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The XRR – Adaptable instruments for optically diverse environments

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XRL being deployed in Mission Bay, CAXRL being deployed in Mission Bay, CABiospherical Instruments Inc (BSI) has released the newest member of the Expandable Technology for Radiometric Applications (XTRA) class of high performance field instruments called the XTRA Reflectance Radiometers (XRR). The XRR is an economically priced multiwavelength radiometer for determining apparent optical properties in aquatic systems. Belonging to the instrument class that also includes the Compact Optical Profiling system (C-OPS), among other microradiometer-based instruments, the XRR is designed to fill the niche that was occupied by the PRR-600 and PRR-2600 as well as the PRR-800; they are very similar in shape to the PRR-600/PRR-2600 instruments, but are smaller in diameter, weigh less, and have greatly improved performance.  

XRRs are available in two measurement geometries: XRL and XRE. The XRL, the most common configuration, features 10 optical-filter microradiometer wavebands (selected from 29 different optical filter wavelengthsof in-water downward  irradiance (Ed) and 10 wavebands of in-water upwelling radiance (Lu). The XRE nominally uses 10 wavebands of downward irradiance (Ed) and 10 wavebands of upward irradiance (Eu). XRRs also take advantage of a new free-fall flotation collar called the “X-SLOWS,” which affords excellent near-surface sampling in an instrument with a traditional "rocket-shaped" design.  XRRs use the same microradiometer detector technology as C-OPS, and thus has the same outstanding radiometric performance specifications as C-OPS. Microradiometers also mean that the XRR can use all of  the same software, surface solar reference, and all of the C-OPS cables and accessories such as the BioSHADE and BioGPS. 

Instrument development and testing phases have been completed, and the XRL or XRE are now ready for procurement and delivery. 



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.

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.


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.


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.


GUVis-3511 Ground-based UV/Visible 19 Waveband Radiometer

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GUVis-3511 radiometer configured with BioSHADE and BioGPS.GUVis-3511 radiometer configured with BioSHADE and BioGPS.In 2019, Biospherical Instruments 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.


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