1. Satellite Thermal
Remote Sensing of
Boiling Springs Lake
Jeff Pedelty
NASA Goddard Space Flight Center
Goddard Center for Astrobiology
2. Overview
• Work in progress
• Description of sensors
– Landsat 7’s ETM+
– TERRA’s ASTER
• Acquisitions of Boiling
Springs Lake
• Temperature determinations &
issues
• Future aerial thermal remote
sensing
ASTER: October 19, 2002
3. Landsat 7 ETM+
• Landsat 7 launched April 1999
• ETM+ is the Enhanced Thematic Mapper Plus
• 16-day repeat cycle
• ~15% duty cycle
• Conterminous US imaged each overpass
– Approximately 10:30AM acquisition
• Single thermal band (10.4-12.5)
• 60m spatial resolution across 185km area
• Data purchased from USGS EROS Data Center ($250
for new acquisitions, $600 < 5/31/2003)
4. Landsat 7 acquisitions of BSL
• Goal was to acquire
seasonal sampling at
reasonable cost
• Scan Line Corrector failure
in May 2003 introduced
luck into acquisition process
– Jan 12, 2005 (gap)
– Feb 11, 2004
– May 20, 2005
– August 21, 2004
– August 24, 2005 (gap)
– October 12, 2002 (free)
Thermal: Feb 2004 Jan 2005
True Color
5. Landsat atmospheric correction
• Upwelling thermal emission includes atmospheric
contribution and attenuation
• Requires local meteorology (e.g. NOAA’s National Center
Environmental Prediction) + radiative transfer
(MODTRAN)
• LTOA = T + Lu + (1 - ) Ld
• http://atmcor.gsfc.nasa.gov is a utility to determine , Lu
and Ld for each acquisition
– Barsi (GSFC), Schott (RIT), Hook/Palluconi (JPL)
• Output is land surface temperature (T)
• Vicarious calibration campaigns suggest ~1-2K accuracy
6. Landsat Temperature Results
Date Lup Ldown Peak T
Feb 2004 0.91 0.55 0.94 26
May 2005 0.81 1.24 2.08 35
Aug 2004 0.75 2.04 3.32 42
Oct 2002 0.91 0.64 1.10 35
7. ASTER instrument
• On EOS TERRA mission (launched 12/99)
• Joint US / Japan instrument (JPL)
• “Zoom Lens” of TERRA
• 15m Vis/NIR, 30m SWIR, 90m Thermal IR
– Total of 14 bands, 5 in the thermal infrared
• <16 day repeat cycle
• 60km swath
• Sophisticated multi-band temperature and
emissivity retrieval algorithms
• Extensive vicarious calibration campaigns
10. ASTER Acquisitions of Lassen
Volcano Monitoring Project (http://www.volcano.si.edu/gvp/volcano/index.htm)
11. ASTER Image Log
• Archived data free to NASA researchers (W.
Turner approval required, NASA HQ)
• 53 Acquisitions from May 2000 - May 2006
• 35 Day
– 15 Clear
– 18 Cloudy or Hazy
• 18 Night
– At least 9 Cloudy or Hazy
• Trying to obtain image concurrent w/ VFG mtg.
15. Issues with ASTER Temperatures
• Spillover to ground?
– Point spread function is not rectangular
– Peak pixel does not measure just lake.
– Lower ground temperatures may be bringing down lake
temperatures. Perhaps indicated in night data?
• Shadowing?
– Lower sun angle in winter could result in shadowing of
hotter parts of the lake.
– Night data indicate this is not a major issue.
• Other unknown systematic effects?
16. Aerial Thermal Remote Sensing
• QWIP detector developed at GSFC
– Quantum Well Infrared Photoconductor
• 1024 x 1024 GaAs array
• 4 bands in thermal IR (T and retrieval)
• Investigating aerial (or even hillside) data
collection at BSL later this summer/fall
• Data collection in winter could validate the
ASTER/Landsat temperature trends.
18. Multispectral Thermal Imager
(MTI)
• DOE technology development mission
• Launched ca 2000
• “Point and Shoot” mission, ~10 scenes/day
• 20m resolution thermal data (~5m and ~10m)
– Highest resolution thermal imaging from space
• Operated ~2 years, now in storage on orbit
• No acquisitions of Lassen/BSL, but Yellowstone
data do exist and I have some in hand.
– Perhaps of interest to others
19. ASTER Imaging Opportunities
• ASTER needs to be tasked to take specific
images
• I have requested an allocation with NASA
HQ under the name of NAI ViFoG
• See me if ASTER data would be useful for
any upcoming field campaigns.
