| dc.description.abstract | FORMOSA-3 satellite occultation data and Chung-Li VHF radar echo data will be used to study the ionospheric Sporadic-E layer (Es layer) in this research. The Es layer could be classified from their different three-Dimensional structure but this thesis only discuss layer-structured Es layer, which thickness is very narrow, about 0.5 ~ 5 km, and the horizontal extension is very wide, about hundred kilometers level. [Jong-Ching Liu, 2015] show that when GPS rays nearly horizontally pass through the layer-structured Es layer, the signal-to-noise ratio (SNR) profile received by FORMOSA-3 will be a ＂U-shaped structure＂, which called defocusing phenomenon. In additional, Jong-Ching Liu also uses the ray trace algorithms to explain the deflection of the propagation path of the radio wave affected by the gradient of the refractive index in the vertical direction. First, analyze the two years satellite occultation data in 2008 and 2011, and select typically layer-structured Es layer events with a ＂U-shaped structure＂ by the quality control method from [Chu et. al., 2014] and the property of defocusing phenomenon. Then discuss the morphological characteristics of the layer-structured Es layer, including the seasonal change in time and the global distribution of height and thickness in space. Use the histogram to quantify the exact height, thickness and their distribution, which are the main result in this research. Secondly, another purpose of this thesis is to verify the simulated results in [Jong-Ching Liu, 2015] to confirm whether the GPS rays almost horizontally pass through the layer-structured Es layer when defocusing phenomenon occurs. To verify this result, the information of Es layer obtained from satellite occultation data is not enough. Also combine with radar echo data to reach the goal. First, get the echo power from the range-time-intensity (RTI) diagram, and use cross-spectrum and radar interferometry to find and locate the field-align irregularity (FAI) echo points in Es layer, and then use the method in [Kuo-Feng Yang, 2008] to retrieve the plane of layer-structured Es layer in three-dimensional space. With this plane equation, the incident angle between the plane of Es layer and the propagation direction of GPS L1 signal could be calculated. Furthermore, it can also be confirmed whether the ＂U-shaped structure＂ observed by the satellite is on the plane of Es layer. | en_US |