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ORSL » Ocean and Coastal Waters » Instruments

Index of Ocean and Coastal Waters Instrumentation

Descriptions of field deployable instruments, lab equipment, calibration reference standards and their sources.

PageInstrument
  
  1  Absorption and Attenuation Meter
  2  GER 1500
  3  HyperSAS
  4  HyperSAS POL
  5  LISST-100X
  6  Lexel Model 95 Ion Laser
  7  Multiangular Hyperspectral Polarimeter
  8  OL Series 455 Integrating Sphere Calibration Standard
  9  LS 55 Fluorescence Spectrometer
 10 Perkin Elmer Lambda 35 UV/Vis Spectrophotometer
 11 Profiler II
 12 SeaPRISM


Absorption and Attenuation Meter (WetLabs)

"The package consists of different WET Labs sensors. An ac-s simultaneously determines the spectral attenuation and spectral absorption of water over 80+ wavelengths from 400 to 730 nm. If a 0.2 m-pore size filter is used attenuation and absorption of colored dissolved matter (CDM) can be measured. The ac-s employs a 25-cm pathlength. Data from two other ancillary instruments, the ECO BB9 and a CTD (conductivity, temperature, and depth) sensor is incorporated in the same serial (RS-232) data stream. The ECO BB9 measures scattering for 9 wavelengths (between 412 and 715 nm) at 117, the angle determined as a minimum convergence point for variations in the volume scattering function (VSF) induced by suspended materials and water itself. As a result, the signal measured by this meter is less determined by the type and size of the materials in the water and is more directly correlated to the concentration of the materials."



GER 1500 (Spectra Vista Corporation)

The GER 1500 is a field portable spectroradiometer covering the UV, Vis and NIR wavelengths from 350 to 1050 nm. It uses a diffraction grating with a silicon diode array. The silicon array has 512 discrete detectors that provide the capability to read 512 spectral bands. A full range of options are available for the GER 1500. These options include alternate collection optics, the following collection optics are available: (1) Standard (4 Nominal), (2) Fiber optic option, (3) 8 field-of-view (FOV) option.



HyperSAS (Satlantic)

"The HyperSAS optical remote sensing system provides high precision hyperspectral measurements of water-leaving spectral radiance with a sensor pointing at 40 from the nadir direction, and downwelling spectral irradiance. The 136-channel HyperOCR radiance and irradiance sensors are mounted above the sea (or land) surface in an aircraft or onboard a ship for simultaneous viewing of the sea surface and sky. Added features of the HyperSAS include internal shutters for accurate dark corrections and fully characterized cosine response for accurate, high quality data." Our system also includes an additional radiance sensor pointing at 40 from the zenith direction for the detection of the incoming light that will be reflected by the ocean surface.



HyperSAS POL (Satlantic)

HyperSAS capabilities were augmented by adding two radiance sensors having two polarizers oriented at 0 and 45°, with respect to a reference axis ("HyperSAS POL"). The final system consists of five Satlantic HyperOCR sensors: one irradiance and four radiance sensors. Three of them are oriented at 40° from the nadir direction and provide the polarized water-leaving signal (which also contains a contribution from the reflected sky/sunlight). Polarizers are installed in front of two of the HyperOCRs and are oriented at 0° and 45° respect to the vertical direction. The third HyperOCR looking at the water doesn't have a polarizer installed; it therefore records the Stokes component I. The forth sensor looks at 40 from the zenith direction and provides the sky radiance. All the radiance sensors are pointing West. There is also an irradiance sensor, looking at the zenith direction, and it is used to normalize the recordings of the radiance sensors. Once the radiance values are normalized by the downwelling irradiance, the (remote sensing) reflectances measured by the sensors can be identified as I, I0, I45 (for the sensors pointing at the water body) and Is for the sensor pointing at the sky. The components of the Stokes vector of the upwelling signal can then be calculated from I, I0, I45, specifically:

where Τ is the transmission of the linear polarizer placed in front of the hyperspectral sensors and χ is its polarization efficiency. The subscript 't' stands for 'total' and implies that the quantities measured contain both a contribution of the water and a contribution of the sky/sun-glint. The DOP is then given by:




LISST-100X (Sequoia Scientific)

"The LISST-100X instrument is a multi-parameter system for in-situ observations of particle size distribution and volume concentration. It also records the optical transmission, pressure and temperature. The instrument is fully self-contained with battery and data-logger. It can be used with supplied programs, or in specially designed modes, e.g. event triggered based on storms (pressure variance) or fronts (temperature front). The size-range is 1.25-250 microns (Model type B). At the heart of the instrument is a collimated laser diode and a specially constructed annular ring detector. Scattering intensity at 32 angles is the primary information that is recorded. This primary measurement is mathematically inverted to get the size distribution, and also scaled to obtain the volume scattering function (VSF). The size distribution is presented as concentration (microL/L) in each of 32 log-spaced size bins. Optical transmission, water depth and temperature are recorded as supporting measurements."



Model 95 Ion Laser (Lexel)

"The Lexel 95-SHG gas-ion laser provides continuous-wave deep ultraviolet coherent laser light with up to 250 mW output. The 95-SHG laser is based on the Lexel 95 series. The 95-SHG is an intracavity frequency-doubled system equipped with a nonlinear BBO crystal to produce Second Harmonic Generation (SHG) deep UV coherent laser light. It uses a simple, stable three-mirror folded cavity design for frequency doubling."

Applications:

    Stimulated fluorescence of phytoplankton.



Multiangular Hyperspectral Polarimeter

This is a custom-built instrument consisting of four HyperOCRs mounted on a scanning system controlled by an underwater electric stepper motor. Four buoys are necessary to float the instrument away from the ship to avoid shadowing effects. The apertures of the sensors are positioned on the pivot point of the motor, in this way the signal is always integrated on the same volume of water for all four sensors. The stepper motor rotates the sensors in a specific meridian plane following a table of angles decided by the user. A fifth HyperOCR records above water downwelling irradiance for normalization purposes. Data is acquired through a custom Labview program which automatically controls the rotation of the electric stepper motor synchronized with the data acquisition of the hyperspectral sensors. Three linear polarizers, oriented at 0°, 45° and 90° respect to a reference axis, and a left-handed circular polarizer, are installed in front of the hyperspectral sensors. From the values of radiance obtained by the HyperOCRs (corrected by the transmission and the polarization efficiency of the polarizers), the elements of the Stokes vector I, Q, U and V can be obtained (in the range 400-750 nm).



OL Series 455 Integrating Sphere Calibration Standard (Optronics Laboratories)

"The OL Series 455 Integrating Sphere Calibration Standard is designed for accurately calibrating microphotometers, image intensifiers, telephotometers and imaging spectroradiometers for photometric, radiometric, or spectroradiometric response. It serves as a highly accurate, large area, uniform, diffusely radiating source with a near normal luminance that can be varied over 6 decades with essentially constant color temperature. The optics head has a 150 W tungsten-halogen reflectorized lamp with a micrometer-controlled variable aperture between the lamp and the entrance port of the integrating sphere. A shutter is located between the lamp and the entrance port of the integrating sphere. The location of the shutter ensures that any stray light (room light) entering the radiating port of the sphere is properly accounted for when auto-zeroing the photometer. In addition to luminance and color temperature, the OL Series 455 can be obtained with calibrations for spectral radiance over all or part of the entire 350 to 2500 nm wavelength range."



LS 55 Fluorescence Spectrometer (Perkin Elmer)

"The LS 55 luminescence spectrometer is a very versatile instrument that allows measurement of fluorescence, phosphorescence, and chemiluminescence or bioluminescence, of a liquid, solid, powder, or thin film sample. The instrument is simple to operate and is controlled by easy-to-use software. The sample is illuminated in the wavelength range of 200 to 800 nm and the emission spectra recorded from 200 to 900 nm. Excitation and emission monochromators can be independently or synchronously scanned. The Model LS 55 Series uses a pulsed Xenon lamp as a source of excitation. Fluorescence data are collected at the instant of the flash while phosphorescence data are collected in the dark period between each flash. The use of the pulsed Xenon lamp obviates the need for a mechanical means of chopping the excitation and emission beams, thus leading to improved precision and speed of analysis."

Applications:

    Excitation-emission matrices of CDOM.



Lambda 35 UV/Vis Spectrophotometer (Perkin Elmer)

The Lambda 35 is a laboratory grade double-beam UV/Vis spectrophotometer. Lambda 35 has been designed for measurements on liquids, solids, pastes and powder samples. Fast scan speeds, accuracy, high-resolution, low stray light, and several modes of operation are features of the Lambda 35. The instrument can scan spectra in absorbance and transmittance modes in the wavelength range between 190 and 1100 nm. It can also obtain kinetic data and can be used for the recording of diffuse reflectance spectra of solid and liquid samples.

Applications:

    Absorption of water samples.



Profiler II (Satlantic)

"The Profiler II can be used as a free-fall profiling device or in conjunction with a detachable float for near-surface measurements. The main housing of the Profiler II body contains the master module and the ancillary module, as well as an internal power conditioning and distribution system. The master module is essentially a microcontroller board that controls the ancillary module and communicates with the slave devices (usually OCR-500 or HyperOCR series instruments) via the SatNet interface. The ancillary slave module is also a microcontroller system (the proxy controller) in the main housing of the Profiler II body. The proxy controller normally obtains measurements from the pressure, tilt, temperature and conductivity sensors, with spare channels available for future integration of additional sensors. On a typical system, one to four optical sensor slave modules are attached to the Profiler II body outside of the main housing. These slave modules obtain and report data to the master module."



SeaPRISM (CIMEL)

From G. Zibordi, N. Strombeck, F. Melin, and J. F. Berthon, "Tower-based radiometric observations at a coastal site in the Baltic Proper", Estuarine Coastal and Shelf Science, 69(3-4), 649-654 (2006): "The SeaPRISM radiometer (CIMEL, Paris) has 1.5° full angle field of view and can perform sun, sky and sea observations at 412, 440, 500, 555, 675, 870 and 1020 nm center-wavelengths. The sea- and sky-viewing angles, together with the related azimuth angle, can be programmed to satisfy different deployment needs or measurement protocols (Zibordi et al., 2004). The SeaPRISM is an element of the Ocean Color sub-network (Zibordi et al., in press) included in the Aerosol Robotic Network (AERONET) of sun-photometers (Holben et al., 1998), was programmed in agreement with an assessed protocol requiring successive measurement sequences each comprising 11 sea- and 3 sky-radiance observations per spectral channel, with sea-viewing angle of 40°, sky-viewing angle of 140 and relative azimuth of 90° with respect to the sun."



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Program Code Copyright © Thomas Legbandt 2010 - 2016


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