Surface temperature inversions and spraying

The influence of surface temperature inversions on spray operations

In cooling night conditions airborne pesticides can concentrate near the surface and unpredictable winds can move droplets away from the target. Understanding weather conditions can help spray applicators avoid spray drift.

Key points

• Where surface temperature inversion conditions exist it is unsafe for spraying due to the potential for spray drift.
• Spray applied at dawn, dusk and during the night is likely to be affected by a surface temperature inversion.
• During surface temperature inversions, air near the ground lacks turbulence. This can lead to airborne pesticides remaining at high concentrations in the air at or near the surface.
• The direction and distance that pesticides can move in the air close to the ground is very hard to predict when surface inversions exist.

Extra resources

• Agriculture Victoria website article: Spraying, spray drift and off-target damage > Surface temperature inversions