Mixed-Phase Arctic Cloud Experiment

M-PACEHans Verlinde

With contributions from

Jerry Harrington, Greg McFarquhar, Eugene Clothiaux,

Scott Richardson, and Chad Bahrmann

Arctic System Synthesis: Is the Arctic Headed Toward a New State?Talk delivered by Jonathan Overpeck for the Arctic System Science (ARCSS) Committee a the SEARCH Open Science Team Meeting, October 2003, Seattle.

Slide Courtesy Jonathan OverpeckFrom ARCSS Big Sky Retreat Participants

Sea ice(5-3)

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Population(0-3)

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MarinePrimaryProd.

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THC(3-3)

Permafrost(2-3)

Terrest. ice(3-2)

Terrest.Biomass

(2-3)

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(in — out)

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Slide Courtesy Jonathan OverpeckFrom ARCSS Big Sky Retreat Participants

Role of clouds in the ArcticThe following figure was taken from a recent NSF document on the hydrological cycle

in the Arctic, detailing feedbacks among sea ice, precipitation, river runoff, and coastal oceans

Vorosmarty et al. 2001

State of knowledge prior to SHEBA

• Cloud fractions > 70% in spring, summer and fall common• Surface energy budget sensitive to cloud properties

– Small changes in cloud fraction and/or effective radius of liquid produce

~40 W m-2 changes at surface (Curry et al. ‘93)– Changes in effective radius for ice produced ~80 W m-2 changes at surface

(Harrington and Olsson, ‘01)

• Connection to other components– Modest changes in cloud properties produced ~3 m changes in equilibrium

sea-ice thickness (Curry and Ebert,’90; Curry et al., ’93)

• In GCM– Changes in sea-ice impact cloudiness: cloud cover responds differently to

reductions in sea-ice concentration depending on cloud and convection parameterizations (Royer et al., ’92)

Where do we stand after SHEBA/FIRE III? - low-level clouds are predominantly mixed-phase and long-lived, with characteristics distinctly different from lower latitude clouds - impact on surface energy budget depend on characteristics of clouds - role of aerosol in cloud characteristics (CCN/IFN)

Where do we need to go?

- need a field experiment that targets mixed-phase clouds in the Arctic

- corroborate & improve cloud models (process studies link to remote sensing)

- data base needed for remote sensing retrieval validation

Courtesy Janet Intrieri

Scientific Questions

Hans Verlinde, Jerry HarringtonM-PACE Scientists

and Greg McFarquhar

UAV Mission Scientist

How are mixed-phase cloud microphysics, radiation, and cloud dynamics linked?

• Local Effects: Mixed-phase microphysics (growth, spatial and temporal distributions) and the subsequent direct and indirect links to radiation and cloud turbulence. How well do cloud models capture these processes?

• Large-Scale Effects: How important is large-scale convergence/divergence of heat and moisture to mixed-phase longevity (vs. local processes)?

• Connections to Observations: Can we use radar/lidar retrievals (which provide measures of cloud properties and turbulence) in a synergistic fashion with cloud models to improve retrievals?

Specific Objectives

• Horizontal structure and variability of the cloud microphysics and dynamics.

• Vertical profiles of microphysics, particularly over the ground based remote sensing sites.

• Coincident radiance/irradiance data above/below cloud layers with in situ microphysical data.

• Impacts of multiple cloud layers on cloud characteristics and measurements.

• Scattering-phase function of different clouds types.

• Water vapor profiles in clear and cloudy conditions.

• Clear sky emissivity.

• Atmospheric structure at corners of grid box during cloudy events.

Observing facilities in place: 1. DOE-ARM ground base observing sites at Barrow and Atqasuk

supplemented with de-pol. lidar (Sassen)2. Oliktok Point – PNNL Atmospheric Remote Sensing Lab. (PARSL),

scanning HIS.3. Enhanced radiosonde releases at Barrow, Atqasuk, Oliktok, and Toolik

Lake.4. In-situ aircraft -- UND Citation (microphysical inst.), based in Deadhorse

• CSU Continuous Flow Diffusion IN counter• NCAR CCN Counter• DMT Cloud Spectrometer and Impactor• SPEC Cloud Particle Imager

5. Remote sensing aircraft – DOE UAV (Proteus) with lidar, cloud radar, and in-situ microphysical inst. Based in Fairbanks.

Potential collaborations:

1. Aerosonde (NSF)2. CIN on Citation (NSF)

Experimental Design

Citation Instrumentation

• State parameters: 2 temperature probes, pressure

• Cooled mirror (EG&G) and laser hygrometer for dew point

• Rosemont ice detector for supercooled water

CSIRO King probe and Nevzorov Probe for LWCCSI and Nevzorov Probe for total condensed water FSSP 100 for cloud droplet spectrum2D-C, 2D-P or HVPS, CPI for particle imagingCloud integration nephelometerNCAR CCN and CSU CFDN IN counter

Proteus Instrumentation• Active remote sensing:

– Millimeter wave cloud radar – Cloud detecting lidar

• Passive Remote sensing– Spectral radiance package– Broadband radiometers– Solar spectral flux radiometers– Scanning high-resolution interferometer sounder– Diffuse field camera

• In Situ:– State parameter package– Cloud, aerosol and precipitation spectrometer (CAPS)– Cloud integrating Nephelometer– Video ice particle sampler– Nevzorov Probe

• Wind finding technique• 2 Vaisala RS90 sensors (P, T, q)• Piezoelectric Plate – to detect icing• KT11 pyrometer (Tsfc down to -40 C)• Olympus 3030Z Digital Camera• GPS (location and altitude)

Aerosonde Payloads

•Wind finding techniqueWind finding technique•Iridium satellite phone (over the horizon comms)Iridium satellite phone (over the horizon comms)•Video camera with thermal and vis channels Video camera with thermal and vis channels •HHPC-6 large particle counterHHPC-6 large particle counter•VIPS (Video Ice Particle Sampler)VIPS (Video Ice Particle Sampler)

Experimental Layout

OliktokBarrow

Relevant Aerosonde Missions

•Long-duration profiling (slant, box, spiral drift)

•Cloud/aerosol dwell sampling and profiling

•Characterization of mesoscale variability in BL structure.

•Cloud field or surface recon with vis or thermal video camera.

•Lagrangian cloud-tracking