Development of an Effective Double-Moment Cloud Microphysics Scheme with Prognostic Cloud Condensation Nuclei (CCN) for Weather and Climate Models

A new double-moment bulk cloud microphysics scheme, the Weather Research and Forecasting (WRF) Double-Moment 6-class (WDM6) Microphysics scheme, which is based on the WRF Single-Moment 6-class (WSM6) Microphysics scheme, has been developed. In addition to the prediction for the mixing ratios of six water species (water vapor, cloud droplets, cloud ice, snow, rain, and graupel) in the WSM6 scheme, the number concentrations for cloud and rainwater are also predicted in the WDM6 scheme, together with a prognostic variable of cloud condensation nuclei (CCN) number concentration. The new scheme was evaluated on an idealized 2D thunderstorm test bed. Compared to the simulations from the WSM6 scheme, there are greater differences in the droplet concentration between the convective core and stratiform region in WDM6. The reduction of light precipitation and the increase of moderate precipitation accompanying a marked radar bright band near the freezing level from the WDM6 simulation tend to alleviate existing systematic biases in the case of the WSM6 scheme. The strength of this new microphysics scheme is its ability toallowflexibilityinvariableraindropsizedistributionbypredictingthenumberconcentrationsofcloudsand rain, coupled with the explicit CCN distribution, at a reasonable computational cost.

[1]  R. Houze,et al.  Kinematic and Precipitation Structure of the 10–11 June 1985 Squall Line , 1991 .

[2]  Peter V. Hobbs,et al.  Fall speeds and masses of solid precipitation particles , 1974 .

[3]  William R. Cotton,et al.  A Numerical Investigation of Several Factors Contributing to the Observed Variable Intensity of Deep Convection over South Florida , 1980 .

[4]  A. Pokrovsky,et al.  Factors Determining the Impact of Aerosols on Surface Precipitation from Clouds: An Attempt at Classification , 2008 .

[5]  M. Murakami,et al.  Numerical Modeling of Dynamical and Microphysical Evolution of an Isolated Convective Cloud , 1990 .

[6]  Jiwen Fan,et al.  Simulations of cumulus clouds using a spectral microphysics cloud‐resolving model , 2007 .

[7]  J. Curry,et al.  A New Double-Moment Microphysics Parameterization for Application in Cloud and Climate Models. Part I: Description , 2005 .

[8]  William R. Cotton,et al.  New RAMS cloud microphysics parameterization. Part II: The two-moment scheme , 1997 .

[9]  D. Short,et al.  Evidence from Tropical Raindrop Spectra of the Origin of Rain from Stratiform versus Convective Clouds , 1996 .

[10]  W. Cotton,et al.  New RAMS cloud microphysics parameterization part I: the single-moment scheme , 1995 .

[11]  Badrinath Nagarajan,et al.  A Numerical Study of a Mesoscale Convective System during TOGA COARE. Part I: Model Description and Verification , 2001 .

[12]  Chien Wang.  A modeling study of the response of tropical deep convection to the increase of cloud condensation nuclei concentration: 1. Dynamics and microphysics , 2005 .

[13]  G. Thompson,et al.  Impact of Cloud Microphysics on the Development of Trailing Stratiform Precipitation in a Simulated Squall Line: Comparison of One- and Two-Moment Schemes , 2009 .

[14]  Da‐Lin Zhang,et al.  A Numerical Study of a Mesoscale Convective System during TOGA COARE. Part II: Organization , 2004 .

[15]  Edwin X. Berry,et al.  An Analysis of Cloud Drop Growth by Collection: Part I. Double Distributions , 1974 .

[16]  M. Ikawa,et al.  Description of a nonhydrostatic model developed at the Forecast Research Department of the MRI , 1991 .

[17]  M. Yau,et al.  A Multimoment Bulk Microphysics Parameterization. Part I: Analysis of the Role of the Spectral Shape Parameter , 2005 .

[18]  K. D. Beheng,et al.  A two-moment cloud microphysics parameterization for mixed-phase clouds. Part 2: Maritime vs. continental deep convective storms , 2006 .

[19]  Jimy Dudhia,et al.  A New Method for Representing Mixed-phase Particle Fall Speeds in Bulk Microphysics Parameterizations , 2008 .

[20]  J. Dudhia,et al.  A Revised Approach to Ice Microphysical Processes for the Bulk Parameterization of Clouds and Precipitation , 2004 .

[21]  S. Rutledge,et al.  Positive Cloud-to-Ground Lightning in Mesoscale Convective Systems , 1990 .

[22]  F. Roux.  The West African Squall Line Observed on 23 June 1981 during COPT 81: Kinematics and Thermodynamics of the Convective Region , 1988 .

[23]  William R. Cotton,et al.  Multiscale Evolution of a Derecho-Producing Mesoscale Convective System , 1998 .

[24]  S. Rutledge,et al.  The Mesoscale and Microscale Structure and Organization of Clouds and Precipitation in Midlatitude Cyclones. VIII: A Model for the “Seeder-Feeder” Process in Warm-Frontal Rainbands , 1983 .

[25]  V. Ramanathan,et al.  Aerosols, Climate, and the Hydrological Cycle , 2001, Science.

[26]  E. Bigg.  The supercooling of water , 1953 .

[27]  Fanyou Kong,et al.  An explicit approach to microphysics in MC2 , 1997 .

[28]  R. Fovell,et al.  Discrete Propagation in Numerically Simulated Nocturnal Squall Lines , 2006 .

[29]  R. Rasmussen,et al.  Explicit forecasting of supercooled liquid water in winter storms using the MM5 mesoscale model , 1998 .

[30]  W. Tao,et al.  Sensitivity of a Cloud-Resolving Model to Bulk and Explicit Bin Microphysical Schemes. Part II: Cloud Microphysics and Storm Dynamics Interactions , 2009 .

[31]  Jean-Pierre Pinty,et al.  A comprehensive two‐moment warm microphysical bulk scheme. II: 2D experiments with a non‐hydrostatic model , 2000 .

[32]  R. Houze,et al.  The Structure and Evolution of Convection in a Tropical Cloud Cluster , 1979 .

[33]  J. Dudhia.  Numerical Study of Convection Observed during the Winter Monsoon Experiment Using a Mesoscale Two-Dimensional Model , 1989 .

[34]  H. D. Orville,et al.  A Numerical Model of a Hail-Bearing Cloud , 1972 .

[35]  Kevin W. Manning,et al.  Explicit Forecasts of Winter Precipitation Using an Improved Bulk Microphysics Scheme. Part I: Description and Sensitivity Analysis , 2004 .

[36]  Jean-Pierre Pinty,et al.  A comprehensive two‐moment warm microphysical bulk scheme. I: Description and tests , 2000 .

[37]  H. D. Orville,et al.  Bulk Parameterization of the Snow Field in a Cloud Model , 1983 .

[38]  Y. Wang,et al.  Implementation of a two‐moment bulk microphysics scheme to the WRF model to investigate aerosol‐cloud interaction , 2008 .

[39]  K. D. Beheng,et al.  A double-moment parameterization for simulating autoconversion, accretion and selfcollection , 2001 .

[40]  R. C. Srivastava.  Parameterization of Raindrop Size Distributions. , 1978 .

[41]  R. Rauber,et al.  Numerical Simulation of the Effects of Varying Ice Crystal Nucleation Rates and Aggregation Processes on Orographic Snowfall , 1986 .

[42]  E. Kessler.  On the distribution and continuity of water substance in atmospheric circulations , 1969 .

[43]  D. W. Johnson,et al.  The Measurement and Parameterization of Effective Radius of Droplets in Warm Stratocumulus Clouds , 1994 .

[44]  G. Powers,et al.  A Description of the Advanced Research WRF Version 3 , 2008 .

[45]  A. Waldvogel,et al.  On the Quantitative Determination of Precipitation by a Radar. , 1970 .

[46]  Edward J. Zipser,et al.  Mesoscale and convective-scale downdrafts as distinct components of squall-line structure , 1977 .

[47]  G. Thompson,et al.  Explicit Forecasts of Winter Precipitation Using an Improved Bulk Microphysics Scheme. Part II: Implementation of a New Snow Parameterization , 2008 .

[48]  G. McFarquhar,et al.  Arctic Mixed-Phase Clouds Simulated by a Cloud-Resolving Model : Comparison with ARM Observations and Sensitivity to Microphysics Parameterizations , 2008 .

[49]  W. Tao,et al.  Sensitivity of a Cloud-Resolving Model to the Bulk and Explicit Bin Microphysical Schemes. Part 1; Validations with a PRE-STORM Case , 2004 .

[50]  James G. Hudson,et al.  Maritime/continental microphysical contrasts in stratus , 2002 .

[51]  Edwin X. Berry,et al.  An Analysis of Cloud Drop Growth by Collection Part II. Single Initial Distributions , 1974 .

[52]  M. Khairoutdinov,et al.  A New Cloud Physics Parameterization in a Large-Eddy Simulation Model of Marine Stratocumulus , 2000 .

[53]  Chien Wang,et al.  A three‐dimensional numerical model of cloud dynamics, microphysics, and chemistry: 1. Concepts and formulation , 1993 .

[54]  S. Twomey,et al.  The nuclei of natural cloud formation part II: The supersaturation in natural clouds and the variation of cloud droplet concentration , 1959 .

[55]  L. Ruby Leung,et al.  Prediction of cloud droplet number in a general , 1997 .

[56]  Joanne Simpson,et al.  Goddard Cumulus Ensemble Model. Part I: Model Description , 1993 .

[57]  W. Tao,et al.  Sensitivity of a Cloud-Resolving Model to Bulk and Explicit Bin Microphysical Schemes. Part I: Comparisons , 2009 .

[58]  Conrad L. Ziegler,et al.  Retrieval of Thermal and Microphysical Variables in Observed Convective Storms. , 1985 .

[59]  Song‐You Hong,et al.  The WRF Single-Moment 6-Class Microphysics Scheme (WSM6) , 2006 .

[60]  B. Ferrier,et al.  A Double-Moment Multiple-Phase Four-Class Bulk Ice Scheme. Part I: Description , 1994 .

[61]  James O. Pinto,et al.  Mesoscale modeling of springtime Arctic mixed-phase stratiform clouds using a new two-moment bulk microphysics scheme , 2005 .

[62]  L. Donner,et al.  Nucleation processes in deep convection simulated by a cloud-system-resolving model with double-moment bulk microphysics , 2007 .

[63]  Remko Uijlenhoet,et al.  A general approach to double moment normalization of drop size distributions , 2004 .

[64]  A. Waldvogel,et al.  The N0 Jump of Raindrop Spectra , 1974 .