Cloud seeding program up and rolling

Hydro Tasmania has welcomed the start of its cloud seeding season, in an ongoing effort to improve rainfall forecasting in important catchment areas in south-east Australia.

Cloud seeding makes an important contribution to Hydro Tasmania’s annual generating capacity by increasing rainfall over hydro storages. A Monash University study found a consistent increase of at least 5 per cent in monthly rainfall over seeded catchment areas.

The Southern Ocean is the source of much of the winter rain across southern Australia. However, some aspects of the ocean’s influence on weather patterns are poorly understood, resulting in limited ability to generate accurate long-term forecasts. Gaining a greater understanding will support development of modelling tools that will result in improved long-term forecasting. This is vital to improving water resource management in many parts of southern Australia, including Tasmania.

Hydro storages are currently at 25.2 per cent –approximately 4.5 per cent lower than the same time last year after particularly dry winter and summer periods.

Catchment areas to be seeded this year are Gordon, Great Lake, Lake Rowallan, Upper Pieman, Lake King William, Lake St. Clair and Lake Echo. As has been the case in recent years, there will be no seeding flights over the King River catchment area, close to Queenstown.

Cloud seeding only occurs when the Bureau of Meteorology forecasts rain and even then only if conditions are favourable for cloud seeding to be successful.

During the 2014 season a total of 30 operational flights were undertaken with conditions suitable for cloud seeding found on 13 occasions. In 2013, there were 28 flights with seeding on 12 occasions.

Hydro Tasmania will conduct flights during the 2015 cloud seeding season to coincide with the passage of satellites over Tasmania, providing ‘in-situ’ validation of satellite measurements. Key measurements will be taken, including air temperature, wind and liquid water content of the atmosphere.

The research is being led by Monash University with support from scientists at Hydro Tasmania, Snowy Hydro, the Bureau of Meteorology, CSIRO, and the Department of Sustainability and Environment (VIC).

The season will run through to October.