modified index of refraction

modified index of refraction

[′mäd·ə‚fīd ′in‚deks əv ri′frak·shən] (meteorology) An atmospheric index of refraction mathematically modified so that when its gradient is applied to energy propagation over a hypothetical flat earth, it is substantially equivalent to propagation over the true curved earth with the actual index of refraction. Also known as modified refractive index; refractive modulus.