Trace Gas Analyzers

LI-7820

LI-7820N2O/H2Trace Gas Analyzer

The LI-7820 N2O/H2Trace Gas Analyzer offers high-precision nitrous oxide measurements in a low power, portable design—enabling it to easily integrate into survey and long-term soil flux systems. Pair it with the LI-7810 CH4/CO2/H2Trace Gas Analyzer or LI-870 CO2/H2Analyzer for CO2 and CH4 measurements at your site.

A combination of several patented technologies with Optical Feedback-Cavity Enhanced Absorption Spectroscopy (OF-CEAS) results in precise and stable N2measurements, for chamber-based soil flux research.

LI-7820 Advantages

  • Connect to the Smart Chamber or the LI-8250 Multiplexer for collecting, processing and viewing N2O fluxes on site or remotely
  • Functions with a low power, weatherized design that operates on hot-swappable, 8-hour batteries
  • Deploys long term with minimum infrastructure requirements (e.g., simple cover or stand) to create a user-friendly solution for lab and field measurements
  • Connects to a smartphone via Wi-Fi-enabled communications to monitor and view live data without a field computer and works with SoilFluxPro™ Software for dataset management

For details on the design and technology used in the LI-7820, visit the Trace Gas Analyzers page.

Measuring N2O fluxes in soil

Designed for soil flux measurements, the LI-7820 N2O/H2O Trace Gas Analyzer brings the precision you need to measure both natural variation in fluxes and large flux events, even in remote areas. With the ability to resolve fluxes quickly, you can take more measurements throughout the day and quickly visualize those fluxes with SoilFluxPro™ Software.

Figure 1. Measurements of N2O flux from soils over a 14-month time period. Measured by the LI-7820 N2O/H2O Trace Gas Analyzer and an LI-8100A Automated Soil CO2 Flux System. Measurements were conducted over an urban lawn in Lincoln, NE, USA, and shows natural variations of N2O fluxes detected by the LI-7820. Results from Xu, et al., 2020.
Figure 2. Soil N2O flux measurements with the LI-7820. The precision of the LI-7820 allows fluxes to be resolved within 2 minutes, for both high fluxes (linear regression coefficients higher than 0.9 when N2O flux was higher than 0.1 nmol m-2 s-1, figures A and B), as well as when fluxes from natural emissions occur that can be extremely low. The LI-7820 is capable of measuring flux rates as low as 0.05 nmol m-2 s-1 in 2 minutes under these conditions (C).

N2O flux measurements from soil are often minimal and close to zero. Natural variation still occurs, however, and is important to quantify. A highly precise analyzer that can quickly resolve small fluxes is essential for detecting minute, natural variations in soil N2O flux. The LI-7820 allows you to take precise measurements of these slight variations and to resolve natural N2O fluxes in addition to measuring large fluxes, such as changes that occur after a fertilizer treatment.

The example given is from a LI-COR long-term soil flux system. The LI-7820 was used to measure larger fluxes emitted during spring thaw events in Lincoln, Nebraska, while also recording smaller natural fluxes. Figure 2 provides an example flux calculated in 2 minutes from a closed-chamber measurement.

LI-7820 Specifications

General

  • Measurement Technique: OF-CEAS (Optical Feedback – Cavity Enhanced Absorption Spectroscopy)
  • Measurement Rate: 1 sample per second (1 Hz)
  • Optical Cavity Volume: 6.41 cm3
  • Flow Rate:
    • 250 sccm nominally in Standard Configuration
    • 150 sccm nominally in High Altitude Configuration
    • 70 sccm nominally in Reduced Flow Rate Configuration with installed kit
  • Total Weight: 10.5 kg (including batteries)
  • Case Dimensions: 51 cm × 33 cm × 18 cm (L × W × H)
  • Operating Temperature Range: -25 °C to 45 °C (without solar load, under normal operating conditions)
  • Operating Humidity Range: 0 to 85% RH (non-condensing, without solar load, under normal operating conditions)
  • Sample Line Humidity Range: 0 to 99.9% non-condensing
  • Operating Pressure Range:
    • 70 to 110 kPa in Standard and Reduced Flow Rate Configurations
    • 50 to 110 kPa in High Altitude Configuration
  • Connectivity: Ethernet and Wi-Fi (not available in some countries)
  • Wi-Fi Compatibility: 2.4 GHz, 802.11 a/b/g/n/ac
  • Power Consumption:
    • Steady State Operation: 22 Watts at 25 °C without batteries charging
    • Warmup: Up to 65 W without batteries charging; up to 100 W with batteries charging
    • Off: Up to 2.3 W when powered from pins 3 and 4 without batteries charging; up to 0.2 W when powered from pins 1 and 5 without batteries charging
  • Power Supply Requirements:
    • Pins 1 and 5 (24 VDC Input): Minimum 6 A at 24 V
    • Pins 3 and 4 (10.5 to 33 VDC Input): Minimum 14 A at 10.5 VDC; 6 A at 24 VDC
  • Power Supply: Universal Power Adapter (Input: 100 to 240 VAC, 50-60 Hz; Output: 24 VDC)
  • Battery Life: 8 hours typical with 2 batteries
  • Pollution Degree: 2
  • Over-voltage Category: II
  • Class 1 Laser Product

N2O Measurements

  • Response Time (T10-T90): all from 0 to 330 ppb
    • ≤ 2 seconds in Standard Configuration
    • ≤ 3 seconds in High Altitude Configuration
  • Range: 0 to 100 ppm
  • Precision (1σ):
    • 0.40 ppb at 330 ppb with 1 second averaging
    • 0.20 ppb at 330 ppb with 5 second averaging
  • Maximum Drift: < 1 ppb per 24-hour period

H2O Measurements

  • Range: 0 to 60,000 ppm
  • Precision (1σ):
    • 45 ppm at 10,000 ppm with 1 second averaging
    • 20 ppm at 10,000 ppm with 5 second averaging

Specifications subject to change without notice.

Brochure

8250-02 Calibration Manifold Insert

8250-02 Calibration Manifold Insert

Soil Gas Flux Measurement Solutions

Soil Gas Flux Measurement Solutions

Field guide to instruments for the earth sciences

Field guide to instruments for the earth sciences

Posters

TGA Urban N2O Soil posterHow do soil temperature and moisture regulate N2flux from an urban lawn?

TGA OF-CEAS posterMeasuring Very Small Soil Fluxes of N2CH4 Using a New OF-CEAS Technology

CO2 concentrations PosterA rapid assessment technique for mapping ground level CO2 concentrations using a light-weight, field-rugged gas analyzer

Soil Methane PosterChamber-based Soil Methane Flux Measurement

Features

What makes LI-COR different?

LI-COR offers hardware, software, and analyzers that are based on extensive scientific research and testing. Patented designs minimize disruption of natural soil gas transport across the soil surface and record high-precision flux measurements to evaluate spatial and temporal variability.

Together, this integrated system provides an entirely comprehensive research solution for measuring large- and small-scale events—including CO2, CH4, or N2greenhouse gas emissions.

Designed for flexibility and convenience

LI-COR soil gas flux systems combine more than 20 years of experience with the latest innovations for flexibility and convenience.

LI-COR Soil Flux System with Smart Chamber, LI-8250 Multiplexer, LI-7810 Trace Gas Analyzer and LI-870 Gas Analyzer.
LI-7820 N2O/H2O Trace Gas Analyzer taking a survey measurement

Tailored for dependable practicality

Each LI-COR gas analyzer is portable, durable, and simple to deploy—allowing you to take CO2CH4, and N2survey and long-term measurements with ease.

Engineered to reduce artificial impact

The importance of soil gas flux chambers to take accurate measurements is often underestimated. An inherent challenge to chamber design is the influence the chamber may have on measurements.

All LI-COR chambers are designed to minimize chamber interference on the natural soil gas flux, and gas production and consumption, leading to accurate, consistent measurements.

LI-COR soil chambers reduce artificial impact
SoilFluxPro Screenshot

SoilFluxPro Software

SoilFluxPro Software simplifies the management and processing of large soil gas flux datasets. SoilFluxPro is powerful, free software included with LI-COR soil gas flux solutions. View, revise, and recompute flux data, get advanced guidance on deadband and stop time, perform quality assurance and quality control, and much more.

Brochure

8250-02 Calibration Manifold Insert

8250-02 Calibration Manifold Insert

Soil Gas Flux Measurement Solutions

Soil Gas Flux Measurement Solutions

Field guide to instruments for the earth sciences

Field guide to instruments for the earth sciences

Posters

TGA Urban N2O Soil posterHow do soil temperature and moisture regulate N2flux from an urban lawn?

TGA OF-CEAS posterMeasuring Very Small Soil Fluxes of N2CH4 Using a New OF-CEAS Technology

CO2 concentrations PosterA rapid assessment technique for mapping ground level CO2 concentrations using a light-weight, field-rugged gas analyzer

Soil Methane PosterChamber-based Soil Methane Flux Measurement

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LI-7820
Trace Gas Analyzers
LI-7820
Trace Gas Analyzers