Cloud Contamination in Landsat Imagery: Cloud Contamination in Landsat Imagery: Cloud-Clearing with LTAP-8Cloud-Clearing with LTAP-8

Samuel N. Goward, UMDDarrel L. Williams, NASA/GSFC

Andrew Macatee, UMDMembers:

USGS/NASA Landsat Science Team

Global Land Remote Sensing in Landsat 7 EraYear 2000 L7 “low-cloud” Coverage – USGS EROS

Map Quality Imageryfrom Remote Sensing

• Land Surface Conditions

–Orthorectified (DEMs)

–Surface Reflectance (Atmosphere)

–Cloud and Shadow-Free

Cloud Contamination Problem L7 16-Day Temporal Repeat – Washington DC region, 2000May 11 May 27 June 12

June 28

July 14 July 30

Cloud Contamination (L7 16-Day Temporal Repeat – Oregon region, 2000)

May 19 June 04 June 20

Aug 07July 22July 06

02JUN02

ACCA 16%

10JUN02

ACCA 5%

18JUN02

ACCA 13%

26JUN02

ACCA 10%

04JUL02

ACCA 2%

12JUL02

ACCA 0%

20JUL02

ACCA 71%

28JUL02

ACCA 10%

05AUG02

ACCA 19%

13AUG02

ACCA 0%

21AUG02

ACCA 55%

29AUG02

ACCA 90%

06SEP02

ACCA 0%

14SEP02

ACCA 80%

22SEP02

ACCA 54%

30SEP02

ACCA 10%

Smallsat Constellations? GEOSS?

Hansen, M, T. Loveland, et al, A Constellation of Mixed-Orbit Micro-Satellites for Monitoring Global Land Change and Ecosystem Dynamics, SDSU& USGS EROS

Conceptual Ground Imaging tracks from a Constellation of 4 Polar and 1 Equatorial Satellites.

June 2002

July 2002

August 2002

No Data

September 2002

Cloud/Shadow Clearingthrough Scene Merging

• GOAL– Combine 2 or more scenes to produce a merged

clear land observations (not image compositing).• APPROACH

– atmospheric adjustment– cloud/shadow identification– land/water mask– “stable” land surface conditions

• QUALITY ASSURANCE– Scatter plot evaluation

June 2nd (red) June 18th (blue)

June 28th (blue) August 13th (red)

July 4th (red) August 5th (blue)