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  • ItemRestricted
    A storm-time global electron density reconstruction model in three-dimensions based on artificial neural networks
    (Elsevier, 2024-02-16) Habarulema, John Bosco; Okoh, Daniel; Burešová, Dalia; Rabiu, Babatunde; Scipión, Danny; Häggström, Ingemar; Erickson, Philip J.; Milla, Marco A.
    We present results of a dedicated global storm-time model for the reconstruction of ionospheric electron density in three-dimensions. Using the storm criterion of |Dst| ≥ 50 nT and Kp ≥ 4, the model is constructed using a combination of radio occultation and ionosonde data during the periods of 2006–2021 and 2000–2020, respectively. From the ionosonde data, only the bottomside electron density profiles up to the maximum height of the F2 layer (hmF2) are considered. In addition to the selection of storm-time data only for the model development, we have investigated the inclusion of time history for the geomagnetic storm indicator Kp at 9 and 33 h in an attempt to take into account the delay of physical processes related to atmospheric gravity waves or traveling ionospheric disturbances and thermospheric composition changes which drive varying ionospheric storm effects during storm conditions. Based on incoherent scatter radar data and in comparison with the IRI 2020 model, the developed storm-time model provides foF2 modelling improvement of above 50% during the storm main phase over Millstone Hill (42.6°N, 71.5°W) and Tromsø (69.6°N, 19.2°E) for the storm periods of 3–6 November 2021 and 23–25 March 2023, respectively. Modelled results for Jicamarca (11.8°S, 77.2°W) show that the storm-time model estimates foF2 by an improvement of over 20% during the main phase of the 07–10 September 2017 storm period. As the ionospheric conditions return to quiet time levels, the IRI 2020 model perform better than the constructed storm -time model.
  • ItemOpen Access
    Climatology of mesosphere and lower thermosphere diurnal tides over Jicamarca (12°S, 77°W): observations and simulations
    (SpringerOpen, 2023-12-14) Suclupe, Jose; Chau, Jorge L.; Conte, Federico J.; Milla, Marco; Pedatella, N. M.; Kuyeng, Karim
    This work shows a 3-year climatology of the horizontal components of the solar diurnal tide, obtained from wind measurements made by a multistatic specular meteor radar (SIMONe) located in Jicamarca, Peru (12°S, 77°W). Our observations show that the meridional component is more intense than the zonal component, and that it exhibits its maxima shifted with respect to the equinox times (i.e., the largest peak occurs in August–September, and the second one in April–May). The zonal component only shows a clear maximum in August–September. This observational climatology is compared to a climatology obtained with the Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension (WACCM-X). Average comparisons indicate that the model amplitudes are 50% smaller than the observed ones. The WACCM-X results are also used in combination with observed altitude profiles of the tidal phases to understand the relative contributions of migrating and non-migrating components. Based on this, we infer that the migrating diurnal tide (DW1) dominates in general, but that from June until September (November until July) the DE3 (DW2) may have a significant contribution to the zonal (meridional) component. Finally, applying wavelet analysis to the complex amplitude of the total diurnal tide, modulating periods between 5 and 80 days are observed in the SIMONe measurements and the WACCM-X model. These modulations might be associated to planetary waves and intraseasonal oscillations in the lower tropical atmosphere.
  • ItemOpen Access
    On the detection of a solar radio burst event that occurred on 28 August 2022 and its effect on GNSS signals as observed by ionospheric scintillation monitors distributed over the American sector
    (EDP Open, 2023-11-28) Wright, Isaac G.; Rodrigues, Fabiano S.; Gomez Socola, Josemaria; Moraes, Alison O.; Monico, João F. G.; Sojka, Jan; Scherliess, Ludger; Layne, Dan; Paulino, Igo; Buriti, Ricardo A.; Brum, Christiano G. M.; Terra, Pedrina; Deshpande, Kshitija; Vaggu, Pralay R.; Erickson, Philip J.; Frissell, Nathaniel A.; Makela, Jonathan J.; Scipión, Danny
    As part of an effort to observe and study ionospheric disturbances and their effects on radio signals used by Global Navigation Satellite Systems (GNSS), alternative low-cost GNSS-based ionospheric scintillation and total electron content (TEC) monitors have been deployed over the American sector. During an inspection of the observations made on 28 August 2022, we found increases in the amplitude scintillation index (S4) reported by the monitors for the period between approximately 17:45 UT and 18:20 UT. The distributed, dual-frequency observations made by the sensors allowed us to determine that the increases in S4 were not caused by ionospheric irregularities. Instead, they resulted from Carrier-to-Noise (C/No) variations caused by a solar radio burst (SRB) event that followed the occurrence of two M-class X-ray solar flares and a Halo coronal mass ejection. The measurements also allowed us to quantify the impact of the SRB on GNSS signals. The observations show that the SRB caused maximum C/No fadings of about 8 dB-Hz (12 dB-Hz) on L1 ~ 1.6 GHz (L2 ~ 1.2 GHz) for signals observed by the monitor in Dallas for which the solar zenith angle was minimum (~24.4°) during the SRB. Calculations using observations made by the distributed monitors also show excellent agreement for estimates of the maximum (vertical equivalent) C/No fadings in both L1 and L2. The calculations show maximum fadings of 9 dB-Hz for L1 and of 13 dB-Hz for L2. Finally, the results exemplify the usefulness of low-cost monitors for studies beyond those associated with ionospheric irregularities and scintillation.
  • ItemOpen Access
    On new two-dimensional UHF radar observations of equatorial spread F at the Jicamarca Radio Observatory
    (Springer Open, 2023-08-09) Rodrigues, F.S.; Milla, M.A.; Scipión, Danny; Apaza, Joab; Kuyeng, Karim; Sousasantos, J.; Massoud, A.A.; Padin, C.
    We describe a mode for two-dimensional UHF (445 MHz) radar observations of F-region irregularities using the 14-panel version of the advanced modular incoherent scatter radar (AMISR-14). We also present and discuss examples of observations made by this mode. AMISR-14 is installed at the Jicamarca Radio Observatory (JRO, 11.95°S, 76.87°W, ~ 0.5° dip latitude) in Peru and, therefore, allows studies of ionospheric irregularities at the magnetic equator. The new mode takes advantage of the electronic beam-steering capability of the system to scan the equatorial F-region in the east–west direction. Therefore, it produces two-dimensional views of the spatial distribution of sub-meter field-aligned density irregularities in the magnetic equatorial plane. The scans have a temporal resolution of 20 s and allow observations over a zonal distance of approximately 400 km at main F-region heights. While the system has a lower angular and range resolution than interferometric in-beam VHF radar imaging observations available at Jicamarca, it allows a wider field-of-view than that allowed with the VHF system. Here, we describe the mode, and present and discuss examples of observations made with the system. We also discuss implications of these observations for studies of ESF at the JRO.
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    Digital receiver modernization using FPGA and JESD204B interface for SDR applications
    (IEEE, Institute of Electrical and Electronics Engineers, 2023) Verástegui, Joaquín; Rojas, John; Tupac, Isaac; Gonzales, Luis
    The latest data acquisition system running at the Jicamarca Radio Observatory (JRO) for the main radar has been used for more than seven years now. Although there are no major inconveniences on the performance, there have been some problems with internal interference which are related to the PCB design that uses old discrete components. A new design is proposed for the digital receivers, giving it more lifetime and flexibility for future modifications. The JESD204B protocol is ideal for radar applications, a JESD204B ADC together with an FPGA was proposed for the new design, making it capable of a wider bandwidth which could adapt the system to an SDR device in the future with the proper software. This paper will present the new PCB design, the IP cores implemented for the FPGA and some preliminary tests with development boards.
  • ItemOpen Access
    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.
  • ItemOpen Access
    Seeing measurements at OAUNI on 2016 and 2017 campaigns
    (IOP Publishing, 2022) Pereyra, Antonio; Tello, J.; Zevallos, M.
    We present seeing measurements at OAUNI site gathered on 2016 and 2017 campaigns using V and R broadband filters. In order to quantify the seeing we used the full-width-at-half-maximum from stellar profiles on photometric sequences during the observational windows of our supernovae program. A typical median seeing of 1” .8 was found on 2016 and a worst value of 2” .0 on 2017. The last one was probably affected by anomalous conditions related to the 2017 extreme climatic event. The monthly first quartile analysis indicates that best seeing conditions can be achieved at a level of 1” .5. In general, our results indicate a reasonable sky quality for the OAUNI site.
  • ItemOpen Access
    Driving Influences of the Doppler Flash Observed by SuperDARN HF Radars in Response to Solar Flares
    (American Geophysical Union, 2022-06) Chakraborty, S.; Qian, L.; Baker, J. B. H.; Ruohoniemi, J. M.; Kuyeng, Karim; Mclnerney, J. M.
    Sudden enhancement in high-frequency absorption is a well-known impact of solar flare-driven Short-Wave Fadeout (SWF). Less understood, is a perturbation of the radio wave frequency as it traverses the ionosphere in the early stages of SWF, also known as the Doppler flash. Investigations have suggested two possible sources that might contribute to it’s manifestation: first, enhancements of plasma density in the D-and lower E-regions; second, the lowering of the F-region reflection point. Our recent work investigated a solar flare event using first principles modeling and Super Dual Auroral Radar Network (SuperDARN) HF radar observations and found that change in the F-region refractive index is the primary driver of the Doppler flash. This study analyzes multiple solar flare events observed across different SuperDARN HF radars to determine how flare characteristics, properties of the traveling radio wave, and geophysical conditions impact the Doppler flash. In addition, we use incoherent scatter radar data and first-principles modeling to investigate physical mechanisms that drive the lowering of the F-region reflection points. We found, (a) on average, the change in E- and F-region refractive index is the primary driver of the Doppler flash, (b) solar zenith angle, ray’s elevation angle, operating frequency, and location of the solar flare on the solar disk can alter the ionospheric regions of maximum contribution to the Doppler flash, (c) increased ionospheric Hall and Pedersen conductance causes a reduction of the daytime eastward electric field, and consequently reduces the vertical ion-drift in the lower and middle latitude ionosphere, which results in lowering of the F-region ray reflection point.
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    Prompt penetration and substorm effects over Jicamarca during the September 2017 geomagnetic storm
    (American Geophysical Union, 2021-08) Fejer, B. G.; Navarro, L. A.; Sazykin, S.; Newheart, A.; Milla, Marco; Condor, Percy
    We used reanalyzed Jicamarca radar measurements to study the response of equatorial ionospheric electrodynamics and spread F during the main phase of the large September 2017 geomagnetic storm. Our observations near dusk on 7 September show very large upward drifts followed by a large short-lived downward drift perturbation that completely suppressed the lower F region plasma irregularities and severely decreased the backscattered power from the higher altitude spread F. We suggest that this large short-lived westward electric field perturbation is most likely of magnetospheric origin and is due to a sudden and very strong magnetic field reconfiguration. Later in the early night period, data indicate large, mostly upward, drift perturbations generally consistent with standard undershielding and overshielding electric field effects, but with amplitudes significantly larger than expected. Our analysis suggests that occurrence of storm-time substorms is one of the major factors causing the large nighttime westward and eastward electric field perturbations observed at Jicamarca near the storm main phase. Our analysis also suggests that magnetospheric substorms play far more important roles on the electrodynamics of the equatorial nighttime ionosphere than has generally been thought.
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    The CosmoAmautas project for equitable scientific education in Peru
    (Nature Research, 2022-02-18) Calistro Rivera, Gabriela; Bardalez Gagliuf, Daniella; Alvarado Urrunaga, Diego; Gonzales Quevedo, Lisseth; Klefman, Daniel; Meza, Erick; Quispe Quispe, Adita; Ramos Lázaro, Jenny Margot; Ricra, José; Rodríguez Marquina, Bruno; Torre Ramirez, Erika
    We all live under the same sky. This accessibility places astronomy in a unique position to inspire awe and connect people from a variety of backgrounds. Astronomy thus has the potential to promote equity and diversity in society, while providing the technical basis for the inclusion of the scientific method in education. Peru is a country with an astronomical tradition that goes back millennia to the most ancient cultures in the Americas. This heritage, in conjunction with the under-exploited world-class quality of the Peruvian skies, makes astronomy a highly applicable tool for scientific and socioeconomic development, as defined by the United Nations Sustainable Development Goals. Such a contribution is timely and urgent as countries in Latin America are experiencing the worst educational crisis in their history due to the COVID-19 pandemic. The case of Peru has been particularly critical, with more than 85% of schools closed throughout 2020 and 2021, and the public education system in a declared state of emergency until 2022. Even before the pandemic, Peru had one of the lowest scores in Latin America in the areas of science and maths based on Programme for International Student Assessment (PISA) evaluations. In particular, the most striking gaps are found between rural and urban female students as evidenced by an illiteracy rate of 21.2% for the female rural population over 15 years old compared with the average national illiteracy rate of 5.5% (ref.), reflecting severe inequalities in education.
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    Mapping irregularities in the postsunset equatorial ionosphere with an expanded network of HF beacons
    (American Geophysical Union, 2021-07) Hysell, D. L.; Rojas, E.; Goldberg, H.; Milla, Marco; Kuyeng, K.; Valdez, A.; Morton, Y. T.; Bourne, H.
    Data from a network of high-frequency (HF) beacons deployed in Peru are used to estimate the regional ionospheric electron density in a volume. Pseudorange, accumulated carrier phase, and signal power measurements for each of the 36 ray paths provided by the network at a 1 min cadence are incorporated in the estimates. Additional data from the Jicamarca incoherent scatter radar, the Jicamarca sounder, and GPS receivers can also be incorporated. The electron density model is estimated as the solution to a global optimization problem that uses ray tracing in the forward model. The electron density is parametrized in terms of B-splines in the horizontal direction and generalized Chapman functions or related functions in the vertical. Variational sensitivity analysis has been added to the method to allow for the utilization of the signal power observable which gives additional information about the morphology of the bottomside F region as well as absorption including absorption in the D and E regions. The goal of the effort is to provide contextual information for improving numerical forecasts of plasma interchange instabilities in the postsunset F region ionosphere associated with equatorial spread F (ESF). Data from two ESF campaigns are presented. In one experiment, the HF data revealed the presence of a large-scale bottomside deformation that seems to have led to instability under otherwise inauspicious conditions. In another experiment, gradual variations in HF signal power were found to be related to the varying shape of the bottomside F layer.
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    Ionospheric echo detection in digital ionograms using convolutional neural networks
    (American Geophysical Union, 2021-08) De la Jara, César; Olivares, C.
    An ionogram is a graph of the time that a vertically transmitted wave takes to return to the earth as a function of frequency. Time is typically represented as virtual height, which is the time divided by the speed of light. The ionogram is shaped by making a trace of this height against the frequency of the transmitted wave. Along with the echoes of the ionosphere, ionograms usually contain a large amount of noise and interference of different nature that must be removed in order to extract useful information. In the present work, we propose a method based on convolutional neural networks to extract ionospheric echoes from digital ionograms. Extraction using the CNN model is compared with extraction using machine learning techniques. From the extracted traces, ionospheric parameters can be determined and electron density profile can be derived.
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    Spectral Analysis of Incoherent Scatter Radar Signals in Faraday/Double Pulse Experiments at the Jicamarca Radio Observatory
    (IEEE, Institute of Electrical and Electronics Engineers, 2021) Flores, Roberto; Milla, Marco; Kuyeng, Karim
    The Jicamarca incoherent scatter radar can be operated in different modes to measure the main physical parameters of the equatorial ionosphere. One of these modes is the Faraday/Double Pulse experiment that was designed to estimate F -region plasma densities and electron/ion temperatures by pointing the Jicamarca antenna beam off-perpendicular to the geomagnetic field. For several years, the data processing for this mode was performed in time domain (correlation analysis), but sometimes the data is contaminated with frequency interference and other unwanted signals that are not easy to remove. To obtain better results, a spectral analysis procedure for this mode has been implemented in Signal Chain, a python-based radar signal processing library developed at the Jicamarca Radio Observatory. Signal Chain includes algorithms for interference and clutter removal to clean the spectral data before estimating the geophysical parameters. The procedure applies an outlier removal algorithm before calculating incoherently averaged power spectra. This algorithm, based on the Hildebrand-Sekhon method, is applied to sequences of spectral data for each frequency bin. Then, the DC clutter from the self- and cross-spectra is removed as a second step in the cleaning process. In this work, we present the results obtained with the spectral analysis procedure applied to the the FaradaylDouble Pulse experiment and compared the electron densities estimated with this method with the ones obtained with the standard correlation analysis.
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    SOPHy: Scanning-system for Observations of Peruvian Hydrometeorological-events
    (IEEE, Institute of Electrical and Electronics Engineers, 2021) Espinoza, Juan C.; Scipión, Danny; Valdez, Alexander; Verástegui, Joaquín
    In this paper we present the current progress in the construction of the first X-band dual-pol mobile weather radar (SOPHy) in Peru. This portable mobile system allows scans in azimuth and elevation with a maximum range of 60 km. The radar transmission and reception systems are based on SDR (Software Defined Radio) technologies for configuration flexibility. The objective of the radar is to study precipitation in an area of several tens of kilometers around the radar, in order to research the climate and atmospheric conditions in Peru.
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    Design of a Programmable Radar Controller ASIC on VHDL for a Modular Radar System
    (IEEE, Institute of Electrical and Electronics Engineers, 2021) Verastegui, Joaquin; Manay, Ivan; Pacheco, Edgardo E.; Milla, Marco
    The Jicamarca Radio Observatory (JRO), funded by the USA National Science Foundation (NSF), operates several radars for different applications, from the main radar, an incoherent scatter radar used mainly for ionospheric activity observations, to ionosondes and wind profilers. Most of these radars use a centralized modular control system that commands all the radar sequences that require the radar modules, these tasks and sequences are controlled by pulsed digital signals. The device responsible for this operation is called the Radar Controller. A large number of customized Radar Controller versions were developed and built at JRO for decades, since the utilization of its first acquisition system. The current version of the Radar Controller is based on an RTL design written on VHDL language that implements a custom arbitrary waveform generator connected to an SRAM memory that stores all the data a given waveform needs. The Radar Controller uses a register based architecture to communicate between blocks internally. In JRO we use a Spartan 6 FPGA and it is controlled by a Tiva C microcontroller board which has an Ethernet port. A Restful API has been implemented on the microcontroller for user configuration. This paper will cover the VHDL RTL design of the current version of the Radar Controller core.
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    Design and development of a low-cost wireless network using IoT technologies for a mudslides monitoring system
    (IEEE, Institute of Electrical and Electronics Engineers, 2021) Meléndez Coveñas, Frank Enrique; Palomares, Ricardo; Milla, Marco; Verastegui, Joaquin; Cornejo, José
    The city of Lima - Peru is affected periodically by mudslides and floods caused by torrential rains near Lima's mountain region. The Jicamarca ravine is especially affected by this phenomenon and is also critical to the population because of its proximity to SEDAPAL's water treatment plant that provides drinking water service to approximately 80% of homes in Lima city. In addition to this, there are a lot of houses located near the riversides affected by the mudslides that could be affected by the overflows. This paper describes the implementation of a low-cost wireless sensor network based on Internet of Things (IoT) technologies designed for monitoring mudslides events made by the association of the Professional School of Electronic Engineering and Telecommunications of the Universidad Nacional Tecnológica de Lima Sur and the Radio Observatorio de Jicamarca, research facility of the Instituto Geofísico del Perú. The network consists of various monitoring stations based on the ESP32 microcontroller and it takes advantage of the Long-Range mode of this device. The radio links created have a range of more than 1 km and all of them are connected to one access point which has a connection to the internet using the IoT technology of the cellular mobile network. The access point sends data to a server in the cloud allowing access to sensors remotely without putting people's lives at risk. This project is part of a program of the Instituto Geofísico del Perú with the goal of implementing a National Mudslide Monitoring Center.
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    High altitude echoes from the equatorial topside ionosphere during solar minimum
    (American Geophysical Union, 2021-02) Derghazarian, S.; Hysell, D. L.; Kuyeng, K.; Milla, Marco
    We describe a new class of nonthermal plasma density irregularities observed in the postmidnight topside equatorial ionosphere under low solar flux conditions. They are distinct from irregularities associated with equatorial spread F (ESF) in terms of their morphology and because they exhibit strong spectral sidebands at the lower-hybrid frequency. The coherent echoes were observed in a series high-altitude radar experiments performed at Jicamarca utilizing long- and coded double-pulse modes and a dual-beam mode. The coded double-pulse mode was used to measure the low-frequency characteristics of the echoes with fine range resolution. Doppler shifts of the main backscatter line were observed to fall between ±150 m/s. The long-pulse mode was employed for high-frequency spectral analysis which revealed the presence of strong spectral sidelobes at the lower-hybrid frequency. A dual-beam mode was used to investigate the horizontal structure of the echoes. Zonal drift speeds of 50–70 m/s were inferred with this mode, and longitudinal dimensions of approximately 270 km were estimated. The study summarizes with a discussion of different mechanisms that may be responsible for the phenomenon and the lower-hybrid sidebands in particular.
  • ItemOpen Access
    Assimilation of sparse continuous near-earth weather measurements by NECTAR model morphing
    (American Geophysical Union, 2020-11) Galkin, I. A.; Reinisch, B. W.; Vesnin, A. M.; Bilitza, D.; Fridman, S.; Habarulema, J. B.; Veliz, Oscar
    Non-linear Error Compensation Technique with Associative Restoration (NECTAR) is a novel approach to the assimilation of fragmentary sensor data to produce a global nowcast of the near-Earth space weather. NECTAR restores missing information by iteratively transforming (“morphing”) an underlying global climatology model into agreement with currently available sensor data. The morphing procedure benefits from analysis of the inherent multiscale diurnal periodicity of the geosystems by processing 24-hr time histories of the differences between measured and climate-expected values at each sensor site. The 24-hr deviation time series are used to compute and then globally interpolate the diurnal deviation harmonics. NECTAR therefore views the geosystem in terms of its periodic planetary-scale basis to associate observed fragments of the activity with the grand-scale weather processes of the matching variability scales. Such approach strengthens the restorative capability of the assimilation, specifically when only a limited number of observatories is available for the weather nowcast. Scenarios where the NECTAR concept works best are common in planetary-scale near-Earth weather applications, especially where sensor instrumentation is complex, expensive, and therefore scarce. To conduct the assimilation process, NECTAR employs a Hopfield feedback recurrent neural network commonly used in the associative memory architectures. Associative memories mimic human capability to restore full information from its initial fragments. When applied to the sparse spatial data, such a neural network becomes a nonlinear multiscale interpolator of missing information. Early tests of the NECTAR morphing reveal its enhanced capability to predict system dynamics over no-data regions (spatial interpolation).
  • ItemOpen Access
    Multistatic specular meteor radar network in Peru: system description and initial results
    (American Geophysical Union, 2021-01) Chau, J. L.; Urco, J. M.; Vierinen, J.; Harding, B. J.; Clahsen, M.; Pfeffer, N.; Kuyeng, Karim; Milla, Marco; Erickson, P. J.
    The mesosphere and lower thermosphere (MLT) region is dominated globally by dynamics at various scales: planetary waves, tides, gravity waves, and stratified turbulence. The latter two can coexist and be significant at horizontal scales less than 500 km, scales that are difficult to measure. This study presents a recently deployed multistatic specular meteor radar system, SIMONe Peru, which can be used to observe these scales. The radars are positioned at and around the Jicamarca Radio Observatory, which is located at the magnetic equator. Besides presenting preliminary results of typically reported large‐scale features, like the dominant diurnal tide at low latitudes, we show results on selected days of spatially and temporally resolved winds obtained with two methods based on: (a) estimation of mean wind and their gradients (gradient method), and (b) an inverse theory with Tikhonov regularization (regularized wind field inversion method). The gradient method allows improved MLT vertical velocities and, for the first time, low‐latitude wind field parameters such as horizontal divergence and relative vorticity. The regularized wind field inversion method allows the estimation of spatial structure within the observed area and has the potential to outperform the gradient method, in particular when more detections are available or when fine adaptive tuning of the regularization factor is done. SIMONe Peru adds important information at low latitudes to currently scarce MLT continuous observing capabilities. Results contribute to studies of the MLT dynamics at different scales inherently connected to lower atmospheric forcing and E‐region dynamo related ionospheric variability.
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    Automatic identification and observations of blanketing sporadic E events in the equatorial region over Jicamarca
    (Institute of Electrical and Electronics Engineers, IEEE, 2020-10-20) Suclupe, José; Pacheco, Edgardo E.; Condor, Percy
    In equatorial regions, equatorial electrojet (EEJ) echoes often overlap with blanketing sporadic E (Esb) echoes. Also, Esb events could be classified as rare events over the Jicamarca Radio Observatory (JRO). For that reason, Esb identification is a big challenge for current software. Until now, the conventional method identifies Esb echoes visually. In this work, an innovative approach for automatic identification and observation of Esb events is presented. We developed an algorithm and implemented the first software to identify Esb events using image processing techniques and machine learning algorithms getting a sensitivity of 89%. We proposed a new criterion to identify Esb events taken into account the normal tendency of the F-layer minimum frequency due mainly to absorbance of the D region. We report the results of the first statistical study of Esb occurrence over JRO (11.95° S, 76.87° W and dip angle ~1°) using the Digital Portable Sounder (DPS) - 4 Digisonde data from 2001 to 2018. We found Esb occurs mainly during the December solstice and also during minimum solar years. We observe the occurrence of Esb with a main peak at 1600 LT and a second peak around 0800 - 0900 LT. Furthermore, we obtained the ΔH between Jicamarca and Piura to measure the intensity of EEJ and counter electrojet (CEJ) and its behavior in time when Esb occurs. Finally, we discuss possible conditions that favor the formation of Esb.