near surface spectral measurements of the land surface heidi steltzer steltzer@nrel.colostate.edu...

Near surface spectral measurements of the land surface

Heidi Steltzersteltzer@nrel.colostate.edu

Plant and Ecosystem EcologistNatural Resource Ecology Laboratory (NREL)

SpecNet – a spectral network

• http://specnet.info

Advantages of near surface spectral measurements

• Scaling– Spatial

• fine resolution imagery• pure pixels

– Temporal• frequent observations

Spatial variability in plant coverComplex or brief growing season

Short grass steppe Patterned ground in the Arctic

NDVI

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Increasing NDVIplot

Multi-spectral digital camera to structure sampling

NDVI is the Normalized Difference Vegetation Index

Images are 20 cm x 20 cm plots in a polar desert ecosystem

NDVI

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NDVI

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. D integrifolia. S arctica

NDVInpvs = 0.21)a

)b

wr = 0.98

R2 = 0.82

-Canopy level

observedestimated

New tool: non-destructive measurements of the leaf area index

Steltzer and Welker (2006) Ecology

Experimental manipulations of climate and other global changes

Alpine tundra

Polar desert

Time since agriculture ceased (yr)

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Time since agriculture ceased (yr)

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Plant cover as a continuous variable

Phenological variation NDVI vs day of year

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Day of Year

NDVI

Snow MeltLines are different years, data was collected using a near surface multi-band radiation sensor

Data from Barrow, AK; Huemmrich et al

Environmental sensor networks

• An LED pyranometer for $20

• Can be converted to measure NDVI or other vegetation indexes

Needs

• Variables of interest– Vegetation and soils– Microbial communities, biological diversity– Direct and indirect assessment

• models

• Instrumentation– Sensors– Platforms– Sensor networks

• Data– Automated analysis of imagery– Bioinformatics/data management

Acknowledgements

• National Science Foundation– Office of Polar Programs

• Tetracam Inc.• Joe DeCant• Jeff Welker• Rich Conant• Fred Hummerich and

other Specnetters• Seth Munson• NREL