Getting the measure of wildfires in Australia

atmosphere.copernicus.eu

We did not seek permission to re-post but consider it ‘fair use’ to re-post in full and credit the original source. Please get in touch if you are the original author and would like the post altered or taken down -The Editors.


Devastating wildfires have been burning across large areas of Australia and Tasmania for several weeks. The Copernicus Atmosphere Monitoring Service (CAMS), implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF) on behalf of the European Union, monitors emissions from such wildfires in order to estimate how dangerous they may be in terms of atmospheric pollution.

This January has been the warmest on record in Australia, and one of the driest compared to the 1981-2010 average. In addition, the country has suffered from record-breaking heatwaves.

Surface temperature anomaly - January
Surface air temperature anomaly for January 2019 relative to the January average for the period 1981-2010. Source: ERA-Interim. (Credit: Copernicus Climate Change Service, ECMWF)

Throughout January, rainfall was below average for Australia as a whole; and the daily total Fire Radiative Power (FRP), a measure of heat output from wildfires, was much higher than usual for Western Australia. For several weeks from mid-January Tasmania experienced numerous fires with smoke plumes visible in satellite images crossing the Tasman Sea as far as New Zealand and beyond.

Plume of organic matter aerosol optical depth
The plume of organic matter aerosol optical depth from bushfires in Tasmania at 18UTC on 30 January 2019. (Credit: Copernicus Atmosphere Monitoring Service, ECMWF)

Although Tasmania avoided the extreme heat of mainland Australia, it still endured its warmest and driest January on record. Throughout the month, the Fire Weather Index, which takes into account numerous variables, including wind speed and precipitation, showed large areas of concern. Levels remained at moderate to extreme for the whole month across much of the state, and ignition sources such as dry lightning led to numerous bushfires, exacerbated by their remote locations and periods of strong winds.

Fire Weather Indices
Fire Weather Indices from 4 January and 29 January, showing fire activity. (Credit:  Copernicus Emergency Management Service)

The island state experienced ongoing devastation and threat of fire for many days, clearly shown in the chart below, which compares the daily total FRP throughout the month with the 2003-2018 average daily total for the same dates.

Time series of daily total Fire Radiative Power (FRP)
Time series of daily total Fire Radiative Power (FRP) from fires in Tasmania in January and February 2019. (Credit: Copernicus Atmosphere Monitoring Service, ECMWF)

Fire forecasting can be complicated, as there are many variables to take into consideration. For example, regions which are experiencing drought, low humidity and high wind speed score highly on the Fire Weather Index. However, there is no global system providing associated information on vegetation; if there is no fuel, there can be no fire. Currently, local knowledge helps identify regions at risk.

While wildfires themselves cause relatively short-term levels of danger, the effects of smoke pollution can have serious long-term effects. CAMS Senior Scientist Mark Parrington, who researches wildfire emissions and their impacts, says:

Hundreds of thousands of hectares of land across Tasmania have been affected by these fires and the resulting smoke contains pollutants. CAMS forecasts the spread of these emissions, which can have serious impacts on health as well as on atmospheric composition.”

Australia is relatively isolated, so the effects have only been felt locally. However, smoke plumes from wildfires in other areas of the globe, such as Siberia, have been seen to spread across the globe. More information can be found through the CAMS Global Fire Assimilation System (GFAS) webpage.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s