WAND Uptake
The data from the individual towers has been viewed more than 16,000 times, helping growers and contractors to identify hazardous inversions and make informed spray decisions.
Once all 100 towers are live, a substantial amount of the Queensland and New South Wales cropping belt will be within 40 km of a WAND tower which will support the provision of critical information for spray hazard identification.
WAND is a major step forward in the fight against spray drift, which has been a significant issue this season across all valleys.
The role of WAND and hazardous surface temperature inversions
Pesticide applications during hazardous surface temperature inversions can lead to spray drift causing severe damage up to several kilometres off target. Current regulations prohibit spraying of agricultural chemicals when hazardous temperature inversions exist. Hazardous inversions have only recently been defined and methods to detect and forecast them specified.
A surface temperature inversion occurs when the air temperature increases with height from the ground surface, which is the opposite of what normally happens (i.e., the temperature profile is ‘inverted’). This results in a layer of cool dense air being trapped below warmer air close to the surface. Not all surface temperature inversions are hazardous, but they must be considered as such, unless recognised instrumentation exists to identify them.
When a hazardous inversion has established, it acts like a barrier, isolating the inversion layer from the normal weather situation, especially the normal wind speed and direction. During a hazardous inversion, air movement is much less turbulent than during the day. Sprays applied in these conditions can become trapped in this cool air layer where there is insufficient turbulence to either deposit or disperse the suspended spray droplets. This lack of turbulence results in the transport of drift over long distances in localised laminar air flows that glide smoothly down slopes, deviate around obstacles, flow parallel to contours and generally flow towards low-lying areas where they converge and concentrate; all the while transporting airborne material such as spray drift.
The Grains Research and Development Corporation (GRDC) and the Cotton Research and Development Corporation (CRDC) partnered with Goanna Ag to deliver Weather and Networked Data or WAND – a spray drift hazardous inversion system that is providing real-time weather data for growers and spray operators about the presence or absence of hazardous temperature inversions.
WAND consist of a network of Profiling Automatic Weather Stations (PAWS) across the grain and cotton regions of NSW, southern and central QLD. The PAWS have remote sensing capability and new proprietary software to provide growers and spray contractors real-time weather data updated every 10 minutes.
To access the WAND network go to www.wand.com.au
PHOTO: This map shows the towers that were live (the black chequered flags) at the end of January and those that are soon to come online (the green pickaxes).
