# Presentation: 165835

## South Carolina Forestry Commission

- March 7, 2006
- Smoke Simulation Analysis
- Gary L. Achtemeier
- USDA Forest Service
- Athens, GA

## Task Description

- The following set of slides summarize a PB-Piedmont post-burn analysis of smoke movement in the aftermath of a 400 acre prescribed burn conducted by the South Carolina Forestry Commission. The burn was conducted on 7 March 2006. The model simulations run from 1600 EST 7 March through 0800 EST 8 March. The site was located on the flat coastal plain of eastern South Carolina and thus provides a test of PB-Piedmont over land with little relief.

## Weather

- Weather during the burn and the post-burn smoke movement period was clear. Synoptic forcing was weak and ill-defined until about 0300 EST 8 March. Initially, synoptic forcing favored winds blowing from the northwest away from where smoke was observed the next morning. After 0300 EST, a weak high pressure area formed along the SC-GA coast and favored light winds from the southwest. The geostrophic wind speed, a measure of the strength of the forcing by the large scale (synoptic) wind field ranged between 7.9 m/sec and 0.4 m/sec but was highly variable from hour to hour. The moderately strong forcing (>5.0 m/sec) would dominate drainage flows in the shallow basins of the coastal plain. Weak synoptic forcing (< 2.0 m/sec) would still be sufficiently strong to oppose and possibly reverse southwest-flowing drainage flows in the coastal plain.

## Modeling Information

- PB-Piedmont Version 5.0-2006
- Grid spacing = 60 m
- Domain size = 302x340 -> 18.1x20.4 km
- Visual domain = 8.2x7.6
- Weather data: Hourly METAR
- Elevation data: USGS 30 m DEM
- Elevation contour interval = 2 meters
- Elevation range is 0-35 meters

## The full 16.9x16.6 km model domain captures the flat topographical relief of the coastal plain. 

- The full 16.9x16.6 km model domain captures the flat topographical relief of the coastal plain.

## The PB-Piedmont viewing domain and observation points for 7 March 2006. The white square encloses the 400 acre burn site. 

- The PB-Piedmont viewing domain and observation points for 7 March 2006. The white square encloses the 400 acre burn site.

## The plume at 1700 EST, 7 March 2006 blows from the northwest. 

- The plume at 1700 EST, 7 March 2006 blows from the northwest.

## The plume at midnight (0000 EST 8 March 2006). Synoptic forcing has shifted to favor winds blowing from the southwest.

## Smoke Location Evaluation:Interpreting 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

## PB-Piedmont analysis & observations 0500 EST

- 1: No smoke (0500)

- 2: Light smoke SE of this point (0509)

- 3: Light smoke NW of this point (0513)

- 4: No smoke (0515)

- Click left mouse button to view observation points.

## PB-Piedmont analysis & observations 0700 EST

- 5: Edge of smoke (0627)

- 6: Light smoke SE of this point (0654)

- 7: Light smoke NW of this point (0700)

- 8: No smoke (0706)

- Click left mouse button to view observation points.

## Summary:

- At 0500 EST, PB-Piedmont correctly placed no smoke at 2 of 2 observation sites.
- At 0500 EST, PB-Piedmont correctly placed smoke between the two observation sites but not as widespread as was observed.
- At 0700 EST, PB-Piedmont correctly placed no smoke at 1 of 1 observation sites.
- At 0700 EST, PB-Piedmont correctly placed smoke near a single site next to the river.
- At 0700 EST, PB-Piedmont correctly placed smoke between the two observation sites but not as widespread as was observed.

## Smoke Matrix

- Smoke Prediction

- Yes                 No

- Smoke Observation

-   No                Yes

- 3

- 4

- 0

- 0