Cyclonic and anticyclonic contributions to atmospheric energetics

Migratory cyclones and anticyclones account for most of the day-to-day weather variability in the extratropics. These transient eddies act to maintain the midlatitude jet streams by systematically transporting westerly momentum and heat. Yet, little is known about the separate contributions of cyclones and anticyclones to their interaction with the westerlies. Here, using a novel methodology for identifying cyclonic and anticyclonic vortices based on curvature, we quantify their separate contributions to atmospheric energetics and their feedback on the westerly jet streams as represented in Eulerian statistics. We show that climatological westerly acceleration by cyclonic vortices acts to dominantly reinforce the wintertime eddy-driven near-surface westerlies and associated cyclonic shear. Though less baroclinic and energetic, anticyclones still play an important role in transporting westerly momentum toward midlatitudes from the upper-tropospheric thermally driven jet core and carrying eddy energy downstream. These new findings have uncovered essential characteristics of atmospheric energetics, storm track dynamics and eddy-mean flow interaction.

Basics of the atmospheric energetics : A brief summary of global and regional atmospheric energetics reflected upon the university curricula

The purpose of this study is to provide an overview of the science and development of atmospheric energetics, its so far matured parts to date, and the direction of the researches. However, we restrict ourselves to the discussion of the very basic results of the researches to reveal the parts the introduction of which can be suggested into the compulsory education of the future meteorologist. This became feasible especially due to the rapid development of the personal computer that makes possible the calculation of the atmospheric energies for students by using their own laptops, so this field of meteorology now can be a tactile reality for them. The founder of atmospheric energetics was Lorenz, who formulated for a global, dry atmosphere the concept of available potential energy, which is the difference between the current energy state of the atmosphere and a reference state with minimum energy. His basic results concerning the global description of atmospheric energetics have already become part of the university curriculum. It is important to be able to describe the energy balance of the atmosphere both locally as well as globally, for which the introduction of enthalpy and exergy seemed appropriate. The advantage of examining the dry atmosphere is that significant simplifications can be applied, but the atmosphere is finally moist, so research has also started in this direction, first with a global and then with a local approach. The key is to find the reference state, which is a complex, computationally demanding task. In this paper, we focus on the most important steps of this process and concentrate on the thermodynamic basis of the new concepts.

Environmental Energetics aspects of anomalous Cyclogenesis over Indian Ocean during 2013

An attempt has been made to understand the dynamics behind anomalous cyclogenesis over Indian Ocean during 2013 cyclone seasons, from an atmospheric energetics point of view. Salient features of the results of this study are:Maximum intensification of all the intense cyclonic vortices was associated with an enhancement in both conversion from eddy available potential energy to eddy kinetic energy (AE to KE ) and zonal kinetic energy to eddy kinetic energy (KZ to KE).During intensification of the storms both AE and AZ have shown to be dissipated, suggesting the intensification of storms at the cost of AE and AZ . For all of these systems baroclinic eddy kinetic energy conversions [conversion from AE to KE ] dominates over barotropic eddy kinetic energy conversions [conversion from KZ to KE]. Anomalous cyclogenesis in 2013, at least partly may be attributed to a positive anomaly in Moist Static Energy (MSE) of the environment along with positive anomaly in baroclinic and barotropic eddy kinetic energy conversion during cyclone seasons over the region under study.Release of convective instability in the atmosphere may also be attributed, at least partly, for anomalous cyclogenesis in 2013.

Applications of an Updated Atmospheric Energetics Formulation

As observations and atmospheric reanalyses have improved, the diagnostics that can be computed with confidence also increase. Accordingly, a new formulation of the energetics of the atmosphere is laid out, with a view to advancing diagnostic studies of Earth’s energy budget and flows. It is utilized to produce assessments of the vertically integrated divergences in both the atmosphere and ocean. Careful conservation of mass is required, with special attention given to the hydrological cycle and redistribution of mass associated with precipitation and evaporation, and a new method for ensuring this is developed. It guarantees that the atmospheric divergence is associated with moisture and precipitation, unlike previous methods. A new term, identified as associated with the enthalpy of precipitation, is included in a preliminary way. It is sensitive to the formulation, and the use of temperature in degrees Celsius instead of Kelvin greatly reduces errors and produces the extra term with values up to about ±5 W m−2. New results for 2000 to 2016 are presented for the vertical-mean and annual-mean diabatic atmospheric heating, atmospheric moistening, and total atmospheric energy divergence. Results for the atmospheric divergence are combined with top-of-atmosphere radiation observations to deduce total surface energy fluxes. Along with estimates of changes in ocean heat content, the Atlantic Ocean meridional heat transports are recomputed for March 2000 through 2013. The new results are compared with previous estimates and an assessment is made of the effects of the new mass balance, change in temperature scale, and the extra precipitation enthalpy term.

Impact of the Warming Pattern on Global Energetics

The warming pattern due to higher greenhouse gas concentrations is expected to affect the global atmospheric energetics mainly via changes in the (i) meridional temperature gradient and (ii) mean static stability. Changes in surface meridional temperature gradients have been previously regarded as the determining feature for the energetics response, but recent studies suggest that changes in mean static stability may be more relevant than previously thought. This study aims to determine the relative importance of these two effects by comparing the energetics responses due to different warming patterns using a fully coupled atmosphere–ocean general circulation model. By means of an additional diabatic forcing, experiments with different warming patterns are obtained: one with a 2xCO2-like pattern that validates the method, one with only the tropical upper-tropospheric warming, and one with only the high-latitude surface warming. The study’s findings suggest that the dominant aspect of the warming pattern that alters the global atmospheric energetics is not its associated meridional temperature gradient changes, but the mean static stability changes. The tropical upper warming weakens the energetics by increasing the mean static stability, whereas the surface warming strengthens it by reducing the mean static stability. The combined 2xCO2-like response is dominated by the tropical upper-tropospheric warming effect, hence the weaker energetic activity. Eddy kinetic energy changes consistently, but the two opposite responses nearly cancel each other in the 2xCO2 case. Therefore, estimates of future changes in storminess may be particularly sensitive to the relative magnitude of the main features of the simulated warming pattern.