Upload
allen-cook
View
215
Download
1
Embed Size (px)
Citation preview
SKYE INSTRUMENTS LTDLlandrindod Wells, United Kingdom
1. SpectroSense2+ Meter2. Spectral Reflectance3. Vegetation Indices4. SpectroSense2+ Configurations
SPECTROSENSE2+
1. SpectroSense2+ Meter2. Spectral Reflectance3. Vegetation Indices4. SpectroSense2+ Configurations
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+
VEGETATION INDICES (VIs)
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+
1. SpectroSense2+ Meter2. Spectral Reflectance3. Vegetation Indices4. SpectroSense2+ Configurations
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+
SPECTROSENSE2+
VEGETATION INDICES (VIs)
• Calculated from reflected radiation
• “Greenness” Indices• Detects presence of vegetation• Estimate plant biomass / cover• Identify plant species• Detect plant health / disease
SPECTROSENSE2+
1. SpectroSense2+ Meter2. Spectral Reflectance3. Vegetation Indices4. SpectroSense2+ Configurations
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
SPECTROSENSE2+
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
SPECTROSENSE2+
Fraction of PARAbsorbed by the plant canopy
fPAR = 1.24 * NDVI -
0.168
Strongly linked to LAI Leaf Area Index
SPECTROSENSE2+
fPAR
Ranges from
-1 ice and snow0 bare soil +1 full vegetation cover
SPECTROSENSE2+
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
SPECTROSENSE2+
PRIRanges from
-1 to +1
Healthy Vegetation
-0.2 to +0.2
SPECTROSENSE2+
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
SPECTROSENSE2+
EVI2
2 band Enhanced Vegetation Index
• Uses just Red and NIR bands• Blue band not required• Good correlation with MODIS
EVI
SPECTROSENSE2+
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
SPECTROSENSE2+
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
-1 ice and snow0 bare soil +1 full vegetation cover
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+
1. SpectroSense2+ Meter2. Spectral Reflectance3. Vegetation Indices4. SpectroSense2+ Configurations
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
SPECTROSENSE2+
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
SPECTROSENSE2+
HAND HELD NDVI SYSTEM
• SpectroSense2+ meter• Two 2 channel sensors• Red and NIR bands• NDVI & RVI• fPAR & LAI• EVI2 & MSAVI
SPECTROSENSE2+
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