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Enhanced Cloud Algorithm From Collocated CALIPSO,CloudSat and MODIS
Sunny Sun-Mack1, Patrick Minnis2, Yuhong Yi1, Yan Chen1, Sharon Gibson1
Qing Trepte1, Pat Heck3, Seiji Kato2, Bruce Wielicki2 (PI)
(1) SSAI, Hampton, VA, USA(2) NASA Langley Research Center, Hampton, VA, USA
(3) CIMSS, Wisconsin, USA
CERES STM May 6-8, 2008, Newport News, VA
• Develop an integrated data set to provide global vertical profilesof aerosols, clouds, and broadband radiative fluxes using combinedNASA A-Train data from
- Aqua CERES (broadband fluxes constrain RTM calcs)- MODIS aerosols (MOD04)- CERES-MODIS cloud properties (from CERES algorithms)- CALIPSO lidar aerosol and cloud data- CloudSat CPR cloud data
• Use CALIPSO and CloudSat data products to
- Develop improved algorithms for CERES-MODIS Ed3 clouds,and future NPP cloud algorithm.
Objectives
Compute ice & water phase solution, select most likely phase based ontemperature, model fits, LBTM classification, 2.1-µm reflectance
DAY: VISST (Visible Infrared Solar-Infrared Split-Window Technique)0.65, 3.8, 10.8, & 12.0 µm see Minnis et al. (1995, 1998, 2007b)
NIGHT: SIST (Solar-infrared Infrared Split-Window Technique) 3.8, 10.8, & 12.0 µm see Minnis et al. (1995, 1998, 2007b)
SNOW (DAY): SINT (Solar-Infrared Infrared Near-Infrared Technique) 2.1, 3.8, 10.8, & 12.0 µm see Platnick (JGR, 2001), Minnis et al. (2007b)
CERES-MODIS Cloud Retrieval Methodology (Apply CERES algorithms to MODIS imager data)
Freq
uenc
y
CALIPSOExtinction QCFlag=0 & 1
Transparent Clouds
CALIPSO Optical Depth
CALIPSOExtinction QCFlag=16 & 17 Fr
eque
ncy Opaque Clouds
CALIPSO Optical Depth Histogram (Single Ice Layer) for July 2006
0 0.5 1 1.5 2 2.5 3
0 0.5 1 1.5 2 2.5 3
Enhanced Cloud Retrieval Along A-Train Track
For single layer and transparent CALIPSO clouds:- If CALIPSO optical depth > 4, no Tcld adjustment
- If CALIPSO optical depth < 4, and if CERES-MODIS cloud is outside of CALIPSO cloud top andbase
Then adjust CERES-MODIS cloud temperatureto CALIPSO value, redo some of the streamlinedVISST / SINT/ SIST to try to retrieve the rest ofcloud properties (tau, size….)
Possible CERES-MODIS Cloud Phase Changes (Before and After the Enhancement)
CERES-MODIS Cloud Phase
AfterEnhancement
BeforeEnhancement
For single transparent calipso clouds:
Before and After Cases
Clear CAL CSat Aero BothCld Ice wat (CERES)
July 15, 2006, Hour 01 0
1
2
3
4 km
Before Enhancement
Day Time
North Pacific Ocean
Clear CAL CSat Aero BothCld Ice wat (CERES)
July 15, 2006, Hour 01 0
1
2
3
4 km
Before Enhancement
After EnhancementCERES Water Cloud
CERES Clear
0
1
2
3
4
Day Time
North Pacific Ocean
2
4
6
8
1
0 km
2
4
6
8
10
Clear CAL CSat Aero BothCld Ice wat (CERES)
July 15, 2006, Hour 01
CERES Ice
After Enhancement
Before Enhancement
CERES Water
Night Time
North Siberia
2
4
6
8
1
0 km
2
4
6
8
10
Clear CAL CSat Aero BothCld Ice wat (CERES)
July 15, 2006, Hour 01
After Enhancement
Before Enhancement
CERES Clear
CERES Water
Night Time
North Siberia
2
4
6 8
10
12
14
km
2
4
6
8
10
12
14
July 15, 2006, Hour 01
CERES Ice
Before Enhancement
After Enhancement
Night Time 0 .1 .2 .5 > .5
CALIPSO Optical Depth
West Europe
CERES Clear
2
4
6 8
10
12
14
km
2
4
6
8
10
12
14
July 15, 2006, Hour 01
CERES Water
CERES Ice
Before Enhancement
After Enhancement
Night Time 0 .1 .2 .5 > .5
CALIPSO Optical DepthWest Europe
2
6
10
1
4
16
July 15, 2006, Hour 01
CERES Water
CERES Ice
Before Enhancement
After Enhancement
Night Time 0 .1 .2 .5 > .5
CALIPSO Optical Depth
2
6
10
14
16 k
m2
6
1
0
14
1
6
West Africa
3 Days of Merged CALIPSO, CloudSat and MODISJuly 2006, day 08, 15, and 22
(1) Non-Polar Region(2) CALIPSO: Single and Transparent Layer(3) CALIPSO: Optical Depth < 4
131, 385 pixels
0.032.4615.59 (%)10.5 (%)71.42 (%)%
BadData
NoRetWaterIceClearCERES(Before)
73.8726.1314.8985.1176.0223.97%
WaterIceWaterIceWaterIceCERES(After)
Before Enhancement
After Enhancement
3 Days of Merged CALIPSO, CloudSat and MODISJuly 2006, day 08, 15, and 22
(1) Non-Polar Region(2) CALIPSO: Single and Transparent Layer(3) CALIPSO: Optical Depth < 4
131, 385 pixels
0.032.4615.59 (%)10.5 (%)71.42 (%)%
BadData
NoRetWaterIceClearCERES(Before)
73.8726.1314.8985.1176.0223.97%
WaterIceWaterIceWaterIceCERES(After)
Before Enhancement
After Enhancement
Majority of missingclouds are water
3 Days of Merged CALIPSO, CloudSat and MODISJuly 2006, day 08, 15, and 22
(1) Non-Polar Region(2) CALIPSO: Single and Transparent Layer(3) CALIPSO: Optical Depth < 4
131, 385 pixels
0.032.4615.59 (%)10.5 (%)71.42 (%)%
BadData
NoRetWaterIceClearCERES(Before)
73.8726.1314.8985.1176.0223.97%
WaterIceWaterIceWaterIceCERES(After)
Before Enhancement
After Enhancement
CERESphase
successfulrate ~ 80%
35.0664.94Water-->Water (74%)
77.8722.13Water-->Ice (26%)
40.7559.25Ice-->Water (15%)
46.5453.46Ice-->Ice (85%)
64.6135.39Clear-->Water (76%)
97.752.25Clear-->Ice (24%)
Less than0.3(%)
Greaterthan 0.3
(%)
CALIPSO TauCERES(before-->after)
Each Phase Category of CALIPSO Optical Depth > 0.3 and <= 0.3
Almost all the missing ice clouds are the clouds with tau < 0.3We have picked all the ice clouds that we possiblly could based onMODIS sensitivity
0.3
Clear--> Ice
35.0664.94Water-->Water (74%)
77.8722.13Water-->Ice (26%)
40.7559.25Ice-->Water (15%)
46.5453.46Ice-->Ice (85%)
64.6135.39Clear-->Water (76%)
97.752.25Clear-->Ice (24%)
Lessthan 0.3
(%)
Greaterthan 0.3
(%)
CALIPSO TauCERES(before-->after)
Assuming CF for single transparent cloud ~ 20%, then CF for missing water cloudwith tau > 0.3 is ~ 4% (0.2 x 0.71 x 0.76 x 0.35), missing water CF ~ 7% for tau < 0.3.
Each Phase Category of CALIPSO Optical Depth > 0.3 and <= 0.3
CF ~ 4% CF ~ 7%
0.3
Clear--> Water
21.29
4.81
20.60
1.68
30.73
5.62
Undetermined(%)
60.8917.82Water-->Water(74%)
14.9780.22Water-->Ice (26%)
69.869.54Ice-->Water (15%)
4.2594.07Ice-->Ice (85%)
52.716.58Clear-->Water (76%)
12.581.87Clear-->Ice (24%)
Water(%)
Ice(%)
CALIPSO PhaseCERES(before-->after)
Cloud Phase Comparisons between CALIPSO and CERES
• CALIPSO is confident with it’s ice phase• Enhanced CERES ice cloud phase is ~ 80-95 % in agreement with CALIPSOice phase
CERES Optical Depth After the Enhancement Comparedwith CALIPSO Optical Depth
Clear (before enhancement) ---> Cloud (after enhancement)
CERE
S O
ptic
al D
epth
CALIPSO Cloud Optical DepthOptical Depth Diff (CERES-CALIPSO)
0.1 x 0.1: 32.40 %0.3 x 0.3: 55.65 %0.5 x 0.5: 66.99 %1.0 x 1.0: 82.50 %
CERES Optical Depth After the Enhancement Comparedwith Calipso Optical Depth
0.1 x 0.1: 4.14 %0.3 x 0.3: 20.8 %0.5 x 0.5: 32.1 %1.0 x 1.0: 49.6 %
Cloud (before enhancement)--> cloud (after enhancement)
CERE
S O
ptic
al D
epth
CALIPSO Cloud Optical DepthOptical Depth Diff (CERES - CALIPSO)
CERES Cloud Top Height Before the EnhancementCompared with Calipso Cloud Top Height
Water Cloud (before enhancement)--> Water Clouds (after)
CERE
S Cl
oud
Top
Heig
ht (k
m) (
befo
re)
CERE
S Cl
oud
Top
Heig
ht (k
m) (
befo
re)
CALIPSO Top Height (km) CALIPSO Top Height (km)
Tau > 0.3 Tau <= 0.3
CERES Cloud Top Height Before the EnhancementCompared with Calipso Cloud Top Height
Ice Cloud (before enhancement)--> Ice Clouds (after)
CERE
S Cl
oud
Top
Heig
ht (k
m) (
befo
re)
CERE
S Cl
oud
Top
Heig
ht (k
m) (
befo
re)
CALIPSO Cloud Top Height (km) CALIPSO Cloud Top Height (km)
Tau > 0.3 Tau <= 0.3
CERES Cloud Particle Size Comparisons(Before and After the Enhancement )
After the enhancement, if still no retrieval De=20 um and re=10 um
Ice Diameter (um) (Before) Water Radius (um) (Before)W
ater
Rad
ius
(um
) (Af
ter)
Ice
Diam
eter
(um
) (Af
ter)
Day Time
Summary and Future PlanSummary and Future PlanFor single transparentFor single transparent layer,layer, tau tau < 4, non-polar region:< 4, non-polar region:
•• Almost all the CERES missing ice cloud (~ 3%) is thinAlmost all the CERES missing ice cloud (~ 3%) is thin cirrus with cirrus with tau tau <<0.30.3
•• Missing water cloud fraction ~ 4% for Missing water cloud fraction ~ 4% for tau tau > 0.3 (room to improve for> 0.3 (room to improve forCERES), 7% for CERES), 7% for tau tau < 0.3< 0.3
• Enhanced CERES ice cloud phase ~ 80-95 % in agreement withCALIPSO ice phase
• After the enhancement, all CERES cloud properties have somecorrelation with CALIPSO.
• The results are very preliminary, only 3 days. Need to look at themore data, more months or years, separated by day / night, ocean /land, polar / non-polar….
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