1. X X X Cloud Variables Top pressure Cloud type Effective radius
Particle phase X
Particle shape
Optical thickness X
Cloud cover/cloud detection
Liquid water
Bottom pressure

2. Bottom pressure/heigth
A chi serve? Aviazione, bilancio radiativo (LW bottom)
Come si stima?
- Spessore (topmolecolare-topO2)
- LWC
- Tipo (climatologia)
- cloud radar

5. Cloud type
A chi serve

7. +

8. +
g = 0.85
= 0.86
= 0.87
Bidirectional reflectance
Optical thickness

9. Ice particle habit
A chi serve

10. Ice Cloud Microphysics CRYSTAL-FACE, A. Heymsfield
25 July 2002
(VIPS)
25 July 2002
(VIPS)
CPI: 7 July 2002
S. Platnick, ISSAOS ‘02

11. Ice cloud microphysics, cont.

12. MODIS ice crystal library habits/shapes
S. Platnick, ISSAOS ‘02

13. Yang et al., “Single-scattering properties of complex ice crystals in terrestrial
Atmosphere”, Contr. Atmos. Phys., 71, , 1998.

14. Effective radius and optical thickness

15. CLM: Cloud microphysical properties

16. mod05

17. Liquid Water Clouds - ocean surface
Retrieval of tc and re
The reflection function of a nonabsorbing band (e.g., 0.86 µm) is primarily a function of optical thickness
The reflection function of a near-infrared absorbing band (e.g., 2.14 µm) is primarily a function of effective radius
clouds with small drops (or ice crystals) reflect more than those with large particles
For optically thick clouds, there is a near orthogonality in the retrieval of tc and re using a visible and near-infrared band
Liquid Water Clouds - ocean surface

18. Ice Clouds - ocean surface
Retrieval of tc and re
Ice Clouds - ocean surface
The reflection function of a nonabsorbing band (e.g., 0.86 µm) is primarily a function of optical thickness
The reflection function of a near-infrared absorbing band (e.g., 2.14 µm) is primarily a function of effective radius
clouds with small drops (or ice crystals) reflect more than those with large particles
For optically thick clouds, there is a near orthogonality in the retrieval of tc and re using a visible and near-infrared band

19. Cloud Optical & Microphysical Properties Retrieval Example
Liquid Water Clouds - ocean surface
Liquid Water Clouds - ice surface

20. Multiple scattering water cloud examples
reflectance vs. asymmetry parameter (g)
1-v0 = 0
g = 0.85
= 0.86
= 0.87
Bidirectional reflectance
Platnick_LAquila
Optical thickness
g = < cos(Q) p(Q)> ~ re
S. Platnick, ISSAOS ‘02

21. Multiple scattering - reflectance water cloud examples
reflectance vs. asymmetry parameter (g)
reflectance vs. 1-v0 (R ~1-v0N)
1-v0 = 0
1-v0 = 0
g = 0.85
g = 0.85
= 0.86
= 0.87
1-v0 = 0.006
Bidirectional reflectance
Platnick_LAquila
1-v0 = 0.020
1-v0 = 0.006
Optical thickness
Optical thickness
g = < cos(Q) p(Q)> ~ re
1-v0 a re
S. Platnick, ISSAOS ‘02

22. Ship track schematic courtesy, P. Durkee N ~ 40 cm-3 W ~ 0.30 g m-3
Platnick_LAquila
N ~ 40 cm-3
W ~ 0.30 g m-3
re ~ 11.2 µm
N ~ 100 cm-3
W ~ 0.75 g m-3
re ~ 10.5 µm
S. Platnick, ISSAOS ‘02

23. Level-1B Image of California Stratus with Ship Tracks
April 25, 2001
marine stratocumulus
Red = 0.65 µm
Green = 0.56 µm
Blue = 0.47 µm

24. Level-1B Image of California Stratus with Ship Tracks
April 25, 2001
3.7 µm band
Red = 0.65 µm
Green = 0.56 µm
Blue = 0.47 µm

25. CLM: Cloud microphysical properties
Cloud effective droplet radius
Cloud optical thickness

26. Cloud phase

28. IR thermodynamic phase retrieval (B. Baum, S. Ackerman, S
IR thermodynamic phase retrieval (B. Baum, S. Ackerman, S. Nasiri, NASA LaRC, U. Wisconsin/CIMSS)
ice
water
Platnick_LAquila
Absorption coefficient (cm-1)
ice
16.7
14.3
12.5
11.1
10.0
9.1
8.3 µm
S. Platnick, ISSAOS ‘02

29. Platnick_LAquila
Nasiri et al., 2002
S. Platnick, ISSAOS ‘02

30. Bispectral IR algorithm
Uncertain
Mixed
Phase
Effect of multilayered clouds
Ice
Platnick_LAquila
Liquid
Water No
Retrieval
S. Platnick, ISSAOS ‘02

31. CLP Cloud phase

32. Ice/Water Clouds Separate in 8.6-11 vs 11-12 um BT plots
Example.

33. Cloud Composition MODIS Image Over Kansas - 21 April 1996 Contrails
Ice Cloud
Infrared Temperature Difference m (Band 29) m (Band 31)
Contrails
Water Cloud
Infrared Temperature Difference m (Band 31) m (Band 32)