how important are temporal constraints and vertical injection of boreal fire emissions? yang chen...
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How Important Are Temporal Constraints and Vertical Injection of Boreal Fire Emissions?
Yang Chen1,3, Qinbin Li1,2, James Randerson3, Evan Lyons2 Ralph Kahn1,4, David Nelson5, David Diner1
1JPL 2UCLA 3UC Irvine 4GSFC 5Raytheon
The 4th GEOS-Chem Meeting, April 7, 2009, Harvard
Summer 2004 Alaska Fire Emissions: Temporal Constraints
GFED v2
Diurnal: A mean diurnal cycle imposed on the 8-day emissions
Synoptic: Synoptic variation imposed on the diurnal emissions
Temporal constraints are added cumulatively
Major fires
Significant diurnal and synoptic variability.
Summer 2004 Alaska Fire Emissions: Vertical Injection
Circles: MISR-derived smoke plume heights Vertical distributions of emissions
600+ plumes10% reached free trop.
Relative Importance of Individual Temporal ConstraintsLittle effect from imposing a mean diurnal cycle.
Effects of Different Smoke Plume Heights on COUniform injection significantly decreases surface CO over source region while increases CO in the upper troposphere – Not a surprise.
Sensitivity of CO to Temporal and Vertical ConstraintsSurface CO over source region decreases while downwind CO increases
Effects on the Columns of CO and BC
1. Columns decrease over source region while increases downwind.
2. Most of that change is due to added temporal variations.
3. CO column change ~2%; BC: 10-20%
kg/km2
Effects on Downwind Vertical Distributions of CO and BC
INTEX-NA 2004, all flights
Black box: Median obs.
1. Uniform injection may overestimate upper tropospheric CO.
2. Not much difference among the temporal constraints and vertical injections.
3. Worse agreement in the lower troposphere.
Effects on Surface BC: Comparison with IMPROVE
µg/m3
1. Going from monthly to 8-day makes largest difference.2. Uniform injection makes things worse – underestimates surface BC.
Temporal
Vertical
Temporal
Vertical
Transport of Boreal Fire CO: The Role of Convection
(a) 300 hPa CO from N.A. biomass burning
(b) B.B. Emissions
(c) Vertical dist. of NA biomass burning CO and convective mass flux
(d) Change in CO due to MISR-derived plume injection
(e) Change in CO due to uniform plume injection
White line: HYSPLIT trajectory
Convection is possibly more important than plume injection height?
Emission-weighted Winds and Deep Convective Mass Fluxes
Positive values: Eastward, northward, upward winds and fluxes
Stronger vertical transport and horizontal advection with higher-temporal frequency emissions compared with the monthly mean emissions.
Any Improvement to CO Column? Temporal Comparison with MOPITT
MOPITT CO with a priori fraction < 50%
1. Some improvement from temporal constraints.2. Uniform injection makes things worse.
Any Improvement to CO Columns? Temporal Comparison with MOPITT
MOPITT CO with a priori fraction < 30%