A Field Spectrometer Designed to Interface With Dataloggers and Continuously Monitor Plant Canopy Reflectance.

Remote sensing is a valuable tool for measuring plant canopy characteristics across multiple spatial and temporal scales. Measurement of hyperspectral reflectance from plant canopies at the field scale is rapidly becoming a means of characterizing plant responses to the environment. Canopy reflectance at specific wavelengths can be used to monitor spectral indices related to plant canopy characteristics such as leaf area index, chlorophyll content, light use efficiency, and water status. Field-scale reflectance measurements of plant canopies can be linked with satellite and aircraft remote sensing to establish and validate reflectance indicators of canopy characteristics. There is also considerable interest in linking field-scale reflectance measurements with water and carbon flux data in an effort to determine relationships between reflectance and fluxes at the scale of a flux tower footprint. Portable spectrometers are widely available, but are typically large and heavy, expensive, and often require manual operation or a dedicated computer for automated data collection. Continuous measurement of hyperspectral reflectance at the canopy-scale has thus been limited. Here we describe the design, operation, and performance of a small, low-cost field spectrometer designed to interface with dataloggers to provide continuous measurements of surface spectral reflectance. Reflectance measurements were made with the spectrometer over multiple canopies and conditions and compared favorably to measurements from a reference spectrometer.