scholarly journals Stratospheric Gravity Waves Generated by Multiscale Tropical Convection

2008 ◽  
Vol 65 (8) ◽  
pp. 2598-2614 ◽  
Author(s):  
Todd P. Lane ◽  
Mitchell W. Moncrieff
Keyword(s):  
Gravity Waves ◽  
Scale Up ◽  
Cloud System ◽  
Cloud Systems ◽  
Multiscale Systems ◽  
Cloud Clusters ◽  
Horizontal Momentum ◽  
The Individual ◽  
Similar Depth ◽  
Convective Organization

Abstract The generation of gravity waves by multiscale cloud systems evolving in an initially motionless and thermodynamically uniform environment is explored using a two-dimensional cloud-system-resolving model. The simulated convection has similar depth and intensity to observed tropical oceanic systems. The convection self-organizes into preferred horizontal and temporal scales involving weakly organized propagating cloud clusters. The multiscale systems generate a broad spectrum of gravity waves with horizontal scales that range from the cloud-system scale up to the cloud-cluster scale. The gravity waves with the largest horizontal scale play an important role in modifying layered tropospheric inflow and outflow to the cloud systems, which in turn influence the multiscale convective organization. Slower-moving short-scale gravity waves make the strongest individual contribution to the vertical flux of horizontal momentum and cause a robust peak in the momentum flux spectrum that corresponds to the lifetime and spatial scale of the individual cloud systems.

scholarly journals Multiscale Aspects of Convective Systems Associated with an Intraseasonal Oscillation over the Indonesian Maritime Continent

2006 ◽  
Vol 134 (6) ◽  
pp. 1682-1696 ◽  
Author(s):  
Yoshiaki Shibagaki ◽  
Toyoshi Shimomai ◽  
Toshiaki Kozu ◽  
Shuichi Mori ◽  
Yasushi Fujiyoshi ◽  
...  
Keyword(s):  
Intraseasonal Oscillation ◽  
Convective Precipitation ◽  
Cloud System ◽  
Mountain Range ◽  
Horizontal Scale ◽  
Maritime Continent ◽  
Cloud Systems ◽  
Convective Systems ◽  
Cloud Clusters ◽  
Orographic Cloud

Abstract Multiscale aspects of convective systems over the Indonesian Maritime Continent in the convectively active phase of an intraseasonal oscillation (ISO) during November 2002 are studied using Geostationary Meteorological Satellite infrared data and ground-based observational data from X-band rain radar, equatorial atmosphere radar, L-band boundary layer radar, and upper-air soundings at Koto Tabang (KT; 0.20°S, 100.32°E; 865 m above mean sea level), West Sumatera, Indonesia. In the analysis period, four super cloud clusters (SCCs; horizontal scale of 2000–4000 km), associated with an ISO, are seen to propagate eastward from the eastern Indian Ocean to the Indonesian Maritime Continent. The SCCs are recognized as envelopes of convection, composed of meso-α-scale cloud clusters (MαCCs; horizontal scale of 500–1000 km) propagating westward. When SCCs reach the Indonesian Maritime Continent, the envelopes disappear but MαCCs are clearly observed. Over Sumatera, the evolution and structure of a distinct MαCC is closely related to the organization of localized cloud systems with a diurnal cycle. The cloud systems are characterized by westward-propagating meso-β-scale cloud clusters (MβCCs; horizontal scale of ∼100 km) developed in eastern Sumatera, and an orographic cloud system formed over a mountain range in western Sumatera. Ground-based observations further revealed the internal structure of the orographic cloud system around KT. A meso-β-scale convective precipitation system with eastward propagation (E-MβCP; horizontal scale of ∼40 km) is found with the formation of the orographic cloud system. This is associated with a low-level wind change from easterly to westerly, considered to be local circulation over the mountain range. The E-MβCP also indicates a multicell structure composed of several meso-γ-scale convective precipitation systems (horizontal scale of <10 km) with multiple evolution stages (formation, development, and dissipation).

scholarly journals Toward an Understanding of Vertical Momentum Transports in Cloud-System-Resolving Model Simulations of Multiscale Tropical Convection

2013 ◽  
Vol 70 (10) ◽  
pp. 3231-3247 ◽  
Author(s):  
Tiffany A. Shaw ◽  
Todd P. Lane
Keyword(s):  
Boundary Layer ◽  
Gravity Waves ◽  
Source Region ◽  
Sensible Heat Flux ◽  
Momentum Transport ◽  
Cloud System ◽  
Model Simulations ◽  
Budget Analysis ◽  
Convective Momentum Transport ◽  
Convective Organization

Abstract This study examines the characteristics of convective momentum transport (CMT) and gravity wave momentum transport (GWMT) in two-dimensional cloud-system-resolving model simulations, including the relationships between the two transports. A linear group velocity criterion is shown to objectively separate CMT and GWMT. The GWMT contribution is mostly consistent with upward-propagating gravity waves and is present in the troposphere and the stratosphere. The CMT contribution forms a large part of the residual (nonupward-propagating contribution) and dominates the fluxes in the troposphere. Additional analysis of the vertical sensible heat flux supports the physical interpretation of the two contributions, further isolating the effects of unstable convection from vertically propagating gravity waves. The role of transient and nonconservative (friction and diabatic heating) processes in generating momentum flux and their dependence on changes in convective organization was assessed using a pseudomomentum budget analysis. Nonconservative effects were found to dominate the transports; the GWMT contribution involved a diabatic source region in the troposphere and a dissipative sink region in the stratosphere. The CMT contribution was consistent with transport between the boundary layer and free troposphere via tilted convection. Transient buoyancy–vorticity correlations highlighted wave sources in the region of convective outflow and the boundary layer. These sources were akin to the previously described “mechanical oscillator” mechanism. Fluxes associated with this upper-level source were most sensitive to convective organization, highlighting the mechanism by which changes in organization are communicated to GWMT. The results elucidate important interactions between CMT and GWMT, adding further weight to suggestions that the two transports should be linked in parameterizations.

scholarly journals Phenotypic plasticity of labile traits in the wild

2013 ◽  
Vol 59 (4) ◽  
pp. 485-505 ◽  
Author(s):  
Jon E. Brommer
Keyword(s):  
Life History ◽  
Phenotypic Plasticity ◽  
Statistical Approach ◽  
Scale Up ◽  
Population Level ◽  
Wild Populations ◽  
Quantitative Genetic ◽  
In The Wild ◽  
The Individual ◽  
Quantitative Genetic Parameters

Abstract Individual-based studies allow quantification of phenotypic plasticity in behavioural, life-history and other labile traits. The study of phenotypic plasticity in the wild can shed new light on the ultimate objectives (1) whether plasticity itself can evolve or is constrained by its genetic architecture, and (2) whether plasticity is associated to other traits, including fitness (selection). I describe the main statistical approach for how repeated records of individuals and a description of the environment (E) allow quantification of variation in plasticity across individuals (IxE) and genotypes (GxE) in wild populations. Based on a literature review of life-history and behavioural studies on plasticity in the wild, I discuss the present state of the two objectives listed above. Few studies have quantified GxE of labile traits in wild populations, and it is likely that power to detect statistically significant GxE is lacking. Apart from the issue of whether it is heritable, plasticity tends to correlate with average trait expression (not fully supported by the few genetic estimates available) and may thus be evolutionary constrained in this way. Individual-specific estimates of plasticity tend to be related to other traits of the individual (including fitness), but these analyses may be anti-conservative because they predominantly concern stats-on-stats. Despite the increased interest in plasticity in wild populations, the putative lack of power to detect GxE in such populations hinders achieving general insights. I discuss possible steps to invigorate the field by moving away from simply testing for presence of GxE to analyses that ‘scale up’ to population level processes and by the development of new behavioural theory to identify quantitative genetic parameters which can be estimated.

scholarly journals Spatial and seasonal variability of medium- and high-frequency gravity waves in the lower atmosphere revealed by US radiosonde data

2014 ◽  
Vol 32 (9) ◽  
pp. 1129-1143 ◽  
Author(s):  
S. D. Zhang ◽  
C. M. Huang ◽  
K. M. Huang ◽  
F. Yi ◽  
Y. H. Zhang ◽  
...  
Keyword(s):  
Energy Density ◽  
Gravity Waves ◽  
Seasonal Variability ◽  
High Frequency ◽  
Lower Atmosphere ◽  
Radiosonde Data ◽  
High Latitudes ◽  
Middle Latitudes ◽  
Momentum Fluxes ◽  
Horizontal Momentum

Abstract. We extended the broad spectral method proposed by Zhang et al. (2013) for the extraction of medium- and high-frequency gravity waves (MHGWs). This method was applied to 11 years (1998–2008) of radiosonde data from 92 stations in the Northern Hemisphere to investigate latitudinal, continuous vertical and seasonal variability of MHGW parameters in the lower atmosphere (2–25 km). The latitudinal and vertical distributions of the wave energy density and horizontal momentum fluxes as well as their seasonal variations exhibit considerable consistency with those of inertial gravity waves. Despite the consistency, the MHGWs have much larger energy density, horizontal momentum fluxes and wave force, indicating the more important role of MHGWs in energy and momentum transportation and acceleration of the background. For the observed MHGWs, the vertical wavelengths are usually larger than 8 km; the horizontal wavelengths peak in the middle troposphere at middle–high latitudes. These characteristics are obviously different from inertial gravity waves. The energy density and horizontal momentum fluxes have similar latitude-dependent seasonality: both of them are dominated by a semiannual variation at low latitudes and an annual variation at middle latitudes; however at high latitudes, they often exhibit more than two peaks per year in the troposphere. Compared with the inertial GWs, the derived intrinsic frequencies are more sensitive to the spatiotemporal variation of the buoyancy frequency, and at all latitudinal regions they are higher in summer. The wavelengths have a weaker seasonal variation; an evident annual cycle can be observed only at middle latitudes.

scholarly journals Opposite outcomes of coinfection at individual and population scales

2018 ◽  
Vol 115 (29) ◽  
pp. 7545-7550 ◽  
Author(s):  
Erin E. Gorsich ◽  
Rampal S. Etienne ◽  
Jan Medlock ◽  
Brianna R. Beechler ◽  
Johannie M. Spaan ◽  
...  
Keyword(s):  
Reproduction Number ◽  
Negative Impact ◽  
Scale Up ◽  
Population Level ◽  
Clear Understanding ◽  
African Buffalo ◽  
Global Public Health ◽  
Individual Level ◽  
Secondary Infections ◽  
The Individual

Coinfecting parasites and pathogens remain a leading challenge for global public health due to their consequences for individual-level infection risk and disease progression. However, a clear understanding of the population-level consequences of coinfection is lacking. Here, we constructed a model that includes three individual-level effects of coinfection: mortality, fecundity, and transmission. We used the model to investigate how these individual-level consequences of coinfection scale up to produce population-level infection patterns. To parameterize this model, we conducted a 4-y cohort study in African buffalo to estimate the individual-level effects of coinfection with two bacterial pathogens, bovine tuberculosis (bTB) and brucellosis, across a range of demographic and environmental contexts. At the individual level, our empirical results identified bTB as a risk factor for acquiring brucellosis, but we found no association between brucellosis and the risk of acquiring bTB. Both infections were associated with reductions in survival and neither infection was associated with reductions in fecundity. The model reproduced coinfection patterns in the data and predicted opposite impacts of coinfection at individual and population scales: Whereas bTB facilitated brucellosis infection at the individual level, our model predicted the presence of brucellosis to have a strong negative impact on bTB at the population level. In modeled populations where brucellosis was present, the endemic prevalence and basic reproduction number (R0) of bTB were lower than in populations without brucellosis. Therefore, these results provide a data-driven example of competition between coinfecting pathogens that occurs when one pathogen facilitates secondary infections at the individual level.

Leadership development strategy: the missing links

2018 ◽  
Vol 32 (1) ◽  
pp. 11-14 ◽  
Author(s):  
Shilpa Kabra Maheshwari ◽  
Jaya Yadav
Keyword(s):  
Leadership Development ◽  
Development Strategy ◽  
Scale Up ◽  
Competitive Growth ◽  
Development Programs ◽  
Leadership Development Programs ◽  
Content Type ◽  
The Individual ◽  
Business Complexity ◽  
Practical Implications

Purpose Current volatile environments, business complexity, and leadership gaps are compelling organizations to deploy effective leadership development strategies. Fueled by competitive growth and people challenges, efforts continue to scale up but fail to create the desired leaders. This paper aims to address the missing links and calls for new ways of deploying leadership development strategy. Design/methodology/approach Qualitative data on experiential feedback have been collected from participants and stakeholders of leadership development programs in Indian organizations. Findings An integrated six-step approach to leadership development has been proposed for scholars and practitioners. Practical implications From the practitioner’s perspective, this study contributes to the field of leadership development by challenging the relevance of current approaches. It also adds to the scholarly literature on leadership development in the context of the organization and the individual. Originality/value Current studies in the area of leadership development in the Indian context are scarce.

Evaluation of Cloud System Success Factors in Supply-Demand Chains

Web Services ◽  
2019 ◽  
pp. 712-727
Author(s):  
Fawzy Soliman
Keyword(s):  
Cloud Computing ◽  
Supply Chain ◽  
Organizational Performance ◽  
Success Factors ◽  
Cloud Services ◽  
Customer Relationship ◽  
Cloud System ◽  
Basic Operation ◽  
Cloud Systems ◽  
Chain Organization

Cloud systems could help companies to optimize the structure and operation of supply chain and improve organizational performance into a higher level. In this chapter, the advantages and basic operation methods of cloud computing are analyzed, and the essential factors that contribute to the success of the cloud system are evaluated through some business examples. Supply chain firms rely on cloud system to share resources and to achieve integration through the Internet. Cloud systems could transform customer relationship and internal operation to achieve sustainable competitive advantages. Cloud services are providing the ability to share information to the supply chain at any time anywhere. This chapter explores the relationship between supply chain organization and cloud computing. This chapter also discusses the benefits and advantage to evaluate of cloud system in successful factors.

Online Mindfulness Interventions

2018 ◽  
pp. 1-27 ◽  
Author(s):  
Farah Ahmad ◽  
Jamie Jianmin Wang ◽  
Christo El Morr
Keyword(s):  
Positive Impact ◽  
Scale Up ◽  
Virtual Community ◽  
Cost Effective ◽  
Mental Wellbeing ◽  
Individual Level ◽  
Symptoms Of Depression ◽  
The Social ◽  
Mindfulness Interventions ◽  
The Individual

The current chapter systematically reviewed literature on online mindfulness interventions. Electronic databases were searched from 2005 to July 2016. The aim was to examine the nature of online mindfulness interventions, design features, and their effectiveness in improving symptoms of depression, anxiety, and stress. The review of selected studies shows that online delivery of mindfulness psycho-education and practice is an area in its infancy. There is evidence that online mindfulness interventions can have a positive impact on mental health in terms of stress, depression, and anxiety; however, large sample studies are needed in order to have conclusive results. Moreover, the extension of online mindfulness interventions beyond the individual level to include a community dimension, such as virtual community features, and a focus on the social determinants of health, needs to be explored in future. The online mindfulness intervention could be a cost-effective way to scale up the promotion of mental wellbeing.

Analysis of Frequently Failing Tasks and Rescheduling Strategy in the Cloud System

2018 ◽  
Vol 9 (1) ◽  
pp. 16-38
Author(s):  
Hongyan Tang ◽  
Ying Li ◽  
Tong Jia ◽  
Xiaoyong Yuan ◽  
Zhonghai Wu
Keyword(s):  
Cloud Computing ◽  
Early Stage ◽  
Cloud System ◽  
Usage Pattern ◽  
Resource Saving ◽  
Computing Systems ◽  
Cloud Systems ◽  
Failure Frequency ◽  
Task Recognition

To better understand task failures in cloud computing systems, the authors analyze failure frequency of tasks based on Google cluster dataset, and find some frequently failing tasks that suffer from long-term failures and repeated rescheduling, which are called killer tasks as they can be a big concern of cloud systems. Hence there is a need to analyze killer tasks thoroughly and recognize them precisely. In this article, the authors first investigate resource usage pattern of killer tasks and analyze rescheduling strategies of killer tasks in Google cluster to find that repeated rescheduling causes large amount of resource wasting. Based on the above observations, they then propose an online killer task recognition service to recognize killer tasks at the very early stage of their occurrence so as to avoid unnecessary resource wasting. The experiment results show that the proposed service performs a 93.6% accuracy in recognizing killer tasks with an 87% timing advance and 86.6% resource saving for the cloud system averagely.

Access to art collections using Encoded Archival Description and beyond: the future of large-scale consortium projects

2001 ◽  
Vol 26 (3) ◽  
pp. 33-39 ◽  
Author(s):  
Richard Rinehart
Keyword(s):  
Large Scale ◽  
Scale Up ◽  
Archival Description ◽  
Arts Organizations ◽  
Art Collections ◽  
Individual Institution ◽  
The Future ◽  
Online Archive ◽  
Cultural Content ◽  
The Individual

In a Herculean effort to distribute information about art collections on a previously unknown scale, museums, arts organizations, libraries, and archives have been hard at work developing standards and implementing testbed projects, large-scale union databases which integrate and disseminate information. Two such projects are ‘Conceptual and Intermedia Online’ (CIAO) and ‘Museums and the Online Archive of California’ (MOAC), both using the Encoded Archival Description to describe and provide access to art and other cultural collections. But what is the future of such collaborations and the content portals they spawn? Will they be able to scale up to include hundreds or thousands of institutions, using current models? What are the limitations for such consortia? What are the limitations for participating institutions? Several options appear on the horizon, and one simple need suggests looking to decentralization, and back to the individual institution, for the solution to sharing art and cultural content on a truly vast scale.

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