Problems of Large-Scale Kinetic Energy Balance—A Diagnostic Analysis in GARP

1974 ◽  
Vol 55 (7) ◽  
pp. 768-778 ◽  
Author(s):  
Ernest C. Kung ◽  
Phillip J. Smith
Keyword(s):  
Energy Balance ◽  
Kinetic Energy ◽  
General Circulation ◽  
Large Scale ◽  
Synoptic Scale ◽  
University Of Missouri ◽  
Diagnostic Studies ◽  
Middle Latitudes ◽  
The University ◽  
Balance Problems

Currently available diagnostic studies on kinetic energy balance in the general circulation are reviewed as one of the basic scientific problems in GARP. The kinetic energy equation and several different approaches in the evaluation of energy variables are discussed in relation to real and modeled atmospheric data. Energy balance problems in the middle latitudes are examined in terms of linkages between processes from energy conversion to dissipation, balance within various systems of circulation, and interactions with sub-synoptic scale disturbances. The kinetic energy budget in large-scale disturbances and the general flow of the tropical circulation are contrasted with those in the middle latitudes. By clarifying the current essential problems in the energetics of the middle latitudes and tropics, ongoing diagnostic studies at the University of Missouri—Columbia and Purdue University are identified in the context of the GARP.

scholarly journals The Troposphere-to-Stratosphere Transition in Kinetic Energy Spectra and Nonlinear Spectral Fluxes as Seen in ECMWF Analyses

2013 ◽  
Vol 70 (2) ◽  
pp. 669-687 ◽  
Author(s):  
B. H. Burgess ◽  
Andre R. Erler ◽  
Theodore G. Shepherd
Keyword(s):  
Kinetic Energy ◽  
General Circulation ◽  
Large Scale ◽  
Zonal Flow ◽  
General Circulation Models ◽  
Energy Spectra ◽  
Spectral Break ◽  
Energy Peak ◽  
Transient Energy ◽  
Aircraft Data

Abstract Global horizontal wavenumber kinetic energy spectra and spectral fluxes of rotational kinetic energy and enstrophy are computed for a range of vertical levels using a T799 ECMWF operational analysis. Above 250 hPa, the kinetic energy spectra exhibit a distinct break between steep and shallow spectral ranges, reminiscent of dual power-law spectra seen in aircraft data and high-resolution general circulation models. The break separates a large-scale “balanced” regime in which rotational flow strongly dominates divergent flow and a mesoscale “unbalanced” regime where divergent energy is comparable to or larger than rotational energy. Between 230 and 100 hPa, the spectral break shifts to larger scales (from n = 60 to n = 20, where n is spherical harmonic index) as the balanced component of the flow preferentially decays. The location of the break remains fairly stable throughout the stratosphere. The spectral break in the analysis occurs at somewhat larger scales than the break seen in aircraft data. Nonlinear spectral fluxes defined for the rotational component of the flow maximize between about 300 and 200 hPa. Large-scale turbulence thus centers on the extratropical tropopause region, within which there are two distinct mechanisms of upscale energy transfer: eddy–eddy interactions sourcing the transient energy peak in synoptic scales, and zonal mean–eddy interactions forcing the zonal flow. A well-defined downscale enstrophy flux is clearly evident at these altitudes. In the stratosphere, the transient energy peak moves to planetary scales and zonal mean–eddy interactions become dominant.

Late Cenozoic plateau uplift and climate change

1990 ◽  
Vol 81 (4) ◽  
pp. 301-314 ◽  
Author(s):  
William F. Ruddiman ◽  
John E. Kutzbach
Keyword(s):  
General Circulation ◽  
Large Scale ◽  
General Circulation Models ◽  
Lapse Rate ◽  
Regional Differentiation ◽  
Late Cenozoic ◽  
Local Responses ◽  
Climatic Trends ◽  
Middle Latitudes ◽  
Physical Impact

ABSTRACTSensitivity experiments with general circulation models show that uplift of plateau and mountain regions in Southern Asia and the American west during the late Cenozoic was an important factor in the evolution of Northern Hemisphere climate. The climatic trends simulated in the uplift experiments agree in direction with most trends observed in the geological record, including the tendencies toward greater regional differentiation of climate, and particularly the fragmentation into wetter and drier climatic patterns at middle latitudes. These climatic trends result from (1) increased orographic diversion of the mid-latitude westerlies, and (2) increased summer heating and winter cooling over the plateaus, which enhances seasonally reversing (monsoonal) changes in wind directions.Most previous hypotheses addressing the physical impact of orography on climate have focused on mountain ranges and have stressed relatively local responses such as upslope precipitation maxima, cooling of mountain crests due to lapse-rate effects on rising terrain, and lee-side rainshadow effects. In contrast, our results emphasise the importance of large-scale plateau orography. By redirecting the basic directions of wind flow both at surface and upper-tropospheric levels, these rising plateaux cause far-reaching climatic changes that extend across the continents as well as over the oceans.

scholarly journals The Predictability of Blocking Character in the Northern Hemisphere Using an Ensemble Forecast System

2019 ◽  
Vol 13 (1) ◽  
pp. 13-28 ◽  
Author(s):  
DeVondria D. Reynolds ◽  
Anthony R. Lupo ◽  
Andrew D. Jensen ◽  
Patrick S. Market
Keyword(s):  
Northern Hemisphere ◽  
Large Scale ◽  
Weather Conditions ◽  
Atmospheric Blocking ◽  
Weather Extremes ◽  
University Of Missouri ◽  
Weather Patterns ◽  
Temperature And Precipitation ◽  
Environmental Prediction ◽  
The University

Introduction: Some weather extremes are the result of atmospheric blocking, which can be responsible for the stagnation of weather patterns. These large-scale quasi-stationary mid-latitude flow regimes can result in significant temperature and precipitation anomalies over the regions that the blocking event impacts or in the upstream and downstream regions. Methods: The ability to predict periods of anomalous weather conditions due to atmospheric blocking is a major problem for medium-range forecasting. Analyzing the National Centers for Environmental Prediction (NCEP) Ensemble 500-hPa pressure level heights (240 hrs.) ten-day forecasts, and using the University of Missouri blocking archive to identify blocking events, the forecasted onset, duration, and intensity of model blocking events are compared to observed blocks. Results and Discussion: The observed blocking events were identified using the University of Missouri blocking archive. Comparing these differences using four Northern Hemisphere case studies occurring over a one-year period across the Northern Hemisphere has shown the continued need for improvement in the duration and intensity of blocking events. Additionally, a comparison of the block intensity to a diagnostic known as the Integrated Regional Enstrophy (IRE) was performed in order to determine if there is a correlation between IRE and these quantities. Conclusion: Having a better understanding of block persistence and their associated anomalies can help society prepare for the damage they can cause.

scholarly journals Cross-Seasonal Influence of the December–February Southern Hemisphere Annular Mode on March–May Meridional Circulation and Precipitation

2015 ◽  
Vol 28 (17) ◽  
pp. 6859-6881 ◽  
Author(s):  
Fei Zheng ◽  
Jianping Li ◽  
Lei Wang ◽  
Fei Xie ◽  
Xiaofeng Li
Keyword(s):  
Southern Hemisphere ◽  
General Circulation ◽  
Large Scale ◽  
Meridional Circulation ◽  
Circulation Model ◽  
Annular Mode ◽  
Southern Hemisphere Annular Mode ◽  
Middle Latitudes ◽  
Mean Meridional Circulation ◽  
Sst Anomalies

Abstract New evidence suggests that interannual variability in zonal-mean meridional circulation and precipitation can be partially attributed to the Southern Hemisphere annular mode (SAM), the dominant mode of climate variability in the Southern Hemisphere (SH) extratropics. A cross-seasonal correlation exists between the December–February (DJF) SAM and March–May (MAM) zonal-mean meridional circulation and precipitation. This correlation is not confined to the SH: it also extends to the Northern Hemisphere (NH) subtropics. When the preceding DJF SAM is positive, counterclockwise, and clockwise meridional cells, accompanied by less and more precipitation, occur alternately between the SH middle latitudes and NH subtropics in MAM. In particular, less precipitation occurs in the SH middle latitudes, the SH tropics, and the NH subtropics, but more precipitation occurs in the SH subtropics and the NH tropics. A framework is built to explain the cross-seasonal impact of SAM-related SST anomalies. Evidence indicates that the DJF SAM tends to lead to dipolelike SST anomalies in the SH extratropics, which are referred to in this study as the SH ocean dipole (SOD). The DJF SOD can persist until the following MAM when it begins to modulate MAM meridional circulation and large-scale precipitation. Atmospheric general circulation model simulations further verify that MAM meridional circulation between the SH middle latitudes and the northern subtropics responds to the MAM SOD.

On the General Circulation of the Atmosphere in Middle Latitudes

1947 ◽  
Vol 28 (6) ◽  
pp. 255-280 ◽  
Keyword(s):  
Experimental Study ◽  
General Circulation ◽  
Circulation Pattern ◽  
University Of Chicago ◽  
Middle Latitudes ◽  
Starting Point ◽  
The University ◽  
Academic Year

SUMMARY A synoptic, theoretical and experimental study of the general circulation of the atmosphere in middle latitudes and of the major perturbations superimposed on this circulation pattern was conducted by a group of research workers at the University of Chicago during the academic year 1946–1947. The principal results of these investigations are summarized below in a series of specific statements. Not all of these conclusions are new, and some require further verification, but it is hoped that they may be of some use as a starting point for further discussions and investigations of the general circulation of the atmosphere.

scholarly journals Energetics of the summer circulation over South America

2001 ◽  
Vol 19 (1) ◽  
pp. 83-97 ◽  
Author(s):  
M. C. de Lima Moscati ◽  
V. B. Rao
Keyword(s):  
Energy Balance ◽  
Kinetic Energy ◽  
South America ◽  
High Frequency ◽  
General Circulation ◽  
South Atlantic Convergence Zone ◽  
Tropical Meteorology ◽  
Temporal Scales ◽  
Summer Circulation ◽  
Environmental Prediction

Abstract. We have investigated the energetics of the summer circulation over tropical and extratropical South America. The kinetic energy equations of divergent (Kχ ) and rotational (Kψ) motion are utilized. All the terms of these equations are calculated on each day for five summers (November-February 1985–1990), using global wind analysis from the National Meteorological Center (NMC), now National Centers for Environmental Prediction (NCEP). The regional kinetic energy balance showed that the energy cycle over South America during the summer is, A P E to Kχ through the term -χ∇2Φ,and Kχ to Kψ through the term f∇ψ ∙ ∇χ. In the literature, several dominant oscillation modes have been noted over South America, namely the annual cycle, inter-annual, seasonal, intraseasonal, and high frequency scales, as revised by Lima. Results of the power spectrum analysis of kinetic energy terms indicate several statistically significant peaks and these have been confirmed with a fouth-order Butterworth filter. A well-defined mode, with a period around 30 days, was detected in the terms -χ∇2Φ and f∇ψ ∙ ∇χ, likely associated with Madden-Julian Oscillation (MJO). Later, we discuss the local kinetic energy balance using Mak’s local energetics scheme. We attempted to verify how the intraseasonal component interacts with other dominant oscillations over South America, such as seasonal cycle and high frequency disturbances,. It is noted that the major interactions among the three temporal scales occur mainly close to the South Atlantic Convergence Zone (SACZ) region. The temporal scale interactions in the Bolivian High (BH) and Northeast Brazil Low (NL) are distinct, and the dominant temporal scales may change from year to year.Key words. Meteorology and atmospheric dynamics (climatology, general circulation, tropical meteorology)

An Energy-Constrained Parameterization of Eddy Buoyancy Flux

2008 ◽  
Vol 38 (8) ◽  
pp. 1807-1819 ◽  
Author(s):  
Paola Cessi
Keyword(s):  
Energy Balance ◽  
Kinetic Energy ◽  
Large Scale ◽  
Coarse Grid ◽  
Horizontal Gradient ◽  
Mixing Length ◽  
Velocity Scale ◽  
Energy Constrained ◽  
Horizontal Flux ◽  
Selection Of

Abstract A parameterization for eddy buoyancy fluxes for use in coarse-grid models is developed and tested against eddy-resolving simulations. The development is based on the assumption that the eddies are adiabatic (except near the surface) and the observation that the flux of buoyancy is affected by barotropic, depth-independent eddies. Like the previous parameterizations of Gent and McWilliams (GM) and Visbeck et al. (VMHS), the horizontal flux of a tracer is proportional to the local large-scale horizontal gradient of the tracer through a transfer coefficient assumed to be given by the product of a typical eddy velocity scale and a typical mixing length. The proposed parameterization differs from GM and VMHS in the selection of the eddy velocity scale, which is based on the kinetic energy balance of baroclinic eddies. The three parameterizations are compared to eddy-resolving computations in a variety of forcing configurations and for several sets of parameters. The VMHS and the energy balance parameterizations perform best in the tests considered here.

scholarly journals Three-dimensional parameterizations of the synoptic scale kinetic energy and momentum flux in the Earth's atmosphere

2011 ◽  
Vol 18 (6) ◽  
pp. 807-827 ◽  
Author(s):  
D. Coumou ◽  
V. Petoukhov ◽  
A. V. Eliseev
Keyword(s):  
Kinetic Energy ◽  
Momentum Flux ◽  
General Circulation ◽  
Three Dimensional ◽  
Circulation Model ◽  
Storm Tracks ◽  
Synoptic Scale ◽  
Dynamical Equations ◽  
Turbulent Diffusion Coefficient ◽  
Energy And Momentum

Abstract. We present a new set of statistical-dynamical equations (SDEs) which can accurately reproduce the three-dimensional atmospheric fields of synoptic scale kinetic energy and momentum flux. The set of equations is closed by finding proper parameterizations for the vertical macro-turbulent diffusion coefficient and ageostrophic terms. The equations have been implemented in a new SD atmosphere model, named Aeolus. We show that the synoptic scale kinetic energy and momentum fluxes generated by the model are in good agreement with empirical data, which were derived from bandpass-filtered ERA-40 data. In addition to present-day climate, the model is tested for substantially colder (last glacial maximum) and warmer (2×CO2) climates, and shown to be in agreement with general circulation model (GCM) results. With the derived equations, one can efficiently study the position and strength of storm tracks under different climate scenarios with calculation time a fraction of those of GCMs. This work prepares ground for the development of a new generation of fast Earth System Models of Intermediate Complexity which are able to perform multi-millennia simulations in a reasonable time frame while appropriately accounting for the climatic effect of storm tracks.

Examining elementary mathematics teachers' justification practices

2019 ◽  
Author(s):  
◽  
Christopher Austin
Keyword(s):  
Teaching And Learning ◽  
Large Scale ◽  
Elementary Mathematics ◽  
Single Case ◽  
Future Research ◽  
University Of Missouri ◽  
Exploratory Factor Analyses ◽  
Using Data ◽  
Teachers Attitudes ◽  
The University

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] This study examined the relationship between elementary teachers' attitudes, beliefs, knowledge, Elementary Mathematics Specialist (EMS) status, and students' opportunities to engage in justification. Guided by a theoretical framework positioning instructional practices as an outcome of psychological factors (Ernest, 1989; Wilkins, 2008), a mixed-methods sequential explanatory design (Ivankova et al., 2006) was used to structure the study. Quantitative analyses were conducted using data from Studying Teacher Expertise and Assignment in Mathematics (STEAM), a large-scale, federally funded project. Interpretable factors representing teachers' attitudes and beliefs about mathematics teaching and learning were empirically derived via exploratory factor analyses. These factors, along with data on teachers' knowledge and instructional practice, were incorporated into a factor score path analysis (Devlieger and Rosseel, 2017). An embedded single-case study (Yin, 2014) was utilized to characterize classrooms described in task-based interviews of 8 EMS-certified teachers representing High, Medium, and Low justification practices. The quantitative investigation resulted in an empirical model of direct effects of teachers' attitudes, beliefs, and EMS status, as well as indirect effects of teachers' knowledge, attitudes, and specialized training on justification practices. Qualitative analysis yieled themes regarding the object and source of challenges for students' justifications and teachers' actions to foster classroom environments for justification. Findings from quantitative and qualitative analyses were synthesized to explain how teacher-level characteristics align with observable classroom practices. Implications for future research and teacher education are offered.

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