Nt
From Glossary of Meteorology
nT
The nanotesler (nT); a measure of geomagnetic field strength.
There are 109 nanoteslers in a tesler, which is the unit of measure of magnetic field strength in the SI system of units. An nT is equal to a gamma. There are 105 gammas in an oersted, which is the unit of measure of magnetic field strength in the cgs system.