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William Blumen

, depending on the initial conditions, either the relative vorticity becomes infinite in a finite time or that the solution is represented as the sum of a steady geostrophic part and a time-dependent inertial oscillation for all time. In this latter case, both frontogenesis and frontolysis occur during one inertial period. The time-dependent motion treated by Tandon and Garrett (1994) corresponds to ∂[ θ / θ (0)]/∂ x 0 = const, which results in w * = w = 0 and u * = u a . As time progresses, the

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Brian D. Gross

examined by means ofprimitive equation model simulations. The front evolves as part of a developing nonlinear baroclinic wave: andpropagates southward toward the ridge. Many of the features in this interaction, such as the anticyclonic distortionof the front, divergence and frontolysis on the windward slope, convergence and frontogenesis in the lee, andthe frontogenetical forcing associated with tilting, have previously been captured by simulations of a passivescalar traversing a ridge. It is shown

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Sean R. Haney
,
Alexandra J. Simpson
,
Jacqueline M. McSweeney
,
Amy F. Waterhouse
,
Merrick C. Haller
,
James A. Lerczak
,
John A. Barth
,
Luc Lenain
,
André Palóczy
,
Kate Adams
, and
Jennifer A. MacKinnon

; Becherer et al. 2020 ). At the same time, a parallel life cycle exists that links mesoscale (often wind-driven) large-scale currents, submesoscale instabilities at their edges, and sharp and often turbulent fronts. Near the ocean surface, submesoscale fronts are often created through confluent flow ( Stone 1966 ; Hoskins 1974 ; Mahadevan and Tandon 2006 ; McWilliams 2016 ). Though secondary circulations act to steepen the front through frontogenesis, in this process rotation still plays an order one

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Ryusuke Masunaga
,
Hisashi Nakamura
,
Takafumi Miyasaka
,
Kazuaki Nishii
, and
Bo Qiu

( Fig. 17b ), while the contribution is negative (i.e., frontolysis) in the unstable regime ( Fig. 17a ). Monthly mean meridional wind confluence contributes positively to the maintenance of the baroclinic zone along the KE jet in each of its stable and unstable regimes ( Figs. 17d,e ), and the particular contribution is somewhat stronger in the stable regime ( Figs. 17e,f ). Fig . 17. (a)–(i) Wintertime composite maps of the dominant terms in frontogenetical function [K (100 km) −1 day −1

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Douglas R. Allen
,
Karl W. Hoppel
,
Gerald E. Nedoluha
,
Stephen D. Eckermann
, and
Cory A. Barton

2014 (red), 25 Oct 2014–10 Apr 2015 (green). (a) Source momentum flux ( τ 0 ), (b) source spectral width ( c 0 ), (c) source weighting ( W ), and (d) product of the source momentum flux and width ( τ 0 × c 0 ). c. Comparison with frontogenesis and convection Finally, we compare the seasonality of the fitting parameters with plausible proxies for GW forcing by convection and fronts/jets from NAVGEM forecast fields. For convection ( C ), we use the NAVGEM cumulus precipitation in 6-h

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Frederick Sanders

close to the average speed of the westerly wind component in the area. Thus the band of strong temperature gradient did not propagate but was transported by the wind in its environment, and its separation from the wind shift and pressure trough was due to the propagation of the former. This explanation was proposed by Sanders (1999) . The weak lee trough discussed above was distinct from this separation process and was not responsible for it. 5. Frontogenesis and frontolysis To

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William Blumen
and
Brian D. Gross

ridge height; b) the con tributions to frontogenesis-frontolysis from the steady ageostrophic divergence field and from the tilting effect of upslope (downslope) translation; c) an estimate of the forced ageostrophic circulation that would be re quired to restore the thermal wind balance, disrupted by the steady mountain circulation. This latter feature is provided as a relatively weak secondary effect, since the steady mountain circulation is assumed to control the displacement of the disturbance

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Peiran Yang
,
Zhao Jing
,
Bingrong Sun
,
Lixin Wu
,
Bo Qiu
,
Ping Chang
, and
Sanjiv Ramachandran

heat transport in the upper ocean have been proposed. In the adiabatic and inviscid framework, the frontogenesis/frontolysis ( Hoskins and Bretherton 1972 ; Hoskins 1982 ) and the mixed layer instability ( Boccaletti et al. 2007 ; Fox-Kemper et al. 2008 ) are two major processes. During frontogenesis, intensification of a front by background confluent flows induces ageostrophic secondary circulation (ASC) with upwelling and downwelling on lighter (commonly warmer) and denser (commonly colder

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William Blumen
and
R. T. Williams

inertial oscillation undergoing alternately frontogenesis and frontolysis. Blumen (2000) finds a critical Rossby number of a c = 1 with the sinsoidal initial temperature field. This is very similar to the value 1.435, which we find for the error function initial temperature field considering the flexibility in defining the Rossby number. Blumen derives the interior solution for u , υ , w , and θ , but omits the barotropic pressure field. In particular the isotherms are always straight lines in

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David M. Schultz
,
Hans Volkert
,
Bogdan Antonescu
, and
Huw C. Davies

of frontogenesis and frontolysis (i.e., frontal strengthening and weakening, respectively) due to deformation, in a way that would later be quantified through the kinematic formulation by Petterssen (1936) ; extrapolated the frontogenesis and frontolysis fields globally to help explain the general circulation of the Earth’s atmosphere; discussed the influence of aerosols on atmospheric visibility, including salt and Saharan dust into Europe; and presented an early version of the Wegener

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