1

Cloud microphysical properties in cirrus during ATTREX

Sarah Woods1, Sara Lance1, Eric Jensen2, Nick Krause1 , R. Paul Lawson1, Bruce Gandrud1, Troy

Thornberry3, Andrew W. Rollins3, Paul Bui2

1 SPEC Incorporated, Boulder, CO2 NASA Ames Research Center, Moffet Field, CA3 NOAA ESRL Chemical Sciences Division, Boulder, CO

2

Instrument Resolution Measurement Range

Measurement Technique

Hawkeye-CPI (cloud particle imager) 2.3 um 2.3 um - 2.36 mm CCD (camera)

Hawkeye-FCDP 2 um 1 um - 50 um Forward Scattering

Hawkeye-2D-S 10 um 10 um - 1.28 mm Diode Array (128)

Habit Classification Feb 16, 2014

3

Spheroids

Columns

BuddingRosettes

Rosettes

Habit classification following Lawson et al.

(2006)

200 um

Habit Occurrence Feb 16, 2014

4

“spheroid”

200 um

Size Distributions

5

• If using FCDP, take a look at 2D-S as well

• Reliable FCDP measurements require higher bin counts per second

March 9-10

6

March 9-10

7

March 9-10

8

Region 1

R1

March 9-10

9

Region 1R1

R1 March 9-10

10

Region 1

Region 2

R2

R1 March 9-10

11

Region 2

R2

March 9-10

12

R1 March 9-10

13

Region 1

Region 2

Region 3

R3R2

March 9-10

14

Region 3

R3R2R1

March 9-10

15

Summary• High resolution images of cirrus particles allow for habit

classification• Predominantly spheroid

• Small irregulars

• Small percentage of columns, plates, rosettes, bullet rosettes

• Continued investigation of habit classification as a function of RHice and temperature for varying cirrus types

• Good correlation between particle probes and NOAA water vapor observations

• Evidence of homogeneous nucleation• For questions on Hawkeye or FCDP data please contact us

16

Size Distributions

17

• If using FCDP, take a look at 2D-S as well

• Reliable FCDP measurements require higher bin counts per second

18

SSice vs Temperature Feb 16

19