Impact of the Wintertime Meteor Showers on the Sporadic E Layer Activity at Midlatitudes

2020 ◽  
Author(s):  
Veronika Barta ◽  
Zbysek Mosna ◽  
Daniel Kouba ◽  
Antal Igaz ◽  
Krisztián Sárneczky
Keyword(s):  
Time Resolution ◽  
Sampling Rate ◽  
Optical Data ◽  
High Time Resolution ◽  
Meteor Showers ◽  
High Sampling Rate ◽  
First Results ◽  
Sporadic E Layer ◽  
Sporadic E ◽  
The Impact

<p>The impact of meteor showers and individual meteors on the ionosphere has been investigated during wintertime meteor showers using synchronised measurements of two DPS-4D Digisondes installed at Pruhonice (50°, 14.5°) and at Sopron (47.63°, 16.72°). Rather short distance between Pruhonice and Sopron allow us to perform special joint campaigns of vertical and oblique sounding under the high sampling rate to detect fine structures within ionospheric plasma.</p><p> </p><p>High cadence campaigns have been performed to observe behavior of sporadic E layer (Es) during the Leonids, Geminids and Quadrantids meteor showers in 2018 and 2019. The time resolution of the ionograms have been set to approximately 0.5 - 2 ionograms per minute. We used vertical and oblique reflections to investigate the fine structure and the movement of Es layer. Based on the first results the oblique sounding is a good technique to detect the Es activity between two stations, however there were periods (typically 10 to 40 minutes of duration) when the Es was observed using oblique trace but there was no observation of Es layer in vertical ionograms. Furthermore, double Es structures have been detected more times for tens of minutes during the observation nights.</p><p> </p><p>Beside the regular behavior of Es we concentrated on observation of intervals of increased plasma frequency in the Es region presumably directly induced by the meteors. In the framework of GINOP-2.3.2-15-2016-00003 (“Kozmikus hatások és kockázatok") an optical camera has been installed at the MTA Széchenyi István Geophysical Observatory (Sopron) in September 2019 with the cooperation of the Konkoly Observatory to monitor the meteors. Therefore, we were able to compare the ionograms measured during meteor showers with the optical data to determine the plasma trails of individual meteors. In the 20-25% of the observed meteors a faint Es layers were detected on the ionograms during and after (< 1 min) the optical record. The direction of the detected plasma traces determined by the SAO Explorer was in good agreement with the direction of the optically observed meteors in most of the cases. Consequently, the plasma trace of individual meteors could be detected on the high time resolution ionograms.</p>

scholarly journals High time resolution and polarization properties of ASKAP-localized fast radio bursts

2020 ◽  
Vol 497 (3) ◽  
pp. 3335-3350 ◽  
Author(s):  
Cherie K Day ◽  
Adam T Deller ◽  
Ryan M Shannon ◽  
Hao Qiu(邱昊) ◽  
Keith W Bannister ◽  
...  
Keyword(s):  
Time Resolution ◽  
Local Environment ◽  
High Time ◽  
Frequency Resolution ◽  
Host Galaxy ◽  
High Time Resolution ◽  
Radio Bursts ◽  
Diverse Range ◽  
Scattering Time ◽  
The Impact

ABSTRACT Combining high time and frequency resolution full-polarization spectra of fast radio bursts (FRBs) with knowledge of their host galaxy properties provides an opportunity to study both the emission mechanism generating them and the impact of their propagation through their local environment, host galaxy, and the intergalactic medium. The Australian Square Kilometre Array Pathfinder (ASKAP) telescope has provided the first ensemble of bursts with this information. In this paper, we present the high time and spectral resolution, full polarization observations of five localized FRBs to complement the results published for the previously studied ASKAP FRB 181112. We find that every FRB is highly polarized, with polarization fractions ranging from 80 to 100 per cent, and that they are generally dominated by linear polarization. While some FRBs in our sample exhibit properties associated with an emerging archetype (i.e. repeating or apparently non-repeating), others exhibit characteristic features of both, implying the existence of a continuum of FRB properties. When examined at high time resolution, we find that all FRBs in our sample have evidence for multiple subcomponents and for scattering at a level greater than expected from the Milky Way. We find no correlation between the diverse range of FRB properties (e.g. scattering time, intrinsic width, and rotation measure) and any global property of their host galaxy. The most heavily scattered bursts reside in the outskirts of their host galaxies, suggesting that the source-local environment rather than the host interstellar medium is likely the dominant origin of the scattering in our sample.

scholarly journals The impact of cloudiness and cloud type on the atmospheric heating rate of black and brown carbon

2020 ◽  
Author(s):  
Luca Ferrero ◽  
Asta Gregorič ◽  
Griša Močnik ◽  
Martin Rigler ◽  
Sergio Cogliati ◽  
...  
Keyword(s):  
Time Resolution ◽  
Direct Determination ◽  
High Time ◽  
High Time Resolution ◽  
Cloud Type ◽  
Heating Rates ◽  
Brown Carbon ◽  
Clear Sky ◽  
Sky Conditions ◽  
The Impact

Abstract. We experimentally quantified the impact of cloud fraction and cloud type on the heating rates (HRs) of black and brown carbon (HRBC and HRBrC).In particular, in this work, we examine in more detail the average cloud effect (Ferrero et al., 2018) using high time-resolution measurements of aerosol absorption at multiple-wavelengths coupled with spectral measurements of the direct, diffuse and surface reflected radiation and lidar data in the Po Valley. The experimental set-up allowed a direct determination of HRBC and HRBrC in any sky condition. The highest values of total HR were found in the middle of the winter (1.43 ± 0.05 K day−1) while the lowest in spring (0.54 ± 0.02 K day−1) Overall the HRBrC accounted for 13.7 ± 0.2 % of the total HR, the BrC being characterized by an AAE of 3.49 ± 0.01. Simultaneously, sky conditions were classified (from clear-sky to cloudy) in terms of fraction of sky covered by clouds (oktas) and cloud types. Cloud types were grouped as a function of altitude into the following classes: 1) low level ( 7 km) cirrus, cirrocumulus-cirrostratus. Measurements carried out in different sky conditions at high-time resolution showed a constant decrease of HR with increasing cloudiness of the atmosphere enabling us to quantify for the first time the bias (in %) in the aerosol HR introduced by improperly assuming clear-sky conditions in radiative transfer calculations. In fact, during the campaign, clear sky conditions were only present 23 % of the time while the remaining time (77 %) was characterized by cloudy conditions. Our results show that, by incorrectly assuming clear-sky conditions, the HR of light absorbing aerosol can be largely overestimated (by 50 % in low cloudiness, oktas = 1–2), up to over 400 % (in complete overcast conditions, i.e., oktas = 7–8). The impact of different cloud types on the HR compared to a clear sky condition was also investigated. Cirrus were found to have a modest impact, decreasing the HRBC and HRBrC by −1– −5 %. Cumulus decreased the HRBC and HRBrC by −31 ± 12 and −26 ± 7 %, respectively, while cirrocumulus-cirrostratus by −60 ± 8 and −54 ± 4 %, which was comparable to the impact of altocumulus (−60 ± 6 and −46 ± 4 %). A high impact on HRBC and HRBrC was found for stratocumulus (−63 ± 6 and −58 ± 4 %, respectively) and altostratus (−78 ± 5 and −73 ± 4 %, respectively), although the highest impact was found to be associated to stratus that suppressed the HRBC and HRBrC by −85 ± 5 and −83 ± 3 %, respectively. Additionally, the cloud influence on the radiation spectrum that interacts with the absorbing aerosol was investigated. Black and brown carbon (BC and BrC) have different spectral responses (a different absorption Angstrom exponent, AAE) and our results show that the presence of clouds causes a greater decrease for the HRBC with respect to to HRBrC going clear sky to complete overcast conditions; the observed the difference is 12 ± 6 %. This means that, compared to BC, BrC is more efficient in heating the surrounding atmosphere in cloudy conditions than in clear sky. Overall, this study extends the results of a previous work (Ferrero et al., 2018), highlighting the need to take into account both the role of cloudiness and of different cloud types to better estimate the HR associated to both BC and BrC, and in turn decrease the uncertainties associated to the quantification of the impact of these species on radiation and climate.

scholarly journals Coherent De-dispersion Observations at Jodrell Bank

2000 ◽  
Vol 177 ◽  
pp. 281-282 ◽  
Author(s):  
S. M. Ord ◽  
I. H. Stairs ◽  
F. Camilo
Keyword(s):  
Interstellar Medium ◽  
High Precision ◽  
Time Resolution ◽  
High Time Resolution ◽  
Inverse Filter ◽  
Filter Function ◽  
Dispersive Effect ◽  
Dispersion Law ◽  
First Results ◽  
Plasma Dispersion

AbstractCoherent de-dispersion removes the dispersive effect of the interstellar medium by convolving the digitally sampled telescope output voltages with an inverse filter function, derived from the tenuous plasma dispersion law. The time resolution obtainable by this method is limited only by the bandwidth that can be sampled sufficiently fast as to avoid aliasing. This allows high time resolution, therefore high precision, timing and polarimetry observations of millisecond pulsars. We present here the first results from the Jodrell Bank coherent de-dispersion system.

scholarly journals Spin-down rate of the transitional millisecond pulsar PSR J1023+0038 in the optical band with Aqueye+

2020 ◽  
Vol 498 (1) ◽  
pp. L98-L103
Author(s):  
Aleksandr Burtovoi ◽  
Luca Zampieri ◽  
Michele Fiori ◽  
Giampiero Naletto ◽  
Alessia Spolon ◽  
...  
Keyword(s):  
Time Resolution ◽  
Timing Analysis ◽  
High Time ◽  
Optical Data ◽  
High Time Resolution ◽  
Millisecond Pulsar ◽  
Photon Counter ◽  
X Ray ◽  
Radio Band

ABSTRACT We present a timing analysis of the transitional millisecond pulsar PSR J1023+0038 using observations taken between 2018 January and 2020 January with the high time resolution photon counter Aqueye+ mounted at the 1.82 m Copernicus telescope in Asiago. We report the first measurement of the timing solution and the frequency derivative of PSR J1023+0038 based entirely on optical data. The spin-down rate of the pulsar is (−2.53 ± 0.04) × 10−15 Hz2, which is ∼20 per cent slower than that measured from the X-ray observations taken in 2013–2016 and ∼5 per cent faster than that measured in the radio band during the rotation-powered state.

scholarly journals A DMA-train for precision measurement of sub 10-nm aerosol dynamics

2016 ◽  
Author(s):  
Dominik Stolzenburg ◽  
Gerhard Steiner ◽  
Paul M. Winkler
Keyword(s):  
Particle Size ◽  
Time Resolution ◽  
Transfer Functions ◽  
Particle Formation ◽  
High Time ◽  
High Time Resolution ◽  
New Particle Formation ◽  
Aerosol Dynamics ◽  
Water Based ◽  
The Impact

Abstract. Measurements of aerosol dynamics in the sub-10 nm size range are crucially important for quantifying the impact of new particle formation onto the global budget of cloud condensation nuclei. Here we present the development and characterization of a differential mobility analyzer – train (DMA-train), operating six DMAs in parallel for high time-resolution particle size-distribution measurements below 10 nm. The DMAs are operated at six different but fixed voltages and hence sizes, together with six state-of-the-art condensation particle counters. Two Airmodus A 10 particle size magnifiers (PSM) are used for channels below 2.5 nm while sizes above 2.5 nm are detected by TSI 3776 butanol or TSI 3788 water based CPCs. We report the transfer functions and characteristics of six identical Grimm S-DMAs as well as the calibration of a butanol-based TSI model 3776 CPC, a water-based TSI model 3788 CPC and an Aimodus A10 PSM. We find cut-off diameters similar to those reported in the literature. The performance of the DMA-train is tested with a rapidly changing aerosol of a tungsten oxide particle generator during warm-up. Additionally we report a measurement of new particle formation taken during a nucleation event in the CLOUD chamber experiment at CERN. We find that the DMA-train is able to bridge the gap between currently well-established measurement techniques in the cluster-particle transition regime, providing high time-resolution and accurate size information of neutral and charged particles even at atmospheric particle concentrations.

scholarly journals A DMA-train for precision measurement of sub-10 nm aerosol dynamics

2017 ◽  
Vol 10 (4) ◽  
pp. 1639-1651 ◽  
Author(s):  
Dominik Stolzenburg ◽  
Gerhard Steiner ◽  
Paul M. Winkler
Keyword(s):  
Particle Size ◽  
Time Resolution ◽  
Transfer Functions ◽  
Particle Formation ◽  
High Time ◽  
High Time Resolution ◽  
New Particle Formation ◽  
Aerosol Dynamics ◽  
Water Based ◽  
The Impact

Abstract. Measurements of aerosol dynamics in the sub-10 nm size range are crucially important for quantifying the impact of new particle formation onto the global budget of cloud condensation nuclei. Here we present the development and characterization of a differential mobility analyzer train (DMA-train), operating six DMAs in parallel for high-time-resolution particle-size-distribution measurements below 10 nm. The DMAs are operated at six different but fixed voltages and hence sizes, together with six state-of-the-art condensation particle counters (CPCs). Two Airmodus A10 particle size magnifiers (PSM) are used for channels below 2.5 nm while sizes above 2.5 nm are detected by TSI 3776 butanol-based or TSI 3788 water-based CPCs. We report the transfer functions and characteristics of six identical Grimm S-DMAs as well as the calibration of a butanol-based TSI model 3776 CPC, a water-based TSI model 3788 CPC and an Airmodus A10 PSM. We find cutoff diameters similar to those reported in the literature. The performance of the DMA-train is tested with a rapidly changing aerosol of a tungsten oxide particle generator during warmup. Additionally we report a measurement of new particle formation taken during a nucleation event in the CLOUD chamber experiment at CERN. We find that the DMA-train is able to bridge the gap between currently well-established measurement techniques in the cluster–particle transition regime, providing high time resolution and accurate size information of neutral and charged particles even at atmospheric particle concentrations.

Solar Corona Investigation by the Coronal Line Photometer at Lomnický Peak

1994 ◽  
Vol 144 ◽  
pp. 431-434
Author(s):  
M. Minarovjech ◽  
M. Rybanský
Keyword(s):  
Solar Corona ◽  
Time Resolution ◽  
Active Regions ◽  
High Time ◽  
High Time Resolution ◽  
List Type ◽  
Type Number ◽  
Coronal Line ◽  
Global Cycle

AbstractThis paper deals with a possibility to use the ground-based method of observation in order to solve basic problems connected with the solar corona research. Namely:1.heating of the solar corona2.course of the global cycle in the corona3.rotation of the solar corona and development of active regions.There is stressed a possibility of high-time resolution of the coronal line photometer at Lomnický Peak coronal station, and use of the latter to obtain crucial observations.

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