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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


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


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


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


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


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



131, 385 pixels

0.032.4615.59 (%)10.5 (%)71.42 (%)%

BadData


73.8726.1314.8985.1176.0223.97%


Before Enhancement

After Enhancement

Majority of missingclouds are water



131, 385 pixels

0.032.4615.59 (%)10.5 (%)71.42 (%)%

BadData


73.8726.1314.8985.1176.0223.97%


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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