scholarly journals The Vorticity Budgets of North Atlantic Winter Extratropical Cyclone Life Cycles in MERRA Reanalysis. Part I: Development Phase*

2014 ◽  
Vol 71 (9) ◽  
pp. 3109-3128 ◽  
Author(s):  
Roohollah Azad ◽  
Asgeir Sorteberg
Keyword(s):  
North Atlantic ◽  
Indirect Effect ◽  
Life Cycles ◽  
Total Effect ◽  
Latent Heating ◽  
Vorticity Advection ◽  
Friction Term ◽  
Forcing Mechanisms ◽  
Adiabatic Term ◽  
Vorticity Tendency

Abstract This series of papers (parts I and II) examines the vorticity budgets of winter North Atlantic extratropical cyclones during the period 1979–2009 using the Modern-Era Retrospective Analysis for Research and Application (MERRA). The authors use a new partitioning technique to combine the Zwack–Okossi (Z–O) equation with the omega equation. The combination provides a possibility to partition the adiabatic term in the Z–O equation into its different forcing mechanisms. Thus, both the direct effect of the dynamic and thermodynamic forcings and their indirect effect on the adiabatic term can be calculated to provide the total effect (direct plus indirect) on the 950-hPa geostrophic vorticity tendency. It is demonstrated that the total-effect diagnostic is a suitable tool to identify the dynamically consistent characteristics of cyclone development in midlatitudes because it possesses less case-to-case variability. The authors found that the vorticity advection is the major forcing process, the tendencies attributed to the ageostrophic vorticity tendency term are considerable, and the opposing effect of the friction term in moderating the deepening is significant. In general, the upper-level dynamics drive the deepening of the cyclones, except at the end of development, where a combination of midlevel latent heating, positive ageostrophic vorticity tendency, and positive indirect effect of vorticity advection contribute to the development. Additionally, the total effects of temperature advection and latent heating on the intensification of cyclones are reduced because of the inclusion of counteractive indirect effects, as are their variabilities within the cyclone composite.

scholarly journals The Vorticity Budgets of North Atlantic Winter Extratropical Cyclone Life Cycles in MERRA Reanalysis. Part II: Decaying Phase*

2014 ◽  
Vol 71 (9) ◽  
pp. 3129-3143 ◽  
Author(s):  
Roohollah Azad ◽  
Asgeir Sorteberg
Keyword(s):  
North Atlantic ◽  
Life Cycles ◽  
Cyclonic Circulation ◽  
Negative Contribution ◽  
Physical Forcing ◽  
Vorticity Advection ◽  
Adiabatic Cooling ◽  
Upper Level ◽  
Forcing Mechanisms ◽  
Vorticity Tendency

Abstract The role of physical forcing mechanisms that contribute to the decay of winter North Atlantic extratropical cyclones during the period 1979–2009 are examined using the Modern-Era Retrospective Analysis for Research and Applications (MERRA). The paired Zwack–Okossi tendency equation and omega equation explained in part I of this paper is employed to investigate the total effects of forcing processes (the direct effect of the forcing mechanisms and the indirect effect of the induced adiabatic cooling) that dissipate the 950-hPa cyclonic geostrophic vorticity at the cyclone center. Composite analyses reveal that the commencement of the decay is associated mainly with the upper-level anticyclonic vorticity advection, cold-air advection, and positive ageostrophic vorticity tendency. The secondary contributor to the dissipation of cyclonic circulation is the lower-tropospheric adiabatic cooling induced mainly by friction and positive ageostrophic vorticity tendency. The dynamics is found to be different at the beginning of the decay than in the later stages. While the negative tilt of troughs aloft and the surface cyclone is required for cyclolysis to occur, low air processes show a greater effect in the termination of the low pressure systems. Further, the total effect of the vorticity advection and temperature advection terms are modest, while the ageostrophic vorticity tendency and friction terms show a greater total negative contribution. This is because the two latter terms decrease the cyclonic geostrophic vorticity at the low center through both their direct and indirect effects. The latent heat release maximizing at 800–700 hPa produces cyclonic circulation, thus reducing the spindown of decaying cyclones.

scholarly journals Calculated Height Tendencies in Two Southern Hemisphere Blocking and Cyclone Events: The Contribution of Diabatic Heating to Block Intensification

2008 ◽  
Vol 136 (9) ◽  
pp. 3568-3578 ◽  
Author(s):  
Douglas E. Tilly ◽  
Anthony R. Lupo ◽  
Christopher J. Melick ◽  
Patrick S. Market
Keyword(s):  
Southern Hemisphere ◽  
Diabatic Heating ◽  
Latent Heating ◽  
Atmospheric Research ◽  
Vorticity Advection ◽  
Surface Cyclone ◽  
Advection Term ◽  
Environmental Prediction ◽  
Vorticity Tendency

Abstract The Zwack–Okossi vorticity tendency equation was used to calculate 500-hPa height tendencies in two intensifying Southern Hemisphere blocking events. The National Centers for Environmental Prediction–National Center for Atmospheric Research gridded reanalyses were used to make each of these calculations. The block intensification period for each event was associated with a deepening surface cyclone during a 48-h period beginning at 1200 UTC 28 July and 1200 UTC 8 August 1986, respectively. These results demonstrate that the diabatic heating forces height rises through the sensible and latent heating terms in these two Southern Hemisphere blocking events. The sensible heating was the larger contributor, second only to (about the same as) the vorticity advection term in the first (second) event. The vorticity advection term has been shown by several studies to be associated with block intensification.

Abstract P238: Importance of Self-Efficacy in the Patient-Reported Physical Function of Patients With Stroke

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Irene L Katzan ◽  
Dolora R Wisco ◽  
Brittany Lapin
Keyword(s):  
Physical Function ◽  
Indirect Effect ◽  
Self Efficacy ◽  
Total Effect ◽  
Pain Interference ◽  
Study Cohort ◽  
Stressful Situation ◽  
Study Objective ◽  
Patient Reported ◽  
The Relationship

Background: Self-efficacy is the belief that one is able to respond to demands of a stressful situation and it has both direct and indirect effects on health. The study objective is to investigate the amount of variance in patient-reported physical function (PF) that is explained by self-efficacy compared to clinician-reported disability and other patient-reported domains of health, and evaluate whether self-efficacy mediates the relationship between PF and other domains of health. Methods: Observational cohort study of 248 patients who were seen in a cerebrovascular clinic 3/18/20 - 7/7/20 and completed the following patient-reported outcome measures (PROMs) as part of the routine office visit: PROMIS PF, general self-efficacy, fatigue, and pain interference. Linear regression models were constructed to determine the amount of variance (adjusted R 2 ) in PROMIS PF score explained by the modified Rankin Scale (mRS) and additional PROM scores. The mRS and individual PROMs were added separately to a base model adjusted for demographic characteristics. Mediation analysis was conducted to determine the extent to which self-efficacy mediated the relationship between PF and other PROMs. Results: Mean age of study cohort was 61.5 (SD=13.5) years and 48.4% were female. The base model explained 4.5% of the variance of PF. Adding PROMIS fatigue resulted in the largest increase in the proportion of variance explained (adj R 2 = 47.7%), followed by PROMIS self-efficacy (40.7%), PROMIS pain interference (38.7%), and mRS (26.6%). Self-efficacy significantly mediated the relationship between fatigue and PF (standardized indirect effect: 0.11 (bias-corrected 95% CI: 0.05-0.18), 20.9% of total effect) and pain interference and PF (standardized indirect effect 0.10 (95% CI: 0.06-0.17), 27.1% of total effect). Conclusion: PROMIS self-efficacy explains more variance in stroke patients’ perceived physical function than their disability. This suggests that interventions to improve self-efficacy could have a significant effect on patient’s perceived health. Patients’ fatigue, despite being partially mediated by self-efficacy, was a large contributor to self-reported PF and should be included as part of an evaluation of patient’s physical health.

scholarly journals External forcing mechanisms controlling the North Atlantic coastal upwelling regime during the mid-Holocene

Geology ◽  
2020 ◽  
Author(s):  
Armand Hernández ◽  
Mário Cachão ◽  
Pedro Sousa ◽  
Ricardo M. Trigo ◽  
Jürg Luterbacher ◽  
...  
Keyword(s):  
North Atlantic ◽  
Coastal Upwelling ◽  
Marine Ecosystem ◽  
External Forcing ◽  
The North ◽  
New Findings ◽  
The North Atlantic ◽  
Eastern North Atlantic ◽  
Forcing Mechanisms ◽  
The Impact

Nearshore upwelling along the eastern North Atlantic margin regulates regional marine ecosystem productivity and thus impacts blue economies. While most global circulation models show an increase in the intensity and duration of seasonal upwelling at high latitudes under future human-induced warmer conditions, projections for the North Atlantic are still ambiguous. Due to the low temporal resolution of coastal upwelling records, little is known about the impact of natural forcing mechanisms on upwelling variability. Here, we present a microfossil-based proxy record and modeling simulations for the warmest period of the Holocene (ca. 9–5 ka) to estimate the contribution of the natural variability in North Atlantic upwelling via atmospheric and oceanic dynamics. We found that more frequent high-pressure conditions in the eastern North Atlantic associated with solar activity and orbital parameters triggered upwelling variations at multidecadal and millennial time scales, respectively. Our new findings offer insights into the role of external forcing mechanisms in upwelling changes before the Anthropocene, which must be considered when producing future projections of midlatitude upwelling activity.

scholarly journals Smartphone Addiction, Narcissism and Aggression: A Mediation Analysis Method

2019 ◽  
Author(s):  
Anjelica Simsek ◽  
Cahit Nuri ◽  
Cemaliye Direktor ◽  
Ahmet Arnavut
Keyword(s):  
Direct Effect ◽  
Indirect Effect ◽  
Mediation Analysis ◽  
Total Effect ◽  
Mediation Effect ◽  
Smartphone Addiction ◽  
Analysis Method ◽  
Variable Effect ◽  
Independent Variable ◽  
Mediator Variable

<p>At this study, meditation effect of aggression was analyzed using Baron and Kenny’s mediation analysis method. Baron and Kenny (1986) indicates that to analyze the effect of mediator variable 3 criteria have to be actualized:</p> <p>1. Independent variable have a significant effect on a mediator variable (way a)</p> <p>2. Mediator variable have a significant effect on a dependent variable (way b)</p> <p>3. Independent variable have a significant effect on a dependent variable (way c)</p> <p>PROCESS program were used the meditational effect, it is an extra macro that is downloading to the Daniel and Hayes’s (2016) SPSS program. In this program mediation effect could be evaluated as; total effect, direct effect and indirect effect scores of mediation variable effect on dependent variable (Preacher & Hayes, 2008).</p>

scholarly journals Family conflict mediates the relationship between past violence and wellbeing among female refugees

2019 ◽  
Vol 29 (Supplement_4) ◽  
Author(s):  
L Okenwa Emegwa ◽  
F Saboonchi
Keyword(s):  
Indirect Effect ◽  
Family Conflict ◽  
Violence Exposure ◽  
Exposure To Violence ◽  
Total Effect ◽  
Family Conflicts ◽  
Targeted Interventions ◽  
Refugee Women ◽  
Syrian Refugee ◽  
Past Exposure

Abstract Background Past exposure to violence has been suggested to have a lasting effect on subjective well being (SWB). Similarly, family conflict is another known predictor of SWB. Research shows that refugee women exposed to gender based violence (GBV) before resettlement may also face post-resettlement family conflicts due to socio-cultural factors, changes in social network and migration-based shifting gender roles. This study examines the role of family conflict as a likely mediator between past exposure to violence and SWB among Syrian refugee women in Sweden. Methods A total of 452 women out of a random sample of 1215 Syrian refugee women in Sweden responded to a questionnaire survey in Arabic. Variables include Past violence i.e. exposure to any of torture, physical or sexual violence preflight or during flight before arriving Sweden; Post-resettlement distressing family conflicts i.e. feeling disrespected or unimportant in the family or distressing conflicts; SWB was measured by WHO-5 wellbeing index. Maximum likelihood estimation with Robust standard errors and bias corrected bootstrapped 95% confidence intervals for all estimates. Results Total effect of past violence on SWB was significant (Estimate = -6.63; CI= -12.73 - -0.46). Similarly, family conflicts were associated with decreased SWB (Estimate = -3.80; CI= -5.17 - -2.40), and past violence exposure increased family conflicts (Estimate = 0.57; 0.13 - 1.08). The total effect of violence exposure on decreased SWB was decomposed into a direct and an indirect effect (mediated via family conflicts). The indirect effect via family conflicts was significant (M= -2.19; C1= -4.30 - 0.59), while decomposing rendered the direct effect non-significant (Estimate= -4.44, CI= -10.51 - 1.52). Conclusions Post-resettlement distressing family conflicts mediate the effect of prior exposure to violence on reduced SWB among refugee women. Key messages Past violence exposure reduces refugee women’s SWB via aggravated family conflicts implying the need for family targeted interventions to improve SWB of female refugees previously exposed to violence. Strategies to improve subjective wellbeing among female refugees should include screening for and addressing all forms of previous and ongoing GBV.

scholarly journals The Importance of Resolving Mesoscale Latent Heating in the North Atlantic Storm Track

2013 ◽  
Vol 70 (7) ◽  
pp. 2234-2250 ◽  
Author(s):  
Jeff Willison ◽  
Walter A. Robinson ◽  
Gary M. Lackmann
Keyword(s):  
Heat Release ◽  
Latent Heat ◽  
North Atlantic ◽  
General Circulation ◽  
Storm Track ◽  
Latent Heating ◽  
Latent Heat Release ◽  
Grid Spacing ◽  
The North ◽  
The North Atlantic

Abstract Theoretical, observational, and modeling studies have established an important role for latent heating in midlatitude cyclone development. Models simulate some contribution from condensational heating to cyclogenesis, even with relatively coarse grid spacing (on the order of 100 km). Our goal is to more accurately assess the diabatic contribution to storm-track dynamics and cyclogenesis while bridging the gap between climate modeling and synoptic dynamics. This study uses Weather Research and Forecasting model (WRF) simulations with 120- and 20-km grid spacing to demonstrate the importance of resolving additional mesoscale features that are associated with intense precipitation and latent heat release within extratropical cyclones. Sensitivity to resolution is demonstrated first with a case study, followed by analyses of 10 simulated winters over the North Atlantic storm track. Potential vorticity diagnostics are employed to isolate the influences of latent heating on storm dynamics, and terms in the Lorenz energy cycle are analyzed to determine the resulting influences on the storm track. The authors find that the intensities of individual storms and their aggregate behavior in the storm track are strongly sensitive to horizontal resolution. An enhanced positive feedback between cyclone intensification and latent heat release is seen at higher resolution, resulting in a systematic increase in eddy intensity and a stronger storm track relative to the coarser simulations. These results have implications for general circulation models and their projections of climate change.

scholarly journals Potential Large-Scale Forcing Mechanisms Driving Enhanced North Atlantic Tropical Cyclone Activity since the Mid-1990s

2018 ◽  
Vol 31 (4) ◽  
pp. 1377-1397 ◽  
Author(s):  
Haikun Zhao ◽  
Xingyi Duan ◽  
G. B. Raga ◽  
Fengpeng Sun
Keyword(s):  
Tropical Cyclone ◽  
North Atlantic ◽  
Large Scale ◽  
Vertical Wind Shear ◽  
Low Level ◽  
The North ◽  
Recent Increase ◽  
Forcing Mechanisms ◽  
Interdecadal Changes

A significant increase of tropical cyclone (TC) frequency is observed over the North Atlantic (NATL) basin during the recent decades (1995–2014). In this study, the changes in large-scale controls of the NATL TC activity are compared between two periods, one before and one since 1995, when a regime change is observed. The results herein suggest that the significantly enhanced NATL TC frequency is related mainly to the combined effect of changes in the magnitudes of large-scale atmospheric and oceanic factors and their association with TC frequency. Interdecadal changes in the role of vertical wind shear and local sea surface temperatures (SSTs) over the NATL appear to be two important contributors to the recent increase of NATL TC frequency. Low-level vorticity plays a relatively weak role in the recent increase of TC frequency. These changes in the role of large-scale factors largely depend on interdecadal changes of tropical SST anomalies (SSTAs). Enhanced low-level westerlies to the east of the positive SSTAs have been observed over the tropical Atlantic since 1995, with a pattern nearly opposite to that seen before 1995. Moreover, the large-scale contributors to the NATL TC frequency increase since 1995 are likely related to both local and remote SSTAs. Quantification of the impacts of local and remote SSTAs on the increase of TC frequency over the NATL basin and the physical mechanisms require numerical simulations and further observational analyses.

Gender, Family Resources, and Success in Science

1996 ◽  
Vol 17 (1) ◽  
pp. 83-113 ◽  
Author(s):  
SANDRA L. HANSON
Keyword(s):  
High School ◽  
Young Women ◽  
Indirect Effect ◽  
Science Achievement ◽  
Young Men ◽  
Total Effect ◽  
Family Resources ◽  
Men And Women ◽  
Large Numbers ◽  
Trajectory Models

This research examines the effect of gender and family resources on success in multiple areas of science. Science experiences are measured using longitudinal science trajectories. Findings show that young women are less likely than young men to persist in science, whether it is science achievement, access, or attitudes. Large numbers of women permanently exit the science pipeline after their sophomore year of high school. However, results from the science trajectory models show that among men and women who are equally qualified, women are not necessarily less likely to persist in science. Results also show that young men have more family resources than young women and some of the total effect of gender on science experiences involves an indirect effect through family resources. In addition, gender interacts with family resources with the effects of many resources being stronger for women than for men.

scholarly journals Holocene evolution of the North Atlantic subsurface transport

2016 ◽  
Author(s):  
Janne Repschläger ◽  
Dieter Garbe-Schönberg ◽  
Mara Weinelt ◽  
Ralph Schneider
Keyword(s):  
Water Transport ◽  
North Atlantic ◽  
Meridional Overturning Circulation ◽  
Published Data ◽  
Subsurface Transport ◽  
Transport Pathways ◽  
The North ◽  
Warm Surface Water ◽  
Meridional Overturning ◽  
Forcing Mechanisms

Abstract. Previous studies suggested that short term freshening events in the subpolar gyre can be counterbalanced by interactions with the subtropical gyre and thus stabilize the Atlantic Meridional Overturning Circulation (AMOC). However, little is known about the intergyre transport pathways. Here, we reconstruct surface and subsurface transport between the subtropical and polar North Atlantic during the last 10000 years, by combining new temperature and salinity reconstructions obtained from surface and subsurface dwelling foraminifera with published data from the tropical and subpolar North Atlantic and published foraminiferal abundance data from the subtropical North Atlantic. These observations imply an overall stable warm surface water transport. Subsurface warm water transport started at about 8 ka with subtropical heat storage, and reached its full strength at about 7 ka, probably associated with the onset of the modern AMOC mode. Comparison of different potential forcing mechanisms suggests a freshwater control on these ocean transport changes.

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