Large Aperture Scintillometer BLS450

The Scintec BLS450 measures atmospheric turbulence and heat flux over path lengths between 100 m (with Path Reduction Aperture, otherwise 500 m) and 6000 m. As part of a meteorological station it can also be used to determine the evapotranspiration over extended areas.

A scintillometer senses turbulence between an optical transmitter and a receiver. The operation principle is based on the modulation of light by atmospheric refractive index fluctuations in the air. The phenomenon is called scintillation and is the reason why stars twinkle at night.

Compared to conventional turbulence measurements with point sensors, scintillometers gather spatially representative results with lower statistical scatter and shorter averaging times. As a double-ended remote sensing system, scintillometers also allow access to terrains like forest or water without need to install in-situ sensors.

Unlike other large aperture scintillometers, the Scintec BLS Series uses LED arrays which produce wide emission angles. The wide emission angle virtually eliminates the need for transmitter alignment and provides more accurate measurement results. In addition, it facilitates the use on towers which are often prone to vibration.

maximum path length 6000 m
LED array eases transmitter alignment
built-in Receiver Alignment Monitor
LED array allows transmitter to be mounted on vibrating towers
measures turbulence over large spatial scales
Signal Processing Unit performs all calculations
6 GB built-in data storage
remote access
infrared window heating available

Data output (includes but is not limited to)
Structure parameter of refractive index fluctuations (Cn2)
Structure parameter of temperature fluctuations (CT2)
Sensible heat flux
Mean, standard deviation, minimum and maximum of intensity
Scintillation index (at user-defined wavelength and path length)
Fried diameter (at user-defined wavelength and path length)
Raw intensity data
Data quality code
General Specifications
No. of transmitting disks
horizontally spaced
No. of LEDs
Optical output power
7.5 W peak
at 880 nm wavelength
Transmitter divergence
full width at half maximum
Receiver field of view
8 mrad
receiver alignment automatically monitored
Corrections for absorption fluctuations and outer scale effect
Crosswind measurement capability
Path length
100 / 500 to 6000 m
with / without Path Reduction Aperture
Pulse repetition rate
1, 5, 25 Hz or continuous
Integration time
1 sec to 60 min
Output ports
Ethernet, RS-232, analogue
Data Storage Capacity
6 GB
Internal clock
date and time
Operating voltage
10 to 15 VDC
AC power supply available
Power consumption: Transmitter "Long Path", "Boost"
30 W / 7 W / 4 W / 2 W
continuous mode/25 Hz/5 Hz/1 Hz pulse repetition rate
Power consumption: Receiver SPU
16 W
Operating temperature
-35°C to +50°C (-30°F to +120°F)
Dimensions and weight: Transmitter
18 x 18 x 14 cm / 4.5 kg
Dimensions and weight: Receiver
61 x 32 x 16 cm / 7.6 kg
Dimensions and weight: SPU
33 x 23 x 18 cm / 8 kg
Power Supply
for BLS450, BLS900 and SLS Series

For operation of BLS450, BLS900 and SLS Series systems with AC power.

Path Reduction Aperture for BLS450
to reduce path length down to 100 m

The Path Reduction Aperture is a set of special disks for the Transmitter and Receiver.

Tripod standard, height 1.80 m

The tripod provides sturdy support for the Transmitter and Receiver of BLS and SLS Series.

Tripod high, height 3.00 m

The tripod provides sturdy support for the Transmitter and Receiver of BLS and SLS Series.

Mounting Screw for BLS/SLS

The Mounting Screw secures the Transmitter and Receiver of BLS and SLS Series to a stable platform

Direct Meteorological Data Input DMI-1
for BLS and SLS Series

The DMI-1 option consists of a temperature sensor, a barometric pressure sensor, a small tower and cables to connect the sensors to the SPU.

Real-Time Heat Flux Extension
for BLS Series

The Real-Time Heat Flux Extension contains two temperature, pressure, wind speed and direction, and a combined temperature and humidity sensors for an accurate calculation of CT2 and sensible heat flux for all - unstable and stable - conditions.

Real-Time Evapotranspiration Extension
for BLS Series

The Real-Time Evapotranspiration Extension contains net radiation, two soil heat flux, precipitation, two temperature, pressure and a combined temperature and humidity sensors for determining the evapotranspiration in terms of latent heat through the so-called energy-balance method.

Real-Time Basic Extension
for BLS and SLS Series

The Real-Time Basic Extension contains temperature, humidity, and pressure sensors for calculation of structure parameter of temperature and in the case of the SLS series also the dissipation rate of turbulent kinetic energy.

Real-Time Upgrade Aspirated Radiation Shield
for BLS and SLS Series

This set of two Aspirated Radiation Shields can be used with the Real-Time Heat Flux and Evapotranspiration Extensions for higher accuracy in temperature measurements.

Real-Time Sensor Interface Software
for BLS and SLS Series

The Real-Time Sensor Interface Software allows data from sensors from Real-Time Extensions or other weather stations connected to the Signal Processing Unit to be integrated into the SRun software.

Weather Station Port Cable, 30 m
for BLS and SLS Series

This optional cable can be plugged into the Weather Station Port of the Signal Processing Unit, it can be used to have the BLS or SLS measurement data transmitted in real-time to your equipment.

Analog Raw Signal Output Cable, 3 m
for BLS and SLS Series

The analog out cable with open wires is optionally available to connect the Analog Out Port of the Signal Processing Unit to an external datalogger or other signal processing equipment.

Related Products
Large Aperture Scintillometer BLS900
Dual-Disk Design

The Dual-Disk Design of the BLS900 provides for instantaneous corrections of absorption fluctuations, saturation of scintillation and outer scale effects.

Large Aperture Scintillometer BLS2000
Dual-Disk Design

The Large Aperture Scintillometer with Dual-Disk Design for very long paths