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SKYE INSTRUMENTS LTD Llandrindod Wells, United Kingdom
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1. SpectroSense2+ Meter 2. Spectral Reflectance 3. Vegetation Indices 4. SpectroSense2+ Configurations SPECTROSENSE2+
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1. SpectroSense2+ Meter 2. Spectral Reflectance 3. Vegetation Indices 4. SpectroSense2+ Configurations SPECTROSENSE2+
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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+
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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+
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VEGETATION INDICES (VIs) Applications Crops & Horticulture, Precision Agriculture Climate Change Satellite Ground Truthing Carbon Balance SPECTROSENSE2+
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VI Calculations NDVI & PRI MODIS EVI EVI2 & MSAVI2 RVI & WBI LAI fPAR Individual readings SPECTROSENSE2+
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1. SpectroSense2+ Meter 2. Spectral Reflectance 3. Vegetation Indices 4. SpectroSense2+ Configurations SPECTROSENSE2+
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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+
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SPECTRAL REMOTE SENSING Measuring Reflected Light VIS, NIR and SWIR wavelengths Each surface has a “fingerprint” spectrum Low values - absorption High values - reflectance SPECTROSENSE2+
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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+
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1. SpectroSense2+ Meter 2. Spectral Reflectance 3. Vegetation Indices 4. SpectroSense2+ Configurations SPECTROSENSE2+
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SIMPLE RATIO VEGETATION INDICES Simple Ratio of two Wavelengths RVIRelative Vegetation Index Uses Red and NIR bands WBIWater Band Index Uses 970nm and 990 nm bands SPECTROSENSE2+
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Relative Vegetation Index RVI =NIR Red SPECTROSENSE2+
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RVI Ranges from 0 to infinity 0 bare soil >0vegetation SPECTROSENSE2+
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Water Band Index WBI = R 900 or R 900 R 970 R 1530 Surface wetness, water vapour flux SPECTROSENSE2+
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WBI For Green Vegetation Range is 0.8 to 1.2 SPECTROSENSE2+
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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+
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Normalised Differential Vegetation Index NDVI = (R NIR - R Red ) (R NIR + R Red ) This has limitations in dense vegetation SPECTROSENSE2+
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NDVI Ranges from -1 ice and snow 0 bare soil +1 full vegetation cover SPECTROSENSE2+
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Fraction of PAR Absorbed by the plant canopy fPAR = 1.24 * NDVI - 0.168 Strongly linked to LAI Leaf Area Index SPECTROSENSE2+
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fPAR Ranges from -1 ice and snow 0 bare soil +1 full vegetation cover SPECTROSENSE2+
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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+
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From NDVI LAI = a * e (b * NDVI) where a = 0.0148, e = exponential, b = 6.192 LAI Leaf Area Index SPECTROSENSE2+
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PRI Photochemical Reflective Index Measure ratios of Green to Yellow Rate of photosynthesis Light Use Efficiency LUE Health Status of plants Productivity of plants SPECTROSENSE2+
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PRI = Photochemical Reflective Index PRI = (R 570 - R 531 ) (R 570 + R 531 ) corresponds with Xanthophyll Cycle activity & LUE Light Use Efficiency SPECTROSENSE2+
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PRI Ranges from -1 to +1 Healthy Vegetation -0.2 to +0.2 SPECTROSENSE2+
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MODIS EVI Enhanced Vegetation Index Uses MODIS bands 1, 2 and 3 Red, NIR and Blue Better sensitivity for high biomass Responsive to canopy structure SPECTROSENSE2+
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MODIS EVI EVI = (R NIR - R Red ) * G (R NIR + C 1 *R Red - C 2 *R Blue + L ) where C 1 =6, C 2 =7.5, L=1, G=2.5 SPECTROSENSE2+
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MODIS EVI Ranges from -1 to +1 Healthy Vegetation 0.2 to 0.8 SPECTROSENSE2+
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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 SPECTROSENSE2+
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EVI2 EVI2 = 2.5 * (R NIR - R Red ) (R NIR + 2.4 * R Red + 1) 2 band Enhanced Vegetation Index SPECTROSENSE2+
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EVI2 Ranges from -1 to +1 Healthy Vegetation 0.2 to 0.8 SPECTROSENSE2+
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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+
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MSAVI2 MSAVI2 = (2*R NIR + 1) - [(2 * R NIR + 1) 2 - 8*(R NIR - R Red )] 2 Modified Soil Adjusted Vegetation Index SPECTROSENSE2+
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MSAVI2 Ranges from -1 ice and snow 0 bare soil +1 full vegetation cover SPECTROSENSE2+
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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 PAR Sensors SPECTROSENSE2+
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Using a pair of PAR Sensors An Incident PAR sensor above the canopy A Line PAR sensor below the canopy LAI = -2 * ln (PAR LQ / PAR I ) LAI Leaf Area Index SPECTROSENSE2+
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1. SpectroSense2+ Meter 2. Spectral Reflectance 3. Vegetation Indices 4. SpectroSense2+ Configurations SPECTROSENSE2+
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SPECTROSENSE 2+.GPS One SpectoSense2+ meter Two identical sensors GPS module for mapping Hand held pole Carry case SPECTROSENSE2+
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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+
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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 = 0.5m 2 area r h 25° Sensor 1 Sensor 2 SPECTROSENSE2+
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HAND HELD NDVI SYSTEM SpectroSense2+ meter Two 2 channel sensors Red and NIR bands NDVI & RVI fPAR & LAI EVI2 & MSAVI SPECTROSENSE2+
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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
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NDVI / PRI SYSTEM SpectroSense2+ meter Two 4 channel sensors Red, NIR, 531 & 570nm bands NDVI & RVI fPAR & LAI EVI2 & MSAVI PRI SPECTROSENSE2+
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LEAF AREA INDEX Two PAR sensors Incident PAR sensor above canopy Line PAR sensor below canopy SPECTROSENSE2+
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SKYE INSTRUMENTS LTD Llandrindod Wells, United Kingdom
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