# Presentation: 308527

## Piedmont National Wildlife Refuge

- January 23, 2004
- 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 585 acre prescribed burn conducted by the Piedmont National Wildlife Refuge. The burn was conducted on 23 January 2004. The model simulations run from 1600 EST 23 January through 0900 EST 24 January.

## Weather

- Weather during the burn and the post-burn smoke movement period was clear and dry. A high pressure system to the west of the burn site in combination with a strong low well to the northeast favored winds blowing initially from the northwest. As high settled south of the burn site, winds shifted to the southwest and diminished during early evening. Then, winds increased for the remainder of the simulation. The geostrophic wind, a measure of the intensity of the synoptic pressure driving the winds, began the period at 13.5 m/sec at 1600 LST, diminished steadily to 8.6 m/sec at 2000 LST, and increased to 18.9 m/sec by the end of the simulation period. This was a case of strong synoptic dominance.

## Modeling Information

- PB-Piedmont Version 3.0-2003
- Grid spacing = 60m
- Domain size = 296x406 -> 17.8x24.4 km
- Visual domain = 10.4x9.3 km
- Weather data: Hourly METAR
- Elevation data: USGS 30 m DEM

## Modeling Information

- The next slide shows the PB-Piedmont viewing domain for the 23 January 2004 smoke simulation. The model burn area is shown by the blue square. The actual burn area is outlined by the white polygon. Smoke observations taken between 2200-2400 LST and again at 0900 LST by Fish & Wildlife Service personnel are located by the red circles. The model smoke plume at 1700 LST for the 10 m surface layer is shown by the yellow dots.

## 1

- PB-Piedmont domain, roads, observation points 1700 LST 23 January 2004

- 2

- 3

- 4

- PB-Piedmont smoke pattern at 1700 LST. Already the wind is shifting to blow from the southwest. Numbered red circles locate smoke observation sites to be discussed in slides to follow.

## PB-Piedmont domain, roads, observation points 1800 LST 23 January 2004

- By 1800 LST, winds shifting to the southwest blew smoke over two of the smoke observation sites.

## Drainage forcing has concentrated smoke in small side valleys downwind from the burn site. Meanwhile, a drainage flow has overcome the synoptic forcing and is pushing smoke down the Falling Creek valley south of the burn site.

- PB-Piedmont domain, roads, observation points 2000 LST 23 January 2004

## 1

- PB-Piedmont domain, roads, observation points 2300 LST 23 January 2004

- The model turns winds too far to blow from the south rather than the southwest. No smoke was reported at Falling Creek Bridge (1). Heavy smoke was reported at the entrance to Wildlife Drive (2). Heavy smoke was reported at the exit to Wildlife Drive (3). Moderate smoke was reported at the shops (4).

- 2

- 3

- 4

## By 0800 LST, Light smoke was still seen across the Falling Creek Bridge (1), smoke was at the Wildlife Drive entrance (2) and exit (3), and no smoke was at the Refuge shop (4).

- PB-Piedmont domain, roads, observation points 0800 LST 24 January 2004

- 1

- 2

- 3

- 4

## By 0900 LST, warming during the morning coupled the model drainages flows with synoptic forcing to turn the winds to blow from the southwest. This blew smoke away from Falling Creek and the Wildlife Drive entrance toward the exit, and the Refuge shop.

- PB-Piedmont domain, roads, observation points 0900 LST 24 January 2004

- 1

- 2

- 3

- 4

## Summary:

- PB-Piedmont placed the west edge of the smoke near or at the Falling Creek bridge (1). No smoke was observed there.
- PB-Piedmont placed dense smoke across the intersection of Juliette Rd and Wildlife Dr entrance (2). Dense smoke was observed there.
- PB-Piedmont moved smoke up drainages just west of the intersection of the intersection of Juliette Rd and Wildlife Dr exit (3) but placed no smoke at the intersection. Dense smoke was observed at the intersection.
- PB-Piedmont placed scattered smoke in the vicinity of the Refuge shops (4). Moderate smoke was observed there.

- Smoke observations were taken between 2200-2400 LST 23 January and at 0920 LST 24 January 2004. The evening smoke observations were compared with PB-Piedmont simulated smoke at 2300 LST.

## Summary:

- PB-Piedmont placed some smoke at the Falling Creek Bridge (1). Moderate smoke was observed there.
- PB-Piedmont placed dense smoke at the intersection of Juliette Rd and the Wildlife Dr entrance (2). Moderate smoke was observed there.
- PB-Piedmont placed no smoke at the intersection of Juliette Rd and the Wildlife Dr exit (3) but did place smoke just to the west of the intersection. Moderate smoke was observed at the intersection.
- PB-Piedmont placed no smoke at the Refuge shops. No smoke was observed there.

- Smoke observations were taken at 0920 LST 24 January 2004. These observations correspond better with the model simulated smoke distribution at 0800 but not at 0900 when surface heating during the morning aided in the mix-out of smoke and establishment of strong southwest winds in the drainage layer. Model results for 0800 are compared with the observations.