Sharper detection of winter temperature changes in the Romanian higher-elevations

•Change points exist in the mid '70s for winter temperatures.•The winter temperatures increase both before and after the change point.•The increasing trend is stronger before the change point and milder afterward.•Winter temperature is described by juxtaposing EA-WR, SCAND, and POL.

This paper investigates winter temperature trends in the Romanian higher-altitude areas, for three types of topographies: depression, slope and summit. The main challenge is that some winter temperature trends, by comparison with the other seasons, are milder and harder to detect. We used a change-point regression model with statistically dependent errors and compared it with a standard change-point model with independent errors. Statistical theory ensures that the former model gives a more accurate trend analysis than the latter. The model with statistically dependent errors detects change-points in the mid 70s and statistically significant increasing trends both before and after the change-point. On the other hand, the model with independent errors does not detect statistically significant increasing trends after the change-points for the winter series. These general results occur for all topography types. A separate multiple regression model reveals that the winter temperature trend changes in the Romanian higher-elevations can be described by a linear additive effect of several global atmospheric circulation patterns.