Brisbane, Queensland 2007
In May-June 2007, Australian Rain Technologies Pty. Ltd. funded a pilot trial of the technology in southeast Queensland, monitored and evaluated by a team from the University of Queensland. The area of influence was defined as the combined catchment area of the Wivenhoe, Somerset and North Pine dams, the main water supply for Brisbane.
The study used direct measurements of rainfall through official Bureau of Meteorology (BOM) stations and an additional 50 University of Queensland measurement stations installed in the area of hypothesized influence. Comparison of monthly rainfall amounts over the trial period inside and outside the area of influence were made and compared to historic values for the same months over the past 50 years. The evaluation team found rainfall within the target area was 28 per cent higher than the surrounding balance of the trial area. Historically the target area has been 12 per cent below the balance of the trial area.
Also noted was unusual intensification of radar returns downwind of Atlant that appeared to be correlated with increases in rainfall.
Bundaberg, Queensland 2008
From January 2008 until May 2008, the Atlant was trialled over the Wide Bay and Burnett district in Queensland, targeting a 70km circle centered on Paradise Dam, southwest of Bundaberg, again monitored by an evaluation team from the University of Queensland (UQ).
The study evaluated historical rainfall analysis of the Central Queensland coast and spatial analysis of rainfall data collected during the trial, as well as: (1) Remote sensing of cloud properties; (2) Ion plume modelling; and (3) Atlant close proximity Ion density measurements in close proximity to Atlant and associated micro-meteorology. Two external control areas well outside any potential influence of the Atlant system but with historical rainfall patterns. 100 UQ rainfall gauges were located uniformly in the target and control areas, to complement Bureau of Meteorology gauges.
The rainfall difference between the control and target areas (averages of all available stations in both areas for Jan-May period) in 2008 was +112mm (Target - Control areas) compared to the long-term average difference of +15mm for the previous 100 years. This means that in the target area there was 26% more rainfall recorded than in the control areas in 2008 (see Figure 12), whereas the long-term average rainfall difference only represents 3% of the value recorded in the control areas. This difference was in the 85th percentile of all values for the last 100 years, which means that only 14 other years had higher positive differences than 2008.
Initial spatial statistical modelling analysis by the University of Wollongong showed a 17.8 per cent increase above anticipated rainfall in a 30-degree downwind arc from the Atlant system, significant at the 99 per cent confidence level. The volume of additional rainfall attributed to the operation of the Atlant system was 95.8 GL.