# Presentation: 757350

## Piedmont National Wildlife Refuge

- 02 March 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 669 acre prescribed burn conducted by the Piedmont National Wildlife Refuge. This burn was conducted on 2 March 2006. The model simulations run from 1700 EST 2 March through 0700 EST 3 March. Model smoke locations are compared with field observations collected by personnel from the Piedmont National Wildlife Refuge.

## Weather

- Weather during the burn and the post-burn smoke movement period was clear. A low east of Georgia combined with a high pressure system to the west to set up strong westerly winds throughout the period of the analysis. Winds gradually shifted from the southwest to the west. The below figure gives a measure of the strength of the large scale (synoptic) forcing during the analysis period. Forcing of 15.0 m/sec was sufficient for ventilation. Forcing declined to 11.9 m/sec, sufficient to block drainage flow formation in east-west oriented valleys but to allow drainage flows in deeper north-south oriented valleys. This allowed for smoke to spread laterally north and south from the burn site.

## Modeling Information

- PB-Piedmont Version 5.0-2006
- Grid spacing = 60m
- Domain size = 296x294 -> 17.8x17.6 km
- Visual domain = 10.6x10.7 km
- Weather data: Hourly METAR
- Elevation data: USGS 30 m DEM
- Elevation contour interval = 10 meters
- Elevation range is 96 – 216 meters

## The PB-Piedmont domain, roads, observation points for 2 March 2006. The yellow polygon encloses the burn site. 

- The PB-Piedmont domain, roads, observation points for 2 March 2006. The yellow polygon encloses the burn site.

## The modeled location of smoke on the ground assumes smoldering is coming from random locations within the model burn areas. Initial winds are from the west at 6.0 m/sec beginning at 1700 EST. Note that this image is just the viewing domain. The time is 1800 EST, 27 minutes before sunset.

## The smoke plume at 2000 2 March 2006. The plume has broken into strips and patches of smoke that are concentrated in the valleys located downwind from the burn site. 

- The smoke plume at 2000 2 March 2006. The plume has broken into strips and patches of smoke that are concentrated in the valleys located downwind from the burn site.

## The PB-Piedmont smoke plume at 0000 EST 3 March 2006. Smoke caught in north/south oriented drainages is carried downstream until it is ventilated from joining northeast/southwest oriented valleys. Thus the smoke fans out laterally from the burn site. Red dots identify areas where smoke and fog may coexist.

## The PB-Piedmont smoke plume at 0600 LST 3 March 2006. Decreased synoptic forcing has allowed a drainage flow to carry smoke southwestward down a valley that runs south of the burn site. Other smoke goes southward in side valleys to be ventilated up and out of northeast/southwest oriented valleys. 

- The PB-Piedmont smoke plume at 0600 LST 3 March 2006. Decreased synoptic forcing has allowed a drainage flow to carry smoke southwestward down a valley that runs south of the burn site. Other smoke goes southward in side valleys to be ventilated up and out of northeast/southwest oriented valleys.

## 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 0700 EST

- 5: No smoke (0616)

- 6: Slight smoke (0620)

- 7: Smoke (0622)

- 8: Smoke (0625)

- 9: Thick smoke (0627)

- 10: Smoke (0630)

- Click left mouse button to view observation points.

- 11: Smoke (0633)

- 12: Slight smoke (0637)

- 13: Slight smoke (0639)

- 14: Slight smoke (0642)

- 16: No smoke (0647)

- 17: No smoke (0650)

- 15: Light smoke (0645)

- 18: No smoke (0652)

- 19: No smoke (0655)

- 20: No smoke (0657)

- 21: Light smoke (0700)

## Summary:

- PB-Piedmont was correct at 15 of the 17 smoke/no-smoke observation points.
- This was a case of strong ventilation driven by synoptic scale forcing. Smoke transported into valleys with NW-SE axes could be carried by drainage flows until intersecting NE-SW oriented valleys where ventilation would occur. This process had the effect of dispersing the smoke over a larger area than if the smoke had been transported just downwind from the burn site.

## Smoke Matrix

- Smoke Prediction

- Yes                 No

- Smoke Observation

-   No                Yes

- 11

- 4

- 2

- 0