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Statement

Wind velocity is a three-dimensional vector quantity with small-scale random fluctuations in space and time superimposed upon a larger-scale organized flow. It is considered in this form in relation to, for example, airborne pollution and the landing of aircraft. The WMO Guide will be considered surface wind as a twodimensional vector quantity specified by two numbers representing direction and speed. The extent to which wind is characterized by rapid fluctuations is referred to as gustiness, and single fluctuations are called gusts.

At the AWS Forni station the CombiSD DNA022 Lsi-Lastem combined wind speed-direction sensor is mounted on a 5m pole.

The CombiSD sensor includes, in a single apparatus, the both transducers for measuring wind speed and wind direction. Its use simplifies the installation and the plant design in respect of the sensors with separate measurements plus giving some other advantages being smaller, lighter and cheaper. The CombiSD DNA022: sensor has a direct signal output. Frequency (Hz) for wind speed and resistance (Ohm) for wind direction. the CombiSD has low power consumption, it can be used in systems with small energy availability.

The technical characteristics are:

- Principle of operation: 3 cups and vane anemometer

- Speed sensor: Optoelectronic disk

- Direction sensor: 2000 Ohm wire potentiometer / Positioning Hall effect sensor

- Housing: Heavy gauge anodised aluminium

- Shaft carriers: Low-torque stainless steel bearings

- Protection (vertical position): IP65

- Mechanical mounting: On 48 50 mm diameter mast

- Electrical outlet terminators: IP65 watertight connector

- Weight (instrument with rotors): 950 gr.

The Physical and operational specification are:

- damage threshold > 75 m/s

- operating temperature: -30°+70°C

The speed measures are specified by:

- Measurement range: 0-60 m/s (using transfer function)

- Threshold: 0,21 m/s

- Response time (63% at 5 m/s): 0.8 s

- Distance constant (delay distance) at 5 m/s: 4 m

- Resolution (integration time=1s): 0.05 m/s

- Accuracy & Linearity: 0,1 m/s+1%VL (readout), if connected to LASTEM data loggers.

The direction measures are specified by:

- Measurement range: 0 ÷ 360

- Threshold: 0,15 m/s

- Response time (at 5 m/s): 0,26 s

- Delay distance (at 5 m/s): 1,32 m

- Damping coefficient (VDI3786): 0,21

- Transfer function: Dir(°)= 355 x R(Ohm)/2000

- Resolution: 0,1

- Accuracy: 1% FS (Full scale)

- Integral linearity: 0,5%

gmd:MD_Metadata

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c78d1c28-3d31-41a7-8a02-43e26634c361   XML

Metadata language

eng

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UTF8

Parent identifier

a0915d40-82b5-40b3-8a32-6c3e90dfa139

Hierarchy level

Series

Date stamp

2025-02-24T09:15:47

Metadata standard name

ISO 19115:2003/19139

Metadata standard version

1.0