Traditional airborne LiDaR has been used successfully to characterize, survey and study fluvial environments. However, because traditional LiDaR uses a near infared wavelength of light, much of the energy transmitted from the instrument is absorbed by water and the rest reflects. Thus, you can get some returns of water-surface topography, but no bathymetric returns beneath the water surface. In coastal environments, bathyetric LiDaRs were developed using a green wavelength of light that would be capable of penetrating the water surface and providing a return of Airborne Lidar Processing System
(ALPS)Experimental Advanced Airborne Research Lidar
(Scanning Hydrographic Opperational Airborne LiDaR Survey)- Now part of Joint Airborne Lidar Bathymetry Technical Center of Expertise
The aim of this research is to determine the utility of Green LiDaR in monitoring rivers both in terms of static-snapshots of habitat characterization and change detection. To do this, a much more sophisticated model of surface representation uncertainty in the DEMs derived from green LiDaR is needed. With a better ability to quantify the spatially variable nature of DEM uncertainty, we can look at how those uncertainties are propagated into analyses derived from those surfaces.
Study Sites & Collaborators
In 2008, Daniele
and I started collaborating to look at the potential of
green LiDaR in change detection work and morphological
. This is the main
As it was one of the few rivers (so far), where
repeat green LiDaR surveys exist, it was an excellent opportunity to
explore its . In a poster presented at AGU in 2009 (Wheaton et al.
we focused initially on a subset of the dataset for Upper Elk Creek
(study-reach shown at left). We have extended the fuzzy inference system
in the DoD
Uncertainty Analysis Software
, to work for green LiDaR and are
currently working on testing and refining this. We next hope to extend
the change detection analysis over the entire surveys for Elk Creek and
Bear Valley Creek to look for distinctive signatures of geomorphic
change between the different systems over system scales.
In the Lemhi
, we are
- McKean J, Nagel D,
Tonina D, Bailey P, Wright CW, Bohn C and Nayegandhi A. 2009a. Remote
Sensing of Channels and Riparian Zones with a Narrow-Beam
Aquatic-Terrestrial LIDAR. Remote Sensing. 1(4): 1065-1096. DOI: 10.3390/rs1041065.
J, Isak D and Wright W. 2009b. Improving
Stream Studies With a Small- Footprint Green Lidar. Eos Trans. AGU.
90(39): 341-342.(See also supplemental
- McKean JA, Isaak DJ and Wright CW. 2008. Geomorphic controls on salmon
nesting patterns described by a new, narrow-beam terrestrial–aquatic
lidar. Ecological Society of America. 6(3): 125-130. DOI:
- Wheaton JM, Tonina D, McKean J and Garrard C.
of geomorphic change on salmonid habitat using a narrow beam
terrestrial-aquatic LiDaR & DEM Uncertainty Accounting, EOS
Transactions. American Geophysical Union: San Francisco, CA, Abstract