TY - EJOU AU - T1 - Determination of Refractivity Gradient and Modified Refractivity Gradient for Cross River State T2 - International Journal of Sustainable Energy and Environmental Research PY - 2018 VL - 7 IS - 2 SN - 2306-6253 AB - In this paper, determination of refractivity gradient and modified refractivity gradient for Cross River state was carried out. The year 2013 Radiosonde meteorological data from Nigerian Meteorological Agency (NIMET) was used. Refractivity, modified refractivity, refractivity gradient and modified refractivity gradient were computed. The results showed that in the year 2013, Cross River state had maximum modified refractivity gradient (dM/dz) of 114.9 (M -units/Km) and it occurred in December whereas the minimum modified refractivity gradient (dM/dz) on 81.9 (M–units/Km) and it occurred in October . Also, in the year 2013, the maximum refractivity gradient (dN/dz) was -42.1 (N-units/Km) and it occurred in December whereas the minimum refractivity gradient (dN/dz) was -75.1 (N-units/Km) and it occurred in October. The standard refractivity gradient of -39 N-units and standard modified refractivity gradient of 118 M-units occurred in December at altitude of 103 meters. In all the months the atmospheric condition was in the normal state except in the month of October where superrefraction occurred. KW - Refractivity KW - Refractivity gradient KW - Radioclimatic factor KW - Modified refractivity gradient. DO - 10.18488/journal.13.2018.72.53.64