HR: 16:30h
AN: H14B-03    [Abstracts]
TI: C-band Radar Observes Water-level Change in Coastal Louisiana Swamp Forests
AU: Rykhus, R
EM: rykhus@usgs.gov
AF: SAIC, USGS EROS, 47914 252 Street, Sioux Falls, SD 57198 United States
AU: * Lu, Z
EM: lu@usgs.gov
AF: SAIC, USGS EROS, 47914 252 Street, Sioux Falls, SD 57198 United States
AU: Crane, M
EM: mcrane@usgs.gov
AF: USGS EROS, 47914 252 Street, Sioux Falls, SD 57198 United States
AU: Kwoun, O
EM: okwoun@usgs.gov
AF: SAIC, USGS EROS, 47914 252 Street, Sioux Falls, SD 57198 United States
AU: Wells, C
EM: cmwells@usgs.gov
AF: USGS, National Wetlands Research Center, Lafayette, LA 70506 United States
AU: Swarzenski, C
EM: cswarzen@usgs.gov
AF: USGS, Water Resources District Office, Baton Rouge, LA 70806 United States
AB: It is commonly recognized that C-band (wavelength of 5.7 cm) radar pulses backscatter from the upper canopy of swamp forests. Consequently, interferometric analysis of C-band imagery has not been exploited to study water-level changes in swamp forests. Using C-band ERS-1 and ERS-2 radar images, we show that interferometric synthetic aperture radar (InSAR) images maintain adequate coherence over swamp forests composed of moderately dense trees with a medium-low canopy closure in southeastern Louisiana over a time window of a few months. The InSAR images acquired during leaf-off seasons (October - April) can maintain coherence up to 5 years. This unexpected phenomenon is believed to be due to double-bounce returns of C-band radar signal reflecting off tree trunks and the water surface. The persistent coherence of C-band radar signal over swamp forests allows us to measure changes in water-level beneath tree cover with an unprecedented degree of vertical accuracy. Future InSAR images with shorter repeat times will be capable of characterizing the temporal evolution of water-level changes to improve hydrological modeling predictions and enhance assessments of future flood hazards over wetlands.
UR: http://edc.usgs.gov/Geo_Apps/
DE: 1850 Overland flow
DE: 1855 Remote sensing (1640)
DE: 1895 Instruments and techniques: monitoring
DE: 6924 Interferometry (1207, 1209, 1242)
SC: Hydrology [H]
MN: Fall Meeting 2005