What is RADAR?What is RADAR?

Active detecting and ranging sensor Active detecting and ranging sensor operating in the microwave portion of the EM operating in the microwave portion of the EM spectrumspectrum

Measures backscatter influenced by:Measures backscatter influenced by:

‘‘Side looking’ with polarization capabilitiesSide looking’ with polarization capabilities

i. Dielectric properties

ii. Incidence angle

iii. Structural properties

iv. Polarization

v. Frequency

RADAR and BiomassRADAR and Biomass

Biomass is Biomass is positively correlated positively correlated with SAR with SAR backscatterbackscatter

The relationship is The relationship is almost exactly almost exactly linear, as linear, as backscatter backscatter intensity increases, intensity increases, biomass increases. biomass increases.

RADAR and Biomass (cont)RADAR and Biomass (cont)

Forest scattering types, a parameter Forest scattering types, a parameter within the biomass regression, varies within the biomass regression, varies between forest cover types:between forest cover types:

i. Surface and volume scattering from the tree crown

ii. Ground-to-trunk scattering

iii. Direct ground scattering

iv. Direct trunk scattering

v. Ground-to-crown scattering

Limitations and Limitations and benefits benefits of RADAR of RADAR

LimitationsLimitations Single bandSingle band Sloping terrainSloping terrain Structure specific- Structure specific-

young vs old standsyoung vs old stands Possible saturation levelPossible saturation level SpeckleSpeckle Layering and Layering and

ShadowingShadowing

BenefitsBenefits Atmospheric interactionsAtmospheric interactions Canopy PenetrationCanopy Penetration Correlation with Correlation with

backscatterbackscatter Accuracy dependent on Accuracy dependent on

data and information of data and information of forest typeforest type

Active sensorActive sensor

Application of RADAR Application of RADAR and Biomassand Biomass

Research on the possibility of operating a P-Research on the possibility of operating a P-band SAR from a satellite to produce a band SAR from a satellite to produce a consistent global map of the Earth's forests, consistent global map of the Earth's forests, in particular for mapping variations in in particular for mapping variations in biomass levels for use in global carbon cycle biomass levels for use in global carbon cycle

and climate change studiesand climate change studies

Estimated biomass (in Estimated biomass (in tons/ha) from an AIRSAR tons/ha) from an AIRSAR image of the Manu National image of the Manu National Park in Peru in the Amazonian Park in Peru in the Amazonian rain forestrain forest

Regressions Regressions with error with error ranging from ranging from 10-24%10-24%

Application of RADAR and Application of RADAR and BiomassBiomass

Using SAR imaging to Using SAR imaging to locate individual trees locate individual trees

Trees are represented by Trees are represented by bright spots. Black circles bright spots. Black circles

indicate ground data of tree indicate ground data of tree locationslocations

Location and size of individual trees Location and size of individual trees can help determine structure of the can help determine structure of the forest to get better biomass forest to get better biomass estimatesestimates

What is LIDAR?What is LIDAR? LIDAR (LIDAR (LiLight ght DDetection etection aand nd

RRanging) is an active, high anging) is an active, high resolution laser scanner resolution laser scanner generally using NIR generally using NIR wavelengthswavelengths

LIDAR sends a short pulse of LIDAR sends a short pulse of laser light energy and laser light energy and measures time until return measures time until return to determine elevation and to determine elevation and stores as (x,y,z)stores as (x,y,z) Some also record the "waveform" of the returned signal, which Some also record the "waveform" of the returned signal, which reveals where—in the space between the ground and the tree topsreveals where—in the space between the ground and the tree tops—the foliage, trunk, and branches are concentrated, multiple —the foliage, trunk, and branches are concentrated, multiple layerslayers

Several thousand laser pulses are fired every second leaving the Several thousand laser pulses are fired every second leaving the aircraft the size of an eraser and hitting the ground at least 75 feet aircraft the size of an eraser and hitting the ground at least 75 feet in diameter in diameter

LIDAR ProcessLIDAR Process

TransectsTransects

LIDAR and BiomassLIDAR and Biomass

LIDAR is able to LIDAR is able to process the initial process the initial return of the return of the laser plus 5 laser plus 5 subsequent subsequent returns for returns for multiple layers of multiple layers of biomassbiomass

LIDAR waveforms LIDAR waveforms are placed are placed together into together into volumetric unitsvolumetric units

Mathematical models estimate biomass given the 3D Mathematical models estimate biomass given the 3D image and forest cover dataimage and forest cover data

Limitations and Benefits of Limitations and Benefits of LIDAR and BiomassLIDAR and Biomass

BenefitsBenefits Active, high resolution, Active, high resolution,

laser sensorlaser sensor Canopy layeringCanopy layering Biomass by layer and Biomass by layer and

typetype Stem vs. Leaf vertical Stem vs. Leaf vertical

biomassbiomass Location accuracyLocation accuracy Topology mappingTopology mappingLimitationsLimitations Atmospheric interactionsAtmospheric interactions Cost and data availabilityCost and data availability Digital spaceDigital space Plot size limitationsPlot size limitations

LIDAR applicationLIDAR application Ecosystem mapping in the tropical rainforests of South AmericaEcosystem mapping in the tropical rainforests of South America

Aerial PhotoAerial Photo

Final LIDAR return Final LIDAR return of ground terrainof ground terrain

11stst LIDAR return of Canopy LIDAR return of Canopy

LIDAR application (cont)LIDAR application (cont) City applications with LIDAR have also surfacedCity applications with LIDAR have also surfaced

LIDAR imageLIDAR imageAerial Aerial photophoto

ConclusionConclusion