표 1. | Table 1. 굴절 기울기 및 상태 분류 | Refractive gradients and condition.

Condition	N-gradient [N/km]	M-gradient [M/km]
Ducting	<−157	<0
Superrefraction	−157∼−79	0∼79
Normal	−79∼0	79∼157
Standard	−39	118
Subrefraction	>0	>157