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Monitoring the Freeze/Thaw Surface State over Alaska ALOS PALSAR ScanSAR Data
Marzi
Azarderakhsh, The City College of New York, mazarderakhsh@ccny.cuny.edu
Kyle
McDonald, The City College of New York, kmcdonald2@ccny.cuny.edu
(Presenter)
Nicnolas
Steiner, The City College of New York, nick.steiner@gmail.com
Ronny
Schroeder, The City College of New York, ronny.schroder@gmail.com
Bruce
Chapman, JPL, bruce.d.chapman@nasa.gov
Andreas
Colliander, JPL, andreas.colliander@jpl.nasa.gov
John
S
Kimball, University of Montana, johnk@ntsg.umt.edu
Land surface freeze/thaw state is a key state variable governing water, carbon and energy cycles across the high latitudes. Spatially comprehensive ground observation networks suitable for characterizing regional-scale freeze/thaw patterns require large fiscal, technological and human resources to implement. Satellite microwave remote sensing thus offers the unique opportunity for a complete synoptic view of the surface freeze/thaw state that otherwise could not be assessed. A primary goal of NASA’s Soil Moisture Active-Passive (SMAP) mission is characterization of land surface freeze/thaw state for northern latitudes.
We employ multi-temporal imagery from terrain-corrected 100 m resolution ALOS PALSAR ScanSAR, over Alaska to investigate backscatter variability in response to land cover and freeze/thaw state. Despite better temporal resolution, ScanSAR lacks constant incidence angle backscatter observations when compared to higher-resolution (6 - 12.5 m) PALSAR fine beam mode data. Thus a method for the normalization of the ScanSAR backscatter responses to incidence angle variations is applied. Our incidence angle correction algorithm relies on ancillary data from a JERS-based Alaska wetlands map as well as MODIS-based land cover information supporting identification of non-inundated vegetated upland regions. Mosaics of PALSAR fine beam data are utilized to evaluate the accuracy of our backscatter normalization procedure. Ground-based measurements of vegetation and soil temperature are employed to examine linkages between backscatter dynamics and land surface freeze/thaw state. Validated freeze/thaw states produced from the corrected ScanSAR imagery over Alaska will be applied to inform the planned freeze/thaw product to be available from SMAP.
This work has been undertaken partly within the framework of the JAXA ALOS Kyoto & Carbon Initiative. PALSAR data have been provided by JAXA/EORC. Portions of this work were carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
Presentation Type: Poster
Session: Poster Session 1-A
(Tue 11:00 AM)
Associated Project(s):
Poster Location ID: 1
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