Navegando por Autor "Cândido, Claudia Maria Nicoli"
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Item Assessing the effects of a minor CIR‐HSS geomagnetic storm on the brazilian low‐latitude ionosphere: ground and space‐based observations(Advancing Earth and Space Sciences) Chingarandi, Frank Simbarashe; Cândido, Claudia Maria Nicoli; Guedes, Fabio Becker; Jonah, Olusegun Folarin; Santos, Stella Pires Moraes; Klausner, Virgínia; Osanyin, Taiwo OlusayoThis paper investigates the effects of a minor G1 Co-rotating Interaction Region (CIR)/High-Speed Stream (HSS)-driven geomagnetic storm that occurred on (13–14 October 2018), during deep solar minimum. We used simultaneous observations from multiple instruments, namely; ground-based Global Navigation Satellite Systems (GNSS) receivers, a Digisonde, ground magnetometers, and space-based observations from the National Aeronautics and Space Administration Global-scale Observations of Limb and Disk (GOLD) and SWARM missions. This study presents a detailed picture of the low-latitude ionosphere response over the Brazilian sector during a minor storm. Our results showed that the minor CIR/HSS-driven storm caused a positive ionospheric storm of over ∼20 TECU in magnitude. For the first time, periodic post-sunset irregularities and Equatorial Plasma Bubbles, equatorial plasma bubbles, were analyzed using GOLD FUV OI 135.6 nm emission, Total Electron Content (TEC) maps, Rate of TEC index, ROTI, and TEC gradients. Fluctuations in the interplanetary magnetic field Bz and changes in the thermospheric column density ratio (∑O/N2) are discussed as the main sources of ionospheric changes during the storm. This paper highlights the importance of monitoring and understanding the impact of Sun-Earth interactions and provides insight into the behavior of the low-latitude ionosphere during minor geomagnetic storms.Item Desenvolvimento de Ferramentas Computacionais para o Estudo de Variações Geomagnéticas e de Distúrbios Ionosféricos Propagantes(2022-03-11) Oliveira, Virgínia Klausner de; Muella, Marcio Tadeu de Assis Honorato; Gomes, Anna Beatriz Silva; Cândido, Claudia Maria Nicoli; Macedo, Humberto Gimenes; Prestes, Alan; São José dos CamposEsta dissertação aborda as assinaturas geomagnéticas e ionosféricas causadas por eventos solares, sísmicos e oceânicos. A atividade solar, principalmente as ejeções de massa coronal e as regiões de interação corrotantes, podem gerar variações geomagnéticas na forma de tempestades magnéticas e eventos HILDCAA em virtude do acoplamento entre a magnetosfera e o vento solar. Por outro lado, durante a ocorrência de terremotos tsunamigênicos verifica-se o desenvolvimento de ondas de gravidade na atmosfera neutra, pois a gravidade atua como uma força restauradora a fim de reestabelecer o equilíbrio após a perturbação inicial. Estas, por sua vez, propagam-se até a termosfera, onde interagem com o plasma ionosférico por meio de colisões entre íons e neutros, produzindo correntes elétricas e campos magnéticos secundários. Consequentemente, variações geomagnéticas irregulares são produzidas, com períodos e amplitudes na ordem de minutos e poucos nT , respectivamente. Além disso, devido ao fenômeno de indução por movimento, os fluxos oceânicos associados a um tsunami também geram variações geomagnéticas, tendo em vista que as águas oceânicas constituem um fluido condutor em movimento que está imerso no campo geomagnético. Em altitudes ionosféricas, as ondas de gravidade colocam a ionosfera em movimento e se manifestam como distúrbios ionosféricos propagantes, isto é, como flutuações de natureza ondulatória na densidade do plasma ionosférico. Esses distúrbios podem ser detectados por meio de várias técnicas de rádio sondagem, mas atualmente as medições do conteúdo eletrônico total obtidas por meio de sinais de satélite são utilizadas com esta finalidade. Tendo em vista o exposto, o propósito do presente trabalho é desenvolver ferramentas computacionais munidas com as principais técnicas matemáticas, tais como análise wavelet e decomposição em modo empírico, para a identificação e caracterização de variações geomagnéticas e distúrbios ionosféricos propagantes causados tanto pela atividade solar quanto por terremotos tsunamigênicos. Além de seu propósito científico, este trabalho tem importância prática, pois a compreensão desses fenômenos pode ajudar no desenvolvimento de sistemas de previsão e alerta do Clima Espacial e de catástrofes, podendo evitar ou mitigar prejuízos econômicos e, principalmente, humanos.Item Geomagnetic Disturbances During the Maule (2010) Tsunami Detected by Four Spatiotemporal Methods(Springer Nature Link) Klausner, Virginia; Macedo, Humberto Gimenes; Cezarini, Marina Vedelago; Ojeda-González, Arian; Prestes, Alan; Cândido, Claudia Maria Nicoli; Kherani, Esfhan Alam; Santos, Thiago de AlmeidaSeparating tsunamigenic variations in geomagnetic field measurements in the presence of more dominant magnetic variations by magnetospheric and ionospheric currents is a challenging task. The purpose of this article is to survey the tsunamigenic variations in the vertical component (Z) and the horizontal component (H) of the geomagnetic field using four spatiotemporal methods. Spatiotemporal analysis has shown enormous potential and efficiency in retrieving tsunamigenic contributions from geomagnetic field measurements. We select the Maule (2010) tsunami event on the west coast of Chile and examine the geomagnetic measurements from 13 ground magnetometers scattered in the Pacific Ocean covering a wide area from Chile, crossing the Pacific Ocean to Japan. The tsunamigenic magnetic disturbances are possibly due to two types of contributions, one arising from direct ocean motion and the other from atmospheric motion, both associated with tsunami forcing. Moreover, even though the tsunami waves decrease considerably with increasing epicentral distance, the tsunamigenic contributions are retrieved from a magnetic observatory in Australia ( 13,000 km radial distance from the epicenter). These results suggest that various types of tsunamigenic disturbances can be identified well from the integrated analysis framework presented in this work.Item Lithosphere atmosphere ionosphere coupling during the September 2015 Coquimbo earthquake(Springer Nature Link) Adhikari, Bhoj Raj; Klausner, Virgínia; Cândido, Claudia Maria Nicoli; Poudel, Prakash; Macedo, Humberto Gimenes; Silwal, Ashok; Gautam, Sujan Prasad; Calabia, Andrés; Shah, MunawarThis study explores temporal variations in seismic data, interplanetary parameters, and geomagnetic indices during the 2015 Coquimbo earthquake. We employ wavelet transform techniques to investigate potential coupling mechanisms between the lithosphere, atmosphere, and ionosphere (LAI), even during geomagnetically disturbed periods. Our analysis is strengthened by evaluating geomagnetic data and all- sky images within a 2000–3000 km radius of the epicenter. We explore the post-Chilean earthquake seismogenic perturbations in the upper atmosphere on September 16–17, 2015. Coseismic and post- seismic events emerge in the Brazilian region 1–3 hrs after the earthquake onset. The co-occurrence and subsequent response of these disturbances to seismic events suggest their seismogenic nature. Addi- tionally, we utilize geomagnetic storm and interplanetary magnetic Beld (IMF) indices to differentiate magnetic Cuctuations arising from solar storms during seismic events. While our study detects magnetic disturbances associated with seismic activity, distinguishing them from the eAects of solar storms in the geomagnetic records or all-sky images remains challenging. These observations prompt further investigation into the intricate interplay between geomagnetic and ionospheric disturbances and their connection to seismic and geomagnetic storm activity.Item Principal component analysis in the modeling of HILDCAAs during the Solar Minimum of Cycle 23/24(Elsevier) Klausner, Virginia; Lamin, Isabelle Cristine Pellegrini; Ojeda-González, Arian; Macedo, Humberto Gimenes; Cândido, Claudia Maria Nicoli; Prestes, Alan; Cezarini, Marina VedelagoIn this article, we propose a new approach to model the high-intensity, long-duration, continuous AE (Auroral Electrojet) activity (HILDCAA) by relaxing one of the criteria originally designed, based on the interplanetary features during the unusual Solar Minimum of Cycle 23/24 (SMC23/24). This relaxation does not intend to suppress or modify the original HILDCAAs’ conception, but propose a new view of the same phenomena by enlarging the sample of events, which in turn may improve space weather monitoring and prediction programs. To assess and classify the Alfvénity associated with HILDCAAs, the values of 4h-Windowed Pearson Cross-Correlation (4WPCC) between the IMF components and the solar wind speed components observed in situ at the Lagrangian point L1 (1 AU) were evaluated. The principal component analysis (PCA) was performed on the dataset and, from the first three principal components, which represent 65% of the accumulative percent variance, we applied principal component regression (PCR) in each of the following parameters: the AE index, the Interplanetary Magnetic Field (IMF) components, the plasma density, the solar wind speed, the temperature, the IMF magnitude, and the SYM-H geomagnetic index. Furthermore, we applied Multiple Linear Regression (MLR) to establish a linear model to express the AE index in terms of the PCR-based model parameters. The AE MLR-based model demonstrated to hold a prognosis potential for HILDCAAs. Despite that, this model is only suitable for the SMC23/24. In this sense, this model might be implemented a real-time analysis for short-term HILDCAA prognosis in the near future.