12 September 2007

NT/QLD border fires

As noted in the previous post, a large fire was occurring on the NT side of the QLD/NT border near the Gulf. This fire was in excess of 150 000 ha.

This fire continues, and what was a smaller fire on the QLD side of the border is gaining some momentum, with several new hotspots in the general vicinity this afternoon. The NAFI map is shown below.

Weather conditions are not particularly favourable for fast-moving fire. While afternoon temperatures are high and relative humidities low, the winds are generally light in the vicinity, keeping fire dangers relatively low

The accompanying MODIS imagery is shown below. These images were captures at 0420 UTC on 11 September from the Aqua satellite. The first image is the so-called true-color image with hotspots indicated in red, grabbed from the near real-time browse images. Pixel resolution is 250 m. The smoke plumes from the two fires in question are clearly visible in this image. The second image is the so-called 7-2-1 image at the same time.

From the MODIS FAQ:


7,2,1 (2,155 nm: 876 nm: 670 nm)



Water=Black or dark blue

Desert/Naturally bare soil=Sandy pink

Burn scar=Red to reddish-brown, depending on the nature of the pre-fire vegetation and the severity of the burn.


Distinguishing burn scars from naturally low vegetation or bare soil. Enhancing floods.

This image has a 500 m pixel resolution. The hotspots are also shown on this image.

The burn scars associated with these fires are readily visible on both images. On the 721 image, the most recent burn scars are a deep red. Older fire scars have a lighter red color. On the true color image, the burn scars are also readily apparent and appear quite dark, looking like burnt spots (which of course they are...)

As something of an aside, the white splotches are small cumulus clouds, associated with the leading edge of the sea breeze. The sea breeze and the QLD fire are interacting at the time of the satellite overpass. The cloud pattern seems distorted at this point, with a band perpendicular to the coast apparently originating at the point of the fire. I am curious to know if this is merely coincidence or if the fire is affecting the atmospheric flow. (Perhaps the island off shore is also playing a role?)

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