scholarly journals Large-scale planetary disturbances in stratospheric temperature at high-latitudes in the southern summer hemisphere

2008 ◽  
Vol 8 (24) ◽  
pp. 7557-7570 ◽  
Author(s):  
M. G. Shepherd ◽  
T. Tsuda
Keyword(s):  
Large Scale ◽  
Planetary Wave ◽  
Radio Occultation ◽  
Local Times ◽  
Late Winter ◽  
Stationary Waves ◽  
The Novel ◽  
Planetary Scale ◽  
Stratospheric Temperature ◽  
Summer Hemisphere

Abstract. The global structure and propagation of large-scale (periods >5 days) waves in the Southern Hemisphere summer (December 2006–February 2007) at 60° S–75° S latitude are examined using temperature data from GPS radio occultation measurements by COSMIC/FORMOSAT 3 satellite constellation at 20 km and 30 km altitude. Spectral analysis has revealed eastward propagating planetary scale perturbations with wavenumbers 1 and 2 and periods of 10, 16 and 23 days, and stationary waves with wavenumbers 1 and 2. The results obtained show a very dynamically active Antarctic summer stratosphere. The novel aspect of the work is in the use of the GPS COSMIC data providing multiple local times each day, thus allowing large-scale wave analysis at high Southern latitudes and revealing planetary wave activity not normally observed in summer, but more consistent with late winter and spring conditions in the stratosphere.

scholarly journals Large-scale planetary disturbances in stratospheric temperature at high-latitudes in the Southern Summer Hemisphere

2008 ◽  
Vol 8 (4) ◽  
pp. 16409-16444 ◽  
Author(s):  
M. G. Shepherd ◽  
T. Tsuda
Keyword(s):  
Large Scale ◽  
Planetary Wave ◽  
Radio Occultation ◽  
Local Times ◽  
Late Winter ◽  
Stationary Waves ◽  
The Novel ◽  
Planetary Scale ◽  
Stratospheric Temperature ◽  
Summer Hemisphere

Abstract. The global structure and propagation of large-scale (periods >5 days) waves in the Southern Hemisphere summer (December 2006–February 2007) at 60° S–75° S latitude are examined using temperature data from GPS radio occultation measurements by COSMIC/FORMOSAT 3 satellite constellation from 10 to 40 km altitude. Spectral analysis has revealed eastward propagating planetary scale perturbations with wavenumbers 1 and 2 and periods of 10-, 16- and 23 days, zonally symmetric waves with the same periods and stationary waves with wavenumber 1 and 2. The presence of the zonally symmetric waves is interpreted as an indication of the coupling of the stationary and traveling waves. The results obtained show a very dynamically active Antarctic summer stratosphere. The novel aspect of the work is in the use of the GPS COSMIC data providing multiple local times each day, thus allowing large-scale wave analysis at high Southern latitudes and revealing planetary wave activity not normally observed in summer, but more consistent with late winter and spring conditions in the stratosphere.

scholarly journals The noctilucent cloud (NLC) display during the ECOMA/MASS sounding rocket flights on 3 August 2007: morphology on global to local scales

2009 ◽  
Vol 27 (3) ◽  
pp. 953-965 ◽  
Author(s):  
G. Baumgarten ◽  
J. Fiedler ◽  
K. H. Fricke ◽  
M. Gerding ◽  
M. Hervig ◽  
...  
Keyword(s):  
Large Scale ◽  
Planetary Wave ◽  
Local Scale ◽  
Sounding Rocket ◽  
Small Scale ◽  
Meteor Radar ◽  
Horizontal Temperature Gradient ◽  
Noctilucent Cloud ◽  
Planetary Scale ◽  
Lidar Observations

Abstract. During the ECOMA/MASS rocket campaign large scale NLC/PMC was observed by satellite, lidar and camera from polar to mid latitudes. We examine the observations from different instruments to investigate the morphology of the cloud. Satellite observations show a planetary wave 2 structure. Lidar observations from Kühlungsborn (54° N), Esrange (68° N) and ALOMAR (69° N) show a highly dynamic NLC layer. Under favorable solar illumination the cloud is also observable by ground-based cameras. The cloud was detected by cameras from Trondheim (63° N), Juliusruh (55° N) and Kühlungsborn. We investigate planetary scale morphology and local scale gravity wave structures, important for the interpretation of the small scale rocket soundings. We compare in detail the lidar observations with the NLC structure observed by the camera in Trondheim. The ALOMAR RMR-lidar observed only a faint NLC during the ECOMA launch window, while the camera in Trondheim showed a strong NLC display in the direction of ALOMAR. Using the high resolution camera observations (t~30 s, Δx<5 km) and the wind information from the meteor radar at ALOMAR we investigate the formation and destruction of NLC structures. We observe that the NLC brightness is reduced by a factor of 20–40 within 100 s which can be caused by a temperature about 15 K above the frostpoint temperature. A horizontal temperature gradient of more than 3 K/km is estimated.

scholarly journals Quasi-stationary planetary waves in late winter Antarctic stratosphere temperature as a possible indicator of spring total ozone

2011 ◽  
Vol 11 (10) ◽  
pp. 28945-28967
Author(s):  
V. O. Kravchenko ◽  
O. M. Evtushevsky ◽  
A. V. Grytsai ◽  
A. R. Klekociuk ◽  
G. P. Milinevsky ◽  
...  
Keyword(s):  
Total Ozone ◽  
Large Scale ◽  
Stationary Wave ◽  
Planetary Waves ◽  
Ozone Hole ◽  
Late Winter ◽  
Stationary Waves ◽  
Wave Effects ◽  
Antarctic Ozone ◽  
Highly Correlated

Abstract. Stratospheric preconditions for the annual Antarctic ozone hole are analysed using the amplitude of quasi-stationary planetary waves in temperature as a predictor of total ozone column behaviour. It is found that the quasi-stationary wave amplitude in August is highly correlated with September–November total ozone over Antarctica with correlation coefficient as high as 0.83 indicating that quasi-stationary wave effects in late winter have a persisting influence on the evolution of the ozone hole during the following three months. Correlation maxima are found in both the lower and middle stratosphere. They are likely manifestations of wave activity influence on chemical ozone depletion and large-scale ozone transport, respectively. Both correlation maxima indicate that spring total ozone tends to increase in the case of amplified activity of quasi-stationary waves in late winter.

scholarly journals Quasi-stationary planetary waves in late winter Antarctic stratosphere temperature as a possible indicator of spring total ozone

2012 ◽  
Vol 12 (6) ◽  
pp. 2865-2879 ◽  
Author(s):  
V. O. Kravchenko ◽  
O. M. Evtushevsky ◽  
A. V. Grytsai ◽  
A. R. Klekociuk ◽  
G. P. Milinevsky ◽  
...  
Keyword(s):  
Total Ozone ◽  
Large Scale ◽  
Stationary Wave ◽  
Planetary Waves ◽  
Ozone Hole ◽  
Wave Number ◽  
Late Winter ◽  
Stationary Waves ◽  
Wave Effects ◽  
Highly Correlated

Abstract. Stratospheric preconditions for the annual Antarctic ozone hole are analyzed using the amplitude of quasi-stationary planetary waves in temperature as a predictor of total ozone column behaviour. It is found that the quasi-stationary wave amplitude in August is highly correlated with September–November total ozone over Antarctica with correlation coefficient (r) as high as 0.83 indicating that quasi-stationary wave effects in late winter have a persisting influence on the evolution of the ozone hole during the following three months. Correlation maxima are found in both the lower and middle stratosphere. These likely result from the influence of wave activity on ozone depletion due to chemical processes, and ozone accumulation due to large-scale ozone transport, respectively. Both correlation maxima indicate that spring total ozone tends to increase in the case of amplified activity of quasi-stationary waves in late winter. Since the stationary wave number one dominates the planetary waves that propagate into the Antarctic stratosphere in late austral winter, it is largely responsible for the stationary zonal asymmetry of the ozone hole relative to the South Pole. Processes associated with zonally asymmetric ozone and temperature which possibly contribute to differences in the persistence and location of the correlation maxima are discussed.

Covalent Atomic Bridges Enable Unidirectional Enhancement of Electronic Transport in Aligned Carbon Nanotubes

2019 ◽  
Author(s):  
Mingguang Chen ◽  
Wangxiang Li ◽  
Anshuman Kumar ◽  
Guanghui Li ◽  
Mikhail Itkis ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Transport ◽  
Large Scale ◽  
The Novel ◽  
Electrical Measurements ◽  
Metal Atoms ◽  
Aligned Carbon Nanotubes ◽  
Transport Channels ◽  
Walled Carbon Nanotubes ◽  
Bulk Structures

<p>Interconnecting the surfaces of nanomaterials without compromising their outstanding mechanical, thermal, and electronic properties is critical in the design of advanced bulk structures that still preserve the novel properties of their nanoscale constituents. As such, bridging the p-conjugated carbon surfaces of single-walled carbon nanotubes (SWNTs) has special implications in next-generation electronics. This study presents a rational path towards improvement of the electrical transport in aligned semiconducting SWNT films by deposition of metal atoms. The formation of conducting Cr-mediated pathways between the parallel SWNTs increases the transverse (intertube) conductance, while having negligible effect on the parallel (intratube) transport. In contrast, doping with Li has a predominant effect on the intratube electrical transport of aligned SWNT films. Large-scale first-principles calculations of electrical transport on aligned SWNTs show good agreement with the experimental electrical measurements and provide insight into the changes that different metal atoms exert on the density of states near the Fermi level of the SWNTs and the formation of transport channels. </p>

scholarly journals Massive and Microscopic Sensemaking During COVID-19 Times

2020 ◽  
pp. 107780042096247 ◽  
Author(s):  
Annette N. Markham ◽  
Anne Harris ◽  
Mary Elizabeth Luka
Keyword(s):  
Critical Pedagogy ◽  
Lived Experience ◽  
Large Scale ◽  
Ethic Of Care ◽  
Feminist Perspective ◽  
The Other ◽  
Self And Other ◽  
Planetary Scale ◽  
Making Sense ◽  
Ongoing Experiment

How does this pandemic moment help us to think about the relationships between self and other, or between humans and the planet? How are people making sense of COVID-19 in their everyday lives, both as a local and intimate occurrence with microscopic properties, and a planetary-scale event with potentially massive outcomes? In this paper we describe our approach to a large-scale, still-ongoing experiment involving more than 150 people from 26 countries. Grounded in autoethnography practice and critical pedagogy, we offered 21 days of self guided prompts to for us and the other participants to explore their own lived experience. Our project illustrates the power of applying a feminist perspective and an ethic of care to engage in open ended collaboration during times of globally-felt trauma.

scholarly journals IoT Traffic: Modeling and Measurement Experiments

IoT ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 140-162
Author(s):  
Hung Nguyen-An ◽  
Thomas Silverston ◽  
Taku Yamazaki ◽  
Takumi Miyoshi
Keyword(s):  
Smart Home ◽  
Large Scale ◽  
Traffic Modeling ◽  
The Novel ◽  
Network Behavior ◽  
Performance Accuracy ◽  
Traffic Generator ◽  
Multiple Devices ◽  
Iot Devices ◽  
The Internet Of Things

We now use the Internet of things (IoT) in our everyday lives. The novel IoT devices collect cyber–physical data and provide information on the environment. Hence, IoT traffic will count for a major part of Internet traffic; however, its impact on the network is still widely unknown. IoT devices are prone to cyberattacks because of constrained resources or misconfigurations. It is essential to characterize IoT traffic and identify each device to monitor the IoT network and discriminate among legitimate and anomalous IoT traffic. In this study, we deployed a smart-home testbed comprising several IoT devices to study IoT traffic. We performed extensive measurement experiments using a novel IoT traffic generator tool called IoTTGen. This tool can generate traffic from multiple devices, emulating large-scale scenarios with different devices under different network conditions. We analyzed the IoT traffic properties by computing the entropy value of traffic parameters and visually observing the traffic on behavior shape graphs. We propose a new method for identifying traffic entropy-based devices, computing the entropy values of traffic features. The method relies on machine learning to classify the traffic. The proposed method succeeded in identifying devices with a performance accuracy up to 94% and is robust with unpredictable network behavior with traffic anomalies spreading in the network.

scholarly journals Multi-Objective Optimization of Integrated Civilian-Military Scheduling of Medical Supplies for Epidemic Prevention and Control

Healthcare ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 126
Author(s):  
Hai-Feng Ling ◽  
Zheng-Lian Su ◽  
Xun-Lin Jiang ◽  
Yu-Jun Zheng
Keyword(s):  
Prevention And Control ◽  
Large Scale ◽  
Medical Services ◽  
The Novel ◽  
Multi Objective ◽  
Medical Supplies ◽  
Problem Instances ◽  
Novel Coronavirus ◽  
And Control ◽  
Minimum Ratio

In a large-scale epidemic, such as the novel coronavirus pneumonia (COVID-19), there is huge demand for a variety of medical supplies, such as medical masks, ventilators, and sickbeds. Resources from civilian medical services are often not sufficient for fully satisfying all of these demands. Resources from military medical services, which are normally reserved for military use, can be an effective supplement to these demands. In this paper, we formulate a problem of integrated civilian-military scheduling of medical supplies for epidemic prevention and control, the aim of which is to simultaneously maximize the overall satisfaction rate of the medical supplies and minimize the total scheduling cost, while keeping a minimum ratio of medical supplies reservation for military use. We propose a multi-objective water wave optimization (WWO) algorithm in order to efficiently solve this problem. Computational results on a set of problem instances constructed based on real COVID-19 data demonstrate the effectiveness of the proposed method.

scholarly journals Comparative genomics suggests a taxonomic revision of the Staphylococcus cohnii species complex

2021 ◽  
Author(s):  
Anna Lavecchia ◽  
Matteo Chiara ◽  
Caterina De Virgilio ◽  
Caterina Manzari ◽  
Carlo Pazzani ◽  
...  
Keyword(s):  
Comparative Genomics ◽  
Species Complex ◽  
Large Scale ◽  
Genomic Sequence ◽  
Bacterial Species ◽  
Taxonomic Revision ◽  
Distinct Species ◽  
The Novel ◽  
Staphylococcus Cohnii ◽  
Taxonomic Assignments

Abstract Staphylococcus cohnii (SC), a coagulase-negative bacterium, was first isolated in 1975 from human skin. Early phenotypic analyses led to the delineation of two subspecies (subsp.), Staphylococcus cohnii subsp. cohnii (SCC) and Staphylococcus cohnii subsp. urealyticus (SCU). SCC was considered to be specific to humans whereas SCU apparently demonstrated a wider host range, from lower primates to humans. The type strains ATCC 29974 and ATCC 49330 have been designated for SCC and SCU, respectively. Comparative analysis of 66 complete genome sequences—including a novel SC isolate—revealed unexpected patterns within the SC complex, both in terms of genomic sequence identity and gene content, highlighting the presence of 3 phylogenetically distinct groups. Based on our observations, and on the current guidelines for taxonomic classification for bacterial species, we propose a revision of the SC species complex. We suggest that SCC and SCU should be regarded as two distinct species: SC and SU (Staphylococcus urealyticus), and that two distinct subspecies, SCC and SCB (SC subsp. barensis, represented by the novel strain isolated in Bari) should be recognized within SC. Furthermore, since large scale comparative genomics studies recurrently suggest inconsistencies or conflicts in taxonomic assignments of bacterial species, we believe that the approach proposed here might be considered for more general application.

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