Similarity hypotheses for the atmospheric surface layer expressed by non-dimensional characteristic invariants - a review

In this paper, similarity hypotheses for the atmospheric surface layer (ASL) are reviewed using nondimensional characteristic invariants, referred to as π -numbers. The basic idea of this dimensional π-invariants analysis (sometimes also called Buckingham’s π-theorem) is described in a mathematically generalized formalism. To illustrate the task of this powerful method and how it can be applied to deduce a variety of reasonable solutions by the formalized procedure of non-dimensionalization, various instances are represented that are relevant to the turbulence transfer across the ASL and prevailing structure of ASL turbulence. Within the framework of our review we consider both (a) Monin-Obukhov scaling for forced-convective conditions, and (b) Prandtl-Obukhov-Priestley scaling for free-convective conditions.It is shown that in the various instances of Monin-Obukhov scaling generally two π-numbers occur that result in corresponding similarity functions. In contrast to that, Prandtl-Obukhov-Priestley scaling will lead to only one π number in each case usually considered as a non-dimensional universal constant. Since an explicit mathematical relationship for the similarity functions cannot be obtained from a dimensional π-invariants analysis, elementary laws of π-invariants have to be pointed out using empirical or/and theoretical findings. To evaluate empirical similarity functions usually considered within the framework flux-profile relationships, so-called integral similarity functions for momentum and sensible heat are presented and assessed on the basis of the friction velocity and the vertical component of the eddy flux densities of sensible and latent heat directly measured during the GREIV I 1974 field campaign

On the meaning of feedback parameter, transient climate response, and the greenhouse effect: Basic considerations and the discussion of uncertainties

In this paper we discuss the meaning of feedback parameter, greenhouse effect and transient climate response usually related to the globally averaged energy balance model of Schneider and Mass. After scrutinizing this model and the corresponding planetary radiation balance we state that (a) the this globally averaged energy balance model is flawed by unsuitable physical considerations, (b) the planetary radiation balance for an Earth in the absence of an atmosphere is fraught by the inappropriate assumption of a uniform surface temperature, the so-called radiative equilibrium temperature of about 255 K, and (c) the effect of the radiative anthropogenic forcing, considered as a perturbation to the natural system, is much smaller than the uncertainty involved in the solution of the model of Schneider and Mass. This uncertainty is mainly related to the empirical constants suggested by various authors and used for predicting the emission of infrared radiation by the Earth's skin. Furthermore, after inserting the absorption of solar radiation by atmospheric constituents and the exchange of sensible and latent heat between the Earth and the atmosphere into the model of Schneider and Mass the surface temperatures become appreciably lesser than the radiative equilibrium temperature. Moreover, neither the model of Schneider and Mass nor the Dines-type two-layer energy balance model for the Earth-atmosphere system, both contain the planetary radiation balance for an Earth in the absence of an atmosphere as an asymptotic solution, do not provide evidence for the existence of the so-called atmospheric greenhouse effect if realistic empirical data are used.Comment: 69 pages, 3 tables and 16 figure

The different effect of consumer learning on incentives to differentiate in Cournot and Bertrand competition

We combine two extensions of the differentiated duopoly model of Dixit (1979), namely Caminal and Vives (1996) and Brander and Spencer (2015a,b), to analyze the effect of consumer learning on firms' incentives to differentiate their products in models of Cournot and Bertrand competition. Products are of different quality, consumers buy sequentially and are imperfectly informed about the quality of the goods. Before simultaneously competing in quantities, firms simultaneously choose their investment into differentiation. Late consumers can observe earlier consumers' decisions and extract information about the quality of the goods. This influences the firms' incentives to differentiate. If firms compete in quantities, they are more likely to invest in differentiation with consumer learning than without. This is in line with implications of the recommendation effect introduced in Conze and Kramm (2016) in a model of spatial differentiation. We also examine the case in which firms compete in prices. Here, the effect of consumer learning is reversed, so that differentiation is less likely with consumer learning. Thus, we find an information-based difference between Cournot and Bertrand competition: in the Bertrand setting consumer learning increases the competition, i.e. products are more likely to be substitutes, and it weakens it in the Cournot model.Wir kombinieren zwei Erweiterungen des Duopol Models mit differenzierten Gütern von Dixit (1979), genauer die von Caminal und Vives (1996) und die von Brander und Spence (2015a,b), um den Effekt von (Bayesianisch) lernenden Konsumenten auf Anreize der Firmen zur Produktdifferenzierung im Cournot und im Bertrand Wettbewerb zu analysieren. Die Produkte haben eine unterschiedliche Qualität, Konsumenten kaufen sequentiell und sind unvollständig über die Produktqualität informiert. Bevor die Firmen simultan über ihre produzierten Mengen entscheiden, wählen sie simultan ihre Investitionen in Produktdifferenzierung. "Spätere" Konsumenten können die Konsumentscheidungen "früherer" Konsumenten beobachten und so Information über die Produktqualität erhalten, also Bayesianisch lernen. Im Cournot Wettbewerb mit lernenden Konsumenten ist es wahrscheinlicher, dass Firmen in Produktdifferenzierung investieren, als ohne. Dieses Ergebnis stimmt überein mit dem Wirken des "Recommendation Effects", welcher in Conze und Kramm (2016a) gezeigt und analysiert wird. Wir untersuchen auch den Bertrand Wettbewerb. Hier ist der Effekt von Konsumentenlernen umgekehrt, so dass Differenzierung mit Konsumentenlernen weniger wahrscheinlich ist also ohne. Wir finden demnach einen informationsbasierten Unterschied zwischen Cournot und Bertrand Wettbewerb: im Bertrand Modell erhöht Konsumentenlernen den Wettbewerb, das heißt Produkte sind mit lernenden Konsumenten eher Substitute als ohne, und im Cournot Modell schwächt es ihn ab

Об'єкти управління підприємством як соціально-економічною системою

Проведено аналіз сутності, функцій, видів підприємств як економічної категорії, систематизовано об’єкти дослідження за теоріями підприємств та визначено, що ними є процес управління потенціалом підприємства за формами організації бізнесу та технологією партнерських взаємовідносин