Temperature inversions in France – Part A: time variations

Temperature inversions in mainland France are computed using a network of 859 sampling sites spread as evenly possible across the country. Each site comprises high station located within 30 km low with which it is paired. We use daily minimum (tn) and maximum (tx) temperatures from Météo-France weather stations over 10 years (2008–2017). The time variations three inversion characteristics (frequency, intensity, duration) explored. primary result frequency inversions. On average, for sites, tn-inversions occur on 63% days tx-inversions 22.6%. Inversion intensity usually weak, mode being 2°C tn 1°C tx. However, intensities may be reached (maximum 23.6°C 22.6°C tx). longest sequence isolated (the destroyed daytime but recurs several days) ran more than four months (126 days). Such most frequently August to October. overnight) 38 days. common November February. persistent (night day) lasted 88 Persistent January. results whole reveal number original points: existence large tx-inversion sequences, seasonal pattern very clearly differentiating tn- tx-inversions, significance atmospheric conditions.