Wildfire smoke transport and impact on air quality observed by a mullti-wavelength elastic-raman lidar and ceilometer in New York city (original) (raw)
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Transport of Canadian forest fire smoke over the UK as observed by lidar
Atmospheric Chemistry and Physics
Layers of aerosol at heights between 2 and 11 km were observed with Raman lidars in the UK between 23 and 31 May 2016. A network of these lidars, supported by ceilometer observations, is used to map the extent of the aerosol and its optical properties. Space-borne lidar profiles show that the aerosol originated from forest fires over western Canada around 17 May, and indeed the aerosol properties-weak volume depolarisation (< 5 %) and a lidar ratio at 355 nm in the range 35-65 sr-were consistent with longrange transport of forest fire smoke. The event was unusual in its persistence-the smoke plume was drawn into an atmospheric block that kept it above northwestern Europe for 9 days. Lidar observations show how the smoke layers became optically thinner during this period, but the lidar ratio and aerosol depolarisation showed little change. The results demonstrate the value of a dense network of observations for tracking forest fire smoke, and show how the dispersion of smoke in the free troposphere leads to the emergence of discrete thin layers in the far field. They also show how atmospheric blocking can keep a smoke plume in the same geographic area for over a week.
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.
Stratospheric Smoke Properties Based on Lidar Observations in Autumn 2017 Over Warsaw
EPJ Web of Conferences, 2020
Smoke layers in the stratosphere were observed during autumn 2017 using PollyXT-UW Raman lidar at the European Aerosol Research Lidar Network in the frame of the Aerosol Cloud and Trace Gases Research Infrastructure, i.e. the EARLINET-ACTRIS site in Warsaw, Poland. The analysis was focused on discriminating very weak signatures of smoke layers in the stratosphere and investigating their optical properties. Preliminary results are presented and discussed. A decrease of the lidar-derived stratospheric aerosol optical depth contribution to the total optical depth was detected after the stratospheric smoke particles circled Northern Hemisphere.
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.
Lidar Measurements of Canadian Forest Fire Smoke Episode Observed in July 2013 over Warsaw, Poland
EPJ Web of Conferences, 2016
This paper presents a preliminary study of aerosol optical properties of air-mass advected on 10 th July 2013 from Canada above Warsaw, Poland, during the forest fire event that occurred in Quebec at the beginning of July 2013. The observations were conducted with use of the modern version of 8-channel Polly XT lidar capable of measuring at 3+2+2+VW and interpreted with available information from the MACC model, the CALIPSO and MODIS satellite sensors, the AERONET data products and the data gathered within the Poland-AOD network.
Among the atmospheric emission sources, wildfires are episodic events characterized by large spatial and temporal variability. Therefore, accurate information on gaseous and aerosol emissions from fires for specific regions and seasons is critical for air quality forecasts. The Spinning Enhanced Visible and Infrared Imager (SEVIRI) in geostationary orbit provides fire observations over Africa and the Mediterranean with a temporal resolution of 15 min. It thus resolves the complete fire life cycle and captures the fires' peak intensities, which is not possible in Moderate Resolution Imaging Spectroradiometer (MODIS) fire emission inventories like the Global Fire Assimilation System (GFAS). We evaluate two different operational fire radiative power (FRP) products derived from SEVIRI, by studying a large forest fire in Antalya, Turkey, in July-August 2008. The EUMETSAT Land Surface Analysis Satellite Applications Facility (LSA SAF) has higher FRP values during the fire episode than the Wildfire Automated Biomass Burning Algorithm (WF_ABBA). It is also in better agreement with the co-located, gridded MODIS FRP. Both products miss small fires that frequently occur in the region and are detected by MODIS. Emissions are derived from the FRP products. They are used along-side GFAS emissions in smoke plume simulations with the Weather Research and Forecasting (WRF) model and the Community Multiscale Air Quality (CMAQ) model. In comparisons with MODIS aerosol optical thickness (AOT) and Infrared Atmospheric Sounding Interferometer (IASI), CO and NH 3 observations show that including the diurnal variability of fire emissions improves the spatial distribution and peak concentrations of the simulated smoke plumes associated with this large fire. They also show a large discrepancy between the currently available operational FRP products, with the LSA SAF being the most appropriate.
Journal of Geophysical Research, 2004
1] Smoke and pollutants from Canadian forest fires are sometimes transported over the United States at low altitudes behind advancing cold fronts. An unusual event occurred in July 2002 in which smoke from fires in Quebec was observed by satellite, lidar, and aircraft to arrive over the Washington, D.C., area at high altitudes. This elevated smoke plume subsequently mixed to the surface as it was entrained into the turbulent planetary boundary layer and had adverse effects on the surface air quality over the region. Trajectory and three-dimensional model calculations confirmed the origin of the smoke, its transport at high altitudes, and the mechanism for bringing the pollutants to the surface. Additionally, the modeled smoke optical properties agreed well with aircraft and remote sensing observations provided the smoke particles were allowed to age by coagulation in the model. These results have important implications for the long-range transport of pollutants and their subsequent entrainment to the surface, as well as the evolving optical properties of smoke from boreal forest fires.
Detection and simulation of wildfire smoke impacting a Mediterranean urban atmosphere
Atmospheric Pollution Research, 2015
The combined use of chemical analysis of organic molecules in atmospheric aerosols (PM1) collected in situ in Barcelona and optical measurements with a light detection and ranging (LIDAR) instrument allowed the characterization of the smoke plume from a wildfire that reached the city in July 2012. A Lagrangian particle dispersion model (FLEXPART) was applied to simulate the smoke plume and to compare the results with in-situ data. The chemical composition of the aerosols collected on 23 July 2012 confirmed the large contribution of biomass burning in the urban air during several hours by the increase of compounds, such as levoglucosan, dehydroabietic acid and polycyclic aromatic hydrocarbons (PAH), which was coincident with an increase of the aerosol density in the boundary layer (BL). According to air-mass trajectory modelling, the origin of the biomass burning particles was