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
- Free ground shipping
- Expedited repair and warranty service
- Lifetime technical support
- More
Overview
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.
Mechanics
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. 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
Select Options
In The News
Climate Change and Microplastics: Monitoring Lake Champlain
Most people go to Lake Champlain for its exceptional views and thrilling boating, but it’s also home to a wide variety of interesting aquatic research projects. From studying microplastics to thermal dynamics of the lake, Timothy Mihuc, director of the Lake Champlain Research Institute (LCRI) at the State University of New York at Plattsburgh (SUNY Plattsburgh), has spent his career studying aquatic ecosystems. As an aquatic biologist, he’s the main investigator on Lake Champlain’s research studies while also managing their grants, employees, and their hands-on buoy work. Over the years, LCRI has received a number of environmental grants that aid in its monitoring research.
Read More
Current Monitoring after the Francis Scott Key Bridge Collapse
On March 26th, according to The Baltimore Sun , a 984-foot, 112,000-ton Dali lost propulsion and collided with a support column of the Francis Scott Key Bridge, collapsing the structure. Soon after the event, search and rescue, salvage crews, and other emergency responders were mobilized after the collision. As salvage efforts progressed in early April, NOAA’s Center for Operational Oceanographic Products and Services (CO-OPS) responded to a request for real-time tidal currents data and deployed a current monitoring buoy—CURBY (Currents Real-time BuoY)—into the Patapsco River north of the Francis Scott Key Bridge.
Read More
Soundscapes of the Solar Eclipse: Citizen Science Supporting National Research
On April 8, 2024, millions of people around the world had their eyes glued to the sky to witness a historic cosmic event. The total solar eclipse captured the headlines and the minds of many who became eager to gaze at the heavens as the sky went dark for a few minutes. However, not everyone used their sense of sight during the eclipse, some were listening to the sounds of the natural world around them as the light faded from above. The Eclipse Soundscape Project is a NASA-funded citizen science project that focuses on studying how the annular solar eclipse on October 14, 2023, and the April 8, 2024 total solar eclipse impacted life on Earth. The project revisits an initiative from the 1930s that showed animals and insects are affected by solar eclipses.
Read More
