The effect of parameterized ice microphysics on the simulation of vortex
                        circulation with a mesoscale hydrostatic model

Zhang, Dalin

doi:10.3402/tellusa.v41i2.11826

Cited by 28 publications

(6 citation statements)

References 41 publications

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“…A sensitivity experiment, in which ice phase was turned off from the control simulation, indicates that the simulated hurricane is 8-10 hPa stronger than the control one at the end of the 72-h integration (not shown), suggesting the importance of the sublimative and melting cooling in suppressing the storm. This is similar to that discussed by Zhang (1989) in association with the development of a midlevel mesovortex. The evaporative cooling rates, peaked in the MBL near the outer edge of the eyewall, range between 1-3ЊC h Ϫ1 .…”

Section: Potential Temperature Budgetssupporting

confidence: 90%

A Multiscale Numerical Study of Hurricane Andrew (1992). Part V: Inner-Core Thermodynamics

2002

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Although considerable progress has been made in understanding the development of hurricanes, our knowledge of their three-dimensional structures of latent heat release and inner-core thermodynamics remains limited. In this study, the inner-core budgets of potential temperature (), moisture (q), and equivalent potential temperature (e) are examined using a high-resolution (⌬x ϭ 6 km), nonhydrostatic, fully explicit simulation of Hurricane Andrew (1992) during its mature or intensifying stage.It is found that the heat energy is dominated by latent heat release in the eyewall, sublimative-evaporative cooling near the eye-eyewall interface, and the upward surface fluxes of sensible and latent heat from the underlying warm ocean. The latent heating () rates in the eyewall range from less than 10ЊC h Ϫ1 to greater than 100ЊC h Ϫ1 , depending upon whether latent heat is released in radial inflow or outflow regions. The latent heating rates decrease inward in the inflow regions and become negative near the eye-eyewall interface. It is shown that the radial advective cooling in the inflow regions accounts for the initiation and maintenance of the penetrative downdrafts at the eye-eyewall interface that are enhanced by the sublimative-evaporative cooling. It is also shown that the vertical advection overcompensates the horizontal advection for the generation of the warm-cored eye, and the sum of latent heating and radial advective warming for the development of intense cooling in the eyewall. The moisture budgets show the dominant upward transport of moisture in the eyewall updrafts (and spiral rainbands), partly by the low-level outflow jet from the bottom eye regions, so that the eyewall remains nearly saturated.The e budgets reveal that e could be considered as an approximately conserved variable in the eyewall above the boundary layer even in the presence of deposition-sublimation and freezing-melting. The development of higher-e surfaces at the eye-eyewall interface is discussed in the context of deep convection, the e gradient and the mass recycling across the eyewall. It is concluded that the simulated hurricane is thermodynamically maintained by the upward surface flux of higher-e air from the underlying warm ocean, the descent of highere air in the upper troposphere along the eye-eyewall interface, and the recycling of some warmed-eye air at the eye-eyewall interface.

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Section: Potential Temperature Budgetssupporting

confidence: 90%

A Multiscale Numerical Study of Hurricane Andrew (1992). Part V: Inner-Core Thermodynamics

2002

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“…The model water cycles used for this study include (1) a simple ice microphysics scheme for grid‐scale precipitation with the prognostic equations for cloud water, cloud ice, rain water and snow [ Zhang , 1989; Dudhia , 1989]; (2) the newest version of the Kain‐Fritsch (KF2) convective parameterization scheme for subgrid scale convection including the effects of shallow convection [ Kain , 2004]; (3) the Eta model's Mellor‐Yamada planetary boundary layer (PBL) scheme [ Janjić , 1994]; (4) a long‐ and short‐wave radiation scheme which interacts with the atmosphere, cloud, and land surface [ Dudhia , 1989]; and (5) the NCEP‐Oregon State University‐Air Force‐Hydrologic Research Lab (NOAH) land surface model [ Chen and Dudhia , 2001a, 2001b].…”

Section: Model Descriptionmentioning

confidence: 99%

Daily to submonthly weather and climate characteristics of the summer 1998 extreme rainfall over the Yangtze River Basin

Liu¹,

Zhang²,

Wang³

2008

J. Geophys. Res.

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[1] In this study, the daily to submonthly weather and regional climate characteristics associated with the extreme rainfall events over the middle to lower reaches of the Yangtze River Basin (YRB-ML) during the summer of 1998 are examined using the National Centers for Environmental Prediction/Department of Energy Reanalysis-2 data and a 54-day high-resolution (i.e., Dx = 4 km) simulation with a regional climate model (RCM). As verified against various observations, the RCM reproduces reasonably well the accumulated daily to biweekly rainfall events, their generation and subsequent evolution along the Meiyu front, and especially the rainfall events over the YRB-ML during the later stage of the 1998 floods. It is found that the early stage of the 1998 floods resembles in many aspects that occurred in normal years, except for a moister-than-climate state and stronger-than-normal low-level jets (LLJs) in Southeast China, whereas the later stage exhibits two abnormal height anomalies to the northeast and southwest of the YRB-ML, facilitating convergence of northeasterly and southwesterly flows along the Meiyu front. It is also found that the Meiyu front weakens in depth and intensity as it migrates northward across and then retreats to the YRB-ML, playing less important roles in rain production. Results show different daily to biweekly rainfall characteristics at the different stages, e.g., from eastward propagation to local generation of mesoscale convective systems and periodical rain production along the Meiyu front, most of which reach their maximum intensities over the YRB-ML during the morning to early afternoon hours. Results indicate that the northeasterly moisture supply enhances the production of steady heavy rain at the later stage of the 1998 floods. It is concluded that the West Pacific subtropical high and the Meiyu front control the general areas of rain production, the lowlevel moisture supply through LLJs and mesoscale disturbances determines whether or not sustaining flooding rains would occur, and what rainfall characteristics are at the daily to biweekly timescales.

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“…Using a two-dimensional (2D) model, Brown (1979) demonstrated that cloud evaporative cooling could induce mesoscale downdrafts beneath the anvil clouds. With a mesoscale hydrostatic model, Zhang (1989) studied the sensitivity of the simulated MCSs associated with the July 1977 Johnstown flood to a twoclass (cloud ice and snow) ice microphysics scheme. He found that freezing and depositional growth assist the development of a midlevel warm-core vortex, while the subcloud-layer melting weakens the concentration of cyclonic vorticity and its associated low pressure system in the lower troposphere.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Hurricane Bonnie (1998). Part II: Sensitivity to Varying Cloud Microphysical Processes

Zhu

Zhang

2006

Journal of the Atmospheric Sciences

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127

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In this study, the effects of various cloud microphysics processes on the hurricane intensity, precipitation, and inner-core structures are examined with a series of 5-day explicit simulations of Hurricane Bonnie (1998), using the results presented in Part I as a control run. It is found that varying cloud microphysics processes produces little sensitivity in hurricane track, except for very weak and shallow storms, but it produces pronounced departures in hurricane intensity and inner-core structures. Specifically, removing ice microphysics produces the weakest (15-hPa underdeepening) and shallowest storm with widespread cloud water but little rainwater in the upper troposphere. Removing graupel from the control run generates a weaker hurricane with a wider area of precipitation and more cloud coverage in the eyewall due to the enhanced horizontal advection of hydrometeors relative to the vertical fallouts (or increased water loading). Turning off the evaporation of cloud water and rainwater leads to the most rapid deepening storm (i.e., 90 hPa in 48 h) with the smallest radius but a wider eyewall and the strongest eyewall updrafts. The second strongest storm, but with the most amount of rainfall, is obtained when the melting effect is ignored. It is found that the cooling due to melting is more pronounced in the eyewall where more frozen hydrometeors, especially graupel, are available, whereas the evaporative cooling occurs more markedly when the storm environment is more unsaturated. It is shown that stronger storms tend to show more compact eyewalls with heavier precipitation and more symmetric structures in the warm-cored eye and in the eyewall. It is also shown that although the eyewall replacement scenarios occur as the simulated storms move into weak-sheared environments, the associated inner-core structural changes, timing, and location differ markedly, depending on the hurricane intensity. That is, the eyewall convection in weak storms tends to diminish shortly after being encircled by an outer rainband, whereas both the cloud band and the inner eyewall in strong storms tend to merge to form a new eyewall with a larger radius. The results indicate the importance of the Bergeron processes, including the growth and rapid fallout of graupel in the eyewall, and the latent heat of fusion in determining the intensity and inner-core structures of hurricanes, and the vulnerability of weak storms to the influence of large-scale sheared flows in terms of track, inner-core structures, and intensity changes.

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The effect of parameterized ice microphysics on the simulation of vortex circulation with a mesoscale hydrostatic model

Cited by 28 publications

References 41 publications

A Multiscale Numerical Study of Hurricane Andrew (1992). Part V: Inner-Core Thermodynamics

A Multiscale Numerical Study of Hurricane Andrew (1992). Part V: Inner-Core Thermodynamics

Daily to submonthly weather and climate characteristics of the summer 1998 extreme rainfall over the Yangtze River Basin

Numerical Simulation of Hurricane Bonnie (1998). Part II: Sensitivity to Varying Cloud Microphysical Processes

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