HS4Cast - a reliable and automatic ice warning and
The goal to minimise the risk of icy roads can only be accomplished by looking into the future. It is obviously not enough to rely on an ice sensor which only reflects the current state of the road. To give road maintenance a fair chance to take countermeasures there must be an alert at least three hours in advance. This can be done by using a model that takes all influences on the road surface temperature into consideration. Moreover, it is necessary to be informed of the state of the road, whether it is/will be dry or wet. We have developed a computer model which is able to forecast the road temperature up to 24 hours in advance using local measurements only. The typical accuracy for a three-hour prediction during a whole winter season is better than 0.75 degrees and is lower still during night-time.
Typical numbers for the forcast are:
These data were computed using a 6 month statistic with 38000 values. No intervention of meteorologists were carried out!
The table shows numbers for the median absolute errors for predictions of the road surface and the air temperatures, respectively. We use the median absolute error as a measurement of the error of the prediction because in the range +/- median absolute error are 50% of the forecasts.
To compare these results we took the 24-hour forecasts for the air temperature at noon in Vienna for the winter 1992/93. The forecasts were published in a daily newspaper and were composed by the Vienna Met Office. The median absolute error of these forecasts is 2.5 °C.
HS4Cast is available in two flavours
The second variant of HS4Cast comes on a dedicated microprocessor board which is installed at the measurement site in combination with the A/D conversion and data transmission equipment. Thus, a sensor site will be transformed into a "smart" station which not only provides measurement data but also forecasts of these data. Both measurements and forecasts can be transmitted to a central station. The dedicated forecast module does not require a particular transmission protocol.
Advantages of HS4Cast
Security in every weather situation ... HS4Cast.