The kinetic and available potential energy budget of a winter extratropical cyclone system

Smith, Phillip J.; Dare, Patricia M.

doi:10.3402/tellusa.v38i1.11697

Cited by 2 publications

(1 citation statement)

References 26 publications

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“…The kinetic energy budget analysis is a useful tool in determining the processes important for the development of weather systems around the globe (Chen et al 1978;Krishnamurti and Ramanathan 1982;Smith and Dare 1986;Fuelberg and Browning 1983;Fuelberg and Buechler 1986;Orlanski and Katsfey 1991;Orlanski and Sheldon 1993;Wiin-Nielsen and Chen 1993). In this study, the energy conversion processes associated with this LLJ case will be presented based on the CTRL run of Chen et al (1997).…”

Section: Introductionmentioning

confidence: 99%

Kinetic Energy Budgets of the Low-Level Jet during TAMEX IOP 5.

Chen

2002

Journal of the Meteorological Society of Japan

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Using results from numerical experiments, budgets of divergent kinetic energy (k D ) and nondivergent kinetic energy (k ND ), are examined for the subsynoptic-scale low-level jet (LLJ) event that occurred during 1-2 June 1987 (TAMEX IOP 5) to diagnose the energy conversion process leading to the LLJ development.Nondivergent kinetic energy (k ND ) dominates the total kinetic energy. The intensification of the LLJ, and the subsynoptic-scale upper-level jet (ULJ) is due to the increase in k ND . Divergent kinetic energy (k D ) is rather small. In the area encompassing the LLJ, the most important energy source of k ND is k D generated from the potential energy (PE) through the cross-contour divergent winds, and then converted into k ND via a conversion process through the transverse secondary circulation across the jet-front system. In the upper troposphere, the cross-contour flow across the ULJ is dominated by the nondivergent winds. The major source for the increase of k ND associated with the intensification of ULJ is the conversion from the potential energy to k ND via cross-contour nondivergent winds. This conversion rate is independent of the strength of the secondary circulation. The upper-level divergence ahead of the upperlevel trough is mainly contributed by the along-stream agesotrophic winds along the ULJ axis, and it provides the upper-level support needed for the LLJ development in the lower troposphere. This mechanism is at variance with the CISK (Condtional Instability of the Second Kind) process in the traditional view.Without the feedback effects from convective heating (NOLH), low-level frontal cyclone fails to fully develop. The secondary circulation is weaker with a much slower energy conversion process from PE to k D , and then to k ND in the lower troposphere. As a result, the simulated LLJ in the NOLH experiment is much weaker. Nevertheless, the intensity of the simulated ULJ without latent heating is about the same as that with latent heating. This is because the conversion from the potential energy to k ND via crosscontour nondivergence winds, is independent of the strength of the transverse secondary circulation across the jet-front system.

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Section: Introductionmentioning

confidence: 99%

Kinetic Energy Budgets of the Low-Level Jet during TAMEX IOP 5.

Chen

2002

Journal of the Meteorological Society of Japan

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Synoptic-Scale Zonal Available Potential Energy Increases in the Northern Hemisphere

Bowley

Atallah

Gyakum

2018

Journal of the Atmospheric Sciences

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Available potential energy (APE), a measure of the energy available for conversion to kinetic energy, has been previously applied to examine changes in baroclinic instability and seasonal changes in the general circulation. Here, pathways in which the troposphere can build the reservoir of zonal available potential energy AZ on synoptic (3–10 day) time scales are explored. A climatology of AZ and its generation GZ and conversion terms are calculated from the National Centers for Environmental Prediction–Department of Energy Reanalysis 2 dataset from 1979 to 2011 for 20°–85°N. A standardized anomaly-based identification technique identifies 183 AZ buildup events, which are grouped into two event types based upon their final AZ standardized anomaly (σ) value: 1) buildup anomalous (BA) events, which exceed 1.5σ, and 2) buildup neutral (BN) events, which do not exceed 1.5σ. Increases in GZ and reductions in baroclinic conversion CA, source and sink terms for AZ, are shown to equally contribute toward increasing AZ in most seasons. A synoptic analysis of composited mass fields for winter BA events (n = 18 events) and winter BN events (n = 28 events) is performed to identify contributions to anomalously low CA and high GZ. A process of high-latitude cooling near 160°E–120°W is found for both composite event types. The cooling processes are characterized by a period of poleward moisture flux and ascent followed by an isolation of the Arctic from the midlatitude flow, resulting in enhanced GZ. Negative anomalies in CA are also diagnosed, which generally occur in regions with northerly dynamic tropopause wind anomalies and neutral to positive thickness anomalies.

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The kinetic and available potential energy budget of a winter extratropical cyclone system

Cited by 2 publications

References 26 publications

Kinetic Energy Budgets of the Low-Level Jet during TAMEX IOP 5.

Kinetic Energy Budgets of the Low-Level Jet during TAMEX IOP 5.

Synoptic-Scale Zonal Available Potential Energy Increases in the Northern Hemisphere

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