Browsing by Author "Espinoza, J."
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Item Open Access Development of a radiofrequency signal generator for ionosonde radar transmitter using low-cost SDR(2023 SWOL Workshop, 2023-10) Estalla, B.; Milla, M.; Verastegui, J.; Espinoza, J.; Scipión, DannyThe Jicamarca Radio Observatory (JRO) is an Instituto Geofísico del Perú (IGP) facility, dedicated to monitor the upper atmosphere with different instruments such as radars, GNSS receivers, magnetometers, among others. Ionosonde is a type of HF radar that uses multiple frequencies to survey the ionosphere and obtain estimates of electron density. In this poster we present the development of a low-cost radiofrequency signal generator for a ionosonde radar transmitter based on the Red Pitaya development board with a sampling frequency of 250 Msps, and the ability to transmit modulated signals with a frequency sweep ranging from 1 MHz to 60 MHz, providing the possibility of using it with other CW radars.Item Open Access Relación entre la reversión de la cota del río (repiquetes), las lluvias y los vientos en niveles bajos sobre el oeste de la cuenca amazónica(Instituto Geofísico del Perú, 2020-10) Figueroa, M.; Armijos Cardenas, Elisa Natalia; Espinoza, J.; Ronchail, J.; Fraizy, P.La agricultura ribereña en épocas de recesión del caudal (junio-octubre) es una de las actividades económicas más importantes de la llanura amazónica. Sin embargo, esta labor se ve afectada por los conocidos “repiquetes”, los cuales son inundaciones repentinas que se desarrollan en plena época de recesión debido a la reversión en el nivel del río. Utilizando datos diarios de nivel del río obtenidos de las reglas limnimétricas de las estaciones localizadas en los ríos Amazonas, Marañón y Ucayali, durante el período 1996-2018; se pudo determinar que de los 73 repiquetes observados en el río Amazonas (reversión ≥ 20 cm), el 64 % de ellos fueron precedidos por repiquetes solo en el río Marañón, y el 5 % fueron repiquetes originados solo en el río Ucayali. El 21 % de los eventos fueron antecedidos por repiquetes en ambos ríos y 10 % no tuvieron precursor aguas arriba. Estos resultados indican que el río Marañón es el principal precursor de los repiquetes originados en el río Amazonas. Analizando la lluvia diaria y vientos en niveles bajos (850 hPa) se puede concluir que los repiquetes registrados en el río Amazonas se originan por las abundantes lluvias en la región de transición Andes-Amazonas entre Perú y Ecuador, las cuales acontecen de tres a cinco días antes del inicio de cada repiquete. Las lluvias precursoras se relacionan con un cambio notable en la dirección del viento meridional, de norte a sur, y a un flujo de humedad hacia el este.Item Restricted The multi‐instrumented studies of equatorial thermosphere aeronomy scintillation system: Climatology of zonal drifts(American Geophysical Union, 1996-12-01) Valladares, C. E.; Sheehan, R.; Basu, S.; Kuenzler, H.; Espinoza, J.A spaced-antenna scintillation system was installed at Ancon, Peru, in May 1994 to measure scintillation of 250-MHz signals from a geostationary satellite by three antennas spaced in the magnetic east-west direction. These measurements were used to establish the climatology of the zonal drift of the irregularities which cause equatorial scintillations. The major objective of this study is to compare this drift climatology to the climatology of zonal neutral wind which is the driver of the equatorial electrodynamics. A comparison of these two climatologies in conjunction with scintillation statistics may provide some clues regarding factors which help or hinder the formation of equatorial spread-F (ESF). With these objectives in mind, the first year's drift and scintillation statistics have been presented as a function of local time, season and magnetic activity and compared with the statistics of ion drift published earlier from incoherent scatter radar observations. The scintillation drift is in good agreement with the Jicamarca radar observations except for the fact that the local time dependence of our drift observations exhibit a broader maximum. The broad maximum may be attributed to lower ion drag experienced in the presence of ESF due to sustained uplifting of the ionosphere. During magnetically active periods, the scintillation drift often exhibits east to west reversals presumably because of the disturbance dynamo effects. The westward drifts during such reversals may be as large as 100 m/s. We have also modeled the zonal drifts as a seasonal basis by using Hedin's neutral wind model and Anderson's fully analytical ionospheric model. The modeled zonal drifts present good quantitative agreement with the drifts obtained with the scintillation technique.Item Open Access Upgrade of Automatic Beam Switching (ABS) at Jicamarca Radio Observatory(Instituto Geofísico del Perú, 2021-06) Gonzales, L.; Espinoza, J.; Verástegui, J.; Ortecho, D.; Milla, Marco; Belleza, A.; Vila, N.Particular beam orientations are required for each experiment to study different atmospheric phenomena at the Jicamarca Radio Observatory (JRO), For an antenna array, this change can be done manually or remotely. JRO has had a beam steering system since 2005 for the remote operation. The remote operation is achieved using IP protocols and addresses associated with each antenna module and a web interface is used for the operation and supervision from the main building. The principle of the RF stage of the system is the phase shift due to change in the coaxial cable length between the source and the antennas in each antenna module. This poster summarizes the requirements of the system upgrade as well as the characteristics of the new electronic, mechanical, RF and interface design for each element of the automatic beam system used at JRO.