It uses a transmissometer
, but is more accurate than RVV since RVV is not based on visible targets.
Quantifying the response of optical backscatter devices and transmissometers
to variations in suspended particulate matter.
The basic transmissometer
set comprises a light transmitter and one or more light receivers which measure the rapidity of light attenuation caused by fog, snow or any other obscuration.
Two human observers located in Beit Dagan (35 m MSL) and at the Ben Gurion airport (41 m MSL), as well as three transmissometers
at the airport, also detected fog between the hours of 2200 UTC 9 December and 0700 UTC 10 December and limited visibility that dropped to as low as hundreds, and even tens, of meters, and particularly when the satellite image was taken [for further details, see David et al.
2009), in mark and recapture studies (Curtis, 2006), in the tracking of vessels with global position systems (GPS) (Palmer, 2008) and in measuring water clarity with beam transmissometers
(Larson et al.
In terms of work carried out to enhance its low visibility capability, this involved the installation of transmissometers
to improve the reliability of information given to ATC during poor visibility conditions; thereby reducing the allowed operating visibility minima to 550 metres.
Pairing scientists with engineers, the 40-employee company makes fluorometers, transmissometers
, scattering sensors and spectrophotometers, all of which collect data from the ocean and beam the information back to the surface, helping scientists learn about important changes in the food chain.
Demand for these source-oriented models requires that researchers go beyond the capabilities of traditional air monitoring techniques, such as transmissometers
and filter traps, to systems that measure a broad range of compounds in real time, continuously, and with high sensitivities.
Some airports solve this problem by placing transmissometers
near the runways, so if you are getting runway visual range (RVR) data in the observation, you know that you can depend on the values.
The frangibility criteria applied to approach masts is also applied to wind direction indicators (wind cones), anemometers (automatic weather stations), localiser supports (if located within 984ft (300m) from the threshold), transmissometers
(RVR) and forward-scatter meters (RVR).
Under MAKE IN INDIA programme, Department has already deployed 20 DRISHTI Transmissometers
at critical Airports and 222 DTH based Digital Cyclone Warning Dissemination Systems (CWDS).
These may include elevated runway taxiway and stopway lights, approach lighting systems, visual approach slope indicator systems, signs and markers, wind direction indicators, ILS equipment, MLS equipment, radar reflectors, anemometers, ceilometers, transmissometers
and security fencing.