The economic costs of frost to agriculture and horticulture can be significant, Dr Stu Powell* writes. As winter and early spring frost in Australia and New Zealand is almost exclusively ‘radiative’ in nature, it forms predictable patterns as a function of surrounding topography and land use.

Climate Consulting provides expert analysis of temperature inversions, katabatic drift and near-surface frost profiling. Their site-specific approach allows orchard managers to make informed decisions on the type, extent and precision placement of frost mitigation.

A frost profile collected across a 480 ha property in NSW helps optimise the positioning of frost fans. 

Deploying a high density of climate equipment across a development enables them to identify the extent of a frost problem. They establish maps of frost risk and frost variability. The maps highlight areas of greatest potential loss and are a powerful tool for quantifying and justifying frost protection.

While wind machines are highly regarded across the majority of Australia’s agricultural regions, factors like machine spacing, placement and operation are critical to success.

Proper planning and advice is the key to determining the likely effectiveness and optimisation of frost reduction strategies by answering the following key questions:

Will frost fans work for us?

This is achieved following analysis of inversion strength and consistency. In weaker inversion conditions, frost fan spacing is tightened to ensure each machine protects a reduced area. Inversion analysis is coupled with local historic frost data to achieve optimal wind machine density.

How many machines will I need?

This is calculated from the frost risk profile map. There is often more than one wind machine configuration option presented at the conclusion of a report.

Are wind machines installed where I need them?

Katabatic drift speed and direction is recorded by climate towers. This information determines the orientation of a frost fan warming footprint and subsequent precision placement of frost fans.

The density of the climate equipment installation is determined by property size and surrounding terrain. The equipment remains in place for 3–6 weeks and in this time sufficient data can usually be collected during clear settled weather. These observations mimic the near-surface environment during spring frost which allows Climate Consulting to define what’s going to work and where protection needs to go.

The cost of this service is reflective of property size and complexity of terrain.

The entire investigative process (including analysis and reporting) takes 6–12 weeks of field observations and reporting (determined by property size). Climate Consulting has helped hundreds of clients make informed decisions regarding the level, efficacy and optimal placement of frost protection since 2002.

*Dr Stu Powell is an agriclimatologist at Climate Consulting NZ. Email: stu@climateconsulting.co.nz