SKYE INSTRUMENTS LTD Llandrindod Wells, United Kingdom

SKYE INSTRUMENTS LTDLlandrindod Wells, United Kingdom

1. SpectroSense2+ Meter2. Spectral Reflectance3. Vegetation Indices4. SpectroSense2+ Configurations

SPECTROSENSE2+


SPECTROSENSE2+

SPECTROSENSE 2+.GPS• 8 channel meter• Display 8 readings at once• Ratio of incident / reflected• Store function• Automatic datalogging• VI & LAI calculations• GPS for field mapping

SPECTROSENSE2+

VEGETATION INDICES (VIs)

• “Greenness” Index• Detects presence of vegetation• Measures ratios of spectral

bands• Estimate plant biomass / cover• Identify plant species• Detect plant health / disease

SPECTROSENSE2+


Applications• Crops & Horticulture, • Precision Agriculture• Climate Change• Satellite Ground

Truthing• Carbon Balance

SPECTROSENSE2+

VI Calculations• NDVI & PRI• MODIS EVI• EVI2 & MSAVI2• RVI & WBI• LAI• fPAR• Individual readings

SPECTROSENSE2+


SPECTROSENSE2+

SPECTRAL REMOTE SENSING

Measuring Reflected Light

• Different surfaces reflect different wavelengths• Easy identification of land, ocean, forest, desert etc• Satellite maps• Ground truth maps

SPECTROSENSE2+

SPECTRAL REMOTE SENSING

Measuring Reflected Light

• VIS, NIR and SWIR wavelengths• Each surface has a “fingerprint” spectrum• Low values - absorption• High values - reflectance

SPECTROSENSE2+

SPECTROSENSE2+

SPECTROSENSE2+

SPECTROSENSE2+

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• Calculated from reflected radiation

• “Greenness” Indices• Detects presence of vegetation• Estimate plant biomass / cover• Identify plant species• Detect plant health / disease

SPECTROSENSE2+


SPECTROSENSE2+

SIMPLE RATIO VEGETATION INDICES

Simple Ratio of two Wavelengths

RVI Relative Vegetation IndexUses Red and NIR

bands

WBI Water Band Index Uses 970nm and 990 nm bands

SPECTROSENSE2+

Relative Vegetation Index

RVI = NIRRed

SPECTROSENSE2+

RVI

Ranges from 0 to infinity

0 bare soil >0 vegetation

SPECTROSENSE2+

Water Band Index

WBI = R900 or R900

R970 R1530

Surface wetness, water vapour flux

SPECTROSENSE2+

WBI

For Green Vegetation

Range is 0.8 to 1.2

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NDVI

Normalised Differential Vegetation Index

• The most widely used “greenness” VI• Measure ratios of NIR to Red• Estimates amount of Biomass &

Ground Cover• Health Status of plants

SPECTROSENSE2+

Normalised Differential Vegetation Index

NDVI = (RNIR - RRed)

(RNIR + RRed)

This has limitations in dense vegetation

SPECTROSENSE2+

NDVI

Ranges from

-1 ice and snow0 bare soil +1 full vegetation cover

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Fraction of PARAbsorbed by the plant canopy

fPAR = 1.24 * NDVI -

0.168

Strongly linked to LAI Leaf Area Index

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fPAR

Ranges from


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LAI Leaf Area Index

LAI = Total upper leaf surface Ground surface area

0 = bare soil 6 = dense forest

Can be estimated using NDVI

SPECTROSENSE2+

From NDVI

LAI = a * e (b * NDVI)

where a = 0.0148, e = exponential, b = 6.192

LAI Leaf Area Index

SPECTROSENSE2+

PRIPhotochemical Reflective Index

• Measure ratios of Green to Yellow• Rate of photosynthesis• Light Use Efficiency LUE• Health Status of plants• Productivity of plants

SPECTROSENSE2+

PRI = Photochemical Reflective Index

PRI = (R570 - R531)(R570 + R531)

corresponds with Xanthophyll Cycle activity & LUE Light Use Efficiency

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PRIRanges from

-1 to +1

Healthy Vegetation

-0.2 to +0.2

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MODIS EVIEnhanced Vegetation Index

• Uses MODIS bands 1, 2 and 3• Red, NIR and Blue• Better sensitivity for high

biomass• Responsive to canopy structure

SPECTROSENSE2+

MODIS EVI

EVI = (RNIR - RRed) * G

(RNIR+ C1*RRed - C2*RBlue + L )

where C1=6, C2=7.5, L=1, G=2.5

SPECTROSENSE2+

MODIS EVIRanges from

-1 to +1

Healthy Vegetation

0.2 to 0.8

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EVI2

2 band Enhanced Vegetation Index

• Uses just Red and NIR bands• Blue band not required• Good correlation with MODIS

EVI

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EVI2

EVI2 = 2.5 * (RNIR - RRed)

(RNIR + 2.4 * RRed + 1)

2 band Enhanced Vegetation Index

SPECTROSENSE2+

EVI2Ranges from

-1 to +1

Healthy Vegetation

0.2 to 0.8

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MSAVI2

Modified Soil Adjusted Vegetation Index

• Uses Red and NIR bands• Compensates for exposed soil areas• Best where vegetation cover is

<40%

SPECTROSENSE2+

MSAVI2

MSAVI2 = (2*RNIR+ 1) - [(2 * RNIR+ 1)2 - 8*(RNIR - RRed)]

2

Modified Soil Adjusted Vegetation Index

SPECTROSENSE2+

MSAVI2

Ranges from


SPECTROSENSE2+

LAI Leaf Area Index

LAI = Total upper leaf surface Ground surface area

0 = bare soil 6 = dense forest

Can be estimated using PAR Sensors

SPECTROSENSE2+

Using a pair of PAR SensorsAn Incident PAR sensor above the canopy

A Line PAR sensor below the canopy

LAI = -2 * ln (PARLQ / PARI)

LAI Leaf Area Index

SPECTROSENSE2+


SPECTROSENSE2+

SPECTROSENSE 2+.GPS

• One SpectoSense2+ meter• Two identical sensors• GPS module for mapping• Hand held pole• Carry case

SPECTROSENSE2+

TWO IDENTICAL SENSORS

• Cosine corrected for incident light measurements

• Narrow angle FOV sensor for reflected light measurements

• Simultaneous readings allow use in any light conditions

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TWO OR FOUR BAND SENSORS

• Specially designed geometry of narrow angle light acceptance

• Changing the height above the ground changes the area of measurement

• E.g. 1.8m height = 0.5m2 arear

h

25°

Sensor 1

Sensor 2

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HAND HELD NDVI SYSTEM

• SpectroSense2+ meter• Two 2 channel sensors• Red and NIR bands• NDVI & RVI• fPAR & LAI• EVI2 & MSAVI

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MODIS EVI SYSTEM

SPECTROSENSE2+

• SpectoSense2+ meter• Two 3 or 4 channel sensors• Blue, Red and NIR bands• NDVI & RVI• fPAR & LAI• MODIS EVI• EVI2 & MSAVI

NDVI / PRI SYSTEM• SpectroSense2+ meter• Two 4 channel sensors• Red, NIR, 531 & 570nm bands• NDVI & RVI• fPAR & LAI• EVI2 & MSAVI • PRI

SPECTROSENSE2+

LEAF AREA INDEX• Two PAR sensors• Incident PAR sensor above canopy• Line PAR sensor below canopy

SPECTROSENSE2+

SKYE INSTRUMENTS LTDLlandrindod Wells, United Kingdom

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SKYE INSTRUMENTS LTD Llandrindod Wells, United Kingdom