1. Lindsey Gulden Physical Climatology December 1, 2005
Using CLM to model biogenic emissions How does uncertainty in land-cover dataset affect model emission estimates?
Lindsey Gulden
Physical Climatology
December 1, 2005

2. Why do we care?

3. Biogenic volatile organic compounds (BVOCs)
Two BVOCs of primary concern: Isoprene (C5H8), monoterpenes

5. What’s “uncertainty in land-cover dataset?”

6. Starting point: Two land-cover datasets

7. Experiment design

8. Use Community Land Model (v. 3) to simulate BVOC emissions in Texas
Offline (means that land-surface model gets meteorological input from data files, not from an atmosphere model)
Resolution: 0.1° x 0.1° (fine resolution!)
Simulation period: January 1, 1993–January 1, 1999; analyzed last 4 years’ data
**Used region-specific BVOC emissions capacities derived from species-based vegetation dataset (Wiedinmyer et al., 2001)

9. Vary bare soil fraction

10. Indirect effects of changing bare soil %

11. Conclusion Implications
Changing bare soil percentage in the land-surface dataset directly and indirectly affects modeled BVOC emissions.
Direct effects are much greater than indirect
Implications
Land-surface model estimation of BVOC emissions inherits all uncertainty associated with input land-cover datasets. Air-quality managers take note.