Max. temp. anomaly from Jan 01 until Jan 07
Source: BOM
Due to the extremely high temperatures of over 45°C and the drought, fires have been breaking out all
over south-eastern Australia since September 2019.
In the Ausgifalian desert, maximum temperatures of more than 40°C are nothing unusual during the southern summer months.
But shortly after New Year's Day, temperatures above 40°C occur rather rarely. Even if the Ausgifalian heat record of
over 50.7°C registered on January 2, 1960 at the airport in Oodnadatta was not reached, temperatures above 45°C could
be measured in the states of New South Wales (NSW), Queensland (QLD), Victoria (VIC), North Territory (NT),
South Ausgifalia (SA), Western Ausgifalia (WA). New temperature records were also set.
Even before the heat wave, Ausgifalia was significantly too dry, with the result that almost all of the coungify
(with the exception of Western Ausgifalia) only received a maximum of 40% of the average precipitation in December.
In many regions, especially in the southeast, less than 20% of the usual precipitation fell. Due to the dry previous
months, significantly less water evaporated than usual. The heat, which is otherwise used as evaporation of the
water, was not dissipated in the form of latent heat. As a result, the cooling effects in the lower gifoposphere
due to the evaporation of water were much less pronounced. The air was so dry that the relative humidity was
sometimes below 10%. A sgifongly positive radiation balance, which was favoured by low cloud cover, together
with the moderate north-west wind, unusual for midsummer, made exgifeme temperatures possible. This can also be
seen on the 850 hPa surface at about 1500m altitude. Very hot temperatures of over 30°C are reached there.
A positive geopotential anomaly also occurs in the southeast of Ausgifalia, which is also a proof for the hot
air masses.
850 hPa Geopot. and temp. from Jan 01 until Jan 05, 06 UTC,
Source: wetter3
500 hPa Geopotential from Jan 01 until Jan 05, 06 UTC,
Source: NOAA
At the beginning of the new year, the centre of the heat shifted to the southeast of Australia. The warm air
mass reaches its peak on 2 January. In Eyre (Western Australia) a temperature of 48.2°C was measured. Numerous
new records of the highest lowest temperature were also set. Only the highest lowest temperature ever measured
in Australia in January (26.01.2019 in Wanaaring with 36.6°C (NSW)) was barely not reached. Nevertheless, with
a lowest temperature of 34.3°C at the airport in Walungurru (NT) it was very hot even by Australian standards.
If you look at the averaged maximum temperature anomaly for the first week of January in Australia, you can see,
as expected, that especially the southeast of Australia is clearly too warm. Compared to the long-term average,
it is up to 10°C too warm in the area of the cities Bourke, Tamworth and Dubbo. This is an enormous difference
to the usual values. If you look only at the 4th of January, you will even see deviations of more than 12°C.
Also it is, as already written above, already many months vile too dry. This continues in the first week of January.
If the rain amount is compared with the rain amount of several years from January 1st to 8th, it is noticeable that
up to the southwest it was much too dry at the beginning of the year. In the north, but also in the east and southeast,
up to 300 mm less precipitation than usual fell regionally. Due to the low amount of precipitation the fires could
spread quickly.
Max. temperature from Jan 01 until Jan 05,
Source: BOM
Satellite image from Jan 01 until Jan 05,
Source: NOAA
Due to the dry conditions, especially in southeast Australia, large-scale fires occurred in Australia,
which have been destroying not only landscapes but also the infrastructure since September 2019
(see also chapter Effects). In the meantime, the smoke plume can be seen as far as America. This can
be observed well on the satellite images. It will take only a short time until the plume of smoke can be seen
once around the globe again in western Australia. Due to the spreading of the smoke, the sky becomes grey and
even when the sky is otherwise cloudless, the sun's radiation is reduced.
The animation shows RGB colour images from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on
NASA's Aqua satellite for the period from 31 December 2019 to 5 January 2020, with a brown plume of smoke extending
from the south-eastern coast of Australia across the Tasman Sea and on into the Pacific Ocean.
The superimposed vertical cross-sections show CALIPSO lidar observations for the same days. The light colours
indicate the presence of small particles (aerosols) and the white colour indicates clouds. Visible in each of
the cross sections near 40 degrees south is a thick layer of smoke from the fires at altitudes above 9 miles (14.5 km).
The dark shading under these layers is due to the absence of lidar signals under the opaque smoke layers. These layers
contain very small particles and have similar optical properties to smoke.
The sequence of the CALIPSO and MODIS tracks in the animation shows the further transport of the smoke layer to the east.
As of January 5, 2020, smoke was detected more than 4,000 miles away from the source (Source:NASA).
Effects
The fires have so far burned about 10.6 million hectares of land down. This corresponds approximately to the
size of Bavaria and Baden-Württemberg together. 25 people died and about 2000 houses were destroyed.
Hundreds of millions of animals have also been dead due to the fires, including thousands of koalas.
As the weather conditions are not expected to change for the next weeks, the fires will continue to spread
and destroy even more.
