Advances in Geophysics 

About: Advances in Geophysics is an academic journal published by Elsevier BV. The journal publishes majorly in the area(s): Turbulence & Turbulent diffusion. It has an ISSN identifier of 0065-2687. Over the lifetime, 381 publications have been published receiving 22476 citations.

Energy Cascade in Large-Eddy Simulations of Turbulent Fluid Flows

Abstract: The derivation of smoothed or filtered momentum and continuity equations for large-scale, energy-containing eddies is considered. Questions regarding the energy loss of large-scale turbulence are discussed along with aspects of turbulent diffusion of a passive scalar. It is found that the large-scale fluctuations satisfy filtered or averaged momentum and continuity equations. An averaging of the nonlinear advection term yields two terms.

The Influence of Mountains on the Atmosphere

Abstract: Publisher Summary The chapter reviews the meteorological phenomena that are associated with topography. The study of airflow past mountains is complicated by the wide range of scales that must be considered. The ratios of the mountain width to each of the natural length scales are important in determining the physical regime of the flow. This idea is emphasized in the chapter by treating the effects of boundary layers and buoyancy. The theory of two-dimensional mountain waves with the help of its governing equations is presented and the observations of mountain waves are presented. The chapter also examines the influence of the boundary layer on mountain flows and slope winds and mountain and valley winds. It considers the perturbation to the wind flow caused by a mountain of intermediate scale where the rotation of the Earth cannot be neglected. For this the flow near mesoscale and synoptic-scale mountains, quasi-geostrophic flow over a mountain, the effect of inertia on the flow over mesoscale mountains, and theories of lee cyclogenesis are discussed. Finally the chapter describes planetary-scale mountain waves; a vertically integrated model of topographically forced planetary waves; the vertical structure of planetary waves; models of stationary planetary waves allowing meridional propagation and lateral; and variation in the background wind.

Data assimilation in meteorology and oceanography

Abstract: Publisher Summary This chapter provides a review of current operational practice and of advanced data assimilation techniques in meteorology. Numerical models can be used to assimilate meteorological and oceanographic data, creating a dynamically consistent, complete and accurate “movie” of the two geofluids, atmosphere, and ocean in motion. The ocean's strong stratification helps determine the most energetic scales and processes for the global ocean circulation. Active research on data assimilation is burgeoning rapidly in both meteorology and oceanography. Operational NWP requirements have produced a mature data-assimilation technology in meteorology, from which climatic research has benefitted as well. Ocean is characterized by transient, energetic motions with a broad spectrum in frequency and wave number. A steady component of the circulation may not even exist, and be only a model resulting from the analysis of data sets sparse in space and time, like hydrographic data sets, for which steadiness is assumed a priori. Thus, in oceanic data-assimilation problems, the choice of a model and related data assimilation scheme and the definition of success of the assimilation process itself depend crucially on the scientific issue of interest as the starting point.

The Properties of Atmospheric Aerosol Particles as Functions of the Relative Humidity at Thermodynamic Equilibrium with the Surrounding Moist Air

Abstract: Publisher Summary The chapter addresses the problems in aerosol measuring techniques and selection of sampling and measuring methods. Theoretic evaluation of mass, size, mean density, and mean refractive index as functions of the relative humidity is discussed. The chapter also discusses techniques for measuring the mass as a function of the relative humidity; determination of the mean density; and measuring the mean complex index of refraction. Results of the measurements, discussion of the results, coefficients of mass increase, mean densities and real parts of the mean complex index of refractions, and applicability of the results are also described. Finally, the chapter then reviews the model computations and approximation formulas based upon measured properties.

Atlantic Air-Sea Interaction

Abstract: Publisher Summary This article is concerned with the causes of the variations in the surface temperature of the Atlantic Ocean from year to year and over longer periods. The processes, which influence the ocean temperature, are partly radiative transfers, partly heat exchange at the interface of ocean and atmosphere, and partly advective heat transfers by the ocean currents. The net radiative heat balance of the ocean is influenced by possible variations of the solar radiative output, and by the transmissivity of the atmosphere for short- and long-wave radiation. Variations in cloudiness would be the factor, most likely to influence measurably the annual radiative heat budget of the ocean. The ocean currents provide important contributions to the local heat budget, positive in the warm currents and negative in the cold currents. The changes in intensity of the oceanic circulation are mainly dictated by changes in the atmospheric circulation, and the resulting changes in the temperature field of the ocean surface must in turn, influence the thermodynamics of the atmospheric circulation. A clarification of these relationships is a prerequisite for the understanding of the mechanism of climatic change. This article will present some empirical findings, which have a bearing on those problems. Before proceeding to display the empirical findings on the large-scale ocean–atmosphere interaction, a brief outline will be given of the theories on the meteorological control of ocean currents and on the interface heat transfers.