Wave Reflection and Focusing prior to the Major Stratospheric Warming of September 2002*

2005 ◽  
Vol 62 (3) ◽  
pp. 640-650 ◽  
Author(s):  
Nili Harnik ◽  
Richard K. Scott ◽  
Judith Perlwitz
Keyword(s):  
Traveling Wave ◽  
Wave Reflection ◽  
Early Stage ◽  
Stationary Wave ◽  
Wave Activity ◽  
Mean Flow ◽  
Low Latitude ◽  
Stage Of Development ◽  
Wave Flux ◽  
Large Burst

Abstract Observations of the Southern Hemispheric winter conditions indicate that the major warming of September 2002 resulted from a combination of stationary wave-1 and traveling wave-2 forcing events and suggest that wave and mean-flow anomalies present earlier that winter may have also played a role. Quantities such as the location of the zero wind line, the strength and wave geometry of the vortex, and the horizontal and vertical wave fluxes all differed significantly from climatological values throughout much of the 2002 winter. An analysis of the anomalous features suggests the hypothesis that the persistence of a traveling wave 2 may have increased the likelihood of the combination with stationary wave 1, leading to the observed unprecedented increase in upward Eliassen–Palm flux preceding the warming. The anomalous conditions of the 2002 winter began as early as mid-May of that year and consisted of a large burst of wave flux into the stratosphere and a strong deceleration of the vortex during its early stage of development. The low-latitude easterly anomaly that resulted from this (unprecedented) event appears to have enhanced the poleward focusing of wave activity in the mid- and upper stratosphere during the rest of the winter. The altered wave geometry of the 2002 vortex allowed internal reflection of traveling wave 2, which helps to explain its unusual persistence during the rest of the winter.

scholarly journals The impact of planetary waves on the latitudinal displacement of sudden stratospheric warmings

2013 ◽  
Vol 31 (8) ◽  
pp. 1397-1415 ◽  
Author(s):  
V. Matthias ◽  
P. Hoffmann ◽  
A. Manson ◽  
C. Meek ◽  
G. Stober ◽  
...  
Keyword(s):  
Large Scale ◽  
Wind Band ◽  
Middle Atmosphere ◽  
Stationary Wave ◽  
Planetary Waves ◽  
Mean Flow ◽  
Mesospheric Temperature ◽  
Simultaneous Decrease ◽  
Wave Flux ◽  
The Impact

Abstract. The Northern Hemispheric winter is disturbed by large scale variability mainly caused by Planetary Waves (PWs), which interact with the mean flow and thus result in Sudden Stratospheric Warmings (SSWs). The effects of a SSW on the middle atmosphere are an increase of stratospheric and a simultaneous decrease of mesospheric temperature as well as a wind reversal to westward wind from the mesosphere to the stratosphere. In most cases these disturbances are strongest at polar latitudes, get weaker toward the south and vanish at mid-latitudes around 50° to 60° N as for example during the winter 2005/06. However, other events like in 2009, 2010 and 2012 show a similar or even stronger westward wind at mid- than at polar latitudes either in the mesosphere or in the stratosphere during the SSW. This study uses local meteor and MF-radar measurements, global satellite observations from the Microwave Limb Sounder (MLS) and assimilated model data from MERRA (Modern-ERA Retrospective analysis for research and Applications). We compare differences in the latitudinal structure of the zonal wind, temperature and PW activity between a "normal" event, where the event in 2006 was chosen representatively, and the latitudinal displaced events in 2009, 2010 and 2012. A continuous westward wind band between the pole and 20° N is observed during the displaced events. Furthermore, distinctive temperature differences at mid-latitudes occur before the displaced warmings compared to 2006 as well as a southward extended stratospheric warming afterwards. These differences between the normal SSW in 2006 and the displaced events in 2009, 2010 and 2012 are linked to an increased PW activity between 30° N and 50° N and the changed stationary wave flux in the stratosphere around the displaced events compared to 2006.

scholarly journals Quasigeostrophic Transient Wave Activity Flux: Updated Climatology and Its Role in Polar Vortex Anomalies

2010 ◽  
Vol 67 (10) ◽  
pp. 3164-3189 ◽  
Author(s):  
Mototaka Nakamura ◽  
Minoru Kadota ◽  
Shozo Yamane
Keyword(s):  
Lower Troposphere ◽  
Polar Vortex ◽  
Wave Activity ◽  
Vertical Flux ◽  
Storm Tracks ◽  
Mean Flow ◽  
Transient Wave ◽  
Upper Troposphere ◽  
Wave Flux ◽  
Wave Activity Flux

Abstract The climatology of transient wave activity flux defined by Plumb has been calculated for each calendar month, for high-frequency (HF) and low-frequency (LF) waves, using the NCAR–NCEP reanalyses for both hemispheres. Wave activity flux of both HF and LF waves shows upward propagation of waves from the lower troposphere into the upper troposphere, then into the lower stratosphere during the summer and at least up to the midstratosphere during other seasons. While the upward flux emanating from the lower troposphere is particularly large in the two storm tracks in the Northern Hemisphere (NH), it is large in most of the extratropics in the Southern Hemisphere (SH). The HF waves radiate equatorward most noticeably in the upper troposphere, whereas the LF waves do not show visible signs of equatorward radiation. The total horizontal flux is generally dominated by the advective flux that represents the eddy enstrophy advection by the mean flow and appears predominantly pseudoeastward. Divergence of the wave activity flux exhibits discernible large-scale characteristics at the lowest level in both hemispheres and in the upper troposphere in the NH. The divergence field indicates acceleration of the pseudoeastward mean flow near the surface in both hemispheres. In the NH, acceleration and deceleration, respectively, of the pseudoeastward mean flow in the storm tracks and downstream of the storm tracks in the upper troposphere are found. Seasonal variations in the wave flux are substantial in the NH but relatively minor in the SH. In the NH, the wave flux fields exhibit generally larger values during the cold months than during warm months. Also, the latitudes at which large wave flux values are seen are higher during warm months, as the jets and storm tracks shift northward from the winter to the summer. Anomalously large vertical flux of both HF and LF wave activity propagating up from the lower troposphere throughout the troposphere and stratosphere in the northern flank of the North Atlantic storm track is found to precede anomalous deceleration in the NH winter polar vortex, while anomalously small vertical flux in the same area precedes anomalous acceleration of the vortex. The accompanying horizontal flux anomalies tend to counteract the action of the anomalous vertical flux. These cases are found to be dissipation of strong anomalies in the polar vortex. The anomalous flux divergence does not prove the active role of the waves in the anomalous change in the polar vortex, however. No signs of the wave flux originating from specific areas preceding anomalous change in the polar vortex are found for the SH.

The Application of UX Research in New Energy Vehicle Innovation

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Menghan TAO ◽  
Ning XIAO ◽  
Xingfu ZHAO ◽  
Wenbin LIU
Keyword(s):  
Early Stage ◽  
Rapid Expansion ◽  
The Other ◽  
Innovative Product ◽  
Stage Of Development ◽  
New Energy ◽  
New Energy Vehicle ◽  
The One ◽  
New Energy Vehicles ◽  
Degree Of Innovation

New energy vehicles(NEV) as a new thing for sustainable development, in China, on the one hand has faced the rapid expansion of the market; the other hand, for the new NEV users, the current NEVs cannot keep up with the degree of innovation. This paper demonstrates the reasons for the existence of this systematic challenge, and puts forward the method of UX research which is different from the traditional petrol vehicles research in the early stage of development, which studies from the user's essence level, to form the innovative product programs which meet the needs of users and being real attractive.

scholarly journals Learning health systems in primary care: a systematic scoping review

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Danielle M. Nash ◽  
Zohra Bhimani ◽  
Jennifer Rayner ◽  
Merrick Zwarenstein
Keyword(s):  
Primary Care ◽  
Quality Improvement ◽  
Health Systems ◽  
Scoping Review ◽  
Early Stage ◽  
Point Of Care ◽  
The United States ◽  
Stage Of Development ◽  
Integrated Health ◽  
Google Search

Abstract Background Learning health systems have been gaining traction over the past decade. The purpose of this study was to understand the spread of learning health systems in primary care, including where they have been implemented, how they are operating, and potential challenges and solutions. Methods We completed a scoping review by systematically searching OVID Medline®, Embase®, IEEE Xplore®, and reviewing specific journals from 2007 to 2020. We also completed a Google search to identify gray literature. Results We reviewed 1924 articles through our database search and 51 articles from other sources, from which we identified 21 unique learning health systems based on 62 data sources. Only one of these learning health systems was implemented exclusively in a primary care setting, where all others were integrated health systems or networks that also included other care settings. Eighteen of the 21 were in the United States. Examples of how these learning health systems were being used included real-time clinical surveillance, quality improvement initiatives, pragmatic trials at the point of care, and decision support. Many challenges and potential solutions were identified regarding data, sustainability, promoting a learning culture, prioritization processes, involvement of community, and balancing quality improvement versus research. Conclusions We identified 21 learning health systems, which all appear at an early stage of development, and only one was primary care only. We summarized and provided examples of integrated health systems and data networks that can be considered early models in the growing global movement to advance learning health systems in primary care.

scholarly journals Open Research Data and Open Peer Review: Perceptions of a Medical and Health Sciences Community in Greece

Publications ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 14
Author(s):  
Eirini Delikoura ◽  
Dimitrios Kouis
Keyword(s):  
Peer Review ◽  
Evaluation System ◽  
Early Stage ◽  
Open Science ◽  
Health Sciences ◽  
Research Data ◽  
Stage Of Development ◽  
Open Research ◽  
Proper Training ◽  
To Receive

Recently significant initiatives have been launched for the dissemination of Open Access as part of the Open Science movement. Nevertheless, two other major pillars of Open Science such as Open Research Data (ORD) and Open Peer Review (OPR) are still in an early stage of development among the communities of researchers and stakeholders. The present study sought to unveil the perceptions of a medical and health sciences community about these issues. Through the investigation of researchers` attitudes, valuable conclusions can be drawn, especially in the field of medicine and health sciences, where an explosive growth of scientific publishing exists. A quantitative survey was conducted based on a structured questionnaire, with 179 valid responses. The participants in the survey agreed with the Open Peer Review principles. However, they ignored basic terms like FAIR (Findable, Accessible, Interoperable, and Reusable) and appeared incentivized to permit the exploitation of their data. Regarding Open Peer Review (OPR), participants expressed their agreement, implying their support for a trustworthy evaluation system. Conclusively, researchers need to receive proper training for both Open Research Data principles and Open Peer Review processes which combined with a reformed evaluation system will enable them to take full advantage of the opportunities that arise from the new scholarly publishing and communication landscape.

scholarly journals Primary Care Networks and Starfield’s 4Cs: A Case for Enhanced Chronic Disease Management

2021 ◽  
Vol 18 (6) ◽  
pp. 2926
Author(s):  
Chuan De Foo ◽  
Shilpa Surendran ◽  
Geronimo Jimenez ◽  
John Pastor Ansah ◽  
David Bruce Matchar ◽  
...  
Keyword(s):  
Primary Care ◽  
Chronic Disease ◽  
Disease Management ◽  
Chronic Disease Management ◽  
Early Stage ◽  
Healthcare Delivery ◽  
Stage Of Development ◽  
Facilitators And Barriers ◽  
Design Options ◽  
First Contact

The primary care network (PCN) was implemented as a healthcare delivery model which organises private general practitioners (GPs) into groups and furnished with a certain level of resources for chronic disease management. A secondary qualitative analysis was conducted with data from an earlier study exploring facilitators and barriers GPs enrolled in PCN’s face in chronic disease management. The objective of this study is to map features of PCN to Starfield’s “4Cs” framework. The “4Cs” of primary care—comprehensiveness, first contact access, coordination and continuity—offer high-quality design options for chronic disease management. Interview transcripts of GPs (n = 30) from the original study were purposefully selected. Provision of ancillary services, manpower, a chronic disease registry and extended operating hours of GP practices demonstrated PCN’s empowering features that fulfil the “4Cs”. On the contrary, operational challenges such as the lack of an integrated electronic medical record and disproportionate GP payment structures limit PCNs from maximising the “4Cs”. However, the enabling features mentioned above outweighs the shortfalls in all important aspects of delivering optimal chronic disease care. Therefore, even though PCN is in its early stage of development, it has shown to be well poised to steer GPs towards enhanced chronic disease management.

The magic bullet for rural development? Exploring the impacts of community telecenters in Bangladesh

2021 ◽  
pp. 026666692199750
Author(s):  
Noore Alam Siddiquee ◽  
Md Gofran Faroqi
Keyword(s):  
Service Delivery ◽  
Rural Areas ◽  
Early Stage ◽  
Rural Livelihoods ◽  
Value Added ◽  
Magic Bullet ◽  
Government Information ◽  
Individual Interviews ◽  
Stage Of Development ◽  
Marginalized Groups

This paper explores the impacts of Bangladesh’s Union Digital Centers (UDCs) as government information and service delivery hubs in rural areas. Drawing on user-surveys and semi-structured individual interviews it demonstrates that the UDCs have produced generally positive yet modest impacts on governance of service delivery. It shows that the UDCs are at an early stage of development, and that they offer only a limited set of services. While they helped extend ICT-enabled services to sections of population that would otherwise have missed them, the UDCs do not have much to do with rural livelihoods and empowerment of the poor and marginalized groups. These findings point to current inadequacies and pitfalls of the UDC approach to development. We argue that enhanced viability and effectiveness of the UDC experiment would warrant embedding more value-added governmental services and further strengthening of their capacity, mandate, and connectivity with government agencies at various levels, among others.

Targets, triggers, and directionality in non-local and local place assimilation in child and adult language

2014 ◽  
Vol 50 (3) ◽  
pp. 273-307
Author(s):  
Mi-Hui Cho ◽  
Shinsook Lee
Keyword(s):  
Longitudinal Study ◽  
Early Development ◽  
Early Stage ◽  
Decisive Role ◽  
Diary Study ◽  
Consonant Harmony ◽  
Stage Of Development ◽  
Place Assimilation ◽  
Korean Child ◽  
Non Local

Abstract Data collected from one Korean child in a longitudinal diary study present novel patterns of consonant harmony in that labials, coronals, and velars can be triggers and targets of both progressive and regressive non-local place assimilation in an early stage of development. The same child also shows some cases of local regressive place assimilation. In another study where 4 children's data were gathered from a naturalistic longitudinal study, local regressive place assimilation as well as conso-nant harmony is witnessed regardless of place features. In adult Korean, however, only coronal to labial/velar and labial to velar local regressive assimilation occurs. This paper argues that the non-local and local place assimilation is connected and shows that the connection can be accounted for in terms of different constraint rankings within the Optimality-theoretic framework. More specifically, it is shown that the Ident-Onset(place) constraint plays a decisive role even in the early stage of acquisition, unlike child English, accounting for the predominant regressive assimilation. Also, the Agree-Place constraint is exploded into two sub-constraints in Stage 3, capturing the asymmetrical behavior of assimilation. Further, the unranking of place features in early development gradually evolves to the fixed ranking which reflects the universal markedness hierarchy in adult Korean.

Genera coelomycetarum. I. Urohendersonia

1971 ◽  
Vol 49 (11) ◽  
pp. 1853-1862 ◽  
Author(s):  
T. R. Nag Raj ◽  
Bryce Kendrick
Keyword(s):  
Early Stage ◽  
Type Material ◽  
Stage Of Development

Study of type material of Urohendersonia platensis, U. indica, and U. stipae reveals that structures described by their original authors as ‘basidia’ or ‘pedicels’ (in contemporary parlance, conidiophores) are, in fact, apical conidium appendages. The true conidiophores and the processes of conidiogenesis are described and illustrated. Urohendersonia has unilocular, ostiolate pycnidia producing three-septate, colored conidia that are enclosed from an early stage of development in a sheath which extends apically as a hyaline, filiform process. Urohendersonia and Hendersonia are delineated. Revised descriptions are given for Urohendersonia and its four species. A fifth species, U. mysorensis, is described as new. A key to the five species is given.

Sign in / Sign up

Export Citation Format

Share Document