A new two-moment cloud microphysics scheme predicting the mixing ratios and number concentrations of five species (i.e., cloud droplets, cloud ice, snow, rain, and graupel) has been implemented into the Weather Research and Forecasting model (WRF). This scheme is used to investigate the formation and evolution of trailing stratiform precipitation in an idealized two-dimensional squall line. Results are compared to those using a one-moment version of the scheme that predicts only the mixing ratios of the species, and diagnoses the number concentrations from the specified size distribution intercept parameter and predicted mixing ratio. The overall structure of the storm is similar using either the one- or two-moment schemes, although there are notable differences. The two-moment (2-M) scheme produces a widespread region of trailing stratiform precipitation within several hours of the storm formation. In contrast, there is negligible trailing stratiform precipitation using the one-moment (1-M) scheme. The primary reason for this difference are reduced rain evaporation rates in 2-M compared to 1-M in the trailing stratiform region, leading directly to greater rain mixing ratios and surface rainfall rates. Second, increased rain evaporation rates in 2-M compared to 1-M in the convective region at midlevels result in weaker convective updraft cells and increased midlevel detrainment and flux of positively buoyant air from the convective into the stratiform region. This flux is in turn associated with a stronger mesoscale updraft in the stratiform region and enhanced ice growth rates. The reduced (increased) rates of rain evaporation in the stratiform (convective) regions in 2-M are associated with differences in the predicted rain size distribution intercept parameter (which was specified as a constant in 1-M) between the two regions. This variability is consistent with surface disdrometer measurements in previous studies that show a rapid decrease of the rain intercept parameter during the transition from convective to stratiform rainfall.

http://kiwi.atmos.colostate.edu/pubs/i1520-0493-137-3-991.pdf

Impact of Cloud Microphysics on the Development of Trailing Stratiform Precipitation in a Simulated Squall Line: Comparison of One- and Two-Moment Schemes

This chapter is concerned with the properties of gases and liquids (primarily water) relevant to Environmental Physics. Physical properties of gases such as density, heat capacity, and molecular diffusivity influence many of the exchanges between organisms or land surfaces and their environment. Evaporation of water from soils, plants, and animals is also important for their heat balance. Basic equations are developed here to specify the Equation of State of gases and the principles by which the state of liquid water can be specified‘ in organisms and soil. These principles will be applied in later chapters.

Properties of Gases and Liquids

Development of a global evapotranspiration algorithm based on MODIS and global meteorology data

A general model of forest ecosystem processes for regional applications I. Hydrologic balance, canopy gas exchange and primary production processes

Prepared by the Task Committee on Standardization of Reference Evapotranspiration of the Environmental and Water Resources Institute of ASCE.

/pdf/the-asce-standardized-reference-evapotranspiration-equation-4utkk2xg08.pdf

The ASCE standardized reference evapotranspiration equation

On the Computation of Saturation Vapor Pressure

A two-dimensional (axisymmetric) numerical cloud model with parameterized microphysics for water drops and ice particles is described. The parameterized liquid-phase processes include condensation, evaporation, autoconversion of small drops to large ones, and collection of small drops by large ones. The solid-phase processes include heterogeneous sorption nucleation, homogeneous contact nucleation, deposition, sublimation, riming and melting. Both liquid and solid particles may precipitate. The model was used to simulate three different conditions of ice generation as a function of temperature: 1) based on classical concepts of the activity of heterogeneous ice-forming nuclei—suggesting continental cumuli; 2) based on field observations of much greater concentrations of ice particles at warmer temperatures than indicated measurements of heterogeneous ice nuclei—suggesting maritime cumuli; and 3) based on nucleus seeding practice when the goal is to stimulate the growth of cumulus clouds. General ...

Ice-Bearing Cumulus Cloud Evolution: Numerical Simulation and General Comparison Against Observations.

Two versions of a numerical model for cumulus convection are compared. One is symmetrical about a vertical plane, the other about a vertical axis. It is found that the axisymmetric model grows more vigorously than the other and more realistically represents the relations between updraft and downdraft, the shape, and other characteristics. The previous findings of Ogura are generally confirmed and extended.

Numerical models of a tropical cumulus cloud with bilateral and axial symmetry1

An existing numerical model of cumulus growth, treating condensation but not precipitation, is modified by the incorporation of a parameterized treatment of liquid phase microphysics. This modification improves the realism of the results in several important respects; among them are maximum height of cloud growth, maximum liquid content, amount and distribution of temperature departure, cloud shape, and occurrence and strength of subcloud downdraft. We found that one of the most important controlling features is the rate of evaporation of droplets. In particular, the introduction of a class of large particles with relatively slow evaporation rate produces a smaller temperature deficit at the cloud summit, hence more vigorous cloud growth. In this model, the upper and lower parts of the cloud are, to a large extent, decoupled dynamically, the development of a strong subcloud downdraft by evaporation of precipitation having little effect on the ultimate extent of cloud growth.

Numerical Experiments on the Relation Between Microphysics and Dynamics in Cumulus Convection

Three mathematical expressions for the terminal velocity of water drops in still air as a function of equivalent radius are compared with the experimental data of Gunn and Kinzer. Two of them, derived by curve-fitting techniques, give excellent results over the full range of meteorological interest, including the Stokes's law regime. A formula to correct for non-standard pressure and temperature is given, and its results are compared with the experimental data of Beard and Pruppacher.

Calculation of the Terminal Velocity of Water Drops

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Francis W. Murray

Author Tools

Chat about Author