13 research outputs found
The South American K Index: Initial Steps from the Embrace Magnetometer Network
In the present paper we present the first steps given towards the development of the South American K index (Ksa) based on the measurement made by the Embrace Magnetometer Network. We present: (a) a description of the magnetometer and of the network; (b) the procedure used to calibrate the network equipments; (c) the procedure to obtain each station K scale and its corresponding upper limits of ranges for the three-hour-range station K indices (thereafter referred as K9 threshold); and (d) some particularities regarding the Quiet Day Curve (QDC) deviation and its long term variation.Facultad de Ciencias Astronómicas y Geofísica
Understanding space weather to shield society: A global road map for 2015-2025 commissioned by COSPAR and ILWS
There is a growing appreciation that the environmental conditions that we
call space weather impact the technological infrastructure that powers the
coupled economies around the world. With that comes the need to better shield
society against space weather by improving forecasts, environmental
specifications, and infrastructure design. [...] advanced understanding of
space weather requires a coordinated international approach to effectively
provide awareness of the processes within the Sun-Earth system through
observation-driven models. This roadmap prioritizes the scientific focus areas
and research infrastructure that are needed to significantly advance our
understanding of space weather of all intensities and of its implications for
society. Advancement of the existing system observatory through the addition of
small to moderate state-of-the-art capabilities designed to fill observational
gaps will enable significant advances. Such a strategy requires urgent action:
key instrumentation needs to be sustained, and action needs to be taken before
core capabilities are lost in the aging ensemble. We recommend advances through
priority focus (1) on observation-based modeling throughout the Sun-Earth
system, (2) on forecasts more than 12 hrs ahead of the magnetic structure of
incoming coronal mass ejections, (3) on understanding the geospace response to
variable solar-wind stresses that lead to intense geomagnetically-induced
currents and ionospheric and radiation storms, and (4) on developing a
comprehensive specification of space climate, including the characterization of
extreme space storms to guide resilient and robust engineering of technological
infrastructures. The roadmap clusters its implementation recommendations by
formulating three action pathways, and outlines needed instrumentation and
research programs and infrastructure for each of these. [...]Comment: In press for Advances of Space Research: an international roadmap on
the science of space weather, commissioned by COSPAR and ILWS (63 pages and 4
figures
Latitude-dependent delay in the responses of the equatorial electrojet and <i>S</i><sub><i>q</i></sub> currents to X-class solar flares
Ionospheric GPS-TEC responses from equatorial region to the EIA crest in the South American sector under intense space weather conditions
We present and discuss the ionospheric F-region observations from equator to the equatorial ionization anomaly (EIA) regions over the South American sector during an intense space weather event occurred between 27 and May 29, 2017. During this geomagnetic storm, the symmetric-H (SYM-H) reached a minimum of −142 nT at ∼0700 UT on May 28, 2017. For this investigation, we analyze the vertical total electron content (VTEC) observations from a chain of nearly 120 Global Positioning System (GPS) stations. Magnetometer measurements obtained at two stations in the low latitude regions are also presented. The observations do not indicate prompt penetration electric field (PPEF) effects in the VTEC variations. Magnetometer's observations over Cuiabá (CBA) and Cachoeira Paulista (CXP) in central west and south parts of Brazil, respectively, have shown a strong cross-correlation with SYM-H in the period between 3 and 48 h. The results also show positive ionospheric storm phase during the recovery phase on May 28, 2017. Positive effect during the recovery phase of the geomagnetic storm is possibly associated with effects of disturbances winds. During the recovery phase, a strong intensification of the EIA took place, possibly related to an additional ionization effect. The VTEC values show differences between the west and east sectors. This indicates that the EIA crest is stronger in the east sector than in the west sector, possibly due to the combination of disturbance wind effects and geomagnetic field geometry where in the east sector the field lines are more inclined.Fil: de Abreu, Alessandro José. Centro de Previsao de Tempo e Estudos Climáticos. Instituto Nacional de Pesquisas Espaciais; Brasil. Instituto Tecnológico de Aeronáutica; BrasilFil: Correia, Emilia. Centro de Previsao de Tempo e Estudos Climáticos. Instituto Nacional de Pesquisas Espaciais; Brasil. Universidade Presbiteriana Mackenzie; BrasilFil: Denardini, Clezio Marcos. Centro de Previsao de Tempo e Estudos Climáticos. Instituto Nacional de Pesquisas Espaciais; BrasilFil: de Jesus, Rodolfo. Centro de Previsao de Tempo e Estudos Climáticos. Instituto Nacional de Pesquisas Espaciais; BrasilFil: Venkatesh, Kavutarapu. Physical Research Laboratory; IndiaFil: Roberto, M.. Instituto Tecnológico de Aeronáutica; BrasilFil: Abalde, José Ricardo. Instituto Tecnológico de Aeronáutica; BrasilFil: Fagundes, Paulo Roberto. Universidade do Vale do Paraíba; BrasilFil: Bolzan, Mauŕicio José Alves. Universidade Federal de Jataí; BrasilFil: Gende, Mauricio Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentin
Analysis of the Sporadic-E Layer Behavior in Different American Stations during the Days around the September 2017 Geomagnetic Storm
The development of sporadic-E (Es) layers over five Digisonde stations in the American sector is analyzed. This work aims to investigate the dynamic of such layers during the days around the geomagnetic storm that occurred on 8 September 2017. Therefore, a numerical model (MIRE) and Radio Occultation (RO) technique are used to analyze the E layer dynamics. The results show a downward movement in low-middle latitudes due to the wind components that had no significant changes before, during, and after the geomagnetic storm. In fact, our data and simulations showed weak Es layers over Boulder, Cachoeira Paulista, and Santa Maria, even though the winds were not low. However, the RO data show the terdiurnal and quarterdiurnal influence in the Es layer formation, which can explain this behavior. In addition, we observed an atypical Es layer type, slant Es layer (Ess), during the main phase of the magnetic storm over Boulder. The possible cause of the Ess layers was gravity waves. Another interesting point is the spreading Es layer occurrence associated with the Kelvin–Helmholtz Instability (KHI). Finally, it is confirmed that the disturbed electric field only influenced the Es layer dynamics in regions near the magnetic equator
Analysis of the Sporadic-E Layer Behavior in Different American Stations during the Days around the September 2017 Geomagnetic Storm
The development of sporadic-E (Es) layers over five Digisonde stations in the American sector is analyzed. This work aims to investigate the dynamic of such layers during the days around the geomagnetic storm that occurred on 8 September 2017. Therefore, a numerical model (MIRE) and Radio Occultation (RO) technique are used to analyze the E layer dynamics. The results show a downward movement in low-middle latitudes due to the wind components that had no significant changes before, during, and after the geomagnetic storm. In fact, our data and simulations showed weak Es layers over Boulder, Cachoeira Paulista, and Santa Maria, even though the winds were not low. However, the RO data show the terdiurnal and quarterdiurnal influence in the Es layer formation, which can explain this behavior. In addition, we observed an atypical Es layer type, slant Es layer (Ess), during the main phase of the magnetic storm over Boulder. The possible cause of the Ess layers was gravity waves. Another interesting point is the spreading Es layer occurrence associated with the Kelvin–Helmholtz Instability (KHI). Finally, it is confirmed that the disturbed electric field only influenced the Es layer dynamics in regions near the magnetic equator