2.5 up to 8.3 %), mainly due to inhibition of the titration rate by nitrogen oxides. Such consistency is not observed for PM 2.5 . In contrast this consistency is not observed for PM 2.5 . In addition we use the results of these sensitivities to explain and quantify the discrepancy between a coarse (∼ 50 km) and a fine (4 km) resolution simulation over the urban area. We show that the ozone bias of the coarse run (+9 ppb) is reduced by ∼ 40 % by adopting a higher resolution emission inventory, by 25 % by using a post-processing technique based on the local inventory (same improvement is obtained by increasing model horizontal resolution) and by 10 % by adopting the annual emission totals of the local inventory. The bias of PM 2.5 concentrations follows a more complex pattern, with the positive values associated with the coarse run (+3.6 µg m −3 ), increasing or decreasing depending on the type of the refinement. We conclude that in the case of fine particles, the coarse simulation cannot selectively incorporate local-scale features in order to reduce its error.

show abstract

Section: Sensitivity To the Resolution Of The Meteorological Input (Esupporting

confidence: 86%

Section: Sensitivity To the Resolution Of The Meteorological Input (Ementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Climate-forced air-quality modeling at the urban scale: sensitivity to model resolution, emissions and meteorology

Markakis

Valari

Perrussel³

et al. 2015

Atmos. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…While we present the mean thermal characteristics of the coastal-urban environment here, additional work is necessary to study the turbulent transport of heat, momentum and moisture within the coastal-urban boundary layer. Current numerical weather prediction models used in the study of the urban boundary layer (e.g., Leroyer et al 2014;Gutiérrez et al 2015b;Ortiz et al 2016;Ramamurthy et al 2017b) lack a realistic representation of urban-coastal interactions, since boundary-layer parametrizations are unable to reproduce the thermal internal boundary layers observed. More effort and sustained observations are necessary to improve the predictability of the thermal conditions in the coastal-urban environment.…”

Section: Discussionmentioning

confidence: 99%

Thermal Structure of a Coastal–Urban Boundary Layer

Melecio-Vázquez

Ramamurthy

Arend

et al. 2018

Boundary-Layer Meteorol

View full text Add to dashboard Cite

We use various temperature profilers located in and around New York City to observe the structure and evolution of the thermal boundary layer. The primary focus is to highlight the spatial variability of potential-temperature profiles due to heterogeneous surface forcing in an urban environment during different flow conditions. Overall, the observations during the summer period reveal the presence of thermal internal boundary layers due to the interaction between the marine atmospheric boundary layer and the convective urban environment. The summer daytime potential-temperature profiles within the city indicate a superadiabatic layer is present near the surface beneath a mildly stable layer. Large spatial variability in the near-surface (0-300 m) potential temperature is detected, with the thermal profile in the lower atmosphere uniquely determined by the underlying surface forcing and the distance from the coast. The summer and winter average night-time potential-temperature profiles show that the atmosphere is still convective near the surface. The seasonal averages of mixing ratio show large variability in the vertical direction.Keywords Coastal boundary layer · Microwave radiometer · Moisture boundary layer · Thermal boundary layer · Urban boundary layer

show abstract

“…In comparison with aerosol backscatter in the boundary layer derived from lidar and CL31 measurements (McKendry et al, 2009;Tsaknakis et al, 2011) or from different ceilometers (Haeffelin et al, 2011), water vapor absorption was not considered, which is not critical as long as only mixing layer heights (e.g. Leroyer et al, 2013;Young and Whiteman, 2015) or cloud base heights (e.g. Martucci et al, 2010) are determined.…”

Section: Introductionmentioning

confidence: 99%

Correction of water vapor absorption for aerosol remote sensing with ceilometers

Wiegner

Gasteiger

2015

Atmos. Meas. Tech.

View full text Add to dashboard Cite

Abstract. In recent years attention was increasingly paid to backscatter profiles of ceilometers as a new source of aerosol information. Several case studies have shown that -although originally intended for cloud detection only -ceilometers can provide the planetary boundary layer height and even quantitative information such as the aerosol backscatter coefficient β p , provided that the signals have been calibrated. It is expected that the retrieval of aerosol parameters will become widespread as the number of ceilometers is steadily increasing, and continuous and unattended operation is provided. In this context however one should be aware of the fact that the majority of ceilometers provides signals that are influenced by atmospheric water vapor. As a consequence, profiles of aerosol parameters can only be retrieved if water vapor absorption is taken into account. In this paper we describe the influence of water vapor absorption on ceilometer signals at wavelengths around λ = 910 nm. Spectrally high-resolved absorption coefficients are calculated from HITRAN on the basis of realistic emission spectra of ceilometers. These results are used as a reference to develop a methodology ("WAPL") for routine and near-real time corrections of the water vapor influence. Comparison of WAPL with the reference demonstrates its very high accuracy. Extensive studies with simulations based on measurements reveal that the error when water vapor absorption is ignored in the β p -retrieval can be in the order of 20 % for mid-latitudes and more than 50 % for the tropics. It is concluded that the emission spectrum of the laser source should be provided by the manufacturer to increase the accuracy of WAPL, and that 910 nm is better suited than 905 nm. With WAPL systematic errors can be avoided, that would exceed the inherent errors of the Klett solutions by far.

show abstract

Subkilometer Numerical Weather Prediction in an Urban Coastal Area: A Case Study over the Vancouver Metropolitan Area

Cited by 57 publications

References 70 publications

Climate-forced air-quality modeling at the urban scale: sensitivity to model resolution, emissions and meteorology

Climate-forced air-quality modeling at the urban scale: sensitivity to model resolution, emissions and meteorology

Thermal Structure of a Coastal–Urban Boundary Layer

Correction of water vapor absorption for aerosol remote sensing with ceilometers

Contact Info

Product

Resources

About