Surname: Yu
First Name: Tian-You
Status= studentyes
Institution: University of Nebraska-Lincoln
E-mail: tian@doppler.unl.edu
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Title: 
Observations of PMSE Using Coherent Radar Imaging:
Direct Evidence of Wave Steepening
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Authors: 
Tian-You Yu, Robert D. Palmer, and Phillip B. Chilson
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Abstract: 
In this work, coherent radar imaging (CRI) was implemented using the
ESRAD (ESrange mst RADar) system in Kiruna, Sweden in the summer of 1998.
Horizontal structures of polar mesosphere summer echoes (PMSE)
are first studied with highly temporal and angular resolution using CRI.
Frequency jumps, which are sudden changes in the radial velocity,
were observed in several regions during this experiment.
By analyzing the spectrograms and the brightness distribution estimates
during two cases of frequency jumps, it was evident that the frequency jump
was caused by a steepened wave structure.
The existence of steepened wave is further verified using a simulation model.


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Discipline Category: Mesosphere