XRL being deployed in Mission Bay, CA

Biospherical 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 wavelengths) of in-water downward  irradiance (E_d) and 10 wavebands of in-water upwelling radiance (L_u). The XRE nominally uses 10 wavebands of downward irradiance (E_d) and 10 wavebands of upward irradiance (E_u). 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.