Space‐based observational constraints for 1‐D fire smoke plume‐rise models

Abstract

[1] We use a plume height climatology derived from space-based Multiangle Imaging Spectroradiometer (MISR) observations to evaluate the performance of a widely used plume-rise model. We initialize the model with assimilated meteorological fields from the NASA Goddard Earth Observing System and estimated fuel moisture content at the location and time of the MISR measurements. Fire properties that drive the plume-rise model are difficult to constrain, and we test the model with four estimates each of active fire area and total heat flux, obtained from Moderate Resolution Imaging Spectroradiometer (MODIS) fire radiative power (FRP) thermal anomalies available for each MISR plume and other empirical data. We demonstrate the degree to which the fire dynamical heat flux (related to active fire area and sensible heat flux) and atmospheric stability structure influence plume rise, although entrainment and possibly other less well constrained factors are also likely to be significant. Using atmospheric stability conditions, MODIS FRP, and MISR plume heights, we find that smoke plumes reaching high altitudes are characterized by higher FRP and weaker atmospheric stability conditions than those at low altitude, which tend to remain confined below the boundary layer, consistent with earlier results. However, over the diversity of conditions studied, the model simulations generally underestimate the plume height dynamic range observed by MISR and do not reliably identify plumes injected into the free troposphere, key information needed for atmospheric models to simulate smoke dispersion. We conclude that embedding in large-scale atmospheric studies an advanced plume-rise model using currently available fire constraints remains a difficult proposition, and we propose a simplified model that crudely constrains plume injection height based on two main physical factors for which some observational constraints often exist. Field experiments aimed at directly measuring fire and smoke plume properties in detail are likely to produce the next major advances in plume-rise modeling.

Fire emission heights in the climate system – Part 2: Impact on transport, black carbon concentrations and radiation

“…Overall, modeling as well as observational studies (e.g., Diner et al, 2008;Val Martin et al, 2010;Ichoku et al, 2012) indicate that wildfire plume heights are highly variable on the global scale. While Freitas et al (2007), Rio et al (2010) and others demonstrated a reasonable performance for their specific plume height parametrizations in particular case studies; other authors including Val Martin et al (2012) and Goodrick et al (2012) presented results that showed a poor to moderate performance of all these models on the global scale.…”

The importance of plume rise on the concentrations and atmospheric impacts of biomass burning aerosol

“…Besides, this range is also applied in a statistical sense since the net emission in the three-dimensional atmospheric transport model might be associated not with a unique fire but a set of sub-grid-scale fires all burning inside the same model grid box. Using the fire radiative power (FRP) to estimate the buoyancy flux does not help to eliminate the use of the prescribed range of the heat flux, since there is still a substantial uncertainty in converting FRP to the convective energy, which has been widely described in the literature (Wooster et al, 2005;Val Martin et al, 2012;Paugam et al, 2015). Moreover, the uncertainty in the FRP retrieval by sensors onboard satellites is also high.…”

Injection heights of springtime biomass-burning plumes over peninsular Southeast Asia and their impacts on long-range pollutant transport

“…We applied daily variations to the emission fluxes by convoluting the monthly emission totals with the satellite-based daily burned area from the Global Fire Emissions Database version 4 (GFED4 - Giglio et al, 2013). Monthly mean biomass-burning emissions for the rest of the world were taken from the Global Fire Emissions Database version 2 (GFED2 -van der Werf et al, 2006) for the year 2001. The GFED2 inventory was not used for PSEA, because it has been shown to be significantly low-biased for the PSEA region (Fu et al, 2012).…”