Thermal Fingerprints

Thermal Mapping uses vehicle-based surveys to quantify the temperature variations across a network. Surveys are conducted under distinct weather conditions and at night-time during the winter.

The highway or runway network is divided into a series of survey routes. These routes will be run in the same direction and order each time a survey is conducted. This ensures that meteorological conditions can be constantly assessed and that survey data can be compared and verified. The surveys are carried out using a specially equipped vehicle fleet and trained personnel with meteorological & climatological expertise. An infrared thermometer mounted in the vehicle automatically logs surface temperatures and the data are logged electronically to disk for processing.

For each survey route the surface temperature data is plotted against the route average; this is the Thermal Fingerprint for that route. Thermal Fingerprints are the unique signature of a highway/runway and quantify the magnitude of temperature variation under each of the three survey conditions (Extreme, Intermediate & Damped). Vaisala uses statistical testing to ensure the reliability and repeatability of Thermal Fingerprint data.

Thermal Maps are then constructed from analysis of the Fingerprints, in conjunction with information on the specific survey weather conditions. Each Thermal Map identifies the pattern and magnitude of road surface temperature variations, indicating the relative differences as colour coded, 1.0°C categories.