Meso-beta scale numerical simulations of terrain drag-induced along-stream circulations Part I: Midtropospheric frontogenesis

Kaplan, Michael L.; Karyampudi, V. Mohan

doi:10.1007/bf01025405

Cited by 12 publications

(2 citation statements)

References 16 publications

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“…At 0400 UTC on 10 November 2017, the density current‐like cold front transitioned to a feature that had characteristics consistent with a bore equatorward of 29°N, when the density current‐like cold front descended from the SAM and impinged on the low‐level stable layer (Figure 13a) not unlike as in the case of a prefrontal bore formation on the lee of the Rocky Mountains during the 13–14 April 1986 lee cyclone, dust storms, and other severe weather events (Cram et al, 1991; Kaplan & Karyampudi, 1992a, 1992b; Karyampudi, Kaplan, et al, 1995; Karyampudi, Koch, et al, 1995). Bore formation occurs when the density/gravity current encroaches on or perturbs the near‐surface stable air (Koch et al, 2008).…”

Section: High‐resolution Simulation Results and Trajectory Analysismentioning

confidence: 99%

Atmospheric Dynamics of a Saharan Dust Outbreak Over Mindelo, Cape Verde Islands, Preceded by Rossby Wave Breaking: Multiscale Observational Analyses and Simulations

et al. 2020

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We investigate the synoptic precursors to the Harmattan wind and dust frontogenesis during the high impact Saharan dust outbreak over the Cape Verde Islands on 13 November 2017. We employ multiscale observations and the Weather Research and Forecasting model Coupled with Chemistry simulations. The analyses indicate that the dust storm was initiated on the lee side of the Saharan Atlas Mountains (SAM) in Algeria on 10 November 2017. This dust storm was associated with a double Rossby wave break linked through nonlinear wave reflection. Two successive Rossby wave breaks contributed to the wave amplification over the Eastern North Atlantic Ocean which transported large magnitude potential vorticity air into the North African continent. The resulting coupled pressure surge was associated with cold air advected equatorward over the SAM which organized the strong near-surface wind that ablated the dust. The simulation results indicate that the dust front was initially related to a density current-like cold front which formed due to the downslope transport of cold airflow over the SAM and then triggered undular bores on the lee side. Each bore perturbed the dust loading and then the subsequent diurnal heating generated differential planetary boundary layer turbulence kinetic energy strengthening the dust frontogenesis. Dust became confined behind the cold surge and interacted with the daytime Saharan planetary boundary layer leading to increased dust loading, while the dust front propagated equatorward. Two distinct dust plumes arrived successively at low levels at Mindelo, Cape Verde Islands: (1) from the coasts of Mauritania and Senegal and (2) from the SAM southern flank.

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Section: High‐resolution Simulation Results and Trajectory Analysismentioning

confidence: 99%

Atmospheric Dynamics of a Saharan Dust Outbreak Over Mindelo, Cape Verde Islands, Preceded by Rossby Wave Breaking: Multiscale Observational Analyses and Simulations

et al. 2020

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“…Theoretical work of Zhang et al . [] and simulations documented in Kaplan and Karyampudi [, ] and Kaplan et al . [, ] have given support to the action of these smaller‐scale processes.…”

Section: Introductionmentioning

confidence: 99%

Subtropical‐polar jet interactions in Southern Plains dust storms

et al. 2013

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The origin of two separate Southern High Plains dust storms, which occurred over a 2 day period in February 2007, is traced to an interaction between the subtropical jet (STJ) and the polar jet (PJ). A large‐scale thermal wind imbalance resulting from the confluence of these two jets led to a series of mesoscale circulations that ultimately produced the dust storms. Understanding the connectivity between the dust storms with differing geometries is central to the present investigation. The study rests on the interpretation of analyses from upper air and surface observations complemented by imagery from satellites, the 32 km gridded data set from the North American Regional Reanalysis, and a fine‐resolution (6 km grid) simulation from the Weather Research and Forecasting model. Principal assertions from the present study are (1) scale interaction is fundamental to the creation of an environment conducive to dust storm development, (2) low to middle tropospheric mass adjustment is the primary response to a large‐scale imbalance, (3) the mesoscale mass adjustment is associated with circulations about a highly accelerative jet streak resulting from the merger of the PJ and STJ, (4) the structure of the jet streak resulting from this merger governs the evolution of the geometry of the dust plumes, with plumes that initially had a straight‐line orientation developing a semicircular geometry, and (5) it is concluded that improvements in dust storm prediction will depend on an augmentation to the upper air network in concert with a flow‐dependent data assimilation strategy.

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Meso-beta scale numerical simulations of terrain drag-induced along-stream circulations. Part II: Concentration of potential vorticity within dryline bulges

Kaplan

Karyampudi

1992

Meteorl. Atmos. Phys.

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Meso-beta scale numerical simulations of terrain drag-induced along-stream circulations Part I: Midtropospheric frontogenesis

Cited by 12 publications

References 16 publications

Atmospheric Dynamics of a Saharan Dust Outbreak Over Mindelo, Cape Verde Islands, Preceded by Rossby Wave Breaking: Multiscale Observational Analyses and Simulations

Atmospheric Dynamics of a Saharan Dust Outbreak Over Mindelo, Cape Verde Islands, Preceded by Rossby Wave Breaking: Multiscale Observational Analyses and Simulations

Subtropical‐polar jet interactions in Southern Plains dust storms

Meso-beta scale numerical simulations of terrain drag-induced along-stream circulations. Part II: Concentration of potential vorticity within dryline bulges

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