Aerosol source plume physical characteristics from space‐based multiangle imaging

Abstract

[1] Models that assess aerosol effects on regional air quality and global climate parameterize aerosol sources in terms of amount, type, and injection height. The multiangle imaging spectroradiometer (MISR) aboard NASA's Terra satellite retrieves total column aerosol optical thickness (AOT), and aerosol type over cloud-free land and water. A stereo-matching algorithm automatically retrieves reflecting-layer altitude wherever clouds or aerosol plumes have discernable spatial contrast, with about 500-m accuracy, at 1.1-km horizontal resolution. Near-source biomass burning smoke, volcanic effluent, and desert dust plumes are observed routinely, providing information about aerosol amount, particle type, and injection height useful for modeling applications. Compared to background aerosols, the plumes sampled have higher AOT, contain particles having expected differences in Angstrom exponent, size, single-scattering albedo, and for volcanic plume and dust cloud cases, particle shape. As basic thermodynamics predicts, thin aerosol plumes lifted only by regional winds or less intense heat sources are confined to the boundary layer. However, when sources have sufficient buoyancy, the representative plumes studied tend to concentrate within discrete, high-elevation layers of local stability; the aerosol is not uniformly distributed up to a peak altitude, as is sometimes assumed in modeling. MISR-derived plume heights, along with meteorological profile data from other sources, make it possible to relate radiant energy flux observed by the moderate resolution imaging spectroradiometer (MODIS), also aboard the Terra spacecraft, to convective heat flux that plays a major role in buoyant plume dynamics. A MISR climatology of plume behavior based on these results is being developed.

Smoke injection heights from agricultural burning in Eastern Europe as seen by CALIPSO

“…In particular, the data scatter could be partly attributed to the fact that the smoke plumes from neighboring fire pixels are probably influencing injection height retrievals at downwind pixels under study. Moreover, the possible presence of dense smoke above the fire area (smoldering versus flaming fires) may lead to underestimates of the FRP values from MODIS due to the emissivity assumed in the retrieval (Kahn et al, 2007). Finally the physical processes including the atmospheric static stability, the vertical wind shears and the horizontal advection, are expected to play an important role adding to the parameters driving the smoke injection.…”

“…This type of information can be directly retrieved by the CALIPSO aerosol layer product which provides a description of the aerosol layers, including their top heights and bottoms. The injection heights of smoke plumes can be also analyzed using stereo-derived plume heights from the Multi-angle Imaging SpectroRadiometer (MISR; Diner et al, 1998), that flies aboard the NASA Earth Observing System's Terra satellite (Kahn et al, 2007;Martin et al, 2009;Mims et al, 2010). The spatial coverage of MISR's multi-angle imaging is vastly greater than that of the CALIPSO lidar, however, CALIPSO lidar is sensitive to the vertical distribution of dispersed aerosol away from sources, where MISR is not (Kahn et al, 2008;Martin et al, 2009;Mims et al, 2010).…”

“…Recently, space-based observations of aerosols have been used for the estimation of smoke injection heights (Labonne et al, 2007;Kahn et al, 2007;Martin et al, 2009;Mims et al, 2010). Attenuated backscatter profiles derived by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite (Winker et al, , 2006(Winker et al, , 2007 can be used to study the vertical structure of smoke aerosols and to define the smoke layer geometrical properties (e.g.…”

Critical evaluation of cloud contamination in the MISR aerosol products using MODIS cloud mask products

“…technique (e.g., Kahn et al, 2007). Note that the operational MISR cloud screening method does not fully exploit the MISR data for aerosol-related applications.…”

Evaluating the Height of Biomass Burning Smoke Aerosols Retrieved from Synergistic Use of Multiple Satellite Sensors over Southeast Asia

“…Height information has implications for air quality issues, as it is a key parameter in deriving surface-level aerosol concentrations from more easily accessible total column aerosol optical depth (AOD) measurements from ground-based or spaceborne remote sensing instruments (van Donkelaar et al, 2006). In addition, an independent data set can contribute to providing chemistry transport models with injection height information for air quality predictions, and serve as an evaluation target for the model results (e.g., Kahn et al, 2007;Koffi et al, 2012).…”