Table Of Contents - Decagon Devices SRS Operator's Manual

SRS Sensors
Contents
1 Introduction
1.1 Customer Support . . . . . . . . . . . . . . . . . . . .
1.2 About This Manual . . . . . . . . . . . . . . . . . . .
1.3 Warranty . . . . . . . . . . . . . . . . . . . . . . . . .
1.4 Seller's Liability . . . . . . . . . . . . . . . . . . . . . .
2 About SRS
2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . .
2.2 Specifications . . . . . . . . . . . . . . . . . . . . . . .
3 Theory
3.1 Normalized Difference Vegetation Index (NDVI) . . .
3.2 Fractional Interception of Photosynthetically Active
Radiation . . . . . . . . . . . . . . . . . . . . . . . . .
3.3 Canopy Phenology . . . . . . . . . . . . . . . . . . . . 10
3.4 Photochemical Reflectance Index (PRI) . . . . . . . . 11
3.5 Sun-Sensor-Surface Geometry Considerations . . . . . 12
3.6 Calculating Percent Reflectance from Paired Up and
Down Looking Sensors . . . . . . . . . . . . . . . . . . 14
4 Connecting the SRS
4.1 Connecting to Decagon Data Logger . . . . . . . . . . 19
4.2 3.5 mm Stereo Plug Wiring . . . . . . . . . . . . . . . 20
4.3 Connecting to a Non-Decagon Logger . . . . . . . . . 20
4.4 Pigtail End Wiring . . . . . . . . . . . . . . . . . . . . 21
5 Communication
5.1 SDI-12 Communication . . . . . . . . . . . . . . . . . 23
6 Understanding Data Outputs
6.1 Using Decagon's Em50 series data loggers . . . . . . . 25
6.1.1
6.1.2
6.2 Using other data loggers . . . . . . . . . . . . . . . . . 26
7 Installing the SRS
7.1 Attaching and Leveling . . . . . . . . . . . . . . . . . 27
7.2 Cleaning and Maintenance . . . . . . . . . . . . . . . . 27
Up Looking Sensor Outputs . . . . . . . . . . . 25
Down Looking Sensor Outputs . . . . . . . . . 25
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