Wildfire Plume Injection Heights Over North America: An Analysis of MISR Observations Maria Val Martin and Jennifer A. Logan (Harvard Univ., USA) Fok-Yan Leung (Washington State Univ., USA) David L. Nelson, Ralph A. Kahn and David J. Diner (NASA) Saulo Freitas (INPE, Brazil) Research funded by NSF and EPA

Wildfire Plume Injection Heights Over North America: An Analysis of MISR Observations Outline: An statistical analysis of aerosol injection heights over North America The use of a 1-D plume-rise model to develop a parameterization of the injection heights of North American wildfire emissions

Multi-angle Imaging SpectroRadiometer- MISR 9 view angles at Earth surface: nadir to 70.5º forward and backward 4 bands at each angle: 446, 558, 672, 866 nm Continuous pole-to-pole coverage on orbit dayside 400-km swath 9 day coverage at equator 2 day coverage at poles Overpass around local noon time in high and mid- latitudes 275 m km sampling In polar orbit aboard Terra since December 1999

Analysis of Fire Plumes: MISR INteractive eXplorer (MINX) ( Cross-section of heights as a function of distance from the source Histogram of heights retrieved by MINX Plume over central Alaska on June 2002

About 3000 plumes digitalized over North America N = N = N = N = N = 690

Plume Distribution and Atmospheric Conditions Meteorological fields from GEOS-4 and GEOS-5 2x2.5 Histogram of Plume Height Retrievals Atmospheric Stability Profile Stable Layer Boundary Layer (BL) Max Avg Median Mode Plume Height? Each individual height

5-30% smoke emissions are injected above the boundary layer Kahn et al, [2008] Distribution of MISR heights-PBL for smoke plumes –25% –15% –28% –18% 2004

Percentage of smoke above BL varies with vegetation type and fire season Vegetation classification based on MODIS IGBP land cover (1x1 km) % Height retrievals with [Height-PBL] > 0.5 km ( Trop Forest Cropland Extra-Trop Forest Boreal Forest Boreal Shrub Non-Bor Shrub Boreal Grass Non-Bor Grass

Kahn et al, [2007] Leung et al, [in prep] 11% 13% 7% 24% 13% Smoke emissions tend to get confined within stable layers in the atmosphere, when they exist Distribution of all individual heights in the FT – Stable Layer MISR Heights – Stable Layer ≈ 0 km

1-D Plume-resolving Model Detailed information in Freitas et al, [2007] Key input parameters: Instant fire size: MODIS fire counts (scaled by max FRP observed over vegetation type [Charles Ichoku, personal communication]) (> 80% fires <25 Ha) Total heat flux: Max MODIS FRP observed over vegetation type x 10 [Wooster et al, 2005] (~ W/m 2 ) RH, T, P, wind speed and direction: from GEOS- 4 meteo fields 2x2.5 Fuel moisture content: from Canadian Fire Weather Model

Simulation of a boreal fire plume in Alaska and a grassland fire plume in Mexico Fire Size= 300 Ha Heat Flux= 18 kW/m 2 Fire Size= 3.8 Ha Heat Flux= 9 kW/m 2 MISR Retrieved Heights MISR Smoke Plume 1D Plume-rise Model Boreal Forest Fire Trop. Grassland Fire

Simulation of a boreal fire plume in Alaska and a grassland fire plume over Mexico Fire Size= 300 Ha Heat Flux= 18 kW/m 2 Fire Size= 3.8 Ha Heat Flux= 9 kW/m 2 MISR Retrieved Heights MISR Smoke Plume 1D Plume-rise Model Boreal Forest Fire Trop. Grassland Fire 6200 m6500 m 600 m 555 m

The 1-D Plume-resolving Model simulates fairly well the observed MISR heights Correlation between simulated plume heights and MISR observed heights over North America

 5-30% of smoke emissions are injected above the BL.  The percentage of smoke that reaches the FT varies with vegetation type and fire season.  When smoke emissions reach the free troposphere, they tend to get trapped in stable layers, if they are present.  1-D plume-resolving model simulates fairly well the observed MISR plume heights.  In the future, we plan to embed the 1-D plume-resolving model with GEOS-Chem to simulate vertical transport of North American wildfire emissions. Concluding Remarks

Extra Slides

The 1D plume-resolving model: Governing equations dynamics thermodynamics water vapor conservation bulk microphysics cloud water conservation rain/ice conservation

The 1D plume-resolving model: The lower boundary conditions