scholarly journals Temporal 10Be and 14C Variations: A Tool for Paleomagnetic Research

Radiocarbon ◽  
1989 ◽  
Vol 31 (2) ◽  
pp. 163-168 ◽  
Author(s):  
G E Kocharov ◽  
A V Blinov ◽  
A N Konstantinov ◽  
V A Levchenko
Keyword(s):  
Solar Activity ◽  
Atmospheric Circulation ◽  
Geomagnetic Field ◽  
Temporal Variations ◽  
Paleomagnetic Data ◽  
Time Period ◽  
Atmospheric Concentrations ◽  
Cosmogenic Radionuclide

Temporal variations of cosmogenic radionuclide atmospheric concentrations can be caused by such global phenomena as solar activity and geomagnetic field changes as well as atmospheric circulation processes. These causes can be distinguished by the comparison of several isotope records corresponding to the same time period. We discuss a possibility for reconstructing the geomagnetic moment during the last 30,000 years from the comparison of 10Be and 14C concentrations in terrestrial archives. The results agree with conventional paleomagnetic data and promise to enrich our knowledge of geomagnetic field variations and reversals.

Impact of solar activity on atmospheric circulation and oceanic surface currents

2021 ◽  
Author(s):  
Sergey Molodykh ◽  
Ashkhen A. Karakhanyan ◽  
Kirill K. Kirichenko
Keyword(s):  
Solar Activity ◽  
Atmospheric Circulation ◽  
Surface Currents ◽  
Oceanic Surface

scholarly journals Impact of VOCs on the formation of ozone in a central China city during severe pollution periods

2018 ◽  
Author(s):  
Bowei Li ◽  
Steven Sai Hang Ho ◽  
Sunling Gong ◽  
Jingwei Ni ◽  
Huairui Li ◽  
...  
Keyword(s):  
Temporal Variations ◽  
Central China ◽  
Compressed Natural Gas ◽  
Pmf Model ◽  
Sampling Campaign ◽  
Time Period ◽  
Ozone Formation Potential ◽  
Range Transport ◽  
Volatile Organic ◽  
First Time

Abstract. In this work, a five-month sampling campaign was conducted for volatile organic compounds (VOCs) for the first time in Zhengzhou City, Henan province, China, where ozone (O3) pollution has shown an increasing trend in recent years. Fifty-seven VOCs defined by the Photochemical Assessment Monitoring Stations (PAMS) were sampled using canister method. Meanwhile, other O3 precursor gases were monitored online at four different sites between the time period of May–September, 2017. The results indicated that the average mixing ratio of ΣPAMS (31.57 ± 23.35 ppbv) in Zhengzhou was lower than the other megacities in China, while alkyne was in a significantly higher proportion. The abundances, compositions and ratios of PAMS showed strong spatial and temporal variations. Alkenes were the largest contributors to the ozone formation potential (OFP). On clear days, higher O3 levels were often accompanied with high ΣPAMS/NOx ratio at each site, demonstrating that the VOCs were more sensitive during the O3 formation period in Zhengzhou. Furthermore, source apportionmemt was conducted with Positive Matrix Factorization (PMF) model, and it was found that the use of compressed natural gas (CNG), the evaporation of gasoline and the exhaust from vehicles were the important sources for ambient VOCs at all four sites. Besides, the meterological conditions and long-range transport from other surrounding provinces also had an impact on the air quality determined using the cluster analysis. It is worth mentioning that the reduction in VOCs' emissions is necessary to suppress the O3 pollution.

scholarly journals Topside equatorial zonal ion velocities measured by C/NOFS during rising solar activity

2014 ◽  
Vol 32 (2) ◽  
pp. 69-75 ◽  
Author(s):  
W. R. Coley ◽  
R. A. Stoneback ◽  
R. A. Heelis ◽  
M. R. Hairston
Keyword(s):  
Solar Activity ◽  
Local Time ◽  
Geomagnetic Field ◽  
General Pattern ◽  
Magnetic Latitude ◽  
Ion Drifts ◽  
F Region ◽  
Westerly Flow ◽  
Solar Local Time ◽  
Ion Velocity

Abstract. The Ion Velocity Meter (IVM), a part of the Coupled Ion Neutral Dynamic Investigation (CINDI) instrument package on the Communication/Navigation Outage Forecast System (C/NOFS) spacecraft, has made over 5 yr of in situ measurements of plasma temperatures, composition, densities, and velocities in the 400–850 km altitude range of the equatorial ionosphere. These measured ion velocities are then transformed into a coordinate system with components parallel and perpendicular to the geomagnetic field allowing us to examine the zonal (horizontal and perpendicular to the geomagnetic field) component of plasma motion over the 2009–2012 interval. The general pattern of local time variation of the equatorial zonal ion velocity is well established as westward during the day and eastward during the night, with the larger nighttime velocities leading to a net ionospheric superrotation. Since the C/NOFS launch in April 2008, F10.7 cm radio fluxes have gradually increased from around 70 sfu to levels in the 130–150 sfu range. The comprehensive coverage of C/NOFS over the low-latitude ionosphere allows us to examine variations of the topside zonal ion velocity over a wide level of solar activity as well as the dependence of the zonal velocity on apex altitude (magnetic latitude), longitude, and solar local time. It was found that the zonal ion drifts show longitude dependence with the largest net eastward values in the American sector. The pre-midnight zonal drifts show definite solar activity (F10.7) dependence. The daytime drifts have a lower dependence on F10.7. The apex altitude (magnetic latitude) variations indicate a more westerly flow at higher altitudes. There is often a net topside subrotation at low F10.7 levels, perhaps indicative of a suppressed F region dynamo due to low field line-integrated conductivity and a low F region altitude at solar minimum.

scholarly journals An early mid-latitude aurora observed by Rozier (Béziers, 1780)

2020 ◽  
Vol 38 (6) ◽  
pp. 1139-1147
Author(s):  
Chiara Bertolin ◽  
Fernando Domínguez-Castro ◽  
Lavinia de Ferri
Keyword(s):  
Solar Activity ◽  
Geomagnetic Field ◽  
18Th Century ◽  
Geomagnetic Latitude ◽  
Careful Analysis ◽  
Universal Time ◽  
Low Latitudes ◽  
Solar Storms ◽  
Mass Ejection ◽  
Atmospheric Phenomena

Abstract. Aurora observations are an uncommon phenomenon at low and mid latitudes that, at the end of the 18th century, were not well known and understood. Low and mid geomagnetic latitude aurora observations provide information about episodes of intense solar storms associated with flares and outstanding coronal mass ejection (CME) and about the variation of the geomagnetic field. However, for many observers at mid and low latitudes, the features of a northern light were unknown, so they could easily report it as a phenomenon without explanation. In this work, we found that an earlier mid geomagnetic latitude aurora was observed in Beauséjour, close to Béziers (43∘19′ N, 3∘13′ E), France, by the abbot François Rozier. He was a meticulous botanist, doctor and agronomist with a special interest in atmospheric phenomena. On 15 August 1780, from 19:55 to 20:07 (Universal Time), François Rozier observed a “phosphoric cloud”. A careful analysis of the report indicates that he was reporting an auroral event. The recovery of auroral events at low and mid latitude during the 1780s is very useful for shedding light on solar activity during this period because there are few records of sunspot observations.

Possible Influence of the Solar Eclipse on the Global Geomagnetic Field

2017 ◽  
Vol 13 (S335) ◽  
pp. 167-170
Author(s):  
Jung-Hee Kim ◽  
Heon-Young Chang
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Solar Eclipse ◽  
Geomagnetic Field ◽  
Geomagnetic Observatory ◽  
Geomagnetic Disturbances ◽  
Solar Eclipses ◽  
A Site

AbstractWe investigate the geomagnetic field variations recorded by INTERMAGNET geomagnetic observatories. We confirm that the effect of solar eclipse can be seen over an interval of 180 minutes centered at the time of maximum eclipse on a site of a geomagnetic observatory. It is found that the effect of the solar eclipse on the geomagnetic field becomes conspicuous as the magnitude of a solar eclipse becomes larger. The effect of solar eclipses is more evident in the second half of the path of Moon’s shadow. We also find that the effect can be overwhelmed, more sensitively by geomagnetic disturbances than by solar activity of solar cycle.

Abstract WP330: Process Measures and Outcomes in Defuse 3 Trial by Day and Week Time Patterns

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Michael Mlynash ◽  
Maarten G Lansberg ◽  
Stephanie Kemp ◽  
Soren Christensen ◽  
Michael P Marks ◽  
...  
Keyword(s):  
Arrival Time ◽  
Stroke Care ◽  
Mortality Rates ◽  
Temporal Variations ◽  
Time Of Day ◽  
Process Measures ◽  
Time Period ◽  
Time Patterns ◽  
Time Of Admission

Introduction: Several studies identified temporal variations in stroke care and suggested that quality of care declines during off-hours and on weekends. Methods: We specified 2 time definitions: a) 8-hour blocks: night (midnight – 7:59), day (8:00 – 15:59), evening (16:00-23:59); b) weekday vs. weekend. We compared process measures and outcomes of the EVT-treated DEFUSE 3 patients based on these definitions. To assign patients to time-blocks, we used date and time of admission to hospital that performed EVT. Results: 92 patients were randomized to EVT treatment: 30% arrived to the treating hospital at night, 49% at day, 21% at evening. Mean age by arrival time 71±14, 70±12, 63±15 (p=0.09); NIHSS 17±5, 15±6, 15±8 (p=0.40); female 39%, 51%, 63% (p=0.27). Weekend admission occurred in 21%. Weekday vs weekend mean age 68±14 vs 72±11 (p=0.19); female 53% vs 37% (p=0.20), higher weekend NIHSS 15±6 vs 18±6 (p=0.04). Onset to arrival at the EVT center varied by time of day: (hrs:mins) 7:04±2:43 night, 8:05±3:01 day, 4:51±2:30 evening, p<0.001. However, day admissions tended to be wake-up/not witnessed strokes more often: 76% vs. 47% evening and 64% night, p=0.09. Transfer times for 57 transfer patients were similar: mean 3:06, 3:09, 3:38. Time from arrival at the treating hospital to groin puncture varied by presenting times: 2:28±1:11 night, 1:45±0:46 day, 2:36±2:32 evening (p=0.02). Time-metrics for weekday vs weekend were similar. Rates of successful reperfusion, 90-day mRS and mRS=0-2 did not differ by time of day or week. There was higher 90-day mortality (32% vs 10%, p=0.02) and in-hospital mortality (21% vs. 4%, p=0.03) on weekend. Symptomatic ICH also occurred more commonly in weekend admits (21% vs 3%, p=0.01). However, after adjustment for age and NIHSS, presenting on weekend was not independently associated with mortality, p=0.13. Conclusions: DEFUSE 3 patients admitted during the day had the longest time from last known well to arrival at the study site due to the high percentage of wake-up strokes admitted during this time period, however, these patients had the shortest arrival to groin puncture times. Although mortality rates were higher for patients who presented on weekends, this may be explained by the fact that these patients were older and had higher NIHSS.

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