Probabilistic Evaluation of the Dynamics and Predictability of the Mesoscale Convective Vortex of 10–13 June 2003

2007 ◽  
Vol 135 (4) ◽  
pp. 1544-1563 ◽  
Author(s):  
Daniel P. Hawblitzel ◽  
Fuqing Zhang ◽  
Zhiyong Meng ◽  
Christopher A. Davis
Keyword(s):  
Large Scale ◽  
Mesoscale Model ◽  
Critical Role ◽  
Probabilistic Evaluation ◽  
Mesoscale Convective ◽  
Upper Level ◽  
Mesoscale Convective Vortex ◽  
Horizontal Grid ◽  
Development And Evolution

Abstract This study examines the dynamics and predictability of the mesoscale convective vortex (MCV) of 10–13 June 2003 through ensemble forecasting. The MCV of interest developed from a preexisting upper-level disturbance over the southwest United States on 10 June and matured as it traveled northeastward. This event is of particular interest given the anomalously strong and long-lived nature of the circulation. An ensemble of 20 forecasts using a 2-way nested mesoscale model with horizontal grid increments of 30 and 10 km are employed to probabilistically evaluate the dynamics and predictability of the MCV. Ensemble mean and spread as well as correlations between different forecast variables at different forecast times are examined. It is shown that small-amplitude large-scale balanced initial perturbations may result in very large ensemble spread, with individual solutions ranging from a very strong MCV to no MCV at all. Despite similar synoptic-scale conditions, the ensemble MCV forecasts vary greatly depending on intensity and coverage of simulated convection, illustrating the critical role of convection in the development and evolution of this MCV. Correlation analyses reveal the importance of a preexisting disturbance to the eventual development of the MCV. It is also found that convection near the center of the MCV the day after its formation may be an important factor in determining the eventual growth of a surface vortex and that a stronger midlevel vortex is more conducive to convection, especially on the downshear side, consistent with the findings of previous MCV studies.

scholarly journals Mesoscale Convective Vortex Formation in a Weakly Sheared Moist Neutral Environment

2007 ◽  
Vol 64 (5) ◽  
pp. 1443-1466 ◽  
Author(s):  
Robert J. Conzemius ◽  
Richard W. Moore ◽  
Michael T. Montgomery ◽  
Christopher A. Davis
Keyword(s):  
Large Scale ◽  
Mesoscale Model ◽  
Tangential Velocity ◽  
Lower Troposphere ◽  
Primary Objective ◽  
Vertical Shear ◽  
Convective System ◽  
Field Campaign ◽  
Mesoscale Convective ◽  
Mesoscale Convective Vortex

Abstract Idealized simulations of a diabatic Rossby vortex (DRV) in an initially moist neutral baroclinic environment are performed using the fifth-generation National Center for Atmospheric Research–Pennsylvania State University (NCAR–PSU) Mesoscale Model (MM5). The primary objective is to test the hypothesis that the formation and maintenance of midlatitude warm-season mesoscale convective vortices (MCVs) are largely influenced by balanced flow dynamics associated with a vortex that interacts with weak vertical shear. As a part of this objective, the simulated DRV is placed within the context of the Bow Echo and Mesoscale Convective Vortex Experiment (BAMEX) field campaign by comparing its tangential velocity, radius of maximum winds, CAPE, and shear with the MCVs observed in BAMEX. The simulations reveal two distinct scales of development. At the larger scale, the most rapidly growing moist baroclinic mode is excited, and exponential growth of this mode occurs during the simulation. Embedded within the large-scale baroclinic wave is a convective system exhibiting the characteristic DRV development, with a positive potential vorticity (PV) anomaly in the lower troposphere and a negative PV anomaly in the upper troposphere, and the positive/negative PV doublet tilted downshear with height. The DRV warm-air advection mechanism is active, and the resulting deep convection helps to reinforce the DRV against the deleterious effects of environmental shear, causing an eastward motion of the convective system as a whole. The initial comparisons between the simulated DRVs and the BAMEX MCVs show that the simulated DRVs grew within background conditions of CAPE and shear similar to those observed for BAMEX MCVs and suggest that the same dynamical mechanisms are active. Because the BAMEX field campaign sampled MCVs in different backgrounds of CAPE and shear, the comparison also demonstrates the need to perform additional simulations to explore these different CAPE and shear regimes and to understand their impacts on the intensity and longevity of MCVs. Such a study has the additional benefit of placing MCV dynamics in an appropriate context for exploring their relevance to tropical cyclone formation.

Trust in scientists in times of pandemic: Panel evidence from 12 countries

2021 ◽  
Vol 118 (40) ◽  
pp. e2108576118
Author(s):  
Yann Algan ◽  
Daniel Cohen ◽  
Eva Davoine ◽  
Martial Foucault ◽  
Stefanie Stantcheva
Keyword(s):  
Large Scale ◽  
Social Trust ◽  
Critical Role ◽  
Individual Level ◽  
Individual Support ◽  
Compliant Behavior ◽  
Paradoxical Effects ◽  
The Government ◽  
Nonpharmaceutical Interventions

This article analyzes the specific and critical role of trust in scientists on both the support for and compliance with nonpharmaceutical interventions (NPIs) during the COVID-19 pandemic. We exploit large-scale, longitudinal, and representative surveys for 12 countries over the period from March to December 2020, and we complement the analysis with experimental data. We find that trust in scientists is the key driving force behind individual support for and compliance with NPIs and for favorable attitudes toward vaccination. The effect of trust in government is more ambiguous and tends to diminish support for and compliance with NPIs in countries where the recommendations from scientists and the government were not aligned. Trust in others also has seemingly paradoxical effects: in countries where social trust is high, the support for NPIs is low due to higher expectations that others will voluntary social distance. Our individual-level longitudinal data also allows us to evaluate the effects of within-person changes in trust over the pandemic: we show that trust levels and, in particular, trust in scientists have changed dramatically for individuals and within countries, with important subsequent effects on compliant behavior and support for NPIs. Such findings point out the challenging but critical need to maintain trust in scientists during a lasting pandemic that strains citizens and governments.

scholarly journals The role of haploinsufficiency of RPS14 and p53 activation in the molecular pathogenesis of the 5q- syndrome

2011 ◽  
Vol 3 (2s) ◽  
pp. 10 ◽  
Author(s):  
Jacqueline Boultwood
Keyword(s):  
Mouse Model ◽  
Large Scale ◽  
Critical Role ◽  
Ribosomal Gene ◽  
Molecular Pathogenesis ◽  
Erythroid Progenitor ◽  
Great Insight ◽  
P53 Activation ◽  
Distinct Subtype

In recent years we have gained great insight into the molecular pathogenesis of the 5q- syndrome, a distinct subtype of myelodysplasia. The demonstration of haploinsufficiency of the ribosomal gene RPS14 (mapping to the commonly deleted region) and the finding that this is the cause of the erythroid defect in the 5qsyndrome represent major advances. A mouse model of the human 5q- syndrome generated by large-scale deletion of the Cd74-Nid67 interval (containing RPS14) further supports a critical role for RPS14 haploinsufficiency. It is widely accepted that ribosomal deficiency results in p53 activation and defective erythropoiesis and the crossing of the ‘5q- mice’ with p53 deficient mice ameliorated the erythroid progenitor defect. Emerging data suggests that the p53 activation observed in the mouse model may also apply to the human 5q- syndrome.

The Carnegie Uaxactun Project and the Development of Maya Archaeology

1990 ◽  
Vol 1 (2) ◽  
pp. 257-276 ◽  
Author(s):  
Stephen L. Black
Keyword(s):  
Large Scale ◽  
Critical Role ◽  
Carnegie Institution ◽  
Field Methods ◽  
Maya Archaeology ◽  
History Of ◽  
Maya Area

AbstractThe Carnegie Institution of Washington's 1924–1937. Uaxactun Project, one of the first large-scale excavations in the Maya area, established the role of dirt archaeology in Maya studies. The archaeologists who worked on this pioneering project developed many field methods and approaches that remain in use today. A review of the project and of the careers of its participants shows the critical role the Carnegie Uaxactun Project has played in the history of Maya archaeology.

Cyclogenesis Simulation of Typhoon Prapiroon (2000) Associated with Rossby Wave Energy Dispersion*

2010 ◽  
Vol 138 (1) ◽  
pp. 42-54 ◽  
Author(s):  
Xuyang Ge ◽  
Tim Li ◽  
Melinda S. Peng
Keyword(s):  
Rossby Wave ◽  
Wave Energy ◽  
Large Scale ◽  
Wave Train ◽  
Energy Dispersion ◽  
Sensitivity Experiment ◽  
Low Level ◽  
Filtering Technique ◽  
Upper Level

Abstract The genesis of Typhoon Prapiroon (2000), in the western North Pacific, is simulated to understand the role of Rossby wave energy dispersion of a preexisting tropical cyclone (TC) in the subsequent genesis event. Two experiments are conducted. In the control experiment (CTL), the authors retain both the previous typhoon, Typhoon Bilis, and its wave train in the initial condition. In the sensitivity experiment (EXP), the circulation of Typhoon Bilis was removed based on a spatial filtering technique of Kurihara et al., while the wave train in the wake is kept. The comparison between these two numerical simulations demonstrates that the preexisting TC impacts the subsequent TC genesis through both a direct and an indirect process. The direct process is through the conventional barotropic Rossby wave energy dispersion, which enhances the low-level wave train, the boundary layer convergence, and the convection–circulation feedback. The indirect process is through the upper-level outflow jet. The asymmetric outflow jet induces a secondary circulation with a strong divergence tendency to the left-exit side of the outflow jet. The upper-level divergence boosts large-scale ascending motion and promotes favorable environmental conditions for a TC-scale vortex development. In addition, the outflow jet induces a well-organized cyclonic eddy angular momentum flux, which acts as a momentum forcing that enhances the upper-level outflow and low-level inflow and favors the growth of the new TC.

scholarly journals Length of the Neurogenic Period—A Key Determinant for the Generation of Upper-Layer Neurons During Neocortex Development and Evolution

2021 ◽  
Vol 9 ◽  
Author(s):  
Barbara K. Stepien ◽  
Samir Vaid ◽  
Wieland B. Huttner
Keyword(s):  
Cognitive Abilities ◽  
Cortical Neurons ◽  
Mammalian Species ◽  
Critical Role ◽  
Exact Nature ◽  
Cortical Neurogenesis ◽  
Brain Functions ◽  
The Relationship ◽  
Development And Evolution

The neocortex, a six-layer neuronal brain structure that arose during the evolution of, and is unique to, mammals, is the seat of higher order brain functions responsible for human cognitive abilities. Despite its recent evolutionary origin, it shows a striking variability in size and folding complexity even among closely related mammalian species. In most mammals, cortical neurogenesis occurs prenatally, and its length correlates with the length of gestation. The evolutionary expansion of the neocortex, notably in human, is associated with an increase in the number of neurons, particularly within its upper layers. Various mechanisms have been proposed and investigated to explain the evolutionary enlargement of the human neocortex, focussing in particular on changes pertaining to neural progenitor types and their division modes, driven in part by the emergence of human-specific genes with novel functions. These led to an amplification of the progenitor pool size, which affects the rate and timing of neuron production. In addition, in early theoretical studies, another mechanism of neocortex expansion was proposed—the lengthening of the neurogenic period. A critical role of neurogenic period length in determining neocortical neuron number was subsequently supported by mathematical modeling studies. Recently, we have provided experimental evidence in rodents directly supporting the mechanism of extending neurogenesis to specifically increase the number of upper-layer cortical neurons. Moreover, our study examined the relationship between cortical neurogenesis and gestation, linking the extension of the neurogenic period to the maternal environment. As the exact nature of factors promoting neurogenic period prolongation, as well as the generalization of this mechanism for evolutionary distinct lineages, remain elusive, the directions for future studies are outlined and discussed.

scholarly journals Infrared and Millimeter Views of the Helix: the Nearest, Massive, Neutral Remnant of a Circumstellar Envelope

1999 ◽  
Vol 191 ◽  
pp. 425-430 ◽  
Author(s):  
P.J. Huggins ◽  
P. Cox ◽  
T. Forveille ◽  
R. Bachiller ◽  
K. Young
Keyword(s):  
Large Scale ◽  
Near Infrared ◽  
Critical Role ◽  
Ring Structure ◽  
Circumstellar Envelope ◽  
3 Dimensional ◽  
Optical Images ◽  
Formation And Evolution ◽  
Visualization Techniques

We present new, infrared and millimeter views of the Helix nebula which illustrate the critical role of remnant, neutral AGB envelopes in the formation and evolution of planetary nebulae. Large scale ∼ 1 000″ mapping of the entire nebula in the CO (J = 2 − 1) line with the CSO reveals the global structure of the envelope. The CO emission forms the familiar ring structure seen in optical images of the Helix, and indicates a massive remnant with ≳ 50% the mass of the ionized nebula. High resolution CO mapping with the IRAM 30 m telescope shows that the whole envelope is fragmented into an intricate array of small clumps, closely related to the cometary globules seen in the central, ionized cavity. 5–17 μm spectroscopy of the Helix with ISOCAM reveals a remarkable near infrared spectrum, dominated by the pure (v = 0 − 0) rotational lines of H2. The H2 lines are excited to a temperature of ∼ 900 K, and likely arise in warm, outer layers of the small clumps seen in CO. Imaging of the H2 emission with ISOCAM over the whole nebula provides a striking portrait of the fragmented neutral envelope. 3-dimensional views of the envelope are also presented, based on CO mapping and using 3-dimensional visualization techniques. Point symmetries dominate the toroidal structure, and suggest an origin for the Helix in equatorial mass-loss on the AGB, shaped by the action of bipolar outflows or jets.

The Atmospheric Controls of Extreme Convective Events over the Southern Arabian Peninsula during the Transition Seasons

2021 ◽  
Author(s):  
Narendra Reddy Nelli ◽  
Diana Francis ◽  
Ricardo Fonseca ◽  
Rachid Abida ◽  
Michael Weston ◽  
...  
Keyword(s):  
Large Scale ◽  
Arabian Peninsula ◽  
Arabian Gulf ◽  
Reanalysis Data ◽  
Convective Systems ◽  
Stratospheric Temperature ◽  
Moisture Advection ◽  
Mesoscale Convective ◽  
Upper Level ◽  
Warming World

<p>In this paper, the processes behind severe convective events over the Arabian Peninsula during spring and autumn seasons and their local-scale impacts are investigated using reanalysis data, satellite-derived and observational products. The focus on the transition seasons is justified as Mesoscale Convective Systems (MCSs) are more common at that time of the year, in particular in the months of March and April. The analysis of 48 events from 2000 to 2019 revealed that they are triggered by low-level wind convergence and moisture advection from the Arabian Sea, Arabian Gulf and/or Red Sea. An equatorward displacement and strengthening of the subtropical jet also precondition the environment, as does the presence of a mid-level trough. The latter is generally part of a large-scale pattern of anomalies that are equivalent barotropic in nature, and therefore likely a response to tropical or subtropical forcing. At more local-scales, a drying of the mid-troposphere between 850 and 250 hPa typically by 50%, a reduction of the upper-level winds by about 5 m s<sup>-1</sup>, and an increase in the upper-tropospheric and lower-stratospheric temperature on averaged by 2-3 K, are typically observed during a MCS event. Over the 20-year period, a statistically significant increase in the MCSs’ spatial extent, intensity and duration over the UAE and surrounding region has been found, suggesting that such extreme events may be even more impactful in a hypothetical warming world. The rainfall they generate, on the other hand, shows an increase that is not statistically significant.</p>

The Amplification of the ENSO Forcing over Equatorial Amazon

2009 ◽  
Vol 10 (6) ◽  
pp. 1561-1568 ◽  
Author(s):  
Vasubandhu Misra
Keyword(s):  
South America ◽  
Diurnal Cycle ◽  
Land Surface ◽  
Large Scale ◽  
French Guiana ◽  
Southern Oscillation ◽  
Moisture Flux ◽  
Precipitation Anomalies ◽  
Upper Level

Abstract The remote influence of the El Niño–Southern Oscillation (ENSO) strongly manifests over the equatorial Amazon (EA)—including parts of southern Venezuela, Guyana, French Guiana, and Suriname—when there is a large-scale anomalous upper-level divergence over continental tropical South America. Modeling studies conducted in this paper suggest that it is because of the modulation of the local diurnal cycle of the moisture flux convergence, which results in the local amplification of the ENSO signal over the EA. Further, it is shown that the local land surface feedback plays a relatively passive but important role of maintaining these interannual precipitation anomalies over the EA region.

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