5. Significant Events: , El Niño, Heat.

The Australian climate of 2002 reflected the changing state of the El Niño/Southern Oscillation (ENSO) phenomenon. Maximum temperatures over Australia between January and early March were warmer than average for , but generally normal to cooler than normal over the rest of the country. Rainfall for the period was generally near average, with some regions of below average rainfall in coastal and central Queensland, as well as southern , and above average rainfall totals in the centre and northern Western Australia. Severe flooding, approaching highest on record, occurred on the Fitzroy River (Western Australia) after an extended period of heavy rainfall from the 20th to 28th of February. For parts of , good rains in February followed an exceptional period of bushfire activity which started in late December 2001 and continued until the second week of January 2002, fanned by hot and dry westerly winds from the interior. The “Black Christmas” fires burnt over half a million hectares, with significant property and livestock losses.

February also brought Australia’s most intense tropical cyclone of the year. Tropical Cyclone Chris, which briefly reached Category 5 intensity with wind gusts to 290 km/h, crossed the coast 160 km north east of Port Hedland (Western Australia) on the 6th of February, bringing some record rainfall totals and local flooding.

Come March, however, with some hints of a developing El Niño in the Pacific, rainfall deficiencies emerged over large sections of the country. By mid-June, the patterns of tropical convections, persistent westerly winds anomalies and the Pacific Ocean temperatures signal indicated that El Niño had been established. These conditions persisted through the remainder of 2002.

Largely as a result, below average rainfall continued for much of Australia. The March to December period saw 97% of Australia experience below median rainfall, with 61% of the country in the lowest 10% of recorded totals (i.e., decile 1), using Australia-wide rainfall records beginning in 1900. This was the second largest area of decile 1 rainfall for any 10-month period on record, inviting comparisons with the 1901/02 “Federation Drought”. Similarly, the April to October period (Australia’s main crop and pasture growing season), saw 68% of the country experiencing decile 1 rainfall, also the record decile 1 area for any 7-month period.

The total annual rainfall averaged over Australia for 2002 was 340 mm, well below the long-term average of 472 mm, and the fourth driest since records commenced in 1900. The three drier years were 1902 (317 mm), 1905 (320 mm) and 1961 (336 mm). On the 26th of March, ended 56 days without rain, its longest completely dry period since 1906. At Rabbit Flat (NT), a 199-day dry spell ran between the 14th of March and the 28th of September. Conversely, slow-moving storms brought 304.6 mm to Exmouth (WA) on the 4th of June, the heaviest one-day rainfall on record for June in Western Australia, and well above Exmouth’s annual average of 272 mm. However for all other days in 2002, Exmouth received a total of 146 mm; only 53% of its annual average. In Perth, 69.6 mm of rain fell on the 17th of April, Perth’s highest April daily rainfall on record. Perth’s 2002 rainfall total of 737.8 mm, however, was still below its long term mean of 770.5 mm.

Preliminary results suggest the lowest rainfall totals for 2002 were 31.4 mm (Marree, SA), 32.8 mm (Roxby Downs, SA), 33.4 mm (Bedourie, Qld) and 36.0 mm (Coober Pedy, SA). These values represent approximately 20% of their long- term mean annual rainfall. The lowest percentage of average annual rainfall for Australia in 2002 was recorded at Winton (Qld), which received only 13% (52.6 mm) of its long-term mean rainfall (414 mm). In a stark example of El Niño versus La Niña rainfall impacts, only 2 years earlier Winton had received 1171 mm (283% of normal), the year 2000 affected in part by weak to moderate La Niña conditions. 9 The impact of the rainfall deficiencies was exacerbated by high evaporation rates in response to the very high daytime temperatures. The Australia-wide mean maximum temperatures were the highest on record for the Austral seasons of autumn, winter and spring (monthly/seasonal Australia-wide temperature records commence 1950). In each of these seasons, the previous records were surpassed by a considerable margin. The autumn Australia-wide maximum temperature anomaly of +1.83°C bettered the previous record set in 1986 by 0.44°C. Similarly, the winter value of +1.41°C was 0.45°C warmer than the old record set in 1996, whilst the spring anomaly of +1.71°C was 0.27°C above the previous record set in 1980. In all, the nine months from March to November saw an all-Australia maximum temperature anomaly of +1.65°C, the warmest on record for this three-season period, eclipsing the previous record set in 1980 by a staggering 0.63°C!

The result of such consistently warm values, both in space and in time, saw the records also eclipsed for the full year (annual Australia-wide temperature records commence 1910, and are compiled from high-quality stations only). The 2002 maximum temperature anomaly of +1.22°C was 0.31°C warmer than the previous record set in 1980. The exceptional warmth recorded during the year was the result of interannual temperature variability overlayed on the longer-term warming trend which has affected Australia and global temperatures for about 50 years.

Heatwave conditions affected the Pilbara (WA) in late October with the all-time Australian daily maximum temperature record for October being exceeded at several locations on different days. The new record for October of 46.9°C was recorded

at Port Hedland on the 22nd. Roebourne (45.8°C) and Mandora (46.7°C) on the 21st and Mandora (46.8°C) and Pardoo (46.7°C) on the 22nd also exceeded the previous October record of 45.6°C, recorded at Marble Bar on 27/10/1960 and at Port Hedland on 25/10/1926, all these locations in Western Australia. Between the 15th and 17th of June, Queensland and northern New South Wales experienced very warm conditions, with Grafton establishing a new NSW June record maximum temperature of 30.5°C on the 16th. On the 25th and 26th of November, experienced two consecutive days with maxima over 37.8°C (100°F) for only the third time in its history, and for the first time in November.

Reduced cloudiness over the continent allowed greater heat loss to space overnight, countering the higher than normal temperatures observed during daytime. Hence minimum temperature anomalies were close to normal for the period from March to December (+0.07°C). In northern Australia, winter minimum temperatures were well below average. Darwin’s August mean minimum temperature (17.8°C) was its lowest August mean minimum on record, while the town of Woolbrook (New South Wales) recorded 9 nights with minimum temperatures below –10°C during July and August.

Impacts of the hot and dry conditions were numerous. Dust-storms became prominent over the interior, with one massive dust storm reaching the coastal cities of Sydney and Brisbane on the 23rd of October (see cover image). Large and devastating bushfires occurred in Queensland, NSW, and WA. Water restrictions and reduced irrigation allocations were introduced in many areas. introduced water restrictions for the first time since 1983, whilst saw its first restrictions since 1966. Agriculture and associated businesses were greatly affected. The Australian Bureau of Statistics forecast the cut in total value of agricultural production to be approximately $5.1 billion for the 2002/03 financial year.

10 A. A major drought over large E. Severe flooding, highest on th th areas of Australia from March to E record, 20 to 28 February. December.

A & H B1. Adelaide: 56-day dry spell B2 F. Slow moving storms th th * 29 January to 25 March, F C resulted in heaviest 1-day fall * D longest since 1906. * for June for WA: 304.6mm at B2. Rabbit Flat: 199-day dry Exmouth on 4th June. Port spell 14th March to 28th A H Hedland got 75% of its 2002 September. total on 5th June.

C. Winton: Very dry: 13.5mm in A G. Perth: 69.6mm in 24 hrs February to November period, G * to 9am 17th April - highest 53mm for the year. * April daily rainfall in record. B1 D. Emerald: slow-moving H. Very hot summer in brought more than 350mm in 24 hours Queensland - highest summer to 9am 4th January. mean maximum temperatures on record in many locations. Also, severe coral bleaching.

I. Very cool summer in south M. Cold spell in central - lowest mean maximum L6 Australia in late June/early temperature on records in July - Alice Springs J J & N th Adelaide and Albany. J & N & P recorded –6.0°C on 30 . * J & P th J. Very cool winter particularly L3 L2 N. Very warm days: 15 to L5 L1 th August. Darwin had lowest * N 17 June - Grafton recorded L4 ** th mean minimum temperaure * * 30.5°C on 16 . (17.8°C) on record. N & P M K. Cold nights in July and O. Perth: maximum August in NSW/SE Qld and in P temperature of 34.3°C on 1st northern Victoria (August). May, a new record for May. K & P 9 nights in Woolbrook (NSW) N & K & P O with minimum temperature of * K –10°C or lower. I * Q P. 19th October: A hot day I with many new records set L1. Port Hedland: highest across Queensland and I & K Australian October temperature of NSW. 46.9°C on 22nd; L2. Mandora: 46.7°C on 21st and I Q. Sydney: maximum nd temperatures more than 46.8°C on 22 . th nd 37.8°C (100°F) on 25 and L3. Pardoo: 46.7°C on 22 . th L4. 46.0°C at Mardie on 22nd. 26 November - first ever for L5. Roebourne: 45.8°C on 21st November. and 45.9°C on 22nd. L6. Wave Hill: 45.0°C on 23rd.

R. Destructive fires continued U. Tropical cyclone "Chris" - from Christmas 2001 into early crossed Western Australia January, esp. in Shoalhaven. U coast as a Category 5 on 6th February. Brought heavy S. Several fire outbreaks in rain/flooding. October to early December. Property destroyed, 2 V V. Severe duststorm on rd deaths. S & V 23 October reaching Sydney and Brisbane. T. Big Desert fire in Numerous (less extensive) December burnt 180 000 ha duststorms in second half T - largest fire in Victoria since of the year, particularly in 1983. September and October. R & S & V

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