FIELD: measurement technology. ^ SUBSTANCE: method of estimation includes application of underwater spectral irradiance meters in air for metrological certification as well as spectral brightness and bioluminescence. To reproduce power irradiance spectral density (PISD) and brightness spectral density (BSD), the photometric lamp -107-1000 is used which lamp is attested in PISD units on the base of reference ribbon lamp -1100-2350 using principle of reproduction of PISD within range of 1x10-1-1x105 W/M3 on the base of inverse-square law of distances. To reproduce PISD within 1x105-1x107 Vt/m3 the attenuator and set of diaphragms MC-13 are used. At preliminary calibration, meter is placed into oven and errors are calculated for test conditions of +5°C-+40°C. Radiation source has to be incandescent lamp. Light-guide is used for transmitting light energy from source to tested meter. Basic metrologic characteristics are calculated including sensitivity or unit of lower order as well as stability of factors of st
