scholarly journals Multi-Scale Transects of Three North American Drylines

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 854
Author(s):  
Loren D. White ◽  
Duanjun Lu
Keyword(s):  
North American ◽  
Mountainous Terrain ◽  
Moist Convection ◽  
Convective Storms ◽  
Multi Scale ◽  
West Texas ◽  
Deep Moist Convection ◽  
Using Data ◽  
Over Time ◽  
Observing Systems

North American drylines are distinct air mass boundaries that have often been examined for their relation to the initiation of severe convective storms. Three cases of drylines occurring in synoptically quiescent environments are analyzed using data obtained from a single mobile platform in concert with data from operational synoptic and mesoscale observing systems. Very distinct moisture contrasts were noted in a nocturnal April case in mountainous terrain in the Trans-Pecos region of West Texas. The other two cases revealed multi-step moisture transitions within synoptically diffuse moisture gradients. Their evolution over time suggests that such multi-step patterns may be associated with diurnal and geographic forcing transitions, as well as positioning of deep moist convection.

scholarly journals Observations of the Relationship between 700-mb Temperatures and Severe Weather Reports across the Contiguous United States

2010 ◽  
Vol 25 (2) ◽  
pp. 799-814 ◽  
Author(s):  
Matthew J. Bunkers ◽  
John R. Wetenkamp ◽  
Jeffrey J. Schild ◽  
Anthony Fischer
Keyword(s):  
United States ◽  
Geographic Location ◽  
Careful Examination ◽  
Moist Convection ◽  
Severe Storm ◽  
Convective Inhibition ◽  
Deep Moist Convection ◽  
Time Of Year ◽  
Using Data ◽  
The Relationship

Abstract The relationship between 700-mb temperatures and convective severe storm reports is examined using data from 1993 to 2006 for the contiguous United States. Severe storm reports are used as a rough “proxy” for the occurrence of deep moist convection, and spatial and temporal distributions of 700-mb temperatures associated with these reports are analyzed. Secondarily, the distributions are assessed by individual severe storm report type, and convective inhibition also is evaluated. The motivation for this study is derived from the occasionally used 10°–12°C at 700 mb rule of thumb for estimating the extent and strength of the capping inversion. Whereas there is a semblance of merit for using this rule at times, its utility is shown to be strongly dependent on 1) geographic location, particularly with respect to surface elevation and the frequency of elevated mixed layers, and 2) the time of year. Calculation of convective inhibition, careful examination of the sounding, and assessment of lifting mechanisms likely are more valuable than 700-mb temperatures when forecasting the potential for deep moist convection and severe storms.

scholarly journals A Five-Year Radar-Based Climatology of Tropopause Folds and Deep Convection over Wales, United Kingdom

2013 ◽  
Vol 141 (5) ◽  
pp. 1693-1707 ◽  
Author(s):  
Bogdan Antonescu ◽  
Geraint Vaughan ◽  
David M. Schultz
Keyword(s):  
United Kingdom ◽  
Deep Convection ◽  
Moist Convection ◽  
Isolated Cells ◽  
Very High Frequency ◽  
High Resolution Data ◽  
Convective Storms ◽  
Deep Moist Convection ◽  
Upper Level ◽  
Western Side

AbstractA five-year (2006–10) radar-based climatology of tropopause folds and convective storms was constructed for Wales, United Kingdom, to determine how deep, moist convection is modulated by tropopause folds. Based on the continuous, high-resolution data from a very high frequency (VHF) wind-profiling radar located at Capel Dewi, Wales, 183 tropopause folds were identified. Tropopause folds were most frequent in January with a secondary maximum in July. Based on data from the U.K. weather radar network, a climatology of 685 convective storms was developed. The occurrence of convective storms was relatively high year-round except for an abrupt minimum in February–April. Multicellular lines (43.5%) were the most common morphology with a maximum in October, followed by isolated cells (33.1%) with a maximum in May–September, and nonlinear clusters (23.4%) with a maximum in November–January. Convective storms were associated with 104 (56.8%) of the tropopause folds identified in this study, with the association strongest in December. Of the 55 tropopause folds observed on the eastern side of an upper-level trough, 37 (67.3%) were associated with convective storms, most commonly in the form of multicellular lines. Of the 128 tropopause folds observed on the western side of an upper-level trough, 42 (32.8%) were associated with convective storms, most commonly isolated cells. These results suggest that more organized storms tend to form in environments favorable for synoptic-scale ascent.

scholarly journals Toward unification of the multiscale modeling of the atmosphere

2011 ◽  
Vol 11 (8) ◽  
pp. 3731-3742 ◽  
Author(s):  
A. Arakawa ◽  
J.-H. Jung ◽  
C.-M. Wu
Keyword(s):  
General Circulation ◽  
Three Dimensional ◽  
General Circulation Models ◽  
Moist Convection ◽  
Modeling Framework ◽  
Continuous Transition ◽  
Convective Clouds ◽  
Multi Scale ◽  
Scale Modeling ◽  
Deep Moist Convection

Abstract. As far as the representation of deep moist convection is concerned, only two kinds of model physics are used at present: highly parameterized as in the conventional general circulation models (GCMs) and explicitly simulated as in the cloud-resolving models (CRMs). Ideally, these two kinds of model physics should be unified so that a continuous transition of model physics from one kind to the other takes place as the resolution changes. With such unification, the GCM can converge to a global CRM (GCRM) as the grid size is refined. This paper suggests two possible routes to achieve the unification. ROUTE I continues to follow the parameterization approach, but uses a unified parameterization that is applicable to any horizontal resolutions between those typically used by GCMs and CRMs. It is shown that a key to construct such a unified parameterization is to eliminate the assumption of small fractional area covered by convective clouds, which is commonly used in the conventional cumulus parameterizations either explicitly or implicitly. A preliminary design of the unified parameterization is presented, which demonstrates that such an assumption can be eliminated through a relatively minor modification of the existing mass-flux based parameterizations. Partial evaluations of the unified parameterization are also presented. ROUTE II follows the "multi-scale modeling framework (MMF)" approach, which takes advantage of explicit representation of deep moist convection and associated cloud-scale processes by CRMs. The Quasi-3-D (Q3-D) MMF is an attempt to broaden the applicability of MMF without necessarily using a fully three-dimensional CRM. This is accomplished using a network of cloud-resolving grids with large gaps. An outline of the Q3-D algorithm and highlights of preliminary results are reviewed.

scholarly journals Simulations of Polarimetric, X-Band Radar Signatures in Supercells. Part II: ZDR Columns and Rings and KDP Columns

2017 ◽  
Vol 56 (7) ◽  
pp. 2001-2026 ◽  
Author(s):  
Jeffrey C. Snyder ◽  
Howard B. Bluestein ◽  
Daniel T. Dawson II ◽  
Youngsun Jung
Keyword(s):  
High Resolution ◽  
Numerical Model ◽  
Wind Shear ◽  
Cross Correlation ◽  
Moist Convection ◽  
Convective Storms ◽  
X Band ◽  
Deep Moist Convection ◽  
Differential Reflectivity ◽  
Forward Operator

AbstractA high-resolution numerical model and polarimetric forward operator allow one to examine simulated convective storms from the perspective of observable polarimetric radar quantities, enabling a better comparison of modeled and observed deep moist convection. Part I of this two-part study described the model and forward operator used for all simulations and examined the structure and evolution of rings of reduced copolar cross-correlation coefficient (i.e., ρhv rings). The microphysical structure of upward extensions of enhanced differential reflectivity (ZDR columns and ZDR rings) and enhanced specific differential phase (KDP columns) near and within the updrafts of convective storms serve as the focus of this paper. In general, simulated ZDR columns are located immediately west of the midlevel updraft maximum and are associated with rainwater lofted above the 0°C level and wet hail/graupel, whereas ZDR rings are associated with wet hail located near and immediately east of the midlevel updraft maximum. The deepest areas of ZDR > 1 dB aloft are associated with supercells in the highest shear environments and those that have the most intense updrafts; the upper extent of the ZDR signatures is found to be positively correlated with the amount and mean-mass diameter of large hail aloft likely as a by-product of the shared correlations with updraft intensity and wind shear. Large quantities of rain compose the KDP columns, with the size and intensity of the updrafts directly proportional to the size and depth of the KDP columns.

scholarly journals Using Ensemble Data Assimilation to Explore the Environmental Controls on the Initiation and Predictability of Moist Convection

2021 ◽  
Keyword(s):  
Water Vapor ◽  
Lead Time ◽  
Weather Prediction ◽  
Convective System ◽  
Convective Activity ◽  
Moist Convection ◽  
Convective Storms ◽  
Environmental Controls ◽  
Deep Moist Convection ◽  
Convective Cells

Abstract Atmospheric deep moist convection has emerged as one of the most challenging topics for numerical weather prediction, due to its chaotic process of development and multi-scale physical interactions. This study examines the dynamics and predictability of a weakly organized linear convective system using convection permitting EnKF analysis and forecasts with assimilating all-sky satellite radiances from a water vapor sensitive band of the Advanced Baseline Imager on GOES-16. The case chosen occurred over the Gulf of Mexico on 11 June 2017 during the NASA Convective Processes Experiment (CPEX) field campaign. Analysis of the water vapor and dynamic ensemble covariance structures revealed that meso-α (2000-200 km) and meso-β (200-20 km) scale initial features helped to constrain the general location of convection with a few hours of lead time, contributing to enhancing convective activity, but meso-γ (20-2 km) or even smaller scale features with less than 30-minute lead time were identified to be essential for capturing individual convective storms. The impacts of meso-α scale initial features on the prediction of particular individual convective cells were found to be classified into two regimes; in a relatively dry regime, the meso-α scale environment needs to be moist enough to support the development of the convection of interest, but in a relatively wet regime, a drier meso-α scale environment is preferable to suppress the surrounding convective activity. This study highlights the importance of high-resolution initialization of moisture fields for the prediction of a quasi-linear tropical convective system, as well as demonstrating the accuracy that may be necessary to predict convection exactly when and where it occurs.

scholarly journals Toward unification of the multiscale modeling of the atmosphere

2011 ◽  
Vol 11 (1) ◽  
pp. 3181-3217 ◽  
Author(s):  
A. Arakawa ◽  
J.-H. Jung ◽  
C.-M. Wu
Keyword(s):  
General Circulation ◽  
Three Dimensional ◽  
General Circulation Models ◽  
Moist Convection ◽  
Modeling Framework ◽  
Continuous Transition ◽  
Convective Clouds ◽  
Multi Scale ◽  
Deep Moist Convection ◽  
Fine Resolution

Abstract. This paper suggests two possible routes to achieve the unification of model physics in coarse- and fine-resolution atmospheric models. As far as representation of deep moist convection is concerned, only two kinds of model physics are used at present: highly parameterized as in the conventional general circulation models (GCMs) and explicitly simulated as in the cloud-resolving models (CRMs). Ideally, these two kinds of model physics should be unified so that a continuous transition of model physics from one kind to the other takes place as the resolution changes. With such unification, the GCM can converge to a global CRM (GCRM) as the grid size is refined. ROUTE I for unification continues to follow the parameterization approach, but uses a unified parameterization that is applicable to any horizontal resolutions between those typically used by GCMs and CRMs. It is shown that a key to construct such a unified parameterization is to eliminate the assumption of small fractional area covered by convective clouds, which is commonly used in the conventional cumulus parameterizations either explicitly or implicitly. A preliminary design of the unified parameterization is presented, which demonstrates that such an assumption can be eliminated through a relatively minor modification of the existing mass-flux based parameterizations. Partial evaluations of the unified parameterization are also presented. ROUTE II for unification follows the "multi-scale modeling framework (MMF)" approach, which takes advantage of explicit representation of deep moist convection and associated cloud-scale processes by CRMs. The Quasi-3-D (Q3-D) MMF is an attempt to broaden the applicability of MMF without necessarily using a fully three-dimensional CRM. This is accomplished using a network of cloud-resolving grids with gaps. An outline of the Q3-D algorithm and highlights of preliminary results are reviewed.

How Collective-Action Failure Shapes Group Heterogeneity and Engagement in Conventional and Radical Action Over Time

2021 ◽  
pp. 095679762097056
Author(s):  
Morgana Lizzio-Wilson ◽  
Emma F. Thomas ◽  
Winnifred R. Louis ◽  
Brittany Wilcockson ◽  
Catherine E. Amiot ◽  
...  
Keyword(s):  
Social Movements ◽  
Collective Action ◽  
Latent Profile Analysis ◽  
Profile Analysis ◽  
Social Identification ◽  
Future Research ◽  
Group Efficacy ◽  
Before And After ◽  
Using Data ◽  
Over Time

Extensive research has identified factors influencing collective-action participation. However, less is known about how collective-action outcomes (i.e., success and failure) shape engagement in social movements over time. Using data collected before and after the 2017 marriage-equality debate in Australia, we conducted a latent profile analysis that indicated that success unified supporters of change ( n = 420), whereas failure created subgroups among opponents ( n = 419), reflecting four divergent responses: disengagement (resigned acceptors), moderate disengagement and continued investment (moderates), and renewed commitment to the cause using similar strategies (stay-the-course opponents) or new strategies (innovators). Resigned acceptors were least inclined to act following failure, whereas innovators were generally more likely to engage in conventional action and justify using radical action relative to the other profiles. These divergent reactions were predicted by differing baseline levels of social identification, group efficacy, and anger. Collective-action outcomes dynamically shape participation in social movements; this is an important direction for future research.

Social Change and Psychological Change in Rural Mali

2016 ◽  
Vol 52 (7) ◽  
pp. 965-981 ◽  
Author(s):  
Carmi Schooler ◽  
Leslie J Caplan ◽  
Pakuy Pierre Mounkoro ◽  
Chiaka Diakité
Keyword(s):  
Social Change ◽  
Environmental Change ◽  
Environmental Conditions ◽  
Economic Hardship ◽  
Psychological Change ◽  
Self Confidence ◽  
Personality Stability ◽  
Psychological Reaction ◽  
Using Data ◽  
Over Time

We examine the effects of socio-environmental change on personality in Mali in three ways, using data from a longitudinal two-wave (1994, 2004) survey conducted in rural Mali. Firstly, we compare the between-wave personality stability of Anxiety, Self-confidence, Mastery/Fatalism, and Authoritarianism with that in USA, Japan, Poland, and Ukraine. Secondly, we examine socio-economic hardship and political instability in pre-industrial Mali. Thirdly, we examine patterns of psychological reaction to political and social change during the study period. Our findings have implications for comparisons and generalizations across times and cultures about the contribution of socio-environmental conditions to over-time change in personality.

Sign in / Sign up

Export Citation Format

Share Document