USGS - California Fire Response -Hyperspectral Remote Sensing

• Collection of airborne hyperspectral data (HyMap sensor)

• Conversion to reflectance using Radiative Transfer Ground Calibration (RTGC) method

• Spectral analysis to characterize and map ash and ash chemistry

Spectral Characteristics of HyMap

Spectral Range: ~ 400-2500 nmSpectral Sampling: ~ 15 nm (126 channels)Spectral Bandpass: ~ 15 nm

Spatial Swath: ~ 2 kmPixel Size: ~ 4 m

HyMap Data Coverage

• Harris Fire 11/15/2007

• Witch/ Poomacha

Fires 11/19/2007

During Hymap collection, field calibration sites were measured with a field spectrometer.

Orange pins = Ash sampling sites.

Content of Hyperspectral Data

• The shapes of spectral reflectance curves can be related to specific materials and chemical concentrations in materials

Example HyMap strip – Witch Fire

Results: AVIRIS Maps

GreenGreenVegetationVegetation

Mineral/AshMineral/Ash

Mineral-1Mineral-1mm

Mineral-2Mineral-2mm

Dry ConiferDry Conifer

Dry & GreenDry & GreenConiferConifer

Straw mattingStraw matting

Ash/CharcoalAsh/Charcoal

Straw mattingStraw matting & Green grass& Green grass

GreenGreenVegetationVegetation

Mineral/AshMineral/Ash

Mineral-1Mineral-1mm

Mineral-2Mineral-2mm

Dry ConiferDry Conifer

Dry & GreenDry & GreenConiferConifer

Straw mattingStraw matting

Ash/CharcoalAsh/Charcoal

Straw mattingStraw matting & Green grass& Green grass