[2] After a few years as forecasting meteorologist he turned to the theory of ionized layers in the terrestrial atmosphere (fundamental book 1945).
After World War II he met the most known colleagues at the meeting of the International Union of Radio Science (URSI) at Paris 1946.
He came to the United States first in 1950 where amongst other colleagues he met David Bates a scholar of Sir Harrie Massey the well-known physico-chemist.
In the following decades Nicolet was often invited to the US but the Institut royal meteorologique de Belgique remained his lifelong scientific home.
[7] King Baudouin of Belgium granted him the title of Baron in 1987 for his important contribution to the success of the International Geophysical Year.