South Carolina Forestry Commission

1
South Carolina Forestry Commission

• February 9, 2006
• Smoke Simulation Analysis
• Gary L. Achtemeier
• USDA Forest Service
• Athens, GA

2
Task Description

• The following set of slides summarize a
  PB-Piedmont post-burn analysis of smoke movement
  in the aftermath of a 100 acre hazard reduction
  burn conducted by the South Carolina Forestry
  Commission. The burn was conducted on 9 February
  2006. The model simulations run from 1600 EST 9
  February through 0800 EST 10 February. The site
  was located on the coastal plain of South
  Carolina.

3
Weather

• Weather during the burn and the post-burn smoke
  movement period was mostly clear. A weak high
  pressure system moved over South Carolina during
  the night, shifting the synoptic forcing to blow
  from the south. The geostrophic wind speed, a
  measure of the strength of the forcing by the
  large scale (synoptic) wind field ranged from
  3.10 m/sec to 6.8 m/sec. This weak forcing was
  strong enough to oppose drainage wind formation
  in the coastal plain.

4
Modeling Information

• PB-Piedmont Version 5.0-2006
• Grid spacing 60 m
• Domain size 321x335 -gt 19.3x20.1 km
• Visual domain 19.3x20.1
• Weather data Hourly METAR
• Elevation data USGS 30 m DEM
• Elevation contour interval NA
• Elevation range is NA

5
The full 19.3x20.1 km model domain captures the
drainages surrounding the burnsite (white square).
6
The PB-Piedmont viewing domain and observation
points (6,7,8) for 9 February 2006 where dense
smoke was observed most of the night. The yellow
polygon encloses the 1000 acre burn site.
7
The plume at 1700 EST, 9 February 2006 blows from
the north away from the observation sites.
8
Smoke Location EvaluationInterpreting the
Observations Shown in the Next Slide

• Red symbol means smoke observed
• Green symbol means smoke not observed
• Circle means model matched observation
• Triangle means model unsuccessful

9
PB-Piedmont analysis observations 2200 EST, 9
February 2006. Red areas indicate where smoke and
fog may coexist.
6 Thick smoke (2230)
7 Thick smoke (2230)
8 Thick smoke (2230)
Click left mouse button to view observation
points.
10
Summary

• PB-Piedmont correctly placed smoke or no smoke at
  3 of the 3 observation sites.
• Very weak synoptic forcing changed the winds from
  blowing from the south to blowing to the north.
  The outcome on the existing smoke plume was to
  scatter smoke widely over the domain.

11
Smoke Location EvaluationInterpreting the
Observations Shown in the Next Slide

• Red symbol means smoke observed
• Green symbol means smoke not observed
• Circle means model matched observation
• Triangle means model unsuccessful

12
PB-Piedmont analysis observations 2200 EST, 9
February 2006. Red areas indicate where smoke and
fog may coexist.
6 Thick smoke (2230)
7 Thick smoke (2230)
8 Thick smoke (2230)
Click left mouse button to view observation
points.
13
Summary

• PB-Piedmont correctly placed smoke or no smoke at
  3 of the 3 observation sites.

14
Smoke Location EvaluationInterpreting the
Observations Shown in the Next Slide

• Red symbol means smoke observed
• Green symbol means smoke not observed
• Circle means model matched observation
• Triangle means model unsuccessful

15
PB-Piedmont analysis observations 2200 EST, 9
February 2006. Red areas indicate where smoke and
fog may coexist.
6 Thick smoke (2230)
7 Thick smoke (2230)
8 Thick smoke (2230)
Click left mouse button to view observation
points.
16
Summary

• PB-Piedmont correctly placed smoke or no smoke at
  2 of the 3 observation sites.
• Synoptic flow dominated drainage flows to divert
  smoke to blow to the northwest.
• Investigation of surrounding airport winds showed
  winds blowing from the south to southwest, still
  not sufficient to place smoke over the observed
  sites.
• The best explanation for the smoke at
  observations 6 and 7 is smoke blown north from
  another burn site located south of the area.

17
Summary

• PB-Piedmont correctly placed smoke or no smoke at
  2 of the 3 observation sites.

18
Overall Summary

• PB-Piedmont correctly placed smoke or no smoke at
  8 of the 9 observation sites.
• From the description given by the observer, it is
  not clear whether smoke was observed at all three
  sites at 0800. He reported only that the area was
  still in heavy smoke.

19
Smoke Matrix
Smoke Prediction
Yes No
1
8
No Yes
Smoke Observation
0
0