LI-COR LI-191R Line PAR Sensors
Features
- Spatially averages PPFD over its 1m length
- Uses a 1m quartz rod under a diffuser to conduct light to a single Quantum sensor
- Improved water resistance for long-term outdoor deployment
| Image | Part# | Product Description | Price | Stock | Order | |
|---|---|---|---|---|---|---|
 | LI-191R-BNC-2 | Line Quantum sensor with microamp output, 2m cable with BNC connector | Check Price | Usually ships in 3-5 days | ||
 | LI-191R-BNC-5 | Line Quantum sensor with microamp output, 5m cable with BNC connector | Check Price | Usually ships in 3-5 days | ||
 | LI-191R-SMV-2 | Line Quantum sensor with standardized mV output, 2m cable with bare leads | Check Price | Usually ships in 3-5 days | ||
 | LI-191R-SMV-5 | Line Quantum sensor with standardized mV output, 5m cable with bare leads | Check Price | Usually ships in 3-5 days | ||
| Image | Part# | Product Description | Price | Stock | Order | |
|---|---|---|---|---|---|---|
 | 2222SB | Extension cable, for use with type BNC or SMV terrestrial light sensors, 15m | Check Price | Usually ships in 3-5 days | ||
 | 2222SB-100 | Extension cable, for use with type BNC or SMV terrestrial light sensors, 30m | Check Price | Usually ships in 3-5 days | ||
 | 2200 | BNC to bare lead adapter, converts BNC type sensors to BL type sensors | Check Price | In Stock | ||
 | 2290 | Sensor millivolt adapter (604 Ohm resistor), for use with LI-190R-BNC, LI-191R-BNC & LI-210R-BNC sensors | Check Price | Usually ships in 3-5 days | ||
 | 2420-BNC | Light sensor amplifier, BNC connector | Check Price | Usually ships in 3-5 days | ||
 | LI-250A | Light meter | Check Price | In Stock | ||
 | LI-1500 | Light sensor logger | Check Price | Usually ships in 3-5 days | ||
 | LI-1500G | Light sensor logger with GPS | Check Price | Usually ships in 3-5 days | ||
The LI-191R Line Quantum Sensor measures Photosynthetically Active Radiation (PAR) integrated over its 1-meter length. It is used to measure sunlight under a plant canopy, where the light field is non-uniform. It measures light in units of Photosynthetic Photon Flux Density (PPFD), which is expressed as μmol s-1 m-2.
A non-uniform light field under a plant canopy is difficult to characterize with a single sensor or multiple sensors arranged in a line because the light field can vary considerably from point to point and over a line.
To solve this problem, the entire LI‑191R diffuser is sensitive to light over its 1-meter length. Since the diffuser is one continuous piece, the LI‑191R essentially integrates an infinite number of points over its surface into a single value that represents light from the entire 1-meter length.
Sensors that use multiple photodiodes potentially induce large uncertainty in measurements because each photodiode can drift independently of the others. The diffuser and single photodiode in the LI‑191R provide stable, integrated measurements that are superior to averages provided by many linear sensors.
Optical filters block radiation with wavelengths beyond 700 nm, which is critical for under-canopy measurements, where the ratio of infrared to visible light may be high.
- Absolute Calibration: ± 10% traceable to National Institute of Science and Technology (NIST). The LI-191 is calibrated via transfer calibration
- Sensitivity: Typically 7 μA per 1,000 μmol s-1 m-2
- Linearity: Maximum deviation of 1% up to 10,000 μmol s-1 m-2
- Response Time: 10 μs
- Temperature Dependence: ± 0.15% per °C maximum
- Cosine Correction: Acrylic diffuser
- Azimuth: < ± 2% error over 360° at 45° elevation
- Sensitivity Variation over Length: ± 7% maximum using a 2.54 cm (1”) wide beam from an incandescent light source.
- Sensing Area: 1 m × 12.7 mm (39.4” × 0.50”)
- Detector: High stability silicon photovoltaic detector (blue enhanced)
- Sensor Housing: Weatherproof anodized aluminum housing with acrylic diffuser and stainless steel hardware.
- Size: 121.3 L × 2.54 W × 2.54 cm D (47.7” × 1.0” × 1.0”)
- Weight: 1.4 kg (3.0 lbs.)
- Cable Length: 2 m, 5 m (6.5', 16.4')
- (1) LI-191R Line PAR Sensor
- (1) Bubble level
- (1) Detachable 10 ft. cable
- (1) Hard-sided carrying case
In The News
Government Officials Ignore Health Risks Associated with E. coli in Boulder Creek
Since 2003 harmful bacteria Escherichia coli (E. coli) levels have created a health risk to recreational users in Boulder Creek. Boulder Creek has been designated as an impaired stream and is not meeting an EPA health-based water quality standard. Concentrations of E. coli increase from the mouth of Boulder Canyon to the University of Colorado-Boulder and beyond based upon data collected by the City of Boulder according to information published by the CU Independent and the Boulder Camera . EM spoke to environmental engineer Art Hirsch of the Boulder Waterkeeper , who is advocating for greater accountability from all entities that own property abutting the stream. “E.
Read More
New Monitoring Site for Ocean Acidification in American Samoa
The National Oceanic and Atmospheric Administration (NOAA) and the Pacific Islands Ocean Observing System (PacIOOS) at the University of HawaiĘ»i at Māno a , in collaboration with other partners, recently deployed a new ocean acidification (OA) monitoring site in Fagatele Bay National Marine Sanctuary , American Samoa. Derek Manzello , a coral ecologist with NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML) in Florida, is the lead PI of ACCRETE: the Acidification, Climate and Coral Reef Ecosystems Team at AOML. Dr. Manzello connected with EM about the deployment. “ACCRETE encompasses multiple projects that all aim to better understand the response of coral reef ecosystems to climate change and/or ocean acidification,” explains Dr.
Read More
Extreme Wave Heights, Ocean Winds Increasing Globally
Around the world, extreme wave heights and ocean winds are increasing. The greatest increase is happening in the Southern Ocean, according to recent research from the University of Melbourne , and Dr. Ian Young corresponded with EM about what inspired the work. “Our main interest is ocean waves, and we are interested in wind because it generates waves,” explains Dr. Young. “Ocean waves are important for the design of coastal and offshore structures, the erosion of beaches and coastal flooding, and the safety of shipping.” Waves also have a role in determining how much heat, energy and gas can be trapped in the ocean. “The major reason why changes in wave height may be important is because of sea level rise,” details Dr. Young.
Read More
