Temperature changes and elevation‐warming relationships in the Carpathian Mountains

• Published in: International journal of climatology 2021-03, Vol.41 (3), p.2154-2172
• Main Authors: Micu, Dana Magdalena, Dumitrescu, Alexandru, Cheval, Sorin, Nita, Ion‐Andrei, Birsan, Marius‐Victor
• Format: Article
• Language: English
• Subjects: Air temperature; Albedo; Atmospheric circulation; Atmospheric circulation changes; Atmospheric circulation effects; Carpathian Mountains region; Climate; Climate change; Climate effects; Cold climates; Datasets; Ecological effects; Elevation; elevation‐dependent warming; Forest vegetation; Freezing; Geomorphology; Global warming; Heat stress; Heat tolerance; Heat waves; Heatwaves; Inhomogeneity; Jenkinson–Colisson classification; Lowlands; Minimum temperatures; Mountains; Permafrost; Southeast Europe; Spring; Spring (season); Summer; Temperature changes; Temperature rise; Temperature trends; trend analysis; Trends; Weathering; Winter
• ISSN: 0899-8418; 1097-0088
• DOI: 10.1002/joc.6952

This paper investigates the elevation‐warming relationships across the Carpathian Mountains, using the 0.1° × 0.1° gridded daily air temperature dataset developed within the CARPATCLIM project, in order to understand the spatial patterns of annual and seasonal temperature trends and test the hypothesis of enhanced warming with elevation. Temperature trend and elevation‐warming analyses were conducted over the 50 years of the dataset (1961–2010). The vertical variations of five key isotherms relevant for the development of cold‐climate weathering, presence of permafrost (−2°C, 0°C, +2°C, +3°C) and spread of forest vegetation (July +10°C) were also examined. The Carpathian Mountains are under visible annual and seasonal warming (stronger in the summer and winter), both daytime and nighttime. The warming process shows a great spatial inhomogeneity, but is more pronounced in the lowlands of the region, generally below 1,000–1,200 m. The correlations between elevation and warming rates across the Carpathians have been found both to be positive and negative, while mostly significant at the 5% level. Evidence of enhanced warming with elevation was found to be related to the minimum temperature increase mostly across the NW and SW Carpathians, at both annual and seasonal scales (winter, summer and spring). Less prominent EDW signals have been identified in the NE, E and S Carpathians (summer), as well as in the NE Carpathians (spring). Parts of the detected temperature trends and EDW signals have been considered to be an effect of the changing atmospheric circulation (i.e. westerly intensification especially in the winter), although other mechanisms and processes could be involved (e.g. snow‐albedo feedbacks in the spring). These results could serve as a reference for further investigations of climate warming effects across the Carpathian Mountains region (e.g. ecological and geomorphic), especially in relation to the augmented summer heat stress (e.g. more frequent heatwaves) and milder winters (e.g. less freezing days). This study represents the first assessment of the elevation dependency of climate warming for the entire Carpathian Mountains region, using a fine‐resolution climatic dataset covering the period 1961–2010. Observed vertical patterns of temperature change in relation to the shifts of five key isotherms, relevant for the development of cold‐climate weathering process, presence of permafrost and spread of vegetation is discussed. Parts of the detect