Temperature – Humidity Index (THI) within the Oltenia Plain between 2000 and 2009

Abstract: Temperature-humidity index, also known as thermal comfort index, represents an extremely used index in mass-media nowadays; it renders an apparent temperature, namely the temperature felt by human body that cools slower at higher values of the relative humidity due to the reduction of the evaporation rate. THI is calculated on the base of several formulas, which corroborate air temperature and relative humidity, the critical threshold being 80. By analysing the statistical date supplied by the Regional Meteorological Center Craiova, it comes out that the years with the highest number of days with THI values above 80 are 2000, 2001, and 2007 for the entire studied territory, when, during summer, the region was affected by numerous heat waves, which led to the frequent exceeding of the 40°C value. The most affected area is located in the central-southern and eastern parts of the Oltenia Plain – 51 days with THI > 80 at Caracal in 2000, 47 days with THI > 80 at Bechet in 2001, and 41 days with THI > 80 at Băileşti in 2007. Regarding the monthly distribution, the most problematic months are, of course, July and August, when it is favoured the penetration of certain extremely hot air masses from northern Africa, as well as thermal convection. During the analysed decade, the highest monthly number of days with values above the threshold was registered at Caracal in August 2000 – 23, at Bechet in August 2001 – 25, and at Băileşti in July 2007 – 20. On the whole, in the 10 analysed years, we remark Băileşti – 76 days in July and 90 in August, Bechet – 84 days in July and 83 in August, and Calafat – 77, respectively 70 days. Increased values of THI mainly affect children and elderly people or those suffering of different diseases. At values lower than 70 of the THI, most of the people feel comfortable, at values comprised between 75 and 80, about half of the population feels thermal discomfort, while at values above 80, even if the discomfort sensation is not obvious, it is recommended to take adequate protection measures.