Characterization of forest fire smoke event near Washington, DC in Summer 2013 with multi-wavelength lidar (original) (raw)
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Sola, 2010
Smoke plumes originating from a forest fire in northern Mongolia were observed with a two-wavelength (1064 nm, 532 nm) polarization (532 nm) lidar in Nagasaki at altitudes of 12 to 14 km and 3 to 10 km on June 10, 2007. Smoke from the same region was also observed in Tsukuba with a 532 nm high-spectralresolution lidar (HSRL) at altitudes of 15 to 15.5 km on June 12, 2007. A two-wavelength data analysis method was applied to the Nagasaki data, and the extinction-to-backscatter ratio (the lidar ratio) at 532 nm was estimated to be 65 ± 5 sr (50 ± 5 sr) for the smoke at 12 to 14 km (3.5 to 4.5 km) altitudes. The particle depolarization ratio (PDR) was 0.14 ± 0.03 (0.12 ± 0.03), and the backscatter-related Angstrom exponent (BAE) between 532 nm and 1064 nm was 1.1 ± 0.2 (0.9 ± 0.1) for the high (low) altitude smoke. The optical thickness of the high (low) altitude plume was approximately 1.0 (0.03). The lidar ratio of the smoke in Tsukuba measured with the HSRL at 15 to 15.5 km was 75 ± 5 sr, and the PDR was 0.15 ± 0.04. The optical thickness was 0.03. The lidar ratio was comparable to those reported previously for forest-fire smoke in the lower troposphere. However, the PDR in the present case was two times higher, and the BAE was slightly lower. A possible explanation of the results involves mixing with solid particles such as those of ash and/or mineral dust in the strong convection found with pyrocumulonimbus. A discussion on lidar methods for characterizing smoke aerosols is also provided.
Atmospheric Chemistry and Physics, 2009
The influence of smoke on the aerosol loading in the free troposphere over Thessaloniki, Greece is examined in this paper. Ten cases during 2001-2005 were identified when very high aerosol optical depth values in the free troposphere were observed with a UV-Raman lidar. Particle dispersion modeling (FLEXPART) and satellite hot spot fire detection (ATSR) showed that these high free tropospheric aerosol optical depths are mainly attributed to the advection of smoke plumes from biomass burning regions over Thessaloniki. The biomass burning regions were found to extend across Russia in the latitudinal belt between 45 • N-55 • N, as well as in Eastern Europe (Baltic countries, Western Russia, Belarus, and the Ukraine). The highest frequency of agricultural fires occurred during the summer season (mainly in August). The data collected allowed the optical characterization of the smoke aerosols that arrived over Greece, where limited information has so far been available. Two-wavelength backscatter lidar measurements showed that the backscatter-relatedÅngström exponent ranged between 0.5 and 2.4 indicating a variety of particle sizes. UV-Raman lidar measurements showed that for smoke particles the extinction to backscatter ratios (so-called lidar ratios) varied between 40 sr for small particles to 100 sr for large particles. Dispersion model estimations of the carbon monoxide tracer concentration profiles for smoke particles indicate that the variability of the optical parameters is a function of the age of the smoke Correspondence to: V. Amiridis (vamoir@space.noa.gr) plumes. This information could be useful on the lidar community for reducing uncertainty in the aerosol backscatter coefficient determination due to the lidar ratio assumption, starting from a simply elastic backscatter lidar as the first satellite-borne lidar CALIPSO.
We measured the smoke caused by the Forest Fires at the region of Baikal Lake during May 2003 by the monitoring with a continuous Mie scattering Lidar. The measurement results coincide well with the prediction model of CFORS and NRL. Results show the capability of plume measurements using the Mie scattering Lidar. Through the comparison of the results of smoke measurements with Asian dust measurements, we retrieved the optical characteristics of 532 nm depolarization ratio, 1064/532 nm ratio of backscattering coefficient, and wavelength dependence of 532 nm and 1064 nm backscattering coefficients.
Aerosol plume observations by the ground-based lidar, sunphotometer, and satellite: cases analysis
2009
Smoke and dust aerosol plumes are observed by the ground-based multi-wavelength elastic-Raman lidar, sunphotometer and space-borne lidar CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization). Lidar-derived multi-wavelength aerosol extinction profiles and column lidar ratios are constrained by the independently measured optical depths. The aloft smoke plume layers from Idaho/Montana forest fires were measured at 2~8 km altitude by the ground lidar on Aug. 14~15, 2007. High aerosol optical depths (AOD) are shown with the value of 0.6~0.8 at wavelength 500 nm and Angstrom exponent of 1.8. The CALIOP observations generally show consistent plume height distribution with the ground lidar, but partly misclassify these smoke plumes as clouds. The forest fire sources and intra-continental smoke transport are clearly illustrated by CALIOP and MODIS satellite imageries. For the moderate dust-like plumes on April 18, 2008, they were observed at the altitude of 2~6 km. Aerosol optical depths vary from 0.2 to 0.4 at wavelength 500 nm with Angstrom exponent <1.0 in the plume-layer. Ground-lidar and CALIOP retrievals show the good agreement in dust-like layer heights, extinction profiles and aerosol species classification.
2020
We present retrievals of tropospheric and stratospheric height profiles of particle mass, volume, surface area, and number concentrations in the case of wildfire smoke layers as well as estimates of smoke-related cloud condensation nuclei (CCN) and ice-nucleating particle (INP) concentrations from backscatter lidar measurements on the ground and in space. Conversion factors used to convert the optical measurements into microphysical properties play a central role in the data analysis, in addition to estimates of the smoke extinction-to-backscatter ratios required to obtain smoke extinction coefficients. The set of needed conversion parameters for wildfire smoke is derived from AERONET observations of major smoke events, e.g.
Atmospheric Chemistry and Physics Discussions
The analysis of the aerosol optical properties derived at fine temporal and spatial scales were performed based on measurements obtained during heat wave event in vicinity of a cold weather front in Warsaw on August 9 th-11 th , 2015. The signals collected by the PollyXT-UW lidar allowed for the calculation of 23 sets of so-called 3β+2α+2δ+wv profiles averaged by 30-minutes periods during 2 nights. The total number of 11 different aerosol types and aerosol mixtures were identified with reference to properties within 116 sub-layers in the profiles and were characterized by the mean values. The statistical sample of various optical properties being in agreement for consecutive profiles allowed to assess the spatiotemporal extent of aerosol/mixture types. The mean lidar ratio values of 53-73 sr (355 nm) and 31-45 sr (532 nm) in the layers dominated by the anthropogenic pollution were found. For the layers dominated by the biomass burning aerosol (fresh, moderately fresh, moderately aged) mean lidar ratio was of 69-114 sr (355 nm) and 57-85 sr (532 nm). The colour ratio of lidar ratio (532/355) higher than 1, characteristic for aged biomass burning aerosol, was found only in one scattered layer, accompanying with low value of extinction related Ångström exponent of 0.60±0.32 and low particle depolarization ratio. The maximum of the particle depolarization ratio of 4.8-5.0 % at 532 nm were observed in a layer likely contaminated with pollen and in a layer dominated by fresh biomass burning aerosol. This study provides an excellent data set for exploration of separation algorithms, aerosol typing algorithms and microphysical inversion.
J. Geophys. …, 2004
High spatial and temporal resolution elastic backscatter lidar data from Baltimore are analyzed with a near-end approach to estimate vertical profiles of the aerosol extinction coefficient. The near-end approach makes use of the (1) aerosol scattering coefficient measured at the surface with a nephelometer (0.530 mm), (2) surface level particle size distribution, and (3) refractive index calculated using Mie theory to estimate the aerosol extinction coefficient boundary condition for the lidar equation. There was a broad range of atmospheric turbidity due to a strong haze event, which occurred because of smoke transport from Canadian forest fires, and led to a wide range of observed atmospheric properties. The index of refraction for aerosols estimated during the entire study period is 1.5-0.47 i, which is typical for soot. The measured surface level aerosol scattering coefficient ranged from s p = 0.002 to s p = 0.541 km À1 , and the computed aerosol extinction coefficient spanned values k p = 0.01 to k p = 1.05 km À1. The derived mass concentration and the mass scattering ranges were 3.96-194 mg m À3 and 0.05-3.260 m 2 g À1 , respectively. The aerosol optical properties were dominated by light absorption by soot.
EPJ Web of Conferences
The intense wildfires from the western Canada in May 2016 injected large amount of smoke into the atmosphere. This paper presents integrated observation of the event by a lidar, ceilometer, and satellite together with models and an assessment of smoke plume impacts on local air quality in New York City (NYC) area. A dense aloft plume on May 20 and a boundary layer plume on May 25 are analyzed. The smoke mixing into planetaryboundary-layer (PBL) and strong diurnal variation of PBL-top are shown. For the 2 nd case, the ground PM 2.5 measurements show a significant increase in both the urban and upwind non-urban areas of NYC. The smoke sources and transport paths are further verified by the satellite observations and HYSPLIT model data.
Applied Optics, 2013
Inversion with two-dimensional (2-D) regularization is a new methodology that can be used for the retrieval of profiles of microphysical properties, e.g., effective radius and complex refractive index of atmospheric particles from complete (or sections) of profiles of optical particle properties. The optical profiles are acquired with multiwavelength Raman lidar. Previous simulations with synthetic data have shown advantages in terms of retrieval accuracy compared to our so-called classical one-dimensional (1-D) regularization, which is a method mostly used in the European Aerosol Research Lidar Network (EARLINET). The 1-D regularization suffers from flaws such as retrieval accuracy, speed, and ability for error analysis. In this contribution, we test for the first time the performance of the new 2-D regularization algorithm on the basis of experimental data. We measured with lidar an aged biomass-burning plume over West/Central Europe. For comparison, we use particle in situ data taken in the smoke plume during research aircraft flights upwind of the lidar. We find good agreement for effective radius and volume, surface-area, and number concentrations. The retrieved complex refractive index on average is lower than what we find from the in situ observations. Accordingly, the single-scattering albedo that we obtain from the inversion is higher than what we obtain from the aircraft data. In view of the difficult measurement situation, i.e., the large spatial and temporal distances between aircraft and lidar measurements, this test of our new inversion methodology is satisfactory.
The Multi-wavelength Raman LIDAR (MRL) system was developed to enable a better understanding of the complex properties of aerosols in the atmosphere. In this study, the microphysical, optical, and radiative properties of mixed aerosols were retrieved using the discrete aerosol observation products from the MRL. The dust mixing ratio, which is the proportion of dust particles to the total mixed, was derived using the particle depolarization ratio. It was employed in the retrieval of backscattering and extinction coefficient profiles for dust and non-dust particles. The vertical profiles of aerosol optical properties were then used as input parameters in the inversion algorithm for the retrieval of microphysical parameters including the effective radius, refractive index, and the single scattering albedo (SSA). Those products were successfully applied to an analysis of radiative flux using a radiative transfer model. The relationship between the MRL derived extinction and aerosol radiative forcing (ARF) in short-wavelength was assessed over Gwangju, Korea. The results clearly demonstrate that the MRL-derived extinction profiles are a good surrogate for use in the estimation of optical, microphysical, and radiative properties of aerosols. It is considered that the analytical results shown in this study can be used to provide a better understanding of air quality and the variation of local radiative effects due to aerosols.