Automated, low-power chamber system for measuring nitrous oxide emissions

Area of Science:

• Environmental Science
• Atmospheric Chemistry
• Soil Science

Background:

• Accurate soil nitric oxide (NO) emissions data are vital for understanding atmospheric NO budgets and emission factors.
• Traditional manual sampling methods may miss episodic emissions, leading to underestimation.

Purpose of the Study:

• To evaluate the performance of a low-power, automated chamber system for continuous soil NO emission measurement.
• To assess the accuracy of continuous measurements compared to traditional weekly sampling.

Main Methods:

• Utilized a Teledyne NO analyzer with a solar/wind-powered automated chamber system.
• Conducted laboratory tests to determine analyzer temperature sensitivity and precision.
• Simulated weekly sampling from continuous hourly flux data to compare emission estimates.

Main Results:

• The NO analyzer exhibited significant temperature sensitivity (zero drift) but negligible span drift.
• The automated system achieved high precision (1.5 nmol mol) comparable to laser-based analyzers.
• Weekly sampling underestimated cumulative NO emissions by missing episodic events, unlike continuous measurements.

Conclusions:

• The automated chamber system provides precise, continuous soil NO emission data.
• The hybrid power system needs enhancements for consistent operation during shoulder seasons.
• Continuous monitoring is superior to weekly sampling for capturing episodic NO emissions and improving budget accuracy.