scholarly journals Simulation study of a Squall line hailstorm using High-Resolution GRAPES-Meso with a modified Double-Moment Microphysics scheme

2021 ◽  
Author(s):  
Zhe Li ◽  
Qijun Liu ◽  
Xiaomin Chen ◽  
Zhanshan Ma ◽  
Jiong Chen ◽  
...  
Keyword(s):  
High Resolution ◽  
Cross Section ◽  
Radar Reflectivity ◽  
Squall Line ◽  
Prediction System ◽  
Precipitation Radar ◽  
Microphysics Scheme ◽  
Reasonable Result ◽  
Double Moment ◽  
Observation Results

Abstract. This study uses the high-resolution GRAPES_Meso (the mesoscale version of the Global/Regional Assimilation and Prediction System) to simulate a severe squall line hailstorm in Shandong province. The accumulated precipitation, radar reflectivity, and cloud hydrometeor properties simulated using a modified double-moment microphysics scheme are compared with observation. Results show that simulations captured the basic character of this squall line hailstorm. The simulated accumulation precipitation and radar reflectivity are comparable with the observation. The cross-section of the dynamic, microphysical, and radar reflectivity structures of the simulated hailstorm was analyzed. The simulated hailstorm has shown a reasonable result in both macrostructure and micro hail production rates. The development of the simulated hailstorm is consistent with the conceptual model of hailstorm evolution. Results imply the ability of high-resolution GRAPES_Meso on forecasting hailstorm.

A New Double-Moment Microphysics Parameterization for Application in Cloud and Climate Models. Part I: Description

2005 ◽  
Vol 62 (6) ◽  
pp. 1665-1677 ◽  
Author(s):  
H. Morrison ◽  
J. A. Curry ◽  
V. I. Khvorostyanov
Keyword(s):  
High Resolution ◽  
Vertical Velocity ◽  
Large Scale ◽  
Climate Models ◽  
The Other ◽  
Microphysics Scheme ◽  
Cloud Models ◽  
Droplet Nucleation ◽  
Double Moment ◽  
Droplet Activation

Abstract A new double-moment bulk microphysics scheme predicting the number concentrations and mixing ratios of four hydrometeor species (droplets, cloud ice, rain, snow) is described. New physically based parameterizations are developed for simulating homogeneous and heterogeneous ice nucleation, droplet activation, and the spectral index (width) of the droplet size spectra. Two versions of the scheme are described: one for application in high-resolution cloud models and the other for simulating grid-scale cloudiness in larger-scale models. The versions differ in their treatment of the supersaturation field and droplet nucleation. For the high-resolution approach, droplet nucleation is calculated from Kohler theory applied to a distribution of aerosol that activates at a given supersaturation. The resolved supersaturation field and condensation/deposition rates are predicted using a semianalytic approximation to the three-phase (vapor, ice, liquid) supersaturation equation. For the large-scale version of the scheme, it is assumed that the supersaturation field is not resolved and thus droplet activation is parameterized as a function of the vertical velocity and diabatic cooling rate. The vertical velocity includes a subgrid component that is parameterized in terms of the eddy diffusivity and mixing length. Droplet condensation is calculated using a quasi-steady, saturation adjustment approach. Evaporation/deposition onto the other water species is given by nonsteady vapor diffusion allowing excess vapor density relative to ice saturation.

Multimoment Ice Bulk Microphysics Scheme with Consideration for Particle Shape and Apparent Density. Part I: Methodology and Idealized Simulation

2020 ◽  
Vol 77 (5) ◽  
pp. 1821-1850 ◽  
Author(s):  
Tzu-Chin Tsai ◽  
Jen-Ping Chen
Keyword(s):  
Solid Phase ◽  
Smooth Transition ◽  
Squall Line ◽  
Diffusional Growth ◽  
Microphysics Scheme ◽  
Line System ◽  
Vertical Distributions ◽  
Double Moment ◽  
Dimensional Simulation ◽  
Moment Approach

Abstract To improve the parameterization of ice-phase microphysics in regional meteorological models, this study developed a triple-moment bulk scheme, which also tracks the variations in the shape and density of several hydrometeors. Solid-phase hydrometeors are classified into pristine ice, snow aggregates, rimed ice, and hailstones based on their physical mechanisms. The new scheme has been incorporated into the Weather Research and Forecasting Model and tested with an idealized two-dimensional simulation of a squall-line system. The simulation successfully revealed the smooth transition from the convective core to the stratiform anvil as well as the alternating pattern in the hydrometeor vertical distributions, as was similarly demonstrated in other similar studies. A few sensitivity tests were performed to reveal the importance of including shape and density variations, which strongly affect the mean particle size by up to 50% and fall speed by as much as 100% for individual hydrometeor categories. Furthermore, the inclusion of a third moment could enhance the diffusional growth rate of small crystals and reduce the ventilation effect of large particles compared with the conventional double-moment approach. These factors have a significant influence on cloud structure and precipitation amounts.

scholarly journals Ice Nucleation Parameterization and Relative Humidity Distribution in Idealized Squall-Line Simulations

2017 ◽  
Vol 74 (9) ◽  
pp. 2761-2787 ◽  
Author(s):  
Minghui Diao ◽  
George H. Bryan ◽  
Hugh Morrison ◽  
Jorgen B. Jensen
Keyword(s):  
Relative Humidity ◽  
Ice Nucleation ◽  
Squall Line ◽  
Microphysics Scheme ◽  
Convective Clouds ◽  
Microphysical Properties ◽  
Double Moment ◽  
Microphysical Processes ◽  
Almost All ◽  
Cloud Evolution

Abstract Output from idealized simulations of a squall line are compared with in situ aircraft-based observations from the Deep Convective Clouds and Chemistry campaign. Relative humidity distributions around convection are compared between 1-Hz aircraft observations (≈250-m horizontal scale) and simulations using a double-moment bulk microphysics scheme at three horizontal grid spacings: Δx = 0.25, 1, and 4 km. The comparisons focus on the horizontal extent of ice supersaturated regions (ISSRs), the maximum and average relative humidity with respect to ice (RHi) in ISSRs, and the ice microphysical properties during cirrus cloud evolution, with simulations at 0.25 and 1 km providing better results than the 4-km simulation. Within the ISSRs, all the simulations represent the dominant contributions of water vapor horizontal heterogeneities to ISSR formation on average, but with larger variabilities in such contributions than the observations. The best results are produced by a Δx = 0.25-km simulation with the RHi threshold for initiating ice nucleation increased to 130%, which improves almost all the ISSR characteristics and allows for larger magnitude and frequency of ice supersaturation (ISS) > 8%. This simulation also allows more occurrences of clear-sky ISSRs and a higher spatial fraction of ISS for in-cloud conditions, which are consistent with the observations. These improvements are not reproduced by modifying other ice microphysical processes, such as a factor-of-2 reduction in the ice nuclei concentration; a factor-of-10 reduction in the vapor deposition rate; turning off heterogeneous contact and immersion freezing; or turning off homogeneous freezing of liquid water.

scholarly journals Diagnosing the Intercept Parameters of the Exponential Drop Size Distributions in a Single-Moment Microphysics Scheme and Impact on Supercell Storm Simulations

2014 ◽  
Vol 53 (8) ◽  
pp. 2072-2090 ◽  
Author(s):  
Charlotte E. Wainwright ◽  
Daniel T. Dawson ◽  
Ming Xue ◽  
Guifu Zhang
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Computational Cost ◽  
Squall Line ◽  
Cold Pool ◽  
Microphysics Scheme ◽  
Single Moment ◽  
Double Moment ◽  
Drop Size Distributions

AbstractIn this study, power-law relations are developed between the intercept parameter N0 of the exponential particle size distribution and the water content for the rain, hail, graupel, and snow hydrometeor categories within the Milbrandt and Yau microphysics scheme. Simulations of the 3 May 1999 Oklahoma tornadic supercell are performed using the diagnostic relations for rain only and alternately for all four precipitating species, and results are compared with those from the original fixed-N0 single- and double-moment versions of the scheme. Diagnosing N0 for rain is found to improve the results of the simulation in terms of reproducing the key features of the double-moment simulation while still retaining the computational efficiency of a single-moment scheme. Results more consistent with the double-moment scheme are seen in the general storm structure, the cold-pool structure and intensity, and the number concentration fields. Diagnosing the intercept parameters for all four species, including those for the ice species, within the single-moment scheme yields even closer agreement with the double-moment simulation results. The decreased cold-pool intensity is very similar to that produced by the double-moment simulation, as is the areal extent of the simulated storm. The diagnostic relations are also tested on a simulated squall line, with similar promising results. This study suggests that, when compared with traditional fixed intercept parameters used in typical single-moment microphysics schemes, results closer to a double-moment scheme can be obtained through the use of diagnostic relations for the parameters of the particle size distribution, with little extra computational cost.

scholarly journals Evaluation of the WRF Double-Moment 6-Class Microphysics Scheme for Precipitating Convection

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Song-You Hong ◽  
Kyo-Sun Sunny Lim ◽  
Yong-Hee Lee ◽  
Jong-Chul Ha ◽  
Hyung-Woo Kim ◽  
...  
Keyword(s):  
Great Plains ◽  
Leading Edge ◽  
Heavy Precipitation ◽  
Summer Monsoon Rainfall ◽  
Squall Line ◽  
Convective System ◽  
Moist Convection ◽  
Microphysics Scheme ◽  
Evolutionary Features ◽  
Double Moment

This study demonstrates the characteristics of the Weather Research and Forecasting (WRF) Double-Moment 6-Class (WDM6) Microphysics scheme for representing precipitating moist convection in 3D platforms, relative to the WSM6 scheme that has been widely used in the WRF community. For a case study of convective system over the Great Plains, the WDM6 scheme improves the evolutionary features such as the bow-type echo in the leading edge of the squall line. We also found that the WRF with WDM6 scheme removes spurious oceanic rainfall that is a systematic defect resulting from the use of the WSM6 scheme alone. The simulated summer monsoon rainfall in East Asia is improved by weakening (strengthening) light (heavy) precipitation activity. These changes can be explained by the fact that the WDM6 scheme has a wider range in cloud and rain number concentrations than does the WSM6 scheme.

scholarly journals Evaluating the Performance of a Convection-Permitting Model by Using Dual-Polarimetric Radar Parameters: Case Study of SoWMEX IOP8

2020 ◽  
Vol 12 (18) ◽  
pp. 3004 ◽  
Author(s):  
Cheng-Rong You ◽  
Kao-Shen Chung ◽  
Chih-Chien Tsai
Keyword(s):  
Model Simulation ◽  
Dynamic Structure ◽  
Southwest Monsoon ◽  
Model Verification ◽  
Squall Line ◽  
Polarimetric Radar ◽  
Subtropical Region ◽  
Microphysics Scheme ◽  
Double Moment ◽  
Reflectivity Data

In this study, a dual-polarimetric radar observation operator is established and modified for the Taiwan area for the purpose of model verification. A severe squall line case during the Southwest Monsoon Experiment Intensive Observing Period 8 (SoWMEX IOP#8) on 14 June 2008, is selected and examined. Because the operator is adopted from the use of the midlatitude region, sensitivity tests are performed to obtain the optimal setting of the operator in the subtropical region. To accurately capture the dynamic structure of the squall lines, the ensemble-based data assimilation system, which assimilates both radial wind and reflectivity data, is used to obtain the optimal analysis field on the mesoscale for evaluating the performance of model simulation. The characteristics of two microphysics schemes are investigated, and the results obtained using the schemes are compared with the S-band dual-polarimetric radar observations. The horizontal and vertical cross-sections show that the analyses resemble the observations. Both schemes can replicate the polarimetric parameter signature such as ZDR and KDP columns. When comparing model simulation with polarimetric parameters through the drawing of contour frequency by altitude diagrams (CFADs), the results reveal that the single moment microphysics scheme performs better than the double moment scheme in this case. However, the reflectivity field in the stratiform area is more accurately captured when using the double moment scheme. Furthermore, validation with polarimetric variables (ZH, ZDR and KDP) histograms shows underestimation of the KDP field in both schemes. Overall, this study indicates the benefit of assimilating radial wind and reflectivity data for the analyses of severe precipitation systems and the necessity of assimilating polarimetric parameters for the accuracy of microphysical processes, especially complex microphysics schemes in subtropical region.

HRTEM simulation of interfacial structure in amorphous multilayers

1989 ◽  
Vol 47 ◽  
pp. 466-467
Author(s):  
Margaret L. Sattler ◽  
Michael A. O'Keefe
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Cross Section ◽  
High Resolution Electron Microscopy ◽  
Interfacial Structure ◽  
Multilayer Sample ◽  
Resolution Electron ◽  
Multilayered Materials ◽  
Simulated Images

Multilayered materials have been fabricated with such high perfection that individual layers having two atoms deep are possible. Characterization of the interfaces between these multilayers is achieved by high resolution electron microscopy and Figure 1a shows the cross-section of one type of multilayer. The production of such an image with atomically smooth interfaces depends upon certain factors which are not always reliable. For example, diffusion at the interface may produce complex interlayers which are important to the properties of the multilayers but which are difficult to observe. Similarly, anomalous conditions of imaging or of fabrication may occur which produce images having similar traits as the diffusion case above, e.g., imaging on a tilted/bent multilayer sample (Figure 1b) or deposition upon an unaligned substrate (Figure 1c). It is the purpose of this study to simulate the image of the perfect multilayer interface and to compare with simulated images having these anomalies.

Cross Section Analysis of Cu Filled TSVs Based on High Throughput Plasma-FIB Milling

2012 ◽  
Author(s):  
Frank Altmann ◽  
Jens Beyersdorfer ◽  
Jan Schischka ◽  
Michael Krause ◽  
German Franz ◽  
...  
Keyword(s):  
High Resolution ◽  
Cross Section ◽  
High Throughput ◽  
Cross Sections ◽  
Electron Backscatter Diffraction ◽  
Grain Structure ◽  
Electron Backscatter ◽  
Section Surface ◽  
Backscatter Diffraction ◽  
Section Analysis

Abstract In this paper the new Vion™ Plasma-FIB system, developed by FEI, is evaluated for cross sectioning of Cu filled Through Silicon Via (TSV) interconnects. The aim of the study presented in this paper is to evaluate and optimise different Plasma-FIB (P-FIB) milling strategies in terms of performance and cross section surface quality. The sufficient preservation of microstructures within cross sections is crucial for subsequent Electron Backscatter Diffraction (EBSD) grain structure analyses and a high resolution interface characterisation by TEM.

Sign in / Sign up

Export Citation Format

Share Document