1. a Geophysics Centre of Evora (CGE) , University of Évora , Rua Romão Ramalho, 59, 7000 Évora, Portugal
2. b Institute of Atmospheric Sciences and Climate (ISAC‐CNR) , Via Gobetti, 101, 40129 Bologna, Italy
3. c STIL‐BAS , Base Observatory , 6000 Stara Zagora, Bulgaria