This paper presents our first experience with the application of the METRo model, which forecasts road surface temperature and road conditions (e.g., wet or dry surface, ice) in the Czech Republic. ...In our version, the model uses online measurements from road weather stations (RWS) in the Czech Republic and weather forecasts from ALADIN, the operational numerical weather prediction NWP model of the Czech Hydrometeorological Institute. The METRo model was quasi-operationally tested during the winter season (November 2012–February 2013) using data from 25 RWS. We compared three model runs with an emphasis on road surface temperature. The first run used the original model and served as a reference. The second run applied model output statistics (MOS) to ALADIN forecasts of temperature and humidity at 2m above the ground, which are required by METRo. The third run applied METRo in a nowcasting mode by starting the model every hour and using new measurements available from the RWS. The results indicated that MOS improved the accuracy of the temperature and humidity at 2m but had little impact on the forecasted road surface temperature. However, the nowcasting scheme significantly improved the accuracy of the forecasts for the initial 3 to 4h. The evaluation of the METRo results suggests that the radiation flux forecast is crucial for an accurate road surface temperature forecast.
•Atmospheric prognostic data were obtained by the ALADIN NWP model.•The improvement of atmospheric data only slightly improves the forecast.•Assimilation of measurements improves nowcasting of road temperature.•Radiation flux forecasts are crucial for road surface temperature forecasts.
In the Canadian Arctic, winter roads are engineered across the frozen land, rivers, and lakes. The strength and longevity of these roads depend on particular weather conditions. Our research focuses ...on the winter road between Tulita and Norman Wells, Northwest Territories, which has been maintained officially by the territorial government since 1982. Statistical analysis of the opening dates for the winter road showed five seasons with extremely early dates and five with extremely late dates. The extremely early-opening seasons are distinguished by anomalously high sea-level pressures, anomalously cold tropospheric air, and northwesterly surface winds during the November. prior to the road opening. The extremely late-opening seasons are characterized by an anomalously strong Aleutian low in the preceding November. The extremely late-opening years are correlated with strong E1 Niño seasons, whereas the extremely early-opening years are not systematically associated with teleconnection patterns. Our analysis of meteorological conditions near Norman Wells, associated with the extreme opening dates for this winter road, may provide planners with more precise information germane to this road construction. Dans l'Arctique canadien, les routes hivernales sont construites sur le sol, les lacs et les rivières gelèes. La soliditè et la durabilité de ces routes dépendent de conditions météorologiques particulières. Nos recherches mettent l'emphase sur la route hivernale officiellement entretenue par le gouvernement territorial depuis 1982, entre Tulita et Norman Wells dans les Territoires du Nord-Ouest. L'analyse des statistiques relativement aux dates d'ouverture de cette route ont permis de dénoter des dates d'ouverture trés hâtives dans le cas de cinq saisons, et très tardives dans le cas de cinq autres saisons. Les années où l'ouverture est extrêmement hâtive dans le cas de pression au niveau de la mer irréguliérement haute, de l'air troposphérique irrégulièrement froid, et des vents de surface du nord-ouest durant le mois de novembre précédant l'ouverture de la route. Les cinq années dont l'ouverture est extrêmement tardive sont précédées par un mois de novembre où la basse pression des Aléoutiennes y est irrégulièrement forte. Les résultats démontrent que les années où l'ouverture est extrêmement tardive sont des saisons influencées par El Niño tandis que les années dont l'ouverture est extrêmement hâtive ne sont pas systématiquement associées avec des signaux de téléconnexions. L'analyse des conditions météorologiques près de Norman Wells, associée avec les dates d'ouvertures extrêmes pour cette route, procure aux planificateurs de ces routes de l'information plus précise pour la construction de celles-ci.
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