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IDENTIFYING E AND F LAYER IONOSPHERIC IRREGULARITIES WITH A SCINTILLATION AURORAL GPS ARRAY
Title
IDENTIFYING E AND F LAYER IONOSPHERIC IRREGULARITIES WITH A SCINTILLATION AURORAL GPS ARRAY
Creator
Sreenivash, Vaishnavi
Date
2018, 2018-05
Description
The Scintillation Auroral GPS Array (SAGA), comprising six kilometer-spaced receivers located in Poker Flat, Alaska, has been deployed for...
Show moreThe Scintillation Auroral GPS Array (SAGA), comprising six kilometer-spaced receivers located in Poker Flat, Alaska, has been deployed for four years to study high latitude scintillation effects on L1 and L2C frequency Global Positioning System (GPS) signals. These scintillations disrupt the GPS signals received on the earth, affecting navigation services. Scintillation is associated with the variations in plasma densities known as irregularities, present in the ionosphere. Research on scintillation has been done from the past using different instruments and techniques, and for multiple purposes. One important prior effort is automated detection of the scintillation of L1 frequency GPS signals. Other successful research includes estimating the drift velocity of irregularities, anisotropy, height and thickness of the scattering layer. It is important to check before studying the properties of irregularities whether the sensors can detect the scintillations happening in the E or F region. In other words, it is essential to check that the sensors are sensitive not only to F region scintillations but also to the E region scintillations. The purpose of this work is to identify the ionospheric region, E or F, which is responsible for the scintillation on the L1 and L2C GPS signals. The scintillations of these GPS signals are further classified based on the type of scintillation i.e., phase scintillation and amplitude scintillation. The scintillation events are categorized as amplitude, phase, or both on L1 or L2C frequency occurring in the E or F region. Using the automated scintillation detection routine, a complete list of phase and amplitude scintillations on all days for both the frequencies L1/L2C in the years 2014 and 2015 is created. The highly scintillating days for 2014 and 2015 are sorted and the irregularities layer associated with these scintillation events are identified. The Poker Flat Incoherent Scatter Radar (PFISR) and All Sky Camera images are used to develop the process of identifying the ionospheric region. The electron density from PFISR is assumed to be an essential parameter to determine the E/F layer irregularities. The All Sky Camera provides the red auroral brightness and the green auroral brightness, where red aurora implies F region and the green aurora implies E region. A summary of a subset of the scintillation events occurring on the highly scintillating days in 2014 and 2015 is provided through this work. It is found that phase scintillation is occurring more predominantly in the high latitudes than the amplitude scintillation. A number of these are attributed to E and F region irregularities. In future, the scintillation events obtained from this work will be used to study the E and F layers irregularities and properties in detail.
M.S. in Mechanical and Aerospace Engineering, May 2018
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