Spectroscopy

• Why spectroscopy? At every scale, our ability to understand photosynthesis and respiration is dependent on our ability to make solid measurements of the photosynthetic and respiratory processes. In recent years, there have been spectacular developments in optical spectroscopy that have created opportunities to make better physiological measurements than ever before. Using these new techniques successfully requires a solid grasp of how they work.

• What’s in this section? In the Spectroscopy section, you’ll find materials that I’ve developed for teaching about optical spectroscopy, as well as summaries of technical papers I’ve led on spectral analysis in laser-based spectrometers. All of these focus on the water molecule. I like to think of this as a “model molecule” that illustrates the general principles of spectroscopy that are relevant to other targets.

• How is this section organized? These materials are organized in four pages.

  • You are here in Introduction, which introduces laser-based spectrometers;

  • Matrix effects describes impacts of the background;

  • Neighbor effects describes impacts of nearby peaks; and

  • Synthesis activities describes the NEON ASI Technical Working Group.

• An introduction to laser-based infrared spectroscopy: Below, I’ve posted two decks of slides that will help you get a running start with a form of laser-based infrared spectroscopy called “cavity ring-down spectroscopy.” The presentations are derived from a workshop that I co-designed and co-taught with Aurora Kagawa-Viviani at the University of Hawai’i at Mānoa in 2017. The workshop was supported by a grant from the Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI) to A. K.-V.

• The grant was made possible by CUAHSI's Instrumentation Discovery Travel Grant (IDTG) program, which enables scientists to learn the details of hydrologic instrument installation, operation, maintenance, and data processing by visiting experts or scheduling reverse site visits. Applicants from traditionally under-served institutions, primarily undergraduate institutions, students at all levels, and early career faculty are encouraged to apply for an IDTG.

• You are also encouraged to re-use these slides! You can download them here: Day 1 and Day 2. If you do re-use them, please include the following acknowledgement:

  • “This material is based on the University of Hawaiʻi at Mānoa workshop: Methods in Stable Isotope Ecohydrology (August 15-16, 2017) which was facilitated by a CUAHSI IDTG award with support from the National Science Foundation (NSF) Cooperative Agreement No. EAR-1849458."