scholarly journals Cloud‐Resolving Model Intercomparison of an MC3E Squall Line Case: Part II. Stratiform Precipitation Properties

2019 ◽  
Vol 124 (2) ◽  
pp. 1090-1117 ◽  
Author(s):  
Bin Han ◽  
Jiwen Fan ◽  
Adam Varble ◽  
Hugh Morrison ◽  
Christopher R. Williams ◽  
...  
Keyword(s):  
Squall Line ◽  
Model Intercomparison ◽  
Stratiform Precipitation ◽  
Cloud Resolving Model ◽  
Case Part

scholarly journals Cloud‐resolving model intercomparison of an MC3E squall line case: Part I—Convective updrafts

2017 ◽  
Vol 122 (17) ◽  
pp. 9351-9378 ◽  
Author(s):  
Jiwen Fan ◽  
Bin Han ◽  
Adam Varble ◽  
Hugh Morrison ◽  
Kirk North ◽  
...  
Keyword(s):  
Squall Line ◽  
Model Intercomparison ◽  
Cloud Resolving Model ◽  
Case Part

scholarly journals Sensitivity of a Cloud-Resolving Model to Bulk and Explicit Bin Microphysical Schemes. Part I: Comparisons

2009 ◽  
Vol 66 (1) ◽  
pp. 3-21 ◽  
Author(s):  
Xiaowen Li ◽  
Wei-Kuo Tao ◽  
Alexander P. Khain ◽  
Joanne Simpson ◽  
Daniel E. Johnson
Keyword(s):  
Cloud Microphysics ◽  
Squall Line ◽  
Mature Stage ◽  
High Temporal Resolution ◽  
Stratiform Region ◽  
Storm Flow ◽  
Cloud Resolving Model ◽  
Storm Dynamics ◽  
Convective Cells ◽  
Heating Profiles

Abstract A two-dimensional cloud-resolving model is used to study the sensitivities of two microphysical schemes, a bulk scheme and an explicit spectral bin scheme, in simulating a midlatitude summertime squall line [Preliminary Regional Experiment for Storm-Scale Operational and Research Meteorology (PRE-STORM), 10–11 June 1985]. In this first part of a two-part paper, the developing and mature stages of simulated storms are compared in detail. Some variables observed during the field campaign are also presented for validation. It is found that both schemes agree well with each other, and also with published observations and retrievals, in terms of storm structures and evolution, average storm flow patterns, pressure and temperature perturbations, and total heating profiles. The bin scheme is able to produce a much more extensive and homogeneous stratiform region, which compares better with observations. However, instantaneous fields and high temporal resolution analyses show distinct characteristics in the two simulations. During the mature stage, the bulk simulation produces a multicell storm with convective cells embedded in its stratiform region. Its leading convection also shows a distinct life cycle (strong evolution). In contrast, the bin simulation produces a unicell storm with little temporal variation in its leading cell regeneration (weak evolution). More detailed, high-resolution observations are needed to validate and, perhaps, generalize these model results. Interactions between the cloud microphysics and storm dynamics that produce the sensitivities described here are discussed in detail in Part II of this paper.

scholarly journals Incorporating Diagnosed Intercept Parameters and the Graupel Category within the ARPS Cloud Analysis System for the Initialization of Double-Moment Microphysics: Testing with a Squall Line over South China

2016 ◽  
Vol 144 (1) ◽  
pp. 371-392 ◽  
Author(s):  
Yujie Pan ◽  
Ming Xue ◽  
Guoqing Ge
Keyword(s):  
Precipitation Forecast ◽  
Squall Line ◽  
Precipitation Region ◽  
Stratiform Region ◽  
Regional Prediction ◽  
Analysis Scheme ◽  
Stratiform Precipitation ◽  
Double Moment ◽  
Analysis System ◽  
Cloud Analysis

Abstract In this study, a new set of reflectivity equations are introduced into the Advanced Regional Prediction System (ARPS) cloud analysis system. This set of equations incorporates double-moment microphysics information in the analysis by adopting a set of diagnostic relationships between the intercept parameters and the corresponding mass mixing ratios. A reflectivity- and temperature-based graupel classification scheme is also implemented according to a hydrometeor identification (HID) diagram. A squall line that occurred on 23 April 2007 over southern China containing a pronounced trailing stratiform precipitation region is used as a test case to evaluate the impacts of the enhanced cloud analysis scheme. The results show that using the enhanced cloud analysis scheme is able to better capture the characteristics of the squall line in the forecast. The predicted squall line exhibits a wider stratiform region and a more clearly defined transition zone between the leading convection and the trailing stratiform precipitation region agreeing better with observations in general, when using the enhanced cloud analysis together with the two-moment microphysics scheme. The quantitative precipitation forecast skill score is also improved.

The Interaction of Simulated Squall Lines with Idealized Mountain Ridges

2006 ◽  
Vol 134 (7) ◽  
pp. 1919-1941 ◽  
Author(s):  
Jeffrey Frame ◽  
Paul Markowski
Keyword(s):  
Squall Line ◽  
Cold Pool ◽  
Cold Air ◽  
Advanced Regional Prediction System ◽  
Topographic Features ◽  
Squall Lines ◽  
Regional Prediction ◽  
Cloud Resolving Model ◽  
Orographic Enhancement ◽  
Flow Transitions

Abstract Numerical simulations of squall lines traversing sinusoidal mountain ridges are performed using the Advanced Regional Prediction System cloud-resolving model. Precipitation and updraft strength are enhanced through orographic ascent as a squall line approaches a ridge. The simulated squall line then weakens as it descends the ridge because some of the cold pool is blocked by the terrain, resulting in less lift along the gust front and weaker convective cells. The flow within the cold pool accelerates slightly and the depth of the cold air decreases owing to upstream blocking, transitioning the flow in the cold pool head from subcritical to supercritical, then back to subcritical at the bottom of the ridge. A hydraulic jump forms when the flow transitions the second time, enabling the development of a new convective line downwind of the mountain. These new updrafts grow and eventually replace the older updrafts that weakened during descent. This process results in the discrete propagation of a squall line just downstream of a ridge, resulting in the formation of rain shadows downstream from topographic features. Discrete propagation only occurs if a ridge is of sufficient height, however. This replacement process repeats itself if a squall line encounters multiple ridges. The risk of damaging winds from a squall line is greater on the lee side of ridges and on the top of high ridges. These terrain-forced intensity fluctuations increase with mountain height, because the higher terrain permits even less cold air to flow over it. A wider ridge results in a more gradual orographic enhancement and downslope-induced weakening.

scholarly journals Microphysical Characteristics of Squall-Line Stratiform Precipitation and Transition Zones Simulated Using an Ice Particle Property-Evolving Model

2018 ◽  
Vol 146 (3) ◽  
pp. 723-743 ◽  
Author(s):  
Anders A. Jensen ◽  
Jerry Y. Harrington ◽  
Hugh Morrison
Keyword(s):  
Transition Zone ◽  
Maximum Diameter ◽  
Squall Line ◽  
Microphysics Scheme ◽  
Particle Properties ◽  
Precipitation Region ◽  
Convective Region ◽  
Stratiform Precipitation ◽  
Fall Speed ◽  
Microphysical Processes

Abstract A quasi-idealized 3D squall-line case is simulated using a novel bulk microphysics scheme called the Ice-Spheroids Habit Model with Aspect-ratio Evolution (ISHMAEL). In ISHMAEL, the evolution of ice particle properties (e.g., mass, shape, maximum diameter, density, and fall speed) are predicted during vapor growth, sublimation, riming, and melting, allowing ice properties to evolve from various microphysical processes without needing separate unrimed and rimed ice categories. ISHMAEL produces both a transition zone and an enhanced stratiform precipitation region, and ice particle properties are analyzed to determine the characteristics of ice that lead to the development of these squall-line features. Rimed particles advected rearward from the convective region produce the enhanced stratiform precipitation region. The transition zone results from hydrometeor sorting; the evolution of ice particle properties in the convective region leads to fall speeds that favor ice advecting rearward of the transition zone before reaching the melting level, causing a local minimum in precipitation rate and reflectivity there. Sensitivity studies show that the fall speed of ice particles largely determines the location of the enhanced stratiform precipitation region and whether or not a transition zone forms. The representation of microphysical processes, such as rime splintering and aggregation, and ice size distribution shape can impact the mean ice particle fall speeds enough to significantly impact the location of the enhanced stratiform precipitation region and the existence of the transition zone.

scholarly journals Evaluation of cloud-resolving model intercomparison simulations using TWP-ICE observations: Precipitation and cloud structure

2011 ◽  
Vol 116 (D12) ◽  
Author(s):  
Adam Varble ◽  
Ann M. Fridlind ◽  
Edward J. Zipser ◽  
Andrew S. Ackerman ◽  
Jean-Pierre Chaboureau ◽  
...  
Keyword(s):  
Model Intercomparison ◽  
Cloud Structure ◽  
Cloud Resolving Model

A gcss model intercomparison for a tropical squall line observed during toga-coare. I: Cloud-resolving models

2000 ◽  
Vol 126 (564) ◽  
pp. 823-863 ◽  
Author(s):  
J.-L. Redelsperger ◽  
P. R. A. Brown ◽  
F. Guichard ◽  
C. How ◽  
M. Kawasima ◽  
...  
Keyword(s):  
Squall Line ◽  
Model Intercomparison ◽  
Toga Coare

Leading and Trailing Anvil Clouds of West African Squall Lines

2011 ◽  
Vol 68 (5) ◽  
pp. 1114-1123 ◽  
Author(s):  
Jasmine Cetrone ◽  
Robert A. Houze
Keyword(s):  
Deep Layer ◽  
Radar Data ◽  
West African ◽  
Squall Line ◽  
Direct Connection ◽  
Precipitation Region ◽  
Cloud Radar ◽  
Squall Lines ◽  
Stratiform Precipitation ◽  
Thick Medium

Abstract The anvil clouds of tropical squall-line systems over West Africa have been examined using cloud radar data and divided into those that appear ahead of the leading convective line and those on the trailing side of the system. The leading anvils are generally higher in altitude than the trailing anvil, likely because the hydrometeors in the leading anvil are directly connected to the convective updraft, while the trailing anvil generally extends out of the lower-topped stratiform precipitation region. When the anvils are subdivided into thick, medium, and thin portions, the thick leading anvil is seen to have systematically higher reflectivity than the thick trailing anvil, suggesting that the leading anvil contains numerous larger ice particles owing to its direct connection to the convective region. As the leading anvil ages and thins, it retains its top. The leading anvil appears to add hydrometeors at the highest altitudes, while the trailing anvil is able to moisten a deep layer of the atmosphere.

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