A Multimoment Bulk Microphysics Parameterization. Part II: A Proposed Three-Moment Closure and Scheme Description

2005 ◽  
Vol 62 (9) ◽  
pp. 3065-3081 ◽  
Author(s):  
J. A. Milbrandt ◽  
M. K. Yau
Keyword(s):  
Shape Parameter ◽  
Cloud Model ◽  
Number Concentration ◽  
Radar Reflectivity ◽  
Moment Closure ◽  
Relative Dispersion ◽  
Size Spectrum ◽  
Mass Content ◽  
Microphysics Scheme ◽  
The One

Abstract Many two-moment bulk schemes use a three-parameter gamma distribution of the form N(D) = N0Dαe−λD to describe the size spectrum of a given hydrometeor category. These schemes predict changes to the mass content and the total number concentration thereby allowing N0 and λ to vary as prognostic parameters while fixing the shape parameter, α. As was shown in Part I of this study, the shape parameter, which represents the relative dispersion of the hydrometeor size spectrum, plays an important role in the computation of sedimentation and instantaneous growth rates in bulk microphysics schemes. Significant improvement was shown by allowing α to vary as a diagnostic function of the predicted moments rather than using a fixed-value approach. Ideally, however, α should be an independent prognostic parameter. In this paper, a closure formulation is developed for calculating the source and sink terms of a third moment of the size distribution—the radar reflectivity. With predictive equations for the mass content, total number concentration, and radar reflectivity, α becomes a fully prognostic variable and a three-moment parameterization becomes feasible. A new bulk microphysics scheme is presented and described. The full version of the scheme predicts three moments for all precipitating hydrometeor categories. Simulations of an idealized hailstorm in the context of a 1D kinematic cloud model employing the one-moment, two-moment, and three-moment versions of the scheme are compared. The vertical distribution of the hydrometeor mass contents using the two-moment version with diagnostic-α relations are much closer to the three-moment than the one-moment simulation. However, the evolution of the surface precipitation rate is notably different between the three-moment and two-moment schemes.

A Multimoment Bulk Microphysics Parameterization. Part I: Analysis of the Role of the Spectral Shape Parameter

2005 ◽  
Vol 62 (9) ◽  
pp. 3051-3064 ◽  
Author(s):  
J. A. Milbrandt ◽  
M. K. Yau
Keyword(s):  
Growth Rates ◽  
Moment Method ◽  
Shape Parameter ◽  
Number Concentration ◽  
Spectral Shape ◽  
Size Spectrum ◽  
Atmospheric Models ◽  
Size Sorting ◽  
The Mean

Abstract With increasing computer power, explicit microphysics schemes are becoming increasingly important in atmospheric models. Many schemes have followed the approach of Kessler in which one moment of the hydrometeor size distribution, proportional to the mass content, is predicted. More recently, the two-moment method has been introduced in which both the mass and the total number concentration of the hydrometeor categories are independently predicted. In bulk schemes, the size spectrum of each hydrometeor category is often described by a three-parameter gamma distribution function, N(D) = N0Dαe−λD. Two-moment schemes generally treat N0 and λ as prognostic parameters while holding α constant. In this paper, the role of the spectral shape parameter, α, is investigated by examining its effects on sedimentation and microphysical growth rates. An approach is introduced for a two-moment scheme where α is allowed to vary diagnostically as a function of the mean-mass diameter. Comparisons are made between calculations using various bulk approaches—a one-moment, a two-moment, and a three-moment method—and an analytic bin model. It is found that the size-sorting mechanism, which exists in a bulk scheme when different fall velocities are applied to advect the different predicted moments, is significantly different amongst the schemes. The shape parameter plays an important role in determining the rate of size sorting. Likewise, instantaneous growth rates related to the moments are shown to be significantly affected by this parameter.

scholarly journals University of Warsaw Lagrangian Cloud Model (UWLCM) 1.0: a modern Large-Eddy Simulation tool for warm cloud modeling with Lagrangian microphysics

2019 ◽  
Author(s):  
Piotr Dziekan ◽  
Maciej Waruszewski ◽  
Hanna Pawlowska
Keyword(s):  
Large Eddy Simulation ◽  
Cloud Model ◽  
Size Spectrum ◽  
Residual Pressure ◽  
Microphysics Scheme ◽  
Dynamical Core ◽  
Large Eddy Simulation Model ◽  
Eddy Simulation ◽  
Computational Performance ◽  
Large Eddy

Abstract. A new anelastic large-eddy simulation model with an Eulerian dynamical core and a Lagrangian particle-based microphysics is presented. The dynamical core uses the MPDATA advection scheme and the generalized conjugate residual pressure solver, while the microphysics scheme is based on the Super-Droplet Method. Algorithms for coupling of the Lagrangian microphysics with the Eulerian dynamics are presented, including spatial and temporal discretizations and a condensation sub-stepping algorithm. The model is free of numerical diffusion in the droplet size spectrum. Activation of droplets is modeled explicitly, making the model less sensitive to local supersaturation maxima than models in which activation is parametrised. Simulations of a drizzling marine stratocumulus give results in agreement with other LES models. Relatively low number of computational particles is sufficient to obtain the correct averaged properties of a cloud. High computational performance is achieved thanks to the use of GPU accelerators.

scholarly journals A New Double-Moment Microphysics Parameterization for Application in Cloud and Climate Models. Part II: Single-Column Modeling of Arctic Clouds

2005 ◽  
Vol 62 (6) ◽  
pp. 1678-1693 ◽  
Author(s):  
H. Morrison ◽  
J. A. Curry ◽  
M. D. Shupe ◽  
P. Zuidema
Keyword(s):  
Climate Models ◽  
Heat Budget ◽  
Number Concentration ◽  
The Arctic ◽  
Liquid Water Path ◽  
Microphysics Scheme ◽  
Radiative Fluxes ◽  
Arctic Clouds ◽  
Single Column ◽  
Double Moment

Abstract The new double-moment microphysics scheme described in Part I of this paper is implemented into a single-column model to simulate clouds and radiation observed during the period 1 April–15 May 1998 of the Surface Heat Budget of the Arctic (SHEBA) and First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment–Arctic Clouds Experiment (FIRE–ACE) field projects. Mean predicted cloud boundaries and total cloud fraction compare reasonably well with observations. Cloud phase partitioning, which is crucial in determining the surface radiative fluxes, is fairly similar to ground-based retrievals. However, the fraction of time that liquid is present in the column is somewhat underpredicted, leading to small biases in the downwelling shortwave and longwave radiative fluxes at the surface. Results using the new scheme are compared to parallel simulations using other microphysics parameterizations of varying complexity. The predicted liquid water path and cloud phase is significantly improved using the new scheme relative to a single-moment parameterization predicting only the mixing ratio of the water species. Results indicate that a realistic treatment of cloud ice number concentration (prognosing rather than diagnosing) is needed to simulate arctic clouds. Sensitivity tests are also performed by varying the aerosol size, solubility, and number concentration to explore potential cloud–aerosol–radiation interactions in arctic stratus.

Optimized Based on Cloud Model Extension Assessment of Slope Stability

2010 ◽  
Vol 163-167 ◽  
pp. 2709-2714
Author(s):  
Feng Guo ◽  
Wei Ya Xu ◽  
Fei Xu
Keyword(s):  
Slope Stability ◽  
Cloud Model ◽  
Assessment Model ◽  
Actual State ◽  
Hydropower Project ◽  
Model Extension ◽  
Project Construction ◽  
The One ◽  
Cloud Model Theory

Evaluation of slope stability in the hydropower project construction is extremely important. This Cloud Model will be introduced to the matter-element extension, the extension assessment is proposed based on the sutra field division of the slope stability assessment model. This method combines the Cloud Model theory and the advantages of the extension assessment .On the one hand, the division of the sutra field by means of Cloud Model can overcome the "hard" division of the evils. On the other hand,with different values of Cloud Drops as a sutra field, the statistical results of Cloud Drops can be used as last stable assessment results. Project case study shows that compared with the conventional method, results of the method of extension are more accurate, which fully accorded with the actual state, proving optimized based on Cloud Model extension assessment of slope stability feasible and effective.

scholarly journals Sensitivity of 89–190-GHz Microwave Observations to Ice Particle Scattering

2020 ◽  
Vol 59 (7) ◽  
pp. 1195-1215
Author(s):  
Ruiyao Chen ◽  
Ralf Bennartz
Keyword(s):  
Radar Reflectivity ◽  
Dual Frequency ◽  
Precipitation Radar ◽  
Brightness Temperatures ◽  
Precipitation Measurement ◽  
Microwave Humidity Sounder ◽  
Slant Path ◽  
The One ◽  
Global Precipitation Measurement ◽  
Global Precipitation

AbstractThe sensitivity of microwave brightness temperatures (TBs) to hydrometeors at frequencies between 89 and 190 GHz is investigated by comparing Fengyun-3C (FY-3C) Microwave Humidity Sounder-2 (MWHS-2) measurements with radar reflectivity profiles and retrieved products from the Global Precipitation Measurement mission’s Dual-Frequency Precipitation Radar (DPR). Scattering-induced TB depressions (ΔTBs), calculated by subtracting simulated cloud-free TBs from bias-corrected observed TBs for each channel, are compared with DPR-retrieved hydrometeor water path (HWP) and vertically integrated radar reflectivity ZINT. We also account for the number of hydrometeors actually visible in each MWHS-2 channel by weighting HWP with the channel’s cloud-free gas transmission profile and the observation slant path. We denote these transmission-weighted, slant-path-integrated quantities with a superscript asterisk (e.g., HWP*). The so-derived linear sensitivity of ΔTB with respect to HWP* increases with frequency roughly to the power of 1.78. A retrieved HWP* of 1 kg m−2 at 89 GHz on average corresponds to a decrease in observed TB, relative to a cloud-free background, of 11 K. At 183 GHz, the decrease is about 34–53 K. We perform a similar analysis using the vertically integrated, transmission-weighted slant-path radar reflectivity and find that ΔTB also decreases approximately linearly with . The exponent of 0.58 corresponds to the one we find in the purely DPR-retrieval-based ZINT–HWP relation. The observed sensitivities of ΔTB with respect to and HWP* allow for the validation of hydrometeor scattering models.

The Effect of using a New Parameterization of Nucleation in the WRF-Chem model on the Cluster Formation Rate and Particle Number Concentration in a Passive Volcanic Plume

2021 ◽  
Author(s):  
Somayeh Arghavani ◽  
Clémence Rose ◽  
Sandra Banson ◽  
Céline Planche ◽  
Karine Sellegri
Keyword(s):  
Particle Number ◽  
Cluster Formation ◽  
Formation Rate ◽  
Number Concentration ◽  
Cloud Formation ◽  
Scale Model ◽  
Volcanic Plume ◽  
Particle Number Concentration ◽  
Microphysics Scheme ◽  
Volcanic Emission

<p>Volcanic eruption is one of the main natural sources of atmospheric particles. In particular, evidence of New Particle Formation (NPF) from volcanic emission is reported in previous studies (Boulon et al., 2011; Sahyoun et al., 2019), which also suggests an essential role of sulfuric acid in this process. In addition, Rose et al. (2019) highlighted a significant contribution of the particles formed in the volcanic plume of the piton de la Fournaise to the budget of potential CCN at the Maïdo observatory, located ~40 km from the vent of the volcano. Therefore, it is predicted that the number and size of the cloud droplets, cloud growing and precipitation processes might be affected by the frequency of occurrence and characteristics of volcanically induced NPF in both local and regional scales, because volcanic plumes can extend far from the vent and even lower heights under the influence of the wind field and atmospheric dispersion. </p><p>Following the study of Planche et al. (2020), the effect of using the New Parameterization of Nucleation (NPN) derived from the measurements performed in the passive volcanic emission plume of Etna (37.748˚ N, 14.99˚ E; Italy) (Sahyoun et al., 2019) in the WRF-Chem model (Weather Research and Forecasting Model coupled with Chemistry) is assessed, with a specific focus on the cluster formation rate and particle number concentration including CCN. In particular, results obtained with the NPN are compared to the predictions obtained with the default model settings, and further with observations.</p><p>In the next step, the resulting aerosol fields will be used to further evaluate the influence of the newly formed and grown particles on cloud formation and properties in a 3D cloud-scale model using a detailed microphysics scheme (DESCAM; Flossmann and Wobrock, 2010; Planche et al. 2010; 2014) . </p>

scholarly journals Particle dispersion processes in two-dimensional turbulence: a comparison with 2-D kinematic simulation.

2007 ◽  
Vol 14 (2) ◽  
pp. 139-151 ◽  
Author(s):  
R. Castilla ◽  
J. M. Redondo ◽  
P. J. Gámez-Montero ◽  
A. Babiano
Keyword(s):  
Turbulent Flows ◽  
Particle Dispersion ◽  
Space Time ◽  
Relative Dispersion ◽  
Kinematic Simulation ◽  
Space Time Structure ◽  
Coherent Vortices ◽  
The One ◽  
Turbulent Particle Dispersion ◽  
Kinematic Simulations

Abstract. We study numerically the comparison between Lagrangian experiments on turbulent particle dispersion in 2-D turbulent flows performed, on the one hand, on the basis of direct numerical simulations (DNS) and, on the other hand, using kinematic simulations (KS). Eulerian space-time structure of both DNS and KS dynamics are not comparable, mostly due to the absence of strong coherent vortices and advection processes in the KS fields. The comparison allows to refine past studies about the contribution of non-homogeneous space-time 2-D Eulerian structure on the turbulent absolute and relative particle dispersion processes. We particularly focus our discussion on the Richardson's regime for relative dispersion.

Using Cloud Model to Improve the Membership Function in Fuzzy Risk Assessment of Reservoir-Induced Seismicity

2013 ◽  
Vol 664 ◽  
pp. 270-275 ◽  
Author(s):  
Ming Zhong ◽  
Qiu Wen Zhang
Keyword(s):  
Risk Assessment ◽  
Membership Function ◽  
Induced Seismicity ◽  
Cloud Model ◽  
Reservoir Induced Seismicity ◽  
Fuzzy Risk Assessment ◽  
The One ◽  
The Relationship ◽  
The Membership Function

Due to the uncertainty and complexity of the causes in reservoir-induced seismicity, the relationship between the environmental factor and the possible earthquake magnitude can be described by membership function. This study aims to propose a fuzzy method to contribute the membership function in which the normal cloud model is applied. Firstly, the cloud model is introduced in detail. Based on normal cloud model, the one-to-many mapping model is presented to deal with the fuzziness and randomness in the membership function. Finally, the case study in Yangtze Three Gorges Reservoir is presented to illustrate the membership cloud function in fuzzy risk assessment of reservoir-induced seismicity. The obtained results show that the proposed method is the viable approaches in solving the problem when the memberships are vague and imprecise.

Short-Lived Climate Forcers over the Arctic between 1995 and 2015 as simulated by the GISS modelE2.1

2020 ◽  
Author(s):  
Ulas Im ◽  
Kostas Tsigaridis ◽  
Cynthia H. Whaley ◽  
Gregory S. Faluvegi ◽  
Zbigniew Klimont ◽  
...  
Keyword(s):  
Coupled Model ◽  
The Arctic ◽  
Mixing State ◽  
State Matrix ◽  
Microphysics Scheme ◽  
Natural Emissions ◽  
Intercomparison Project ◽  
The One ◽  
Goddard Institute ◽  
Space Sciences

<p>The Arctic Monitoring and Assessment Programme (AMAP) is currently assessing the impacts of Short-Lived Climate Forcers (SLCF) on Arctic climate and air quality. In support of the assessment, we used the NASA Goddard Institute of Space Sciences (GISS) Earth System Model (modelE2.1), with prescribed sea surface temperature and sea-ice fraction, to simulate SLCF concentrations globally between 1995 and 2015. Two simulations were conducted, using the One-Moment Aerosol (OMA) and the Multiconfiguration Aerosol TRacker of mIXing state (MATRIX) aerosol modules. OMA is a mass-based scheme in which aerosols are assumed to remain externally mixed and have a prescribed and constant size distribution, while MATRIX is an aerosol microphysics scheme based on the quadrature method of moments, which is able to explicitly simulate the mixing state of aerosols. Anthropogenic emissions from the ECLIPSE v6b emissions database were used, along with emissions from aircrafts and open biomass burning from the Coupled Model Intercomparison Project Phase 6 (CMIP6), while the natural emissions of sea salt, DMS, isoprene and dust are calculated interactively. The simulated monthly surface concentrations of sulfate (SO<sub>4</sub>), black carbon (BC), organic carbon (OA), and ozone (O<sub>3</sub>) are compared with observations from a set of Arctic stations, extracted from the EBAS and IMPROVE databases, as well as a few additional locations. Simulated aerosol optical depths (AOD) are also compared with Advanced Very-High Resolution Radiometer (AVHRR). The study will present the evaluation of the modelE2.1 in simulating SLCF levels over the Arctic using different aerosol schemes, along with observed and simulated trends of SLCFs over the Arctic between 1995 and 2015.</p><div> <div> <div> </div> </div> </div>

Bin-Emulating Hail Melting in Three-Moment Bulk Microphysics

2020 ◽  
Vol 77 (10) ◽  
pp. 3361-3385 ◽  
Author(s):  
Edward R. Mansell ◽  
Daniel T. Dawson II ◽  
Jerry M. Straka
Keyword(s):  
Substantial Effect ◽  
Size Spectrum ◽  
Dependent Manner ◽  
Particle Spectrum ◽  
Microphysics Scheme ◽  
Ice Particles ◽  
Distribution Shape ◽  
Mean Size ◽  
The Mean ◽  
Bin Microphysics

AbstractA three-moment bulk microphysics scheme is modified to treat melting in a size-dependent manner that emulates results from a spectral bin scheme. The three-moment bulk framework allows the distribution shape to change and accommodate some direct effects of melting on both the hail and raindrop size distributions. Reflectivity changes and shed raindrop sizes are calculated over discrete size ranges of the hail particle spectrum. Smaller ice particles are treated as melting into drops of the same mass, whereas large particles shed drops as they melt. As small ice particles are lost, the size spectrum naturally becomes narrower and the mean size of small hail can increase. Large hail with a narrow spectrum, however, can decrease in size from melting. A substantial effect is seen on the rain median volume diameter when small drops are shed from large melting hail. The NSSL bulk scheme is compared with bin microphysics in steady-state hail shafts and in a supercell storm case. It is also shown that melting (or any substantial removal of mass) induces gravitational size sorting in bulk microphysics to increase hail size despite the design of the process rates to maintain the mean size of the melting ice. This unintended side effect can be a correct behavior for small hail, but not for large hail with a narrow distribution, when mean hail size should decrease by melting.

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