Identification

Title

Sensitivity of modeled arctic mixed-phase stratocumulus to cloud condensation and ice nuclei over regionally varying surface conditions

Abstract

A two-moment microphysics scheme implemented in the polar version of the mesoscale model MM5 is used to simulate a mixed-phase stratocumulus deck observed during the Fall 2004 Mixed-Phase Arctic Cloud Experiment (MPACE). In situ aircraft instrumentation and remote sensors gathered extensive microphysical and radiative data that serve as a testbed for the model. Model results are reasonably similar to observations in terms of the liquid microphysical properties, while the ice microphysical properties are more significantly biased, especially the ice crystal concentration. Sensitivity tests examine the impact of increased cloud condensation and ice nucleus concentrations. Increasing the concentration of cloud condensation nuclei to values typical for polluted 'Arctic haze' conditions substantially reduces the mean droplet size, but has little impact on the downwelling longwave flux because the cloud already emits as a blackbody (except near the Arctic Ocean pack ice edge). However, the smaller droplet size does lead to a slight increase in liquid water path and more significant decrease (~50%) in the ice water path and snowfall rate due to reduced collision-coalescence and riming of snow by droplets. Increasing the ice nucleus concentration specified from MPACE observations by 1 - 2 orders of magnitude produces a substantial reduction in liquid water path and downwelling longwave flux at the surface over interior northern Alaska, but has less impact over the open ocean and coastal regions. However, a large discrepancy between the observed ice nucleus and ice crystal concentrations, leading to the under-prediction of simulated crystal concentration, also suggests that additional ice initiation mechanisms (not included in current models) may have occurred in the real cloud layer.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d7319w3x

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

2008-03-04T00:00:00Z

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