道路气象
To many, the name Italy is associated with sun andwarm weather. This is often a true enough picture. ButItaly is also a country of mountains; snow and ice could show upanywhere, throughout winter. This is why the Province ofPerugia, in the very center of Italy, has set up a program forforecasting of ice formation on road surfaces. The program isoperated by the University of Perugia and Ecosearch, aCampbell Scientific systems integrator based in Italy. The firstpart of the program is aimed to verify: 1) The relation betweenmeteorological parameters indicating possible ice formation and theactual formation of ice in three selected sites and 2) thevariability of road surface temperature. Based on the results ofthis first part of the program, an extended net-work ofmeteorological stations would be implemented in the future.
道路气象
The sensors mounted on the front of the roadmap vehicles are aGarmin geographic position sensor and an IRTS precision infraredthermometer (silver cylinder pointed downward at an angle).
The monitoring stations
Due to budget limitations, costly ice detection systems(spectral cam-eras) could not be considered. On the otherhand, extended studies showed that the reliability of traditionalsystems based on road temperature, wetness and conductivity are far from reliable. It was therefore decided to approach theproblem pragmatically. Three experimental stations would monitorthe main meteorological parameters, together with soil temperature,conductivity and heat flux. In addition, a wetness sensorequipped with a heater would work as an ice detector: when themeteorological parameters indicate that ice formation is possible,the heater goes on. The change in resistance would indicatethe transition from dry to wet (in this case, the ice melted by theheater would wet the sensor surface).The University of Perugiawould then develop an algorithm to relate weather and roadparameters to the actual ice formation on the wetness sensor (thesensor itself is placed right above a surface reproducing the roadsurface coating).
ACR10X is embedded in a protective travel case; data areaccessed via a Data View display
The mapping system In
order to evaluate the variability of road surface temperature,mapping systems were required. These consisted of a dataacquisition system (CR10X) connect-ed to an infrared precisionthermometer(IRTS-P from Apogee); the exact position of each readingwas determined by a high precision GPS system from Garmin,(shownleft on the front wing of the vehicle) coupled with an electronicodometer from Trumeter (pictured below on the rear of thevehicle.)The mapping system needed to be as "friendly" aspossible. The operator must be able to input his code and theroad code allowing him to see the measured values on adisplay. The system is therefore equipped with the Data Viewdisplay and an additional keypad has been connected. Thesystem has an external fast connector for the temperature sensor,GPS and odometer. The internal battery can be rechargedthrough the vehicle cigar lighter connection. Three systemsare installed on three road maintenance vehicles. The precision of the temperature measured by the IRTS-P on thesurface is verified through comparison with a highprecision contact thermometer from Delta Ohm.