# Presentation: 802343

## Piedmont National Wildlife Refuge

- January 27, 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 1018 acre prescribed burn conducted by the Piedmont National Wildlife Refuge. The burn was conducted on 27 January 2006. The model simulations run from 1600 EST 27 January through 0800 EST 28 January. 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 and dry. A high pressure system to the east of the burn site favored winds blowing from the east during the day of the 27th. The high expanded westward into central Georgia during the night and weakened large scale forcing thus creating conditions favorable for drainage flow dominance. The geostrophic wind speed, a measure of the strength of the forcing by the nearby high pressure center decreased from a moderately strong 9.9 m/sec at 7:00 PM (favoring ventilation) to relatively weak 6.1 m/sec by 7:00 AM (favoring drainage wind formation).

## Modeling Information

- PB-Piedmont Version 5.0-2006
- Grid spacing = 60m
- Domain size = 308x332 -> 18.5x19.9 km
- Visual domain = 9.8x10.4 km
- Weather data: Hourly METAR
- Elevation data: USGS 30 m DEM
- Elevation contour interval = 10 meters
- Elevation range is 100 – 220 meters

## The PB-Piedmont domain, roads, observation points for 27 January 2006. The yellow polygon encloses the burn site. 

- The PB-Piedmont domain, roads, observation points for 27 January 2006. The yellow polygon encloses the burn site.

## The modeled location of smoke on the ground assume smoldering is coming from random locations within the model burn area. Initial winds are from the east at 1.0 m/sec beginning at 1600 EST. Note that this image is just the viewing domain. The time is 1800 EST, four minutes after sunset.

## Drainage forcing in PB-Piedmont at 1900 EST breaks up the plume into subplumes with the bulk of the smoke carried westward by strong large scale east winds. 

- Drainage forcing in PB-Piedmont at 1900 EST breaks up the plume into subplumes with the bulk of the smoke carried westward by strong large scale east winds.

## The PB-Piedmont smoke plume at 0300 28 January 2006. This pattern remains essentially unchanged for the duration of the period. The red dots identify where model smoke is located in areas of 100% relative humidity thus identifying where smoke and fog might be colocated.

## 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 28 January 2006

- 5: Light smoke (0620)

- 6: Smell of smoke (0625)

- 7: Smoke interior (0631)

- 8: Moderate smoke (0636)

- 9: Dense Smoke (0639)

- 10: No smoke (0641)

- 11: No smoke (0644)

- Click left mouse button to view observation points.

- 12: No smoke (0652)

- 13: No smoke (0700)

- 14: No smoke (0705)

- 15: Light smoke (0708)

- 16: Smoke present (0715)

- 17: Light smoke (0718)

## Summary: Points 5-17

- PB-Piedmont correctly placed smoke at 11 of the 13 points where both smoke or non smoke were observed .
- Model failure to put smoke where dense smoke was observed at Point 9 may be luck of the draw. The observation was taken at the burn site boundary and the model did not locate smoke sources near Point 9.
- Model failure at Point 11 may be due to location of observation. Model placed smoke east of stream but not west. Thus Point 11 is on a smoke boundary.

## PB-Piedmont analysis & observations 0800 EST 28 January 2006

- 18: Light smoke (0723)

- 19: No smoke (0725)

- 20: Smoke interior (0734)

- 21: No smoke (0740)

- 22: Dense Smoke (0746)

-  23: Light smoke (0748)

-  24: No smoke (0758)

- Click left mouse button to view observation points.

- 25: No smoke (0811)

- 26: Light smoke (0820)

- 27: Smoke in drain (0823)

- 28: Light smoke (0829)

- 29: Smoke in drain (0831)

- 30: Light smoke (0836)

## Summary: Points 18-30

- PB-Piedmont correctly placed smoke at 11 of the 13 points where both smoke or non smoke were observed .
- Model placed smoke at Point 19 where smoke was not observed (green triangle). Given the location of drainages, it is hard to accept that no smoke was at point 19.
- Model failed to locate smoke at Point 23 where smoke was observed (red triangle). Given the location of Point 23 relative to the burn site, it is hard to accept that smoke was at Point 23.

## General Summary:

- PB-Piedmont correctly placed smoke at 22 of the 26 points where both smoke or non smoke were observed .
- Two of the model failures could be explained by proximity of a smoke boundary and lack of a nearby smoke source.
- Two of the model failures could not be explained.
- PB-Piedmont will likely not produce smoke all along the boundaries of the site as smoke is simulated from randomly selected points – mostly in the interior of the block being burned.

## Smoke Matrix

- Smoke Prediction

- Yes                 No

- Smoke Observation

-   No                Yes

- 8

- 3

- 1

- 1