Maria Val Martin and J. Logan (Harvard Univ., USA) D. Nelson, C. Ichoku, R. Kahn and D. Diner (NASA, USA) S. Freitas (INPE, Brazil) F.-Y. Leung (Washington State Univ., USA) Research funded by NSF and EPA Wildfire Plume Injection Heights Over North America: An Analysis of MISR, MODIS and a 1-D Plume-rise Model

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 Wildfire Plume Injection Heights Over North America: An Analysis of MISR, MODIS and a 1-D Plume-rise Model

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

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

About 3500 plumes digitalized over North America

Plume Distribution, Atmospheric Conditions and Fire Properties Meteorological fields from GEOS-4 and GEOS-5 2x2.5 Fire Properties from MODIS Fire Radiative Power Histogram of Plume Height Retrievals Atmospheric Stability Profile Max Avg Median Mode Plume Height? Each individual height Stable Layer Boundary Layer (BL) Leung et at, Poster B31C-0302

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% Val Martin et al, in preparation

Tropical Forest Cropland Temperate Forest Boreal Forest Boreal Shrub Non-Boreal Shrub Boreal Grassland Non-Boreal Grassland Vegetation type based on MODIS IGBP land cover map ( 1x1 km resolution Classification of plume distribution by vegetation type

Percentage of smoke above BL varies with vegetation type and fire season % Height retrievals with [Height-PBL] > 0.5 km Number of plumes

Close relationship between plume distribution, fire intensity and fire size Plume Height versus Fire Intensity Plume Height versus Fire Size

Fire intensity drives the interannual variability of plume heights Distribution of MISR heights and MODIS FRP by year 200

Also, fire intensity drives the seasonality of plume heights Boreal Forest 2002 and

1-D Plume-resolving Model Detailed information in Freitas et al, [2007] Key input parameters: Instant fire size: MODIS FRP (max FRP observed in each biome  1 km 2 burned [Charles Ichoku, personal communication]) Total heat flux: Max MODIS FRP observed over vegetation type x 10 [Wooster et al, 2005; Freeborn et al., 2008] RH, T, P, wind speed and direction: from GEOS- 4 meteo fields 2x2.5 Fuel moisture content: from the 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= 3.3 Ha Heat Flux= 9 kW/m 2 MISR Retrieved Heights MISR Smoke Plume 1D Plume-rise Model Boreal Forest Fire Grassland Fire

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= 3.3 Ha Heat Flux= 9 kW/m 2 MISR Retrieved Heights MISR Smoke Plume 1D Plume-rise Model Boreal Forest Fire Grassland Fire 5025 m5425 m 1200 m 900 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 All Plumes

 5-30% of smoke emissions are injected above the BL.  The percentage of smoke that reaches the FT depends on fire characteristics (e.g., vegetation type, fire intensity, etc) and year-to-year variations.  Fire intensity drives the seasonality and interannual variability of the plume heights.  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 1-D Plume-resolving Model simulates fairly well the observed MISR heights Correlation between simulated plume heights and MISR observed heights over North America Boreal Forest Plumes

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 Temperate Forest Plumes

Model simulated heights versus MISR observed heights by year

Model simulated heights versus MISR observed heights by vegetation

Smoke emissions tend to get confined within stable layers in the atmosphere, when they exist 11% 13% 7% 24% 13% Distribution of all individual heights in the FT – Stable Layer MISR Height – Stable Layer Height ≈ 0 km

Relationship between simulated heights and 1-D model input parameters

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

Intensity of the fire drives the interannual variability of plume heights

Also, fire intensity drives the seasonality of plume heights Trop Forest

Also, fire intensity drives the seasonality of plume heights Temperate Forest

Also, fire intensity drives the seasonality of plume heights Boreal Shrub

Also, fire intensity drives the seasonality of plume heights Boreal Grassland

Also, fire intensity drives the seasonality of plume heights NonBoreal Grassland

Also, fire intensity drives the seasonality of plume heights Cropland