scholarly journals The Efficiency of Upward Wave Propagation Near the Tropopause: importance of the form of the refractive index

2021 ◽  
Author(s):  
Israel Weinberger ◽  
Chaim I. Garfinkel ◽  
Ian P. White ◽  
Thomas Birner
Keyword(s):  
Wave Propagation ◽  
Inversion Layer ◽  
Vertical Component ◽  
Index Of Refraction ◽  
Buoyancy Frequency ◽  
Level Data ◽  
Wave Flux ◽  
Drazin Index ◽  
Vertical Gradients

AbstractThe connection between the polar stratospheric vortex and the vertical component of the Eliassen-Palm flux in the lower stratosphere and upper troposphere is examined in model level data from the ERA-5 reanalysis. The particular focus of this work is on the conditions that lead to upward wave propagation between the tropopause and the bottom of the vortex near 100 hPa. The ability of four different versions of the index of refraction to capture this wave propagation are evaluated. The original Charney and Drazin index of refraction includes terms ignored by Matsuno that are shown to be critical for understanding upward wave propagation just above the tropopause in both the climatology and during extreme heat flux events. By adding these terms to the Matsuno index of refraction, it is possible to construct a useful tool that describes wave flux immediately above the tropopause and at the same time also describes the role of meridional variations within the stratosphere. It is shown that a stronger tropopause inversion layer tends to restrict upward wave propagation. It is also shown that while only 38% of extreme wave-1 Eliassen-Palm flux vertical component (Fz) at 100hPa events are preceded by extreme Fz at 300hPa, there are almost no extreme events at 100hPa in which the anomaly at 300hPa is of opposite sign or very weak. Overall, wave propagation near the tropopause is sensitive to vertical gradients in buoyancy frequency, and these vertical gradients may not be accurately captured in models or reanalysis products especially with lower vertical resolutions.

The Efficiency of Upward Wave Propagation Near the Tropopause

2021 ◽  
Author(s):  
Israel Weinberger ◽  
Chaim Garfinkel
Keyword(s):  
Heat Flux ◽  
Wave Propagation ◽  
Inversion Layer ◽  
Vertical Component ◽  
Reanalysis Data ◽  
Extreme Heat ◽  
Index Of Refraction ◽  
Scale Model ◽  
Buoyancy Frequency ◽  
Transmission And Reflection Coefficients

<p>Extreme states of the polar stratospheric vortex are typically followed by anomalous surface circulation. These extreme stratospheric vortex states are in turn often associated with extreme heat flux between the tropopause and 100 hPa. </p><p>The goal of this work is to better understand upward wave propagation between the tropopause and the bottom of the vortex near 100 hPa using both theory and reanalysis data.</p><p>Following Charney and Drazin (1961) we analytically solve a quasi-geostrophic planetary-scale model with three different layers: troposphere, tropopause inversion layer (TIL) and stratosphere. We allow for different buoyancy frequencies in each layer and show the dependence of transmission and reflection coefficients on the buoyancy frequencies, TIL depth and mean-state zonal wind. The dependence of heat flux in the TIL and stratosphere, as well as phase-lines for the wave solution, are presented. This analysis highlights the key role that the TIL and jumps in buoyancy frequency play for upward wave propagation.</p><p>We then use reanalysis data to consider the importance of this effect in observations. Four different specifications of the index of refraction are compared: that derived by Charney and Drazin in 1961, that derived by Matsuno in 1970, and two that relax some of the assumptions used in the derivations of the first two. The Charney and Drazin index of refraction includes terms ignored by Matsuno that are critical for understanding upward wave propagation just above the tropopause in both the climatology and associated with extreme heat flux events. By adding these ignored terms to the Matsuno index of refraction, it is possible to construct a useful tool that describes wave flux immediately above the tropopause and at the same time also describes the role of meridional gradients within the stratosphere. Specifically, a stronger tropopause inversion layer (TIL) tends to restrict upward wave propagation. It is also shown that while only 38% of extreme wave-1 Eliassen-Palm flux vertical component (F<sub>z</sub>) at 100hPa events are preceded by extreme F<sub>z</sub> at 300hPa, there are almost no extreme events at 100hPa in which the anomaly at 300hPa is of opposite sign or very weak.  </p>

The Efficiency of Upward Wave Propagation Near the Tropopause

2020 ◽  
Author(s):  
Israel Weinberger ◽  
Chaim Garfinkel ◽  
Thomas Birner
Keyword(s):  
Heat Flux ◽  
Wave Propagation ◽  
Index Of Refraction ◽  
Buoyancy Frequency ◽  
Median Percentage ◽  
Weather Forecasts ◽  
The Difference ◽  
The Impact ◽  
Positive Index ◽  
Anomalous Heat

<p>Recent work has highlighted that not all periods with anomalous heat flux at 100hPa were preceded by anomalous heat flux in the troposphere (Birner and Alberts 2017; White et al 2019; Camara et al 2019), and the goal of this work is to understand the factors that govern the efficiency of upward wave propagation near the tropopause. The index of refraction of Matsuno (1970) has been used to offer guidance on the direction of wave propagation within the stratosphere. Specifically, waves are preferentially refracted towards regions with a more positive index of refraction and ducted away from regions in which the index of refraction is more negative. However, the index of refraction was derived under the assumption that buoyancy frequency is constant at all height levels, which is clearly not true near the tropopause. This assumption allowed Matsuno to ignore certain height dependent buoyancy frequency terms, and here we explore the impact of these terms near the tropopause.</p><p>Using the dataset of the European Center for Medium-Range Weather Forecasts Reanalysis version 5 (ERA5) we defined 'transmitting' composites consisting of more efficient upward propagation events between 300hPa and 100hPa. Similarly, periods of less efficient upward propagation events between 300hPa and 100hPa are composited as 'decaying' events. We computed the index of refraction profile using a median, percentage of negative days and the trimmed mean (Wilks 2011), and also consider the terms neglected by Matsuno. We find that  the index of refraction can account for the difference between the decaying and transmitting composite.</p>

What's Happening to Profits at Cazenovia Creations?

2013 ◽  
Vol 8 (1) ◽  
pp. 24-29 ◽  
Author(s):  
Margaret Garnsey ◽  
Andrea Hotaling
Keyword(s):  
Financial Analysis ◽  
Financial Statements ◽  
Internal Controls ◽  
Net Income ◽  
Database Query ◽  
Microsoft Access ◽  
Level Data ◽  
Query Tool ◽  
Transaction Level

ABSTRACT In this case, students assume the role of an accounting professional asked by a client to investigate why net income is not as strong as expected. The students must first analyze a set of financial statements to identify areas of possible concern. After determining the areas to investigate, the students use a database query tool to see if they can determine causes by examining transaction level data. Finally, the students are asked to professionally communicate their findings and recommendations to their client. The case provides students with experience in using query-based approaches to answering business questions. It is appropriate for students with basic query and financial analysis skills and knowledge of internal controls. A Microsoft Access database with transaction details for the final seven months of the current year as well as financial statements for the current and prior year are provided.

Financial Access of Latin America and Caribbean Firms: What Are the Roles of Institutional, Financial, and Economic Development?

2021 ◽  
pp. 097265272110153
Author(s):  
Lan Khanh Chu
Keyword(s):  
Economic Development ◽  
Latin America ◽  
Jel Classification ◽  
Caribbean Region ◽  
Country Level ◽  
Level Data ◽  
Latin America And Caribbean ◽  
The Impact ◽  
Moderating Role

This article examines the impact of institutional, financial, and economic development on firms’ access to finance in Latin America and Caribbean region. Based on firm- and country-level data from the World Bank databases, we employ an ordered logit model to understand the direct and moderating role of institutional, financial, and economic development in determining firms’ financial obstacles. The results show that older, larger, facing less competition and regulation burden, foreign owned, and affiliated firms report lower obstacles to finance. Second, better macro-fundamentals help to lessen the level of obstacles substantially. Third, the role of institutions in promoting firms’ inclusive finance is quite different to the role of financial development and economic growth. JEL classification: E02; G10; O16; P48

scholarly journals From Loschmidt daemons to time-reversed waves

2016 ◽  
Vol 374 (2069) ◽  
pp. 20150156 ◽  
Author(s):  
Mathias Fink
Keyword(s):  
Wave Propagation ◽  
Time Reversal ◽  
Degrees Of Freedom ◽  
Point Of View ◽  
Propagation Time ◽  
Reversal Invariance ◽  
Spatial Boundary ◽  
Dual Approaches ◽  
Spatio Temporal

Time-reversal invariance can be exploited in wave physics to control wave propagation in complex media. Because time and space play a similar role in wave propagation, time-reversed waves can be obtained by manipulating spatial boundaries or by manipulating time boundaries. The two dual approaches will be discussed in this paper. The first approach uses ‘time-reversal mirrors’ with a wave manipulation along a spatial boundary sampled by a finite number of antennas. Related to this method, the role of the spatio-temporal degrees of freedom of the wavefield will be emphasized. In a second approach, waves are manipulated from a time boundary and we show that ‘instantaneous time mirrors’, mimicking the Loschmidt point of view, simultaneously acting in the entire space at once can also radiate time-reversed waves.

scholarly journals Dynamics of Extreme Stratospheric Negative Heat Flux Events in an Idealized Model

2018 ◽  
Vol 75 (10) ◽  
pp. 3521-3540 ◽  
Author(s):  
Etienne Dunn-Sigouin ◽  
Tiffany Shaw
Keyword(s):  
Heat Flux ◽  
Wave Propagation ◽  
Recent Work ◽  
Wave Interaction ◽  
Higher Order ◽  
Negative Events ◽  
Flow Mechanism ◽  
Mean Flow ◽  
Idealized Model

Recent work has shown that extreme stratospheric wave-1 negative heat flux events couple with the troposphere via an anomalous wave-1 signal. Here, a dry dynamical core model is used to investigate the dynamical mechanisms underlying the events. Ensemble spectral nudging experiments are used to isolate the role of specific dynamical components: 1) the wave-1 precursor, 2) the stratospheric zonal-mean flow, and 3) the higher-order wavenumbers. The negative events are partially reproduced when nudging the wave-1 precursor and the zonal-mean flow whereas they are not reproduced when nudging either separately. Nudging the wave-1 precursor and the higher-order wavenumbers reproduces the events, including the evolution of the stratospheric zonal-mean flow. Mechanism denial experiments, whereby one component is fixed to the climatology and others are nudged to the event evolution, suggest higher-order wavenumbers play a role by modifying the zonal-mean flow and through stratospheric wave–wave interaction. Nudging all tropospheric wave precursors (wave-1 and higher-order wavenumbers) confirms they are the source of the stratospheric waves. Nudging all stratospheric waves reproduces the tropospheric wave-1 signal. Taken together, the experiments suggest the events are consistent with downward wave propagation from the stratosphere to the troposphere and highlight the key role of higher-order wavenumbers.

scholarly journals How Johnson Fought the War on Poverty: The Economics and Politics of Funding at the Office of Economic Opportunity

2014 ◽  
Vol 74 (2) ◽  
pp. 351-388 ◽  
Author(s):  
Martha J. Bailey ◽  
Nicolas J. Duquette
Keyword(s):  
New Deal ◽  
War On Poverty ◽  
Economic Opportunity ◽  
Johnson Administration ◽  
Level Data ◽  
Office Of Economic Opportunity ◽  
Economic Opportunity Act ◽  
Political Variables ◽  
Economics And Politics

This article presents a quantitative analysis of the geographic distribution of spending through the 1964 Economic Opportunity Act (EOA). Using newly assembled state- and county-level data, the results show that the Johnson administration directed funding in ways consistent with the War on Poverty's rhetoric of fighting poverty and racial discrimination: poorer areas and those with a greater share of nonwhite residents received systematically more funding. In contrast to New Deal spending, political variables explain very little of the variation in EOA funding. The smaller role of politics may help explain the strong backlash against the War on Poverty's programs.

scholarly journals Exploring the role of family ties on life satisfaction in later life in Europe

2019 ◽  
Vol 31 (2-2019) ◽  
pp. 180-198
Author(s):  
Aïda Solé-Auró ◽  
Clara Cortina
Keyword(s):  
Life Satisfaction ◽  
Age Groups ◽  
Later Life ◽  
Network Size ◽  
Protection Factor ◽  
Family Ties ◽  
Individual Level ◽  
Long Run ◽  
Level Data

We analyzed the relationship between family ties and the life satisfaction of people between the ages of 50 and 85 years in 13 European countries. We aim at determining the effects of partnership (being currently in a partnership) and parenthood (having remained childless). We use individual-level data from the sixth wave of the Survey of Health, Ageing and Retirement in Europe (SHARE). The analyses are restricted to respondents who are partnered or who have ever been married. We apply a multivariate analysis to examine the association of life satisfaction with family ties for men and for women. We add controls for age groups and education level, and we pay special attention to the role of individuals’ network size. Our findings indicate that in all countries, having no partner has the strongest and most negative association with life satisfaction. However, there was no clear association between not having children and life satisfaction across countries. We also find an important role of some protector variables, such as having a strong network which, in most countries, significantly increase one’s life satisfaction. We find that there is a relationship between individuals’ family situation and life satisfaction, but it is restricted to being in a partnership. The protection factor of having a partner improves one’s life satisfaction at older ages much more than protection by having children. This finding can reduce the concern about the long run implications of increasing childlessness among younger cohorts as it is not necessarily associated to a higher risk of low life satisfaction.

scholarly journals Job Quality In The Micro And Small Business Sector In Ethiopia: Evidence From Firm-Level Data

2021 ◽  
Author(s):  
Berihu Assefa Gebrehiwot
Keyword(s):  
Poverty Reduction ◽  
Occupational Safety ◽  
Job Creation ◽  
Job Quality ◽  
Small Enterprises ◽  
Firm Level ◽  
Highly Educated ◽  
Level Data ◽  
Micro And Small Enterprises

Abstract Using a large dataset from the 10 largest cities in Ethiopia, this paper studies what entrepreneurial characteristics and attributes contribute to quality job creation in the micro and small enterprises (MSE) sector. We measure job quality in two ways – i) using wage and contract, and ii) health and occupational safety variables. We find that micro and small enterprises that create quality jobs tend to be operated by highly educated and experienced entrepreneurs. This highlights the role of human capital in quality job creation and poverty reduction. Further, we find that micro and small enterprises that create quality jobs tend to be larger in size and managed by professionally recruited managers.

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