A diagnostic technique for the local measurement of emissions from the molecular hydrogen has been developed. In the presence of an external magnetic field, the emission position can be deduced from the Zeeman patterns in the spectral line shape, and with the aid of the coronal model the rovibronic emission intensity provides the local rovibrational temperatures. In order to evaluate the Zeeman effect on the hydrogen molecule, a quantum-mechanical calculation is performed. The experimentally observed Fulcher- α rovibronic band spectra under a magnetic field strength of about 7 T are well represented by the calculation. The temporal evolution of the emission position as well as the rovibrational temperatures are measured in the 8.2 GHz lower hybrid current drive discharges of the TRIAM-1M tokamak [H. Zushi, Nucl. Fusion 45, S142 (2005)]. The measured emission is found to originate from the region where the plasma comes in contact with the limiter, and the observed increase in the rotational temperature suggests a rise in the limiter surface temperature. © 2007 American Institute of Physics.