Identification

Title

Effects from time dependence of ice nucleus activity for contrasting cloud types

Abstract

The role of time-dependent freezing of ice nucleating particles (INPs) is evaluated with the "Aerosol-Cloud" (AC) model in 1) deep convection observed over Oklahoma during the Midlatitude Continental Convective Cloud Experiment (MC3E), 2) orographic clouds observed over North California during the Atmospheric Radiation Measurement (ARM) Cloud Aerosol Precipitation Experiment (ACAPEX), and 3) supercooled, stratiform clouds over the United Kingdom, observed during the Aerosol Properties, Processes And Influences on the Earth's climate (APPRAISE) campaign. AC uses the dynamical core of the WRF Model and has hybrid bin- bulk microphysics and a 3D mesoscale domain. AC is validated against coincident aircraft, ground-based, and satellite observations for all three cases. Filtered concentrations of ice (.0.1-0. 2 mm) agree with those observed at all sampled levels. AC predicts the INP activity of various types of aerosol particles with an empirical parameterization (EP), which follows a singular approach (no time dependence). Here, the EP is modified to represent time-dependent INP activity by a purely empirical approach, using our published laboratory observations of time-dependent INP activity. In all simulated clouds, the inclusion of time dependence increases the predicted INP activity of mineral dust particles by 0.5-1 order of magnitude. However, there is little impact on the cloud glaciation because the total ice is mostly (80%-90%) from secondary ice production (SIP) at levels warmer than about -36 DEG;C. The Hallett-Mossop process and fragmentation in ice-ice collisions together initiate about 70% of the total ice, whereas fragmentation during both raindrop freezing and sublimation contributes ,10%. Overall, total ice concentrations and SIP are unaffected by time-dependent INP activity. In the simulated APPRAISE case, the main causes of persistence of long-lived clouds and precipitation are predicted to be SIP in weak embedded convection and reactivation following recirculation of dust particles in supercooled layer cloud.

Resource type

document

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code

https://n2t.org/ark:/85065/d77085f7

codeSpace

Dataset language

eng

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code identifying the spatial reference system

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geoscientificInformation

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Text

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title

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reference date

date type

publication

effective date

2016-01-01T00:00:00Z

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publication

effective date

2023-08-01T00:00:00Z

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Copyright author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

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None

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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

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 date

2025-07-11T15:15:44.867114

Metadata language

eng; USA