Status of the MODIS Land-SurfaceTemperature/Emissivity Product:

New Validations and Improvements

Zhengming WanUniversity of California, Santa Barbara

July 24, 2002

MODIS Science Team Meeting

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Credit also to:

Validation of MODIS LST Products

Simon Hook (JPL), Zhao-liang Li (GRTR/LSIIT, France),

William C. Snyder (May 1995 – April 1997), Yulin Zhang (Dec 1994 -), Qincheng Zhang (July 2001 -),

Pengxin Wang (Sept 2001 – Feb 2002), Xialin Ma (Oct 1997 – Mar 2001), Ruibo Wang (Apr 1998 –

May 2001), Yuezhong Feng (1997 – 1998).

Special thanks for supports fromNASA HQ, EOS Project Office, MODIS Science Team, MSST,

GSFC DAAC, EDC DAAC, NSIDC, MODLAND, MCST, SDDT, MODAPS, LDOPE,

NASA/Ames/Airborne Sensor Facility, NASA/JPL/AVIRIS Team, NASA Dryden Flight RC,

Robert Jellison (UCSB/SNARL), Richard E. Plant (UC Davis),

Stan Hunewill and Jeff Hunewill (Hunewill Guest Ranch), Sophie Moreau (ABTEMA, Bolivia),

Arnaud Yves & Roland Bosseno (IRD, Bolivia), etc.

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Outline of the Presentation

Validations of the MODIS LST product

Plan for the Fall of 2002

Conclusion of the MOD11 Status

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New improvements of the MODIS LST code

New LST results from Terra and Aqua MODIS data

Validation results of the MODIS LST products

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A LST validationpaper is in pressfor Remote Sensingof Environment.

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50 100 150 200 250 300 350

data day

Ts

(K)

mod11A1_tahoe_day

ts_insitu_tahoe_day

mod11A1_tahoe_nit

ts_insitu_tahoe_nit

Comparison of LSTs in MOD11A1 with those measured by Dr. Hook in Lake Tahoe in 2000

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Seasonal variation shown by the MODIS LSTs at accuracy better than 0.6K.

Validation of the MODIS LST product in wetatmospheric conditions: (1) three TIR radiometers

deployed in a rice field in State of Mississippi

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Since late June 2002.

Validation of the MODIS LST product in wetatmospheric conditions: (2) five TIR radiometers

deployed in a soybean field in State of Mississippi

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Since late June 2002.

New improvements of the MODIS LST code

2. Use the MODIS BRDF product (MOD43B1C) as input.

5. The Terra and Aqua MODIS data may be used jointly in the

3. the range of viewing zenith angle separated into 5 sub-ranges

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1. Lake pixels in clear-sky at MOD35 confidence 66% and higherare processed (per suggestions from Simon Hook and others).

(0-24, 24-38, 38-49, 49-58, 58-65) instead of 4.

4. Parallel processing for data of odd days and even days so thatthe production rate may be doubled.

day/night LST algorithm for better spatial and angular coverage.

6. A split-window method was incorporated into the day/nightalgorithm to ensure that the retrieved emissivities can be usedby split-window algorithms.

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0.8

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1.6

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20 21 22 23 24 25 27 28 29 30 31 32 33 34 35 36

band

NEdT

( K

)Terra MODIS

Aqua MODIS

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-0.2

0

0.2

0.4

0.6

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1

20 22 23 29 31 32

band

cali

brat

ion

bias

(K

)

Terra MODIS

Aqua MODIS

Estimated bias in calibration ofMYD021KM.A2002177.0600 over Lake Titicaca compared with bias in Terra MODIS TIRbands (Wan et al 2002).

Estimated NEdT values based on L1Bgranules MOD021KM.A2002177.0300and MYD021KM.A2002177.0600 (June26, 2002) over Lake Titicaca

Estimate of the NEdT and Calibration Accuracy of the early Aqua MODIS TIR data

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K

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LSTs retrieved from Terra and Aqua MODIS dataon data days 176-177 and 185-190 (06/25-26 & 07/4-9)

daytimeTerra

nighttimeTerra

daytimeAqua

nighttimeAqua

to show spatial distribution of the diurnal variation

in data days 176-177 and 185-190 (06/25-26 & 07/4-9)Surface emissivities retrieved by Terra and Aqua MODIS

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Color composite image with emissivities in bands 29, 22, and 20 as RGB components.

Color composite image with emissivities inbands 29, 31, and 32 enhanced by the equaliz-ation histogram method as RGB components.

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0.65

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0.75

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0.85

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0.95

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3 4 5 6 7 8 9 10 11 12 13 14 15

wavelength (micron)

emis

sivi

ty

sand1

sand2

sand3

sand4

sahara_em20

sahara_em22

sahara_em23

sahara_em29

sahara_em31

sahara_em32

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Compare the retrieved surface emissivities over SaharaDesert to those measured from sand samples in the Lab

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0.91

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wavelength (micron)

emis

sivi

ty

water_10deg

water_34deg

water_48deg

caspian_em20

caspian_em22

caspian_em23

caspain_em29

caspian_em31

caspian_em32

Compare the retrieved surface emissivities in Caspian Sea to the calculated water surface emissivities

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Plan for the Fall of 2002

1. To validate the MODIS LST product in wet atmospheric

2. To conduct field campaigns in the areas of Mono Lake, Lake

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conditions with field measurement data in State of Mississippi.

Tahoe, and Walker Lake in CA and NV in the period of August5-16 with MAS day/night flights around the Terra and Aquaoverpass times to estimate the calibration of Aqua MODISTIR bands and to validate the MODIS LST product.

Conclusion of the MOD11 Product Status

1. The LST products were validated within 1K with insitu LSTs in 19 cases (including 14 cases over land sites)in the LST range of 263-322K and the atmospheric cwvrange of 0.4-3.0cm, and Simon Hook’s Lake Tahoe data

2. Validated MODIS LST products will be generatedin the next reprocessing (collection 4 by Oct. 2002)

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in 2000-2002.

while validation activities will be continued especiallyfor the Aqua MODIS LST products.