Changes in Cold Indices in the Recent Past in Dolj County, Romania

Socio-economic activity during cold season depends on a large degree by the air temperature and, in some cases, also on ground temperatures. In this context, the present study focused on two cold-season indices with practical applications, namely number of frost days (i.e., with minimum air temperature equal or below 0 °C) and number of frozen soil days (i.e., within minimum ground temperature equal or below 0 °C). The aim of the study was twofold: firstly, to investigate the observed changes of these indices in the last years; secondly, to assess the performance of alternative data sources for deriving information targeting specific beneficiaries of this climate-based information. The analysis concentrated on the area of Dolj county for the period October-April 2011-2022 and three data sources were used: observation data from weather stations, UERRA reanalysis dataset and E-OBS observation-based dataset. The results showed that for both indices the trend was negative. With low values of FD and FSD, autumn was a more favorable period for various activities than the early spring, whereas winter months were mostly unfavorable for outdoor activities. Thus, the study provided useful information for various end-users (e.g., in agriculture, construction sector) for better planning their activities.