Estimation and Investigation of the Variability of Tropospheric Radio Refractivity and Radio Field Strength over Accra, Ghana

he average refractivity gradient and the average effective earth radius (k – factor) estimated for Accra during the period under investigation were found to be -44.1405 N-units/km and 1.39 respectively suggesting that the propagation in this geographical location is mostly super – refractive. The highest and lowest mean values of FSV were found during the dry and rainy seasons in the months of January and June with 3.0998 dB and 0.0158 dB respectively.

Surface Radio Refractivity of Akure and Ondo town, Southwest Nigeria

The surface radio refractivity, refractivity gradient at 1km above ground surface and the effective earth radius factor, K over Akure and Ondo town of South west Nigeria has been investigated using Ten (10) years daily data of the meteorological parameters of Pressure, air temperature and humidity. The result showed that the mean monthly value of the surface refractivity at the Ondo station is generally slightly higher than that of Akure. The monthly mean value of refractivity at the two stations was found to be strongly correlated with a value of 0.915. The most negative refractive gradient value observed at Ondo and Akure are of -46.48N-units/km and -45.64N-units/km respectively and the least effective earth radius factor, k value of 1.421 and 1.410 were observed at the station respectively. These results showed that the Ondo and Akure station were generally super-refractive. The Ondo station was however found to be slightly more super-refractive than the Akure station.

An Experiment in the Earth Physics Leaning: Sunlight Observation for Determining Radius of The Earth

In the learning of the earth physics, sometime students got comfusing due to they cannot imagine how to determine the physical property of the earth such as, its mass, its volume and its diameter. This study was focused on how to use the sunlight for degermation of the earth radius through the simple experiment. In this study, an accurate and simple method have been introduced to the student on how to measure the earth radius. The experiment just used a camera and then the student started to determine the earth radius. In the end of the experiment student can explain how the sunlight can be used to determine the earth radius mathematically. They found that the radius of the earth is about 6243.04 km with a standard deviation of 13.70 km. The average results that is obtained by student is actually within 1.9% of the real value of the earth radius which is at 6371 km. This study shows that the real experiment is definitely able to show the real experience on how to determine the earth radius.