Supplementary material to "Postmidnight equatorial plasma irregularities on June solstice during low solar activity – a case study"

Author(s):  
Claudia M. N. Candido ◽  
Jiankui Shi ◽  
Inez S. Batista ◽  
Fabio Becker-Guedes ◽  
Emília Correia ◽  
...  
2019 ◽  
Vol 37 (4) ◽  
pp. 657-672
Author(s):  
Claudia M. N. Candido ◽  
Jiankui Shi ◽  
Inez S. Batista ◽  
Fabio Becker-Guedes ◽  
Emília Correia ◽  
...  

Abstract. We present a case study of unusual spread-F structures observed by ionosondes at two equatorial and low-latitude Brazilian stations – São Luís (SL: 44.2∘ W, 2.33∘ S; dip angle: −6.9∘) and Fortaleza (FZ: 38.45∘ W, 3.9∘ S; dip angle: −16∘). The irregularity structures observed from midnight to postmidnight hours of moderate solar activity (F10.7 < 97 sfu, where 1 sfu = 10−22 W m−2 s−1) have characteristics different from typical post-sunset equatorial spread F. The spread-F traces first appeared at or above the F-layer peak and gradually became well-formed mixed spread F. They also appeared as plasma depletions in the 630.0 nm airglow emissions made by a wide-angle imager located at the nearby low-latitude station Cajazeiras (CZ: 38.56∘ W, 6.87∘ S; dip angle: −21.4∘). The irregularities appeared first over FZ and later over SL, giving evidence of an unusual westward propagation or a horizontal plasma advection. The drift-mode operation available in one of the ionosondes (a digital portable sounder, DPS-4) has enabled us to analyze the horizontal drift velocities and directions of the irregularity movement. We also analyzed the neutral wind velocity measured by a Fabry–Pérot interferometer (FPI) installed at CZ and discuss its possible role in the development of the irregularities.


2018 ◽  
Author(s):  
Claudia M. N. Candido ◽  
Jiankui Shi ◽  
Inez S. Batista ◽  
Fabio Becker-Guedes ◽  
Emília Correia ◽  
...  

Abstract. We present a case study of unusual spread-F structures observed by ionosondes at two equatorial and low latitude Brazilian stations – Sao Luis (SL: 44.2° W, 2.33° S, dip angle: −6.9°) and Fortaleza (FZ: 38.45° W, 3.9° S, dip angle: −16°). The irregularity structures observed from midnight to post-midnight hours of moderate solar activity (F10.7 


2017 ◽  
Author(s):  
Raphael Schneeberger ◽  
Miguel De la Varga ◽  
Daniel Egli ◽  
Alfons Berger ◽  
Florian Kober ◽  
...  

2021 ◽  
pp. geochem2021-051
Author(s):  
Sarah Hashmi ◽  
Matthew I. Leybourne ◽  
Stewart Hamilton ◽  
Daniel Layton-Matthews ◽  
M. Beth McClenaghan

A geochemical study over the southwestern part of the South Range of the Sudbury Igneous Complex (SIC) was completed to assess the suitability of surficial media (humus, B-horizon soil and C-horizon soil) for delineating geochemical anomalies associated with Ni-Cu-PGE mineralization. Another objective was to test whether Na pyrophosphate can eliminate the effects of anthropogenic contamination in humus. Results of this study suggest that the natural geochemical signature of humus is strongly overprinted by anthropogenic contamination. Despite no indication of underlying or nearby mineralization, metal concentrations in humus samples by aqua regia collected downwind from smelting operations are higher compared to background, including up to 13 times higher for Pt, 12 times higher for Cu and 9 times higher for Ni. The high anthropogenic background masks the geogenic signal such that it is only apparent in humus samples collected in the vicinity of known Ni-Cu-PGE deposits. Results of this study also demonstrate that anthropogenically-derived atmospheric fallout also influences the upper B-horizon soil; however, lower B-horizon soil (at > 20 cm depth) and C-horizon soil (both developed in till) are not affected. Glacial dispersal from Ni-Cu-PGE mineralization is apparent in C-horizon till samples analyzed in this study. Compared to the background concentrations, the unaffected C-horizon till samples collected immediately down-ice of the low-sulfide, high precious metal (LSHPM) Vermilion Cu-Ni-PGE deposit are enriched over 20 times in Pt (203 ppb), Au (81 ppm) and Cu (963 ppm), and over 30 times in Ni (1283 ppm).Supplementary material:https://doi.org/10.6084/m9.figshare.c.5691080


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