Browsing by Author "Chau, J.L."

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    Estimation of spectral parameters from oblique Equatorial Electrojet echoes using a double skewed Gaussian model at JRO
    (2023 CEDAR Workshop, 2023) Flores, Roberto; Milla, M.; Kuyeng, Karim; Hysell, D.L.; Chau, J.L.
    Coherent echoes from the equatorial electrojet (EEJ) region are detected at the Jicamarca Radio Observatory (JRO) by using an array of 16 Yagi antennas with a main beam pointed obliquely to the west with an elevation of about 35 deg. The spectrum of these observations are composed of two types of EEJ echoes (Type I and Type II)[1] from which we can estimate their main spectral parameters such as Doppler shift and spectral width independently for each type. Previously, the method applied to obtain these parameters was a standard fitting approach based on a double Gaussian model. However, in some cases, the shape of the spectral measurements are not symmetric (resembling the shape of a skewed distribution). Based on simulations, we determined that the skewed shape of the oblique EEJ spectrum comes from the fact that the measured spectrum is the result of the sum of spectral contributions coming from different heights, with different Doppler shifts and spectral widths weighted by the antenna beam shape. The overall result is an asymmetric spectrum with a peak that does not coincide with the average Doppler shift. Thus in order to account for this effect, we have implemented a double skewed Gaussian distribution model to fit the oblique EEJ measurements and estimate their spectral parameters. In this work, we present the results obtained in the simulation showing the skewed shape of the spectrum. Based on our simulations, we have also proved that the shift of the skewed Gaussian model can be interpreted as the Doppler shift of the echoes. In addition, some examples of the new fitting procedure are shown in comparison with the classical Gaussian fitting where it can be seen the better agreement between the data and the double skewed Gaussian model.
    Palabras clave:Equatorial electrojetDoppler shiftGaussian fitting
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    Inferring Zonal Wind Profiles in the Equatorial Electrojet From Coherent Scatter
    (URSI, 2022-10-16) Hysell, D.L.; Chau, J.L.; Conte, J.F.; Flores, Roberto; Milla, M.A.
    Zonal wind estimates in the equatorial electrojet derived from coherent scatter echoes, specular meteor trail echoes, and optical limb scans are compared. While the three techniques exhibit broad overall agreement, significant differences in the results of the three techniques appear. The differences can be attributed in large part to horizontal inhomogeneity in the winds and the dissimilar averaging kernels of the three techniques.
    Palabras clave:Zonal windsEquatorial ElectrojetSpecular meteors
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    SIMONe Peru: deployment and operations
    (Instituto Geofísico del Perú, 2020-06) Suclupe, J.; Kuyeng, K.; Milla, Marco; Chau, J.L.; Urco, M.; Pfeffer, N.; Clahsen, M.; Vierinen, J.; Erickson, P.
    SIMONe Peru is a modern multistatic specular meteor radar which allows measuring winds in the mesosphere and lower thermosphere (MLT) between 70 and 110 km in altitude. Its main objective is to study the atmospheric dynamic in this region. Moreover, the system provides a higher number of detections compared to other systems and gives good statistics from detections in this region. This system started operations on september 2019 in the central coast of Peru. This work presents a general outline of the SIMONe Peru system, as well as the some preliminary results that allow us to operate and monitor it.
    Palabras clave:Meteor radarAtmospheric dynamicsAeronomy