Identification

Title

On the covariability of cloud and rain water as a function of length scale

Abstract

Microphysics parameterizations in large-scale models often account for subgrid variability in the calculation of process rates by integrating over assumed subgrid distributions of the input variables. The variances and covariances that define distribution width may be specified or diagnosed. The correlation rho of cloud and rain mass mixing ratio/liquid water content (LWC) is a key input for accurate prediction of the accretion rate and a constant value is typically assumed. In this study, high-frequency aircraft measurements with a spatial resolution of approximate to 22 cm are used to evaluate the scaling behavior of cloud and rain LWC (q(c) and q(r), respectively) and to demonstrate how and why covariability varies with length scale l. It is shown that power spectral densities of both q(c) and q(r) exhibit scale invariance across a wide range of scales (2.04-142 m for q(c); 33-1.45 x 10(4) m for q(r)). Because the cloud-rain cospectrum is also scale invariant, rho is therefore expected to vary with l. Direct calculation of rho shows that it generally increases with l, but there is significant variability in the rho-l relationship that primarily depends on cloud drop number concentration N and cloud cellular organization, suggesting that rho may also vary with cloud regime. A parameterization of rho as a function of l and N is developed from aircraft observations and implications for diagnosis of rho from limited-area model output are also discussed.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7hh6p5r

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2019-08-01T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact