LIDAR & HYPERSPECTRAL IMAGING AT THE NEAR SURFACE OBSERVATORY
An Overview of New Earth Surface Imaging Capabilities at the Bureau of Economic Geology
The Bureau of Economic Geology (BEG) in the Jackson School of Geosciences at UT-Austin has purchased a new airborne instrument system that includes topographic lidar, bathymetric lidar, color/infrared imaging, and hyperspectral scanning. This new system enhances our ability to collect research-grade, high-resolution topographic (land-surface) and shallow bathymetric (lake, river, or seafloor) data. Bathymetric lidar and color/infrared and hyperspectral imaging capa-bilities significantly expand applications into fluvial, lacustrine, and shallow-marine settings and land, water, and vegeta-tion imaging applications across the geosciences. The new system is manufactured by Airborne Hydrography AB (AHAB), under the instrument name Chiroptera. In addition to Chiroptera, which forms the backbone of our capabilities, BEG operates an older topographic lidar system (Optech 1225) that will continue to be available for use, as well as two ground-based systems (including a recently purchased Optech model ILRIS-LR) that are used for high-resolution mapping of outcrops and that allow us to create point-cloud outputs of any object with range capabilities of about 3 km.
BEG has a long history of conducting research- quality lidar surveys along the Texas Gulf Coast, including projects for monitoring Texas coastal (gulf and bay) environments, determining susceptibility of coastal lands to tropical-storm flood-ing and overwash, and quantifying hurricane impact and subsequent coastal recovery. BEG intends to continue working in this area of Texas but expand into terrestrial environments as well. We see substantial opportunities for expanding this data collection and analysis using the new system with its bathymetric and imaging capabilities and providing services to internal and external research communities and multiple State and Federal agencies interested in the geosciences. Other potential applications include (but are not limited to)
• Creating detailed watershed topographic models,
• Characterizing dynamic Earth systems and change over time,
• Studying modern analogs of ancient carbonate and clastic sedimentary rocks,
• Determining uplift and down-drop rates in tectonically active areas,
• Conducting rapid-response surveys where detailed topographic data are critical to hazard assessment, and
• Quantifying vegetation assemblages, invasion of nonnative species through aquatic and terrestrial ecosystems, and estimates of evapotranspiration rates.
BEG's Chiroptera lidar system consists of two active sensors, which make use of near infrared wavelength for topographic, and near infrared+green wavelengths for bathymetry. Imaging system consists of five passive sensors: RGB natural color/color infrared camera, hy-perspectral visible near infrared (VNIR) and shortwave infrared (SWIR) camera, and broad band microwave infrared (MWIR) and longwave infrared (LWIR) camera.
System Specifications Imaging system consists of 50 Megapixel natural color/color infrared DigiCAM camera; Hyperspectral camera-HyperScan VNIR-micro 16, which covers spec-tral range from visible (0.4μm) to near infrared (1 μm) with 255 spectral bands; HyperScan SWIR-2500 sensor, which covers spectral range from 1μm to 2.5μm with 300 spectral bands; Broadband MWIR sensor, which covers spectral range from 3 to 5μm; and Microbolometer longwave infrared (LWIR) sensor, which covers spectral range from 7 to 15μm.
Specifications for the Chiroptera's topographic, bathymetric and hyperspectral capabilities
Among the first studies employing the Bureau's Chiroptera lidar unit is the BEG lidar team's regional lidar survey near Dead Horse, Alaska in July and August, 2013. The survey, covering an area of roughly 450 square kilometers, gathered more than 13 billion topographic data points and more than 1.5 billion bathymetric data points.