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Compact Optical Profiling System (C-OPS)

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C-OPS is a next-generation optical profiling system for determining apparent optical properties in aquatic systems. It consists of two 7 cm diameter radiometers: one measures in-water upwelling radiance, and the other either downward irradiance or upward irradiance, pressure/depth, and dual axes tilts. Both radiometers are equipped with up to 19 optical-filter microradiometers (selected from 29 different wavelengths) and are mounted on a unique free-fall, kite-like backplane. To avoid influences from the shadow of the boat or dock, the frame can be optimized for either slow descent rates for work in very shallow (e.g. 3 m) and coastal waters, or faster descent rates for observations in the open ocean. C-OPS is so lightweight it can be hand deployed by almost anyone, and the system can be operated from either small or large vessels. An above-water reference irradiance instrument is also available to measure global irradiance.


  • Complete, integrated system for measuring radiometric variables in coastal waters with submersible and above-water instrumentation (for both turbid coastal and clear oceanic waters);
  • Submersible instruments are optimized for measuring vertical profiles of radiance and irradiance in aquatic systems;
  • Radiometrically matching surface reference system;
  • Rapid sampling rates: 15 data frames per second from up to 4 instruments simultaneously;
  • Hand-deployed from small vessels and large ships;
  • Free-fall descents with very slow descent rates -- adjustable buoyancy;
  • Based on microradiometer technology with 10 decades of dynamic range;
  • Ideal for both ocean color, and satellite calibration and validation, shallow- or deep-water research
  • Highlighted in NASA’s Ocean Ecology Science Research Portal in the Instrument Development section.

Download: C-OPS from the NASA Technical Memorandum "Advances in Measuring the Apparent Optical Properties (AOPs) of Optically Complex Waters," NASA Tech. Memo. 2010–215856.


BSI's scale of spectral irradiance

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FEL lamp used for calibrationsFEL lamp used for calibrations

Calibrations performed at Biospherical Instruments are traceable to the scale of spectral irradiance maintained by the National Institute of Standards and Technology (NIST). NIST distributes this scale in the form of 1000 W tungsten-halogen lamps of type FEL. An article describing how this scale is maintained at BSI is here.


Biospherical Instruments introduces the GUVis-3511

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GUVis-3511 radiometer configured with BioSHADE and BioGPS.GUVis-3511 radiometer configured with BioSHADE and BioGPS.Biospherical Instruments has just released the GUVis-3511, the latest member of BSI's line of atmospheric radiometers. The GUVis-3511 is based on BSI’s proprietary microradiometer technology and available with up to 19 channels, ranging from 305 to 1,640 nm.  The instrument can also be equipped with a shadowband accessory to determine the direct solar irradiance. Depending on configuration, the GUVis-3511 affords the measurement of the UV Index and the retrieval of aerosol optical depth, cloud optical thickness, and total column ozone. Click here for more information and here for a paper published in Atmospheric Measurement Techniques using the instrument for shipborne measurements of aerosol optical depth.


Measurements during the 2017 total solar eclipse

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Total solar eclipse of 21 August 2017 observed with GUVis-3511.Total solar eclipse of 21 August 2017 observed with GUVis-3511.

BSI performed measurements with a GUVis-3511 radiometer in Oregon during The Great American Eclipse of August 21, 2017. An in-depth article about the campaign is here.


Biospherical OCULLAR Prototype featured in NASA's Cutting Edge

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OCULLAR sensor at sunsetOCULLAR sensor at sunset

Biospherical Instruments has developed a novel instrument that is capable of measuring light over 14 decades of dynamic range. The prototype sensor, known as the Ocean Color Underwater Low Light Advanced Radiometer (OCULLAR), resulted from a collaboration between Biospherical Instruments and NASA/GSFC scientist Dr. Stanford Hooker. The instrument pairs a miniature photomultiplier tube (PMT) with a Biospherical microradiometer coupled to a silicon photodetector. A microprocessor embedded in the microradiometer activates the PMT when low-light conditions are detected, and is powered off under higher light conditions where the silicon detector microradiometers take over. The first field campaign using the prototype successfully collected data under moonlit skies, including using a BioSHADE (shadowband) accessory to measure direct and diffuse components of moonlight. The prototype successfully proved the concept but had only one channel. A commercial product with 7 channels is currently under development. The new system will support ocean color research using both Sun and Moon as light sources.

An article featuring OCULLAR was published by NASA is here.


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