# Presentation: 725859

## Vertical Motions and Microphysics in Arctic Mixed-Phase Stratus

- Matthew Shupe

*With contributions from*
- Pavlos Kollias, Ed Luke, Ola Persson,
- Greg McFarquhar, Michael Poellot, Ed Eloranta
- John Daniel, Gijs DeBoer, Chuck Long, Dave Turner
- Hans Verlinde, Amy Solomon

*ARM Science Team Meeting 2007*

## Status of Ground-Based Observational Methods

- Cloud Classification

- M-PACE
- Vertical Motions & Microphysics

- A Conceptual Model

_**Topics**_

## Status of Ground-based Retrievals

- Phase
- Classification

- Microphysics

- Radiation

- Dynamics

## Status of Ground-based Retrievals

_**Status of Ground-based Retrievals**_

- Boundaries

- LWP

- IWP

- Phase
- Balance

- Optical
- Depth

- Vertical
- Velocity

## The Spectrum of our Knowledge

- “Known”

_**The Spectrum of our Knowledge**_

- Unknown

- Certain

- Phase
- Classification

- Cloud
- Boundaries

- Vertical
- Velocity

- LWP

- Liquid Re
- (thin clouds)

- IWC/IWP

- Ice Re

- Phase balance
- (layer)

- LWC
- (adiabatic)

- Liquid
- optical depth

- Ice
- extinction

- Ice
- optical depth

- Turbulent
- dissipation rate

- Aerosol
- profile

- LWC
- No assumption

- Liquid Re
- (Thick clouds)

- Liquid
- extinction
- (thick)

*From Ground-based Sensors*

- Phase balance
- (resolved)

- Liquid
- extinction
- (thin)

- Radiative
- Forcing

- Heating
- Rate

- Need further validation

- Need new methods

## Cloud Phase Classification

- MMCR Doppler spectra-based technique

_**Cloud Phase Classification**_

*Slide from P. Kollias & E. Luke*

## Vertical Velocity     

- Identify cloud liquid
- Spectral broadening corrections
- Left edge of spectrum plus corrections

*Assumption*:  Liquid droplets trace vertical air motions.

_**Vertical Velocity **_**    **
**     **_**Retrieval**_

## An Example

_**An Example**_

## Aircraft Comparisons at M-PACE

- Different
- Air mass?

## Results from M-PACE: Single layer stratus

- More liquid and less ice than SHEBA

- Mean upward motion in cloud

## Time Series Analysis

_**Time Series Analysis**_

- Dominant scales:
- 0.7 – 10 km

- Dominant scales:
- 2 – 10 km

## Cloud Response to Vertical Motions

## In Focus

_**In Focus**_

- Motions at 7, 2, and 0.5 km wavelengths

- Ice forms in updrafts near cloud top,
- falls out.

- Liquid persists throughout cycle, supported by almost complete ice fallout

## A Conceptual Model

_**A Conceptual Model**_

**          **_**Updraft**_
- Cloud top lifts
- LWC near adiabatic
- Ice particle nucleation
- Limited ice concentration
- IWC maximum near liquid base
- RH ~ 100% in cloud layer

**       **_**Downdraft / neutral**_
- Cloud top descends
- LWC sub-adiabatic (evaporation)
- Ice particles fall out
- IWC negligible
- RH < 100% in cloud layer

## Representative?

_**Representative?**_

- Change at the coastline?

- Barrow

## Conclusions

-  ***Still some gaps in our abilities:***
- Most importantly the vertical dist’n of liquid properties
-  ***New classification methods:***
- Radar Doppler spectra are rich with information
-  ***Vertical velocity retrievals:***
- Provide for a better understanding of microphysical-dynamical processes
-  ***Conceptual model:***
- Describes cloud structure in autumn at Barrow