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MODIS Level 3:
Future Issues and Considerations
Brent Maddux
MODIS Level 3:
Future Issues and Considerations
Brent Maddux
2001-2004 Cloud Fraction Mean 1
0.5
0
⺋ Do they represent known physical phenomenon well?
⺋ What is L3 saying? ₪ Some limitations of L3 SDSs ₪ How do we interpret the data effectively?
⺋ decrease the limitations ⺋ improve physical meaning and interpretation
How do the MODIS L3 products look:
Going from information to knowledge:
Next steps:
DJF High Cloud DJF All CloudHIRSHIRS
Aqua
TerraTerra
Aqua
1.0
0.8
0.6
0.4
0.2
0.0
Dust or high aerosol events
200 400 600 800 1000mb
Cloud Top Pressure May 1st, 2003
₪ Events last several days
₪ Few if any visible clouds
₪ 750-900 mb
₪ For daily data this can be accounted for, but not weekly or monthly.
0 200 400 600 800
Aqua
Terra
Difference
-800 -400 0 400 800
Cloud Ice Water Path December 2002
Major ice cloud events?
g/m^2
g/m^2
0 150 300
Difference
Cloud Liquid Water Path December 2002
Aqua
Terra
g/m^2
g/m^2
-150 0 150
Major liquid cloud events?
Possible Solutions:
0 15 30
Ocean Mass Concentration
₪ Conduct secondary data processing
₪ Remove questionable data
₪ Create uncertainty products
0 500 1000
Cloud Top Pressure
1x10^-6 g/m^2
mb
0 15 30 45 60
µm
0 200 400 600 800
0 250 500 750 1000
g/m^2
mb
Ice Particle Size and Tropical Deep Convection Evolution
-Uniform re ice over cores
-Isolated deep convection
-Evident cirrus shields
₪ Ice particle size increase away from deep convection
Ice Particle Radius
Ice Water
Path
Cloud Top
Pressure
₪ What would scatter plots show?
Mean SDS Comparisons
₪ Mean phase properties can’t be fully characterized
0 15 30 45 60
0 15 30 45 60
Ice Effective Radius (µm)
Clo
ud T
op P
ress
ure
(m
b)
Ice Effective Radius (µm)
Wate
r Path
of
Ice
(g/m
^2
)0
1
00
0 2
00
0
0 5
00
10
00
IWP vs Re Ice
CTP vs Re Ice
₪ cloud regimes
₪ cloud height or phase
₪ particle size or path
Ambiguous
Property comparison limitations:
₪ data subsets (large particle size, phase, etc)
₪ multiple data set comparison
Possible solutions:
₪ new joint histogram (in collection 5)
₪ means of property subsets
₪ multi dimensional histograms
Mean Ice Properties:
Summary and Conclusions:
₪ Implement a secondary processing between L2 and L3.
₪ Add additional SDSs
1) that can be used to further compare the microphysical properties of clouds and other atmospheric parameters
2) that allow for a further intuitive interpretations
3) near nadir.
Image courtesy of MODIS Rapid Response Project at NASA/GSFC
Nov 2001
October 2002