Apogee MQ-650 Gebruikershandleiding - Pagina 13

Blader online of download pdf Gebruikershandleiding voor {categorie_naam} Apogee MQ-650. Apogee MQ-650 20 pagina's. Underwater epar meter

Immersion Effect Correction Factor

When a radiation sensor is submerged in water, more of the incident radiation is backscattered out of the diffuser

than when the sensor is in air (Smith, 1969; Tyler and Smith, 1970). This phenomenon is caused by the difference

in the refractive index for air (1.00) and water (1.33), and is called the immersion effect. Without correction for the

immersion effect, radiation sensors calibrated in air can only provide relative values underwater (Smith, 1969;

Tyler and Smith, 1970). Immersion effect correction factors can be derived by making measurements in air and at

multiple water depths at a constant distance from a lamp in a controlled laboratory setting.

The MQ-650 sensor has an immersion effect correction factor of 1.25. The immersion effect correction factor is

already accounted for in the MQ-650 meter firmware so there is no need to apply the correction factor to your

measurements. If you wish to use your meter to make measurements in air, simply divide the measured number

by the immersion effect (1.25).

When making underwater measurements, only the sensor and cable can go in the water. The handheld meter is

not waterproof and must not get wet. If the meter might get wet from splashing, we recommend placing it in a

plastic bag or other container to help protect it from accidentally getting wet.

NOTE: The handheld meter portion of the instrument is not waterproof. Do not get the meter wet or leave the

meter in high humidity environments for prolonged periods of time. Doing so can lead to corrosion that could void

the warranty.

Further information on underwater measurements and the immersion effect can be found on the Apogee

webpage (http://www.apogeeinstruments.com/underwater-par-measurements/).

Smith, R.C., 1969. An underwater spectral irradiance collector. Journal of Marine Research 27:341-351.

Tyler, J.E., and R.C. Smith, 1970. Measurements of Spectral Irradiance Underwater. Gordon and Breach, New York,

New York. 103 pages