Transcript Heymsfield

Ice Initiative Steering
Committee Meeting
March 23/24 2005
Questionaire: Research Focus for ICE
Ice Initiation/Nucleation:
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Initiation and initial stages of ice formation
Homogeneous nucleation
Heterogeneous nucleation
Water vapor density
Fundamental understanding of ice initiation
Electrical charge effects on scavenging and
nucleation
Aerosols and Gas
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Indentify the cloud-active aerosol particles
Document t he impact of aerosol episodes on
ice formation (dust storms, wil d fires, ..)
Use glaciogenic seeding experiment as a
research tool
Identify anthropogenic effects on ice
Role and effects of organic compounds
Ice Processes and Evolution of Ice
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Supercooled water, drizzle, aircraft icing
Depositional growth rate
Growth habits of crystals
Aggrega tion
Size distributions & concentrations
Detecting ice at small sizes and
discrimi nating from li quid
Secondary ice production
Cloud Types, Regions, Processes
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Cumulus congestus: tops, bases, entrainment
Wave Clouds
Altocumulus
Orographic Clouds / Topography
Tropical Cyclones and Hurricanes
equipment_probes
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The standard probes
CPI and the other new SPEC probe, the updated 2DC, if you will, that Paul Lawson
described at the workshop
Electric field and conductivity measurements, droplet charges and aerosol particle charges.
Those alread y on the SPEC Learjet plus IN measur ements from another aircraft (UW
Kingair or similar)
Ice nuclei, FSSP, CCN, CN, CPI (or VIPS, cloud scope), 2dc
2Dc, 2Dp, 260X, FSSP-types, aerosol spectrometer, SID-2
equipment_newprobes
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TDL hyr ogmeter and vertic al air ve locity for the Lear
Collection system, such as an arrang ement of glass filaments which can be exposed to
the ambient air for the purpos e of catching aerosol/IN to be brought back to the lab for ice
crystal nucleation and growth experiments and compositional analysis.
possible airborn e disdrometer
SID-2 if avail able, 2D-S potentially
equipment_lidar
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Interested in general in othe r radar primarily for directing aircraft operations and later
analyses relating cloud motions, structure and microphysics to location of observations.
equipment_rada
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S-Polka
Doppler radar would be critical to any cumulus experiment.
Cloud radar such as the UW Kingair
U. Wyoming mm radar fo r wave cloud profiling
equipment_lab
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Input from field studies would be helpful to design lab simulation studies in the AIDA
chamber and to focus on most relevant aerosol mixtures and nucleation modes. The lab
conditions are closest to wave clouds.
We will use results from others
I have a number of growth chambers and refriger ation units which can cove r the entire
range of growt h temperatures , pressures , and ice supersaturations in the atmosphere.
Would likely append studies of fun damental processes to existing fund ed research,
especially to extend into heterogeneou s ice nucleation regime.
equipment_modeling
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Compre hensive observat ions cover ing all of the processes potentially involve d in ice
initiation (as opposed to just microphysics, just aerosols, just radar, etc.)
Interaction with other modelers of similar clouds.
Collabor ation after field program
Scientific Overview Document:
Status
Table of Contents
1. Executive Summary................................ ................................ ............................... 3
2. Introductio n................................ ................................ ................................ ........... 5
2.1 Prim ary (Heterogeneous) Ice Formation Processes ................................ .................. 6
2.2 Secondary Ice Formation Processes ................................ ................................ ......... 6
2.3 Dependence on Droplet Spectrum................................ ................................ ............ 7
2.4 Evaporation Effects on Ice Formation................................ ................................ ...... 7
2.5 Air Parcel History................................ ................................ ................................ .... 8
2.6 Dust as Ice Nuclei................................ ................................ ................................ .... 9
2.7 Clim ate Impli cations ................................ ................................ ............................. 10
2.8 Modeli ng Studies................................ ................................ ................................ ... 10
2.9 Summ ary and Recomm endations................................ ................................ ........... 11
3. Scientific Direction ................................ ................................ .............................. 13
3.1 Layer and wave cloud studies ................................ ................................ ................ 14
3.1.1Wave clouds................................ ................................ ................................ .......... 14
3.1.2Observing ice concentrations and first ice formation................................ .............. 15
3.1.3Dust events................................ .............................. Error! Bookmark not defined.
3.2 Caribbean maritim e convective studies................................ ................................ .. 16
3.2.1The ICE experim ent in the Caribbean. ................................ ................................ ... 16
3.2.2The development of ice in tropical maritim e clouds. ................................ .............. 17
3.2.3Liquid water and updrafts ................................ ................................ ...................... 17
3.2.4Dust events in the Caribbean ................................ ................................ ................. 18
3.2.5Ice formation regions................................ ................................ ............................. 19
3.2.6New tools for observing ice formation in convective clouds ................................ .. 19
3.2.7Tropical Cloud Sampli ng Strategies................................. ................................ ...... 20
3.3 Airborne measurements of ice nuclei ................................ ................................ ..... 20
3.4 Laboratory Studies ................................ ................................ ................................ 22
3.4.1Laboratory experim ents to support cloud studies ................................ ................... 22
3.5 Numerical Modeli ng................................ ................................ .............................. 25
4. Project Coordination and Data Management ................................ .................... 25
5. References ................................ ................................ ................................ ............ 25
6. Appendices ................................ ................................ ................................ ........... 25
6.1 List of Participants................................ ................................ ................................ . 25
6.2 Experim ent Plans................................ ................................ ................................ ... 25
6.2.1Layer and Wave Clouds................................ ................................ ......................... 25
6.2.2Convective Clouds ................................ ................................ ................................ 27
6.3 Facili ties and resources ................................ ................................ .......................... 29
Late Winter/Early Spring
Experiment