Transcript IC2008MHT - fap.if.usp.br

Criando nuvens de gelo em laboratório
Prof. Manfredo H Tabacniks
IFUSP/UMBC/NASA
30 de outubro de 2008
Climate Change 2007: Syntesis Report. IPCC
Climate Change 2007: Syntesis Report. IPCC
Atmospheric scatterers
Wavelength
Rain
 drops
Ice crystals
(hail, etc. greater)
Cloud drops
(typically 5-10 µm)
<
size ≈ wavelength
>
Air molecules
~0.0004 µm
Coarse aerosol
(sand, dust
sea salt)
Most aerosol
(>0.01 µm)
Frequency
C
R
C
D = Diffusion
C = Collision Coalescence
R = Warm Rainout
M = Mixed Phase
G = Glaciation
Suppression of
collision-coalescence
Suppression of
2
warm rainout
1
Clean
Polluted
R
Clean
M
Delay in droplet freezing
D
M
M
2
D
G
M
1
Delay in droplet freezing
G
M
Aerosol Impact on Clouds
Microphysics and
Thermodynamics
D = Diffusion
C = Collision Coalescence
R = Warm Rainout
J. Vanderlei Martins, A. Marshak, L. A. Remer, D.
M = Mixed Phase
Rosenfeld, Y. J. Kaufman, R. Fernandez-Borda, I.
G = Glaciation
Koren, V. Zubko, P. Artaxo – ACPD 7, 4481-4519,
2007Suppression of
1
collision-coalescence
Suppression of
2
warm rainout
Smoke!!!
Cloud Base
0.55mm
2.1mm
Light Scattering Process
light in
Asymmetry
Martins, V. personal comm.
light out
(1-Absorption)
Measuring Clouds
J. Vanderlei Martins, Alexander Marshak, Tobias Zinner, Lorraine Remer, ACP 2006, 2007, 2008.
Ratio 2.1/2.25mm
Proxy for ice/water
separation
14
# observed cases
12
10
reflectance ratio - water
8
reflectance ratio - ice
mi ratio - ice T=-25C
6
simulations
miRange
ratio from
- water
T = 22C
mi ratio - water T = -8C
4
2
0
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
(Reflectances)
Ratio
2.1/2.25mm
 andm1/mi
Ratio
and mi for
2.1/2.25m
1
água -30ºC  gelo
água -30ºC  água 0ºC
água 0ºC  gelo
gelo 0ºC  gelo -30ºC
Fermi (1936, p. 77)
Kostinski & Cantrell, JAS 65 (2008) 2961-71
aerosol generator and reactor
vacuum
pump
light
~100mm
analyzer
dewar
ringing
absorpmeter
P
~m
T
mixer 2
thermal
insulation
T
INEF
reactor
drier
humidifier
cooler
humid air (N2)
cold (freezing) air
drift tube
or/and
diffusion dryer
T
P
~30 cm
Di ~10mm
f1 ~1 L/min
mixer 1
MFM
N2
(soil dust)
+ suitable
solvent
aerosol
generator
Di ~20mm
M
F
M
dry N2
~20 cm
f2
~1-10 L/min