scholarly journals Hypothetical route of the introduction of Schmallenberg virus into Ireland using two complementary analyses

2017 ◽  
Vol 182 (8) ◽  
pp. 226-226 ◽  
Author(s):  
Guy McGrath ◽  
Simon J More ◽  
Ronan O’Neill
Keyword(s):  
Atmospheric Dispersion ◽  
Low Frequency ◽  
Meteorological Conditions ◽  
Schmallenberg Virus ◽  
Long Distance ◽  
Biting Midges ◽  
Atmospheric Dispersion Modelling ◽  
Response Systems ◽  
Meteorological Modelling ◽  
Wind Flows

Ireland lost its official freedom from Schmallenberg virus (SBV) in October 2012. The route of introduction is uncertain, with long-distance displacement of infected Culicoides, biting midges, by suitable wind flows considered to be the most likely source. The authors investigated the potential introduction of SBV into Ireland through a Culicoides incursion event in the summer of 2012. They conducted SBV serology on archived bovine sera to identify the prospective dispersal window, then used atmospheric dispersion modelling during periods around this window to identify environmental conditions the authors considered suitable for atmospheric dispersal of Culicoides from potential infected source locations across Southern England. The authors believe that there was one plausible window over the summer of 2012, on August 10–11, based on suitable meteorological conditions. They conclude that a potential long-range transportation event of Culicoides appears to have occurred successfully only once during the 2012 vector competent season. If these incursion events remain at a low frequency, meteorological modelling has the potential to contribute cost-effectively to the alert and response systems for vectorborne diseases in the future.

scholarly journals Variation of Low-Frequency Time-Code Signal Field Strength during the Annular Solar Eclipse on 21 June 2020: Observation and Analysis

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1216
Author(s):  
Xin Wang ◽  
Bo Li ◽  
Fan Zhao ◽  
Xinyu Luo ◽  
Luxi Huang ◽  
...  
Keyword(s):  
Field Strength ◽  
Solar Eclipse ◽  
Low Frequency ◽  
Signal Propagation ◽  
Normal Operation ◽  
Time Code ◽  
Long Distance ◽  
Time Service ◽  
Annular Solar Eclipse ◽  
Signal Field

Due to the occlusion of the moon, an annular solar eclipse will have an effect on the ionosphere above the earth. The change of the ionosphere, for the low-frequency time-code signal that relies on it as a reflection medium for long-distance propagation, the signal field strength, and other parameters will also produce corresponding changes, which will affect the normal operation of the low-frequency time-code time service system. This paper selects the solar eclipse that occurred in China on 21 June 2020, and uses the existing measurement equipment to carry out experimental research on the low-frequency time-code signal. We measured and analyzed the signal field strength from 20 June 2020 to 23 June 2020, and combined solar activity data, ionospheric data, and geomagnetic data, and attempted to explore the reasons and rules of the change of signal parameters. The results showed that the field strength of the low-frequency time-code signal changed dramatically within a short time period, the max growth value can reach up to 17 dBμV/m and the variation trend yielded ‘three mutations’. This change in signal field strength is probably due to the occurrence of a solar eclipse that has an effect on the ionosphere. When the signal propagation conditions change, the signal strength will also change accordingly.

Meteorological conditions influence on quantification of site effects at low frequency using the seismic ambient noise

2015 ◽  
Author(s):  
Rabah Bensalem* ◽  
Djamal Machane ◽  
Jean-Luc Chatelain ◽  
Mohamed Djeddi ◽  
Hakim Moulouel ◽  
...  
Keyword(s):  
Site Effects ◽  
Ambient Noise ◽  
Low Frequency ◽  
Meteorological Conditions ◽  
Seismic Ambient Noise

scholarly journals Meteorological conditions over Antarctic blue-ice areas and their influence on the local surface mass balance

2001 ◽  
Vol 47 (156) ◽  
pp. 37-50 ◽  
Author(s):  
Richard Bintanja ◽  
Carleen H. Reijmer
Keyword(s):  
Mass Balance ◽  
Low Frequency ◽  
Meteorological Conditions ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
Wind Speeds ◽  
Dry Conditions ◽  
The Difference ◽  
Sublimation Rates ◽  
Different Characteristics

AbstractThis paper addresses the causes of the prevailing meteorological conditions observed over an Antarctic blue-ice area and their effect on the surface mass balance. Over blue-ice areas, net accumulation is zero and ablation occurs mainly through sublimation. Sublimation rates are much higher than over adjacent snowfields. The meteorological conditions favourable for high sublimation rates (warm, dry and gusty) are due to the specific orographic setting of this blue-ice area, with usually a steep upwind mountainous slope causing strong adiabatic heating. Diabatic warming due to radiation, and entrainment of warm air from aloft into the boundary layer augment the warming. The prevailing warm, dry conditions explain roughly 50% of the difference in sublimation, and the different characteristics of blue ice (mainly its lower albedo) the other 50%. Most of the annual sublimation (∼70%) takes place during the short summer (mainly in daytime), with winter ablation being restricted to occasional warm, dry föhn-like events. The additional moisture is effectively removed by entrainment and horizontal advection, which are maximum over the blue-ice area. Low-frequency turbulent motions induced by the upwind mountains enhance the vertical turbulent transports. Strong gusts and high peak wind speeds over blue-ice areas cause high potential snowdrift transports, which can easily remove the total precipitation, thereby maintaining zero accumulation.

Optimizing the calculation grid for atmospheric dispersion modelling

2015 ◽  
Vol 142 ◽  
pp. 103-112
Author(s):  
S. Van Thielen ◽  
C. Turcanu ◽  
J. Camps ◽  
R. Keppens
Keyword(s):  
Atmospheric Dispersion ◽  
Dispersion Modelling ◽  
Atmospheric Dispersion Modelling ◽  
Calculation Grid

Innovative Atmospheric Dispersion Modelling in Support of Smart Farming Applications Within the Frame of the EU LIFE+ GAIA SENSE Project

2021 ◽  
pp. 195-200
Author(s):  
F. Barmpas ◽  
George Tsegas ◽  
Nicolas Moussiopoulos ◽  
E. Fragkou
Keyword(s):  
Atmospheric Dispersion ◽  
Dispersion Modelling ◽  
Atmospheric Dispersion Modelling ◽  
Smart Farming ◽  
The Eu

Cross-sectional study of British wild deer for evidence of Schmallenberg virus infection

2020 ◽  
Vol 187 (8) ◽  
pp. e64-e64
Author(s):  
Rebecca Marie Southwell ◽  
Kenneth Sherlock ◽  
Matthew Baylis
Keyword(s):  
Great Britain ◽  
Fallow Deer ◽  
Cross Sectional Study ◽  
Schmallenberg Virus ◽  
Biting Midges ◽  
Cross Sectional ◽  
Single Region ◽  
Postmortem Blood ◽  
The Uk ◽  
Wild Deer

BackgroundSchmallenberg virus (SBV) is an orthobunyavirus, carried by Culicoides biting midges, that causes reproductive problems in adult ruminants when infected during their gestation period. SBV was first detected in ruminants in the UK in 2011/2012 and then again in 2016. The reason behind the 2016 re-emergence of SBV is unknown, but one possibility is that it can be maintained in wildlife, such as deer. SBV has been detected at high seroprevalence in deer in a number of European countries, but only once in the UK in a single region.MethodsThe purpose of this study was to survey wild deer across Great Britain for recent evidence of SBV. Deer hunters were recruited for the purpose of providing postmortem blood samples to be tested for SBV antibodies.ResultsThe seroprevalence of SBV in the British wild deer population was 13.8 per cent; found in red, roe, muntjac and fallow deer species, with more in deer further south.ConclusionThese results support the growing concern that SBV is now endemic in Great Britain and highlight the need to know the role of wildlife in SBV transmission.

scholarly journals Schmallenberg virus: a systematic international literature review (2011-2019) from an Irish perspective

2019 ◽  
Vol 72 (1) ◽  
Author(s):  
Áine B. Collins ◽  
Michael L. Doherty ◽  
Damien J. Barrett ◽  
John F. Mee
Keyword(s):  
Scientific Literature ◽  
Current Knowledge ◽  
Clinical Signs ◽  
Control Measures ◽  
Schmallenberg Virus ◽  
Transmission Risk ◽  
Surveillance Program ◽  
Emerging Viruses ◽  
Biting Midges ◽  
Irish Case

Abstract In Autumn 2011, nonspecific clinical signs of pyrexia, diarrhoea, and drop in milk yield were observed in dairy cattle near the German town of Schmallenberg at the Dutch/German border. Targeted veterinary diagnostic investigations for classical endemic and emerging viruses could not identify a causal agent. Blood samples were collected from animals with clinical signs and subjected to metagenomic analysis; a novel orthobunyavirus was identified and named Schmallenberg virus (SBV). In late 2011/early 2012, an epidemic of abortions and congenital malformations in calves, lambs and goat kids, characterised by arthrogryposis and hydranencephaly were reported in continental Europe. Subsequently, SBV RNA was confirmed in both aborted and congenitally malformed foetuses and also in Culicoides species biting midges. It soon became evident that SBV was an arthropod-borne teratogenic virus affecting domestic ruminants. SBV rapidly achieved a pan-European distribution with most countries confirming SBV infection within a year or two of the initial emergence. The first Irish case of SBV was confirmed in the south of the country in late 2012 in a bovine foetus. Since SBV was first identified in 2011, a considerable body of scientific research has been conducted internationally describing this novel emerging virus. The aim of this systematic review is to provide a comprehensive synopsis of the most up-to-date scientific literature regarding the origin of SBV and the spread of the Schmallenberg epidemic, in addition to describing the species affected, clinical signs, pathogenesis, transmission, risk factors, impact, diagnostics, surveillance methods and control measures. This review also highlights current knowledge gaps in the scientific literature regarding SBV, most notably the requirement for further research to determine if, and to what extent, SBV circulation occurred in Europe and internationally during 2017 and 2018. Moreover, recommendations are also made regarding future arbovirus surveillance in Europe, specifically the establishment of a European-wide sentinel herd surveillance program, which incorporates bovine serology and Culicoides entomology and virology studies, at national and international level to monitor for the emergence and re-emergence of arboviruses such as SBV, bluetongue virus and other novel Culicoides-borne arboviruses.

scholarly journals Atmospheric Dispersion Modelling at the London VAAC: A Review of Developments since the 2010 Eyjafjallajökull Volcano Ash Cloud

Atmosphere ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 352 ◽  
Author(s):  
Frances M. Beckett ◽  
Claire S. Witham ◽  
Susan J. Leadbetter ◽  
Ric Crocker ◽  
Helen N. Webster ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Dispersion Model ◽  
Source Parameters ◽  
Atmospheric Dispersion ◽  
Lessons Learned ◽  
Dispersion Modelling ◽  
Atmospheric Dispersion Modelling ◽  
Volcanic Ash Cloud ◽  
Atmospheric Dispersion Model ◽  
Ash Cloud

It has been 10 years since the ash cloud from the eruption of Eyjafjallajökull caused unprecedented disruption to air traffic across Europe. During this event, the London Volcanic Ash Advisory Centre (VAAC) provided advice and guidance on the expected location of volcanic ash in the atmosphere using observations and the atmospheric dispersion model NAME (Numerical Atmospheric-Dispersion Modelling Environment). Rapid changes in regulatory response and procedures during the eruption introduced the requirement to also provide forecasts of ash concentrations, representing a step-change in the level of interrogation of the dispersion model output. Although disruptive, the longevity of the event afforded the scientific community the opportunity to observe and extensively study the transport and dispersion of a volcanic ash cloud. We present the development of the NAME atmospheric dispersion model and modifications to its application in the London VAAC forecasting system since 2010, based on the lessons learned. Our ability to represent both the vertical and horizontal transport of ash in the atmosphere and its removal have been improved through the introduction of new schemes to represent the sedimentation and wet deposition of volcanic ash, and updated schemes to represent deep moist atmospheric convection and parametrizations for plume spread due to unresolved mesoscale motions. A good simulation of the transport and dispersion of a volcanic ash cloud requires an accurate representation of the source and we have introduced more sophisticated approaches to representing the eruption source parameters, and their uncertainties, used to initialize NAME. Finally, upper air wind field data used by the dispersion model is now more accurate than it was in 2010. These developments have resulted in a more robust modelling system at the London VAAC, ready to provide forecasts and guidance during the next volcanic ash event.

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