Annales Geophysicae最新文献

{"title":"Comparison of meteor radar and TIDI winds in the Brazilian equatorial region","authors":"Ana Roberta Paulino, Delis Otildes Rodrigues, Igo Paulino, Lourivaldo Mota Lima, Ricardo Arlen Buriti, Paulo Prado Batista, Aaron Ridley, Chen Wu","doi":"10.5194/angeo-2023-23","DOIUrl":"https://doi.org/10.5194/angeo-2023-23","url":null,"abstract":"<strong>Abstract.</strong> Using data collected from a meteor radar deployed at São João do Cariri (7.4°, 36.5° S) and the TIMED Doppler Interferometer (TIDI) on board the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite for 2006, comparisons of the horizontal winds (meridional and zonal components) were made in order to evaluate these techniques for scientific investigation and pointed out advantages of each instrument. A grid of ± 5 degrees of latitude and longitude centered at São João do Cariri was used to calculate the mean winds from the TIDI, which have a resolution of 2.5 km altitude starting from 82.5 km up to 102 km altitude. Otherwise, the meteor radar computes the winds for 7 layers of 4 km thickness overlapping 0.5 km above and below, which produces layers spaced by 3 km from 81 to 99 km altitude. When almost simultaneous measurements were compared, substantial discrepancies were observed in the vertical wind profiles. It happened because the meteor radar uses one hour bin size to estimate the wind from the echoes detected in the whole sky. While the TIDI measures instantaneous winds from the airglow emissions. In contrast, when the longer period of observation was taken into account, the meteor radar daily winds, averaged within a time interval of one month, were smoothed and showed more clearly the characteristics of the propagation of tides. The responses of the horizontal wind to the intraseasonal, semiannual and annual oscillations were satisfactory for the both techniques.","PeriodicalId":50777,"journal":{"name":"Annales Geophysicae","volume":"3 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138541777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the relationship between the mesospheric sodium layer and the meteoric input function","authors":"Yanlin Li, Tai-Yin Huang, Julio Urbina, Fabio Vargas, Wuhu Feng","doi":"10.5194/angeo-2023-20","DOIUrl":"https://doi.org/10.5194/angeo-2023-20","url":null,"abstract":"<strong>Abstract.</strong> This study examines the relationship between the concentration of atmospheric sodium and its Meteoric Input Function (MIF). We use the measurements from the Colorado State University (CSU) Lidar and the Andes Lidar Observatory (ALO) with a new numerical model that includes sodium chemistry in the mesosphere and lower thermosphere (MLT) region. The model is based on the continuity equation to treat all sodium-bearing species and runs at a high temporal resolution. The model simulation employs data assimilation to compare the MIF inferred from the meteor radiant and the MIF derived from the new sodium chemistry model. The simulation captures the seasonal variability of sodium number density compared with lidar observations over CSU site. However, there were discrepancies for the ALO site, which is close to the South Atlantic Anomaly (SAA) region, indicating it is challenging for the model to capture the observed sodium over ALO. The CSU site had significantly more lidar observations (27,930 hours) than the ALO sites (1872 hours). The simulation revealed that the uptake of the sodium species on meteoric smoke particles was a critical factor in determining the sodium concentration in MLT, with the sodium removal rate by uptake found to be approximately three times that of the NaHCO₃ dimerization. Overall, the study's findings provide valuable information on the correlation between MIF and sodium concentration in the MLT region, contributing to a better understanding of the complex dynamics in this region. This knowledge can inform future research and guide the development of more accurate models to enhance our comprehension of the MLT region's behavior.","PeriodicalId":50777,"journal":{"name":"Annales Geophysicae","volume":"55 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138541760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluid models capturing Farley–Buneman instabilities","authors":"E. Rojas, K. Burns, D. Hysell","doi":"10.5194/angeo-41-281-2023","DOIUrl":"https://doi.org/10.5194/angeo-41-281-2023","url":null,"abstract":"Abstract. It is generally accepted that modeling Farley–Buneman instabilities requires resolving ion Landau damping to reproduce experimentally observed features. Particle-in-cell (PIC) simulations have been able to reproduce most of these but at a computational cost that severely affects their scalability. This limitation hinders the study of non-local phenomena that require three dimensions or coupling with larger-scale processes. We argue that a form of the five-moment fluid system can recreate several qualitative aspects of Farley–Buneman dynamics such as density and phase speed saturation, wave turning, and heating. Unexpectedly, these features are still reproduced even without using artificial viscosity to capture Landau damping. Comparing the proposed fluid models and a PIC implementation shows good qualitative agreement.\u0000","PeriodicalId":50777,"journal":{"name":"Annales Geophysicae","volume":"70 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78936351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comparison of Jason-2 plasmasphere electron content measurements with ground-based measurements","authors":"Andrew J. Mazzella Jr., E. Yizengaw","doi":"10.5194/angeo-41-269-2023","DOIUrl":"https://doi.org/10.5194/angeo-41-269-2023","url":null,"abstract":"Abstract. Previous studies utilizing the Global Positioning System\u0000(GPS) receivers aboard Jason satellites have performed measurements of\u0000plasmasphere electron content (PEC) by determining the total electron\u0000content (TEC) above these satellites, which are at altitudes of about 1340 km. This study uses similar methods to determine PEC for the Jason-2\u0000receiver for 24 July 2011. These PEC values are compared to previous\u0000determinations of PEC from a chain of ground-based GPS receivers in Africa\u0000using the SCORPION method, with a nominal ionosphere–plasmasphere boundary\u0000at 1000 km. The Jason-2 PECs with elevations greater than 60∘\u0000were converted to equivalent vertical PEC and compared to SCORPION vertical\u0000PEC determinations. In addition, slant (off-vertical) PECs from Jason-2\u0000were compared to a small set of nearly co-aligned ground-based slant PECs.\u0000The latter comparison avoids any conversion of Jason-2 slant PEC to\u0000equivalent vertical PEC, and it can be considered a more representative\u0000comparison. The mean difference between the vertical PEC (ground-based\u0000minus Jason-2 measurements) values is 0.82 ± 0.28 TEC units (1 TEC unit=1016 electrons m−2). Similarly, the mean difference\u0000between slant PEC values is 0.168 ± 0.924 TEC units. The Jason-2 slant\u0000PEC comparison method may provide a reliable determination for the\u0000plasmasphere baseline value for the ground-based receivers, especially if\u0000the ground stations are confined to only midlatitude or low-latitude\u0000regions, which can be affected by a non-negligible PEC baseline.\u0000","PeriodicalId":50777,"journal":{"name":"Annales Geophysicae","volume":"20 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90199886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Statistical distribution of mirror-mode-like structures in the magnetosheaths of unmagnetised planets – Part 1: Mars as observed by the MAVEN spacecraft","authors":"C. Simon Wedlund, M. Volwerk, C. Mazelle, S. Rojas Mata, G. Stenberg Wieser, Y. Futaana, J. Halekas, D. Rojas-Castillo, C. Bertucci, J. Espley","doi":"10.5194/angeo-41-225-2023","DOIUrl":"https://doi.org/10.5194/angeo-41-225-2023","url":null,"abstract":"Abstract. In this series of papers, we present statistical maps of mirror-mode-like (MM) structures in the magnetosheaths of Mars and Venus and calculate the probability of detecting them in spacecraft data. We aim to study and compare them with the same tools and a similar payload at both planets. We consider their dependence on extreme ultraviolet (EUV) solar flux levels (high and low) and, specific to Mars, on Mars Year (MY) as well as atmospheric seasons (four solar longitudes Ls).\u0000We first use magnetic-field-only criteria to detect these structures and present ways to mitigate ambiguities in their nature. In line with many previous studies at Earth, this technique has the advantage of using one instrument (a magnetometer) with good time resolution, facilitating comparisons between planetary and cometary environments. Applied to the magnetometer data of the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft from November 2014 to February 2021 (MY32–MY35), we detect events closely resembling MMs lasting in total more than 170 000 s, corresponding to about 0.1 % of MAVEN's total time spent in the Martian plasma environment. We calculate MM-like occurrences normalised to the spacecraft's residence time during the course of the mission. Detection probabilities are about 1 % at most for any given controlling parameter. In general, MM-like structures appear in two main regions: one behind the shock and the other close to the induced magnetospheric boundary, as expected from theory. Detection probabilities are higher on average in low-solar-EUV conditions, whereas high-solar-EUV conditions see an increase in detections within the magnetospheric tail. We tentatively link the former tendency to two combining effects: the favouring of ion cyclotron waves the closer to perihelion due to plasma beta effects and, possibly, the non-gyrotropy of pickup ion distributions. This study is the first of two on the magnetosheaths of Mars and Venus.\u0000","PeriodicalId":50777,"journal":{"name":"Annales Geophysicae","volume":"101 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73378136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Concerning the detection of electromagnetic knot structures in space plasmas using the wave telescope technique","authors":"S. Toepfer, K. Glassmeier, U. Motschmann","doi":"10.5194/angeo-41-253-2023","DOIUrl":"https://doi.org/10.5194/angeo-41-253-2023","url":null,"abstract":"Abstract. The wave telescope technique is broadly established in the analysis of spacecraft data and serves as a bridge between local measurements and the global picture of spatial structures. The technique is originally based on plane waves and has been extended to spherical waves, phase-shifted waves and planetary magnetic field representation. The goal of the present study is the extension of the wave telescope technique using electromagnetic knot structures as a basis. As the knots are an exact solution of Maxwell's equations they open the door for a new modeling and interpretation of magnetospheric structures, such as plasmoids.\u0000","PeriodicalId":50777,"journal":{"name":"Annales Geophysicae","volume":"351 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76573884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of the terdiurnal tide on the sporadic E (Es) layer development at low latitudes over the Brazilian sector","authors":"P. A. Fontes, M. Muella, L. Resende, V. Andrioli, P. Fagundes, V. G. Pillat, P. Batista, A. J. Carrasco","doi":"10.5194/angeo-41-209-2023","DOIUrl":"https://doi.org/10.5194/angeo-41-209-2023","url":null,"abstract":"Abstract. Sporadic E (Es) layers are patches of high ionization observed at\u0000around 100–140 km height in the E region. Their formation at low latitudes\u0000is primarily associated with the diurnal and semidiurnal components of the\u0000tidal winds via the ion convergence driven by the wind shear mechanism.\u0000However, recent studies have shown the influence of other tidal modes, such\u0000as the terdiurnal tide. Therefore, this work investigates the effect of\u0000terdiurnal tide-like oscillations on the occurrence and formation of the Es layers\u0000observed over Palmas (10.17∘ S, 48.33∘ W; dip lat.\u0000−7.31∘), a low-latitude station in Brazil. The analysis was\u0000conducted from December 2008 to November 2009 by using data collected from\u0000CADI (Canadian Advanced Digital Ionosonde). Additionally, the E\u0000Region Ionospheric Model (MIRE) was used to simulate the terdiurnal tidal\u0000component in the Es layer development. The results show modulations of 8 h\u0000periods on the occurrence rates of the Es layers during all seasonal periods.\u0000In general, we see three well-defined peaks in a superimposed summation of\u0000the Es layer types per hour in summer and autumn. We also observed that the\u0000amplitude modulation of the terdiurnal tide on the Es occurrence rates\u0000minimizes in December in comparison to the other months of the summer\u0000season. Other relevant aspects of the observations, with complementary\u0000statistical and periodogram analysis, are highlighted and discussed.\u0000","PeriodicalId":50777,"journal":{"name":"Annales Geophysicae","volume":"1 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83328846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identifying gravity waves launched by the Hunga Tonga–Hunga Ha′apai volcanic eruption in mesosphere/lower-thermosphere winds derived from CONDOR and the Nordic Meteor Radar Cluster","authors":"G. Stober, A. Liu, A. Kozlovsky, Z. Qiao, Witali Krochin, Guochun Shi, J. Kero, M. Tsutsumi, N. Gulbrandsen, S. Nozawa, M. Lester, Kathrin Baumgarten, E. Belova, N. Mitchell","doi":"10.5194/angeo-41-197-2023","DOIUrl":"https://doi.org/10.5194/angeo-41-197-2023","url":null,"abstract":"Abstract. The Hunga Tonga–Hunga Ha′apai volcano eruption was a unique event that caused many atmospheric phenomena around the globe. In this study, we investigate the atmospheric gravity waves in the mesosphere/lower-thermosphere (MLT) launched by the volcanic explosion in the Pacific, leveraging multistatic meteor radar observations from the Chilean Observation Network De Meteor Radars (CONDOR) and the Nordic Meteor Radar Cluster in Fennoscandia. MLT winds are computed using a recently developed 3DVAR+DIV algorithm. We found eastward- and westward-traveling gravity waves in the CONDOR zonal and meridional wind measurements, which arrived 12 and 48 h after the eruption, and we found one in the Nordic Meteor Radar Cluster that arrived 27.5 h after the volcanic detonation. We obtained observed phase speeds for the eastward great circle path at both locations of about 250 m s−1, and they were 170–150 m s−1 for the opposite propagation direction. The intrinsic phase speed was estimated to be 200–212 m s−1. Furthermore, we identified a potential lamb wave signature in the MLT winds using 5 min resolved 3DVAR+DIV retrievals.\u0000","PeriodicalId":50777,"journal":{"name":"Annales Geophysicae","volume":"17 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80712334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of the super-powerful tropospheric western Pacific phenomenon of September–October 2018 on the ionosphere over China: results from oblique sounding","authors":"L. Chernogor, K. Garmash, Q. Guo, V. Rozumenko, Yu. Zheng","doi":"10.5194/angeo-41-173-2023","DOIUrl":"https://doi.org/10.5194/angeo-41-173-2023","url":null,"abstract":"Abstract. Doppler measurements at oblique propagation paths from\u0000the city of Harbin, the People's Republic of China (PRC), to 10 high-frequency (HF) radio\u0000broadcast stations in the PRC, Japan, Mongolia, and the Republic of Korea\u0000captured the response in the ionosphere to the activity of the super typhoon, Typhoon Kong-rey,\u0000from 30 September to 6 October 2018. The Harbin Engineering University\u0000coherent software-defined radio system generates the database containing\u0000the complex amplitudes of the radio signals that have been acquired along 14 propagation\u0000paths since 2018. The complex amplitudes are used for calculating the\u0000temporal dependences of the Doppler spectra and signal amplitudes, and the\u0000Doppler spectra are used to plot the Doppler shift as a function of time,\u0000fD(t), for all rays. The scientific objectives of this study are to\u0000reveal the possible perturbations caused by the activity of Typhoon Kong-rey\u0000and to estimate the magnitudes of wave parameters of the ionospheric plasma\u0000and radio signals. The amplitudes, fDa, of the Doppler shift variations\u0000were observed to noticeably increase (factor of ∼2–3) on 1–2 and 5–6 October 2018, while the 20–120 min periods, T, of the Doppler\u0000shift variations suggest that the wavelike disturbances in the ionosphere\u0000are caused by atmospheric gravity waves. The periods and amplitudes of\u0000quasi-sinusoidal variations in the Doppler shift, which have been determined\u0000for all propagation paths, may be used to estimate the amplitudes, δNa, of quasi-sinusoidal variations in the electron density. Thus,\u0000T≈20 min and fDa≈0.1 Hz yield δNa≈0.4 %, whereas T≈30 min and\u0000fDa≈0.2 Hz give δNa≈1.2 %. If\u0000T≈60 min and fDa≈0.5 Hz, then δNa≈6 %. The periods T are found to change within the\u000015–120 min limits, and the Doppler shift amplitudes, fDa, show\u0000variability within the 0.05–0.4 Hz limits.\u0000","PeriodicalId":50777,"journal":{"name":"Annales Geophysicae","volume":"10 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85949738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ionosonde and GPS total electron content observations during the 26 December 2019 annular solar eclipse over Indonesia","authors":"Jiyo Harjosuwito, A. Husin, V. Dear, J. Muhamad, Agri Faturahman, Afrizal Bahar, A. Syetiawan, R. Pradipta","doi":"10.5194/angeo-41-147-2023","DOIUrl":"https://doi.org/10.5194/angeo-41-147-2023","url":null,"abstract":"Abstract. We report the investigation of the ionospheric response to the passage of an annular solar eclipse over Southeast Asia on 26 December 2019 using multiple sets of observations. Two ionosondes (one at Kototabang and another at Pontianak) were used to measure dynamical changes in the ionospheric layer during the event. A network of ground-based GPS receiver stations in Indonesia was used to derive the distribution of total electron content (TEC) over the region. In addition, extreme ultraviolet (EUV) images of the Sun from the Atmospheric Imaging Assembly (AIA) instrument on board the Solar Dynamics Observatory (SDO) satellite were also analyzed to determine possible impacts of solar-active regions on the changes that occurred in the ionosphere during the eclipse. We found −1.62 and −1.90 MHz reductions (24.0 % and 27.5 % relative reduction) in foF2 during the solar eclipse over Kototabang and Pontianak, respectively. The respective TEC reductions over Kototabang and Pontianak during the eclipse were −4.34 and −5.45 TECU (24.9 % and 27.9 % relative reduction). Data from both ionosondes indicate a consistent 34–36 min delay between maximum eclipse and minimum foF2. The corresponding time delays for eclipse-related TEC reduction at these two locations were 40 and 16 min, respectively. The ionospheric F layer was found to descend with a speed of 9–19 m s−1 during the first half of the eclipse period. We also found an apparent rise in the ionospheric F-layer height near the end of the solar eclipse period, equivalent to a vertical drift velocity of 44–47 m s−1. The GPS TEC data mapping along a set of cross-sectional cuts indicates that the greatest TEC reduction actually occurred to the north of the solar-eclipse path, opposite of the direction from which the lunar shadow fell. As the central path of the solar eclipse was located just to the north of the southern equatorial ionization anomaly (EIA) crest, it is suspected that such a peculiar TEC reduction pattern was caused by plasma flow associated with the equatorial fountain effect. Net perturbations of TEC were also computed and analyzed, which revealed the presence of some wavelike fluctuations associated with the solar-eclipse event. Some of the observed TEC perturbation patterns that propagated with a velocity matching the lunar shadow may be explained in terms of nonuniform EUV illumination that arose as various active regions on the Sun went obstructed and unobstructed during the eclipse. The remaining wavelike features are likely to be traveling ionospheric disturbances (TIDs) generated by the passage of the solar eclipse on top of other diurnal factors.\u0000","PeriodicalId":50777,"journal":{"name":"Annales Geophysicae","volume":"56 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81399023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}