Thermal Mapping Weather Conditions

Under similar weather conditions a highway or runway will exhibit a constant and predictable pattern of surface temperature variations. The degree of temperature variation will alter between different weather conditions. To establish the relationship between local environmental factors and prevailing weather, Thermal Mapping uses three distinct weather categories to identify the changes in surface temperature variation.

Extreme Weather Conditions:

Calm and clear conditions, usually associated with anticyclonic systems (high pressure), or high pressure ridges between cyclonic systems (low pressure). The lack of cloud or wind allows the surface to cool very rapidly at night and is likely to produce the greatest degree of variation in night-time surface temperatures across an area.

Damped Weather Conditions:

Associated with cyclonic systems (low pressure), total low level cloud with moderate winds. The cloud cover acts as a blanket, reflecting energy back to the surface at night, whilst the wind promotes the mixing of surface air layers. This combination of factors results in the smallest degree of variation in night-time surface temperatures.

Intermediate Weather Conditions:

Arise from various meteorological features such as transient ridges or frontal approaches commonly associated with medium/high level cloud and moderate winds. Surface temperature variations will be greater than under Damped conditions but not as pronounced as under Extreme conditions.

Ideally, Thermal Mapping surveys should be conducted under all three weather conditions. However, the Extreme and/or Intermediate scenarios can be used for locating weather stations or for Route Optimization, depending on the local situation.