Assessment of WRF/Chem Simulated Vertical Distributions of Particulate Matter from the 2009 Minto Flats South Wildfire in Interior Alaska by CALIPSO Total Backscatter and Depolarization Measurements

Madden, James M.; Mölders, Nicole; Sassen, Kenneth

doi:10.4236/ojap.2015.43012

Cited by 5 publications

(6 citation statements)

References 60 publications

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“…These discrepancies can be explained by the timelag between the WRF/Chem cross-sections and the overestimation of wind-speeds. The offsets were of similar magnitude as those found by [47] in another subarctic study. Comparison of WRF/Chem vertical-integrated horizontal distributions of smoke extend with MODIS data (e.g.…”

Section: Discussionsupporting

confidence: 88%

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Theoretical Investigations on Mapping Mean Distributions of Particulate Matter, Inert, Reactive, and Secondary Pollutants from Wildfires by Unmanned Air Vehicles (UAVs)

Mölders¹,

Butwin²,

Madden³

et al. 2015

OJAP

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Evaluated Weather Research and Forecasting model inline with chemistry (WRF/Chem) simulations of the 2009 Crazy Mountain Complex wildfire in Interior Alaska served as a testbed for typical Alaska wildfire-smoke conditions. A virtual unmanned air vehicle (UAV) sampled temperatures, dewpoint temperatures, primary inert and reactive gases and particular matter of different sizes as well as secondary pollutants from the WRF/Chem results using different sampling patterns, altitudes and speeds to investigate the impact of the sampling design on obtained mean distributions. In this experimental design, the WRF/Chem data served as the "grand truth" to assess the mean distributions from sampling. During frontal passage, the obtained mean distributions were sensitive to the flight patterns, speeds and heights. For inert constituents mean distributions from sampling agreed with the "grand truth" within a factor of two at 1000 m. Mean distributions of gases involved in photochemistry differed among flight patterns except for ozone. The diurnal cycle of these gases' concentrations led to overestimation (underestimation) of 20 h means in areas of high (low) concentrations as compared to the "grand truth." The mean ozone distribution was sensitive to the speed of the virtual UAV. Particulate matter showed the strongest sensitivity to the flight patterns, especially during precipitation. N. Mölders et al.

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Section: Discussionsupporting

confidence: 88%

“…In the interpretation of the CALIPSO data, we used the same considerations and thresholds as [46] [47]. In theory, perfectly spherical particles show no backscattering in the perpendicular, or orthogonal plane, while irregular shapes cause perpendicular backscattering [43] [48].…”

Section: Discussionmentioning

confidence: 99%

Theoretical Investigations on Mapping Mean Distributions of Particulate Matter, Inert, Reactive, and Secondary Pollutants from Wildfires by Unmanned Air Vehicles (UAVs)

Mölders¹,

Butwin²,

Madden³

et al. 2015

OJAP

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“…In 2017, Beaver's air quality was influenced by a wildfire to the southwest in July, and by the Canadian Border fire to the north in September (cf. The NAAQS was exceeded on six consecutive days in July (12)(13)(14)(15)(16)(17), and on three consecutive days in August (15)(16)(17) as well as September (6)(7)(8) (Figure 8 (Table 2).…”

Section: Beavermentioning

confidence: 99%

Particulate Matter Exposure of Rural Interior Communities as Observed by the First Tribal Air Quality Network in the Yukon Flat

Edwin¹,

Mölders²

2018

JEP

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A tribal-owned network of aerosol monitors and meteorological stations was installed at Ts'aahudaaneekk'onh Denh (Beaver), Gwichyaa Zheh (Fort Yukon), Jałgiitsik (Chalkyitsik), and Danzhit Khànląįį (Circle) in the Yukon Flats, Alaska. Surface inversions occurred under calm wind conditions due to radiative cooling. In May, local emissions governed air quality with worst conditions related to road and river dust. As the warm season progressed, worst air quality was due to transport of pollutants from upwind wildfires. During situations without smoke or when smoke existed at layers above the surface inversion, concentrations of particulate matter of less than 2.5 micrometer in diameter or less (PM 2.5) were explainable by the local emissions; 24-h means remained below 25 μg•m −3. Absorption of solar radiation in the smoke layer and upward scattering enhanced stability and fostered the persistence of the surface inversions. During smoke episodes without the presence of a surface inversion, daily mean concentrations exceeded 35 μg•m −3 often for several consecutive days, at all sites. Then concentrations temporally reached levels considered unhealthy.

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“…Higher altitudes of wildfire smoke in the model than the observations have also been reported in the previous studies [ Madden et al ., ; Archer‐Nicholls et al ., ], which are generally associated with plume injection height, convective transport, deposition and dispersion process, vertical resolution of the model, and the assumption of a daily constant emission rates of wildfires at the same location [ Val Martin et al ., ; Colarco et al ., ; Kipling et al ., ]. Having aerosol injected into the wrong portion of the vertical column can have many implications; e.g., it can impact the simulated ground‐level air quality [ Colarco et al ., ] and the atmospheric heating rates at different altitudes.…”

Section: Resultsmentioning

confidence: 99%

An agricultural biomass burning episode in eastern China: Transport, optical properties, and impacts on regional air quality

Han

Voulgarakis

et al. 2017

JGR Atmospheres

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Agricultural biomass burning (ABB) has been of particular concern due to its influence on air quality and atmospheric radiation, as it produces large amounts of gaseous and aerosol emissions. This paper presents an integrated observation of a significant ABB episode in Nanjing, China, during early June 2011, using combined ground‐based and satellite sensors (Moderate Resolution Imaging Spectroradiometer, Atmospheric Infrared Sounder, Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), and Ozone Monitoring Instrument products). The time‐height distribution, optical properties, sources and transport of smoke, and its impacts on air quality are investigated. Lidar profiles indicate that the smoke aerosols are confined to the planetary boundary layer (PBL) and have a depolarization ratio of less than 0.08. The aerosol optical depths increase from 0.5 to 3.0 at 500 nm, while the extinction‐related Angstrom exponent increases from 1.1 to 1.6 at the wavelength pair of 440–870 nm. The single‐scattering albedo becomes lower at 670–1020 nm following the ABB intrusion and particularly shows a decreasing tendency between wavelengths of 440 to 1020 nm. The absorption Angstrom exponent (0.7) is smaller than 1.0, which may indicate the aged smoke particles mixed or coated with the urban aerosols. Surface particular matter PM10 and PM2.5 show a dramatic increase, reaching hourly mean of 800 µg/m3 and 485 µg/m3, respectively, which results in a heavy air pollution event. The stagnant and high‐moisture weather provides favorable conditions for the aerosols to accumulate near the surface. Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) also illustrate that the large‐scale aerosols are primarily present in the PBL and transported to the ocean, but some dense smoke plumes are misclassified as cloud or polluted dust. By comparing with the observations, we found that the Weather Research and Forecasting–Chemistry model captured the accumulation and downwind transport of surface PM2.5 from 20:00 on 2 June to 10:00 on 3 June (phase 1) but showed a dramatic underestimate from 20:00 on 3–4 June (phase 2) when dense aerosols are present. Such a discrepancy in the model is associated with the improper vertical apportion of transported smoke and atmospheric diffusion conditions when comparing with the observed aerosol and wind profiles. In addition, the model simulations indicate that the transported smoke can contribute to 50–70% of the ground‐level PM2.5 in Nanjing.

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Assessment of WRF/Chem Simulated Vertical Distributions of Particulate Matter from the 2009 Minto Flats South Wildfire in Interior Alaska by CALIPSO Total Backscatter and Depolarization Measurements

Abstract: J. M. Madden et al.120

Cited by 5 publications

References 60 publications

Theoretical Investigations on Mapping Mean Distributions of Particulate Matter, Inert, Reactive, and Secondary Pollutants from Wildfires by Unmanned Air Vehicles (UAVs)

Theoretical Investigations on Mapping Mean Distributions of Particulate Matter, Inert, Reactive, and Secondary Pollutants from Wildfires by Unmanned Air Vehicles (UAVs)

Particulate Matter Exposure of Rural Interior Communities as Observed by the First Tribal Air Quality Network in the Yukon Flat

An agricultural biomass burning episode in eastern China: Transport, optical properties, and impacts on regional air quality

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