Mesoscale Lake-effect Snowstorms in the Vicinity of Lake Michigan: Linear Theory and Numerical Simulations

Hsu, Hsiao-Ming

doi:10.1175/1520-0469(1987)044<1019:mlesit>2.0.co;2

Cited by 22 publications

(19 citation statements)

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“…If this was the case then there must have been a transition from the heat island circulation, characterised in our observations by warming and drying of the mixed layer, to the roll circulation. Although no observations were available in the present study to investigate the transition, the modelling results of Hsu (1987) and Kang and Kimura (1997) suggest that the interaction of the mean wind with convergence in the updraft portion of the heat island circulation initiate the roll circulation.…”

Section: Discussionmentioning

confidence: 75%

Modification of the Atmospheric Boundary Layer by a Small Island: Observations from Nauru

Matthews

Hacker

Cole

et al. 2007

Monthly Weather Review

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Nauru, a small island in the tropical Pacific, generates plumes of clouds that may grow to several hundred km length. This study uses observations to examine the mesoscale disturbance of the marine atmospheric boundary layer by the island that produces these cloud streets. Observations of the surface layer were made from two ships in the vicinity of Nauru and from instruments on the island. The structure of the atmospheric boundary layer over the island was investigated using aircraft flights.Cloud production over Nauru was examined using remote sensing instruments.During the day the island surface layer is warmer than the marine surface layer and wind speed is lower than over the ocean. Surface heating forces the growth of a thermal internal boundary layer, above which a street of cumulus clouds forms. The production of clouds results in reduced downwelling shortwave irradiance at the island surface. A plume of warm-dry air develops over the island which extends 15 -20 km downwind.

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Section: Discussionmentioning

confidence: 75%

Modification of the Atmospheric Boundary Layer by a Small Island: Observations from Nauru

Matthews

Hacker

Cole

et al. 2007

Monthly Weather Review

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“…Even for wind-parallel bands occurring during ''lakee¤ect snow storms'' over Lake Michigan, numerous observational studies (e.g., Kelly 1982;Kristovich 1993;Kristovich et al 2003) and model simulations (e.g., Hsu 1987;Hjelmfeld 1990;Ballentine et al 1998) have not discussed band circulations in association with vertical shear. Recent numerical model studies (e.g., Cooper et al 2000;Laird et al 2003;Laird et al 2004) and observations (Miles and Verlinde 2005) are relevant to the mode of organization regarding linear or cellular types and to cloud morphology.…”

Section: Introductionmentioning

confidence: 99%

Kinematic and Thermodynamical Structures of Longitudinal-Mode Snow Bands over the Sea of Japan during Cold-Air Outbreaks Part I: Snow Bands in Large Vertical Shear Environment in the Band-Transverse Direction

Yamada¹,

Murakami²,

Mizuno³

et al. 2010

Journal of the Meteorological Society of Japan

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The kinematic and thermodynamical structures of two longitudinal-mode (termed ''L-mode'') snow bands over the Sea of Japan occurring on February 8, 1991 and January 21, 1993 are analyzed mainly based on dualDoppler radar data. The L-mode snow bands with multicellular structure in 1991 and 1993 formed, respectively, at the early onset of and toward the end of cold-air outbreaks, where the magnitude of the band-transverse vertical shear was roughly 2 Â 10 À3 s À1 approximately in the lower-half of the mixed layer. This magnitude was larger than that associated with L-mode snow bands characterized by axi-symmetric circulation, which will be described in Part II. Thermodynamical structures and the spatial distributions of water substances in the two snow bands were inferred from variational-based retrieval.A pronounced feature of the airflow structures in both snow bands was upshear-tilting updrafts in the bandtransverse vertical cross-section. At least two factors could account for their formation: the existence of a certain depth of the vertical layer of the environmental band-transverse system-relative wind components directing to the upshear, and the lower terminal fall velocities of snow and graupels. The retrieval results showed that both snow bands had a subsaturated cold pool beneath the band around the surface, whose collision with the unstable ambient air could have been responsible for overall upward motion in the bands. With regard to the energetics of the band circulation, energy production by buoyancy and the band-transverse shear was dominant.The repeated formation of new cells was observed in the two snow bands in the downshear side, which may have been triggered by the low-level collision of the outflow from active cells or a cold pool with the unstable ambient air. As the new cell developed enough, the older cell significantly decayed. Consequently, the successive formation of cells did not change the overall echo pattern of the L-mode snow bands without producing elongated echoes branching o¤ into the downshear direction at large angles to the orientation of the L-mode snow bands.

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“…He determined that when the wind direction was between WSW and NNW, multiple bands can develop 2-20 km apart and align themselves parallel to the wind. Hsu (1987) used both a linear analytic model and a nonlinear numerical model to study the effects of wind direction on lake-effect storms near Lake Michigan. His results indicated that three convergence centers develop near the eastern shore when a westerly wind prevails, two cells or snow bands develop when a northwesterly wind prevails, and a single midlake band develops when a northerly wind prevails.…”

Section: Introductionmentioning

confidence: 99%

A numerical investigation of wind speed effects on lake-effect storms

Sousounis

1993

Boundary-Layer Meteorol

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Abstract. Observations of lake-effect storms that occur over the Great Lakes region during late autumn and winter indicate a high sensitivity to ambient wind speed and direction. In this paper, a twodimensional version of the Penn State University/National Center for Atmospheric Research (PSU/ NCAR) model is used to investigate the wind speed effects on lake-effect snowstorms that occur over the Great Lakes region.Theoretical initial conditions for stability, relative humidity, wind velocity, and lake/land temperature distribution are specified. Nine different experiments are performed using wind speeds of U = 0, 2, 4,..., 16 m s -1. The perturbation wind, temperature, and moisture fields for each experiment after 36 h of simulation are compared.It is determined that moderate (4-6m s -1) wind speeds result in maximum precipitation (snowfall) on the lee shore of the model lake. Weak wind speeds (0 ~< U < 4 m s 1) yield significantly higher snowfall amounts over the lake along with a spatially concentrated and intense response. Strong wind speeds (6 < U ~< 16 m s -1) yield very little, if any, significant snowfall, although significant increases in cloudiness, temperature, and perturbation wind speed occur hundreds of kilometers downwind from the lake.

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Mesoscale Lake-effect Snowstorms in the Vicinity of Lake Michigan: Linear Theory and Numerical Simulations

Cited by 22 publications

References 0 publications

Modification of the Atmospheric Boundary Layer by a Small Island: Observations from Nauru

Modification of the Atmospheric Boundary Layer by a Small Island: Observations from Nauru

Kinematic and Thermodynamical Structures of Longitudinal-Mode Snow Bands over the Sea of Japan during Cold-Air Outbreaks Part I: Snow Bands in Large Vertical Shear Environment in the Band-Transverse Direction

A numerical investigation of wind speed effects on lake-effect storms

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