Frequency domain interferometry studies of mesospheric layers at Jicamarca

Abstract

Equatorial mesospheric scattering layer widths and motions were measured using the high‐resolution frequency domain interferometry technique at Jicamarca. Layer widths as small as ∼200 m were identified, as well as oscillatory vertical layer motions with 1–1.5 km peak‐to‐peak amplitudes. Layers are shown to oscillate with the vertical component of simultaneously observed gravity wave perturbation velocities. There is some suggestion in the data that lower mesospheric layers are more horizontally structured and patchy than higher mesospheric layers.

Frequency domain interferometry mode observations of PMSE using the EISCAT VHF radar

“…As discussed by Kudeki and Stitt (1990) the estimate of the coherence given by Eq. (2) will be contaminated by noise.…”

“…As we discuss later, this is accomplished by operating the radar at two or more closely spaced frequencies. The FDI technique has already been treated in several publications, for example (Franke (1990), Kudeki and Stitt (1990) and Franke et al (1992). Therefore, we only brie¯y summarize the technique here.…”

“…According to Kudeki and Stitt (1990), S 12 is related to properties of a singular atmospheric scattering layer through the expression…”

“…This allows detection of the presence of thin scattering layers within the radar volume. We note that FDI has proven eective in a number of studies in the lower to middle atmosphere (Kudeki and Stitt, 1990;Chilson et al, 1997b;Muschinski et al, 1999); however, with the exception of one 37-min data set of observations (Franke et al, 1992), this technique has not been utilized to date for the study of PMSE.…”

A discussion on the variations of MST/ST radar echo power with an atmospheric layer resolved by frequency domain interferometry technique

“…For example, Kudeki and Stitt [1990] compared the vertical Doppler velocity and the vertical displacement velocity of the mesospheric thin layer induced by the FDI technique and showed a reasonable agreement between them; on the other hand, the FDI observations of large-scale vertical motion in the atmosphere made by Muschinski et al [1999] displayed a disagreement between the two velocities. Recently, Chilson et al [1997] analyzed the phase relations between the oscillations of signal-tonoise ratio (SNR), vertical Doppler velocity, amplitude of the normalized complex cross-correlation function (coherence), and the height of the tropospheric billows associated with the Kelvin-Helmholtz (KH) instability to study the characteristics of the KH billows.…”