Ultrasonic Anemometer
Wind Research 400 model
The highly accurate Wind Research 400 3-axis ultrasonic anemometer is a powerful tool for serious wind and turbulence studies. With on-line turbulence calculations and the ability to connect additional sensors to produce a compact, portable station the Wind Research 400 is ideal for use as part of an eddy-flux station.
Features
- separate measuring head and electronics which further reduces flow distortion and error
- up to 50 Hz sampling rate
- wind speed range 0.01 - 45 m/s (0 - 100 mph)
- digital and analogue outputs
- verifies and reports data quality
- 6 external sensor inputs with time delay capability for time-modulated data output
- 16 bit resolution on analogue inputs
- 4 analogue channel outputs
- 2 x TTL and 2 x PT100 inputs
- on-line turbulence calculations
- mains or battery power
- field calibration kit
- transport case
What it does
The Wind Research 400 provides the following information in various data outputs which can be polled or output automatically:
- instantaneous and averaged data for the three component wind vectors
- virtual temperature
- horizontal wind speed and direction plus vertical wind component
- chart mode (provides 0-540º wind direction and speed values)
- NMEA value outputs
- raw data mode (uncorrected) or 2D / 3D head corrected data
Data can be averaged by several methods:
- scalar or vectoral
- clock synchronised or running average
- separate output rates and sampling times
Some other important features:
- user definable north orientation (range 0-359º alignment off axis)
- data quality control to perform confidence checks on raw data
- date / time stamps with several options
- check sum information
- calibration validity output monitoring
Near real-time turbulence calculations:
- mean wind components (3D) and temperature
- Standard Deviations (SD) of components and temperature
- covariances of different components and temperature
- SD values comparing mean wind to parallel component as well as the horizontally and vertically perpendicular wind component
- turbulence intensities
- friction velocity
- Drag coefficient
- Monin-Obukhov stability
- momentum and heat fluxes
- u, v, w
- direction and velocity mean components or values
Examples of data output
Normal data example (instantaneous). Every data string starts with a header line that consists of the string SNC followed by a space and 12 characters for the date/time stamp, another space and finally the UTC string i.e.:
SNC 940815090015 UTC
x = 1.83 y = -0.79 z = 0.20 T = 20.17
Turbulence data example (averaged).The following lines display the averaged data using a fixed format: up to 4 values per line each preceded by its name (5 characters, right-aligned), a space character, an equals sign and an 8 character (right-aligned) floating point number with a fixed number of decimal digits (possibly with trailing zeros). This number will be replaced by 8 space characters in case of invalid data. The values are separated by a space character. The names of the data and their ordering can be understood from the following example:
SNC 940815090015 UTC AVE 600 SMP 10 AZI 0 SDQ 100 HTR
x = |
1.74 |
y = |
-0.93 |
z = |
-0.14 |
T = |
0.62 |
xsig = |
0.91 |
ysig = |
0.89 |
zsig = |
0.43 |
Tsig = |
0.47 |
xycov = |
-0.3911 |
xzcov = |
-0.2010 |
xTcov = |
-0.1801 |
|
|
yzcov = |
0.0961 |
yTcov = |
0.2170 |
zTcov = |
0.1200 |
|
|
psig = |
1.07 |
qsig = |
0.70 |
rsig = |
0.40 |
|
|
tp = |
0.54 |
tq = |
0.35 |
tr = |
0.20 |
|
|
ustar = |
0.39 |
Tstar = |
0.31 |
Cd = |
0.04 |
|
|
MOs = |
-0.03 |
mf = |
-0.19 |
hf = |
144.60 |
|
|
u = |
-0.93 |
v = |
1.74 |
w = |
-0.14 |
|
|
vel = |
1.98 |
dir = |
151.9 |
|
|
|
|
where:
AVE |
the averaging time |
SMP |
the sampling rate in Hertz |
AZI |
the devise azimuth |
SDQ |
the sonic data quality |
HTR |
informs the user that the sensor head heating is turned on |
x |
mean x wind component in the sensor related orthogonal co-ordinate system (parallel to the black arrow on the electronic box); unit m/s |
y |
mean y wind component in the sensor related orthogonal co-ordinate system (horizontally perpendicular to x); unit m/s |
z |
mean z wind component in the sensor related orthogonal co-ordinate system (vertical); unit m/s |
T |
mean temperature; unit ºC |
xsig |
standard deviation of x; unit m/s |
ysig |
standard deviation of y; unit m/s |
zsig |
standard deviation of z; unit m/s |
Tsig |
standard deviation of T; unit K |
xycov |
covariance of x and y; unit m2/s2 |
xzcov |
covariance of x and z; unit m2/s2 |
xTcov |
covariance of x and T; unit mK/s |
yzcov |
covariance of y and z; unit m2/s2 |
yTcov |
covariance of y and T; unit mK/s |
zTcov |
covariance of z and T; unit mK/s |
psig |
standard deviation of the wind component parallel to the mean wind direction; unit m/s |
qsig |
standard deviation of the wind component horizontally perpendicular to the mean wind direction; unit m/s |
rsig |
standard deviation of the wind component vertically perpendicular to the mean wind direction; unit m/s |
tp |
longitudinal turbulence intensity |
tq |
transversal turbulence intensity |
tr |
vertical turbulence intensity |
ustar |
friction velocity u.; unit m/s |
Tstar |
characteristic temperature T.; unit K |
Cd |
drag coefficient Cd |
MOs |
Monin-Obukhov stability parameter; unit m-1 |
mf |
vertical momentum flux; unit kg/ms2 |
hf |
vertical heat flux; unit W/m2 |
u |
mean west-east wind component
(depends on setting of parameter AZ); unit m/s |
v |
mean south-north wind component
(depends on setting of parameter AZ); unit m/s |
w |
mean vertical wind component; unit m/s |
vel |
mean horizontal wind velocity; unit m/s |
dir |
mean horizontal wind direction
(depends on setting of parameter AZ); unit º |
The following data strings will be displayed for the analogue inputs/counters:
2 x PT100 inputs |
6 x analogue input channels |
2 x TTL counters |
e1 and e2 |
e3 to e8 |
c1 and c2 |
e1sig and e2sig |
e3sig to e8sig |
|
e1zco and e2zco |
e3zco to e8zco |
|
where:
2 x PT100 inputs |
e1 and e2
|
mean Pt100 temperatures
(based on a0, a1 values of the basic system); unit ºC |
e1sig and e2sig
|
standard deviations of the Pt100 temperatures
(based on a0, a1 values of the basic system); unit K |
e1zco and
e2zco |
covariances of the Pt100 temperatures
(based on a0, a1 values of the basic system) with z; unit Km/s |
6 x analogue inputs |
e3 to e8
|
mean values of the analogue input channels
(based on a2 ... a7 values of the basic system); unit V |
e3sig to e8sig
|
standard deviations of the analogue input channels
(based on a2 ... a7 values of the basic system); unit V |
e3zco to e8zco
|
covariances of the analogue input channels
(based on a2 ... a7 values of the basic system) with z; unit Vm/s |
2 x TTL counters |
c1 and c2 |
Counted events (based on c0, c1 values of the basic system); unit 1 |
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Specifications of the Wind Research 400 ultrasonic anemometer
Wind Speed |
|
Range |
0.01 - 45 m/s (0 - 100 mph) |
Accuracy |
+/- 2 % (full scale output) |
Resolution |
0.01 m/s (steps) |
Wind Direction |
|
Range |
0 - 359º or 0- 540º |
Accuracy |
+/- 2º |
Resolution |
0.4o (steps) |
Digital Output |
|
Type |
RS232, RS422 |
Sampling rate |
50 Hz |
Averaging |
up to 3600 seconds |
Analogue Outputs x 4 |
|
Type |
0-5 V, 0- 10 V, 0-20 mA, 4-20 mA |
Resolution |
12 bit |
Scalable |
Yes |
Analogue Inputs x 6 |
|
Type |
+/- 2.5 V, +/- 5 V, +/- 10 V |
Resolution |
16 bit |
Sample delay option |
Yes |
PRT inputs |
2 |
TTL inputs |
2 |
PT100 inputs |
2 |
Power |
|
Requirements |
9-36 VDC or 115 / 230 VAC |
Current draw |
180 mA (@ 24 VDC) |
Data |
|
Turbulence data |
Yes (see above for more information) |
Sonic temperature: |
|
with digital output |
-30ºC to 50ºC (-22ºF to 122ºoF)
in non-condensing environments |
with analogue output |
measures within a 40º span (user configurable) of the above range with a resolution of 0.01ºC |
Units of measure |
m/s, knots, mph, km/h, ºC |
General |
|
IP rating |
IP65 |
Size |
32 cm x 69 cm (12 x 27 inches) |
Weight |
7.1 kgs (15 Ibs) |
Materials: |
|
|
sensor head
|
stainless steel (V4A) |
|
electronic housing
|
powder-coated die-cast aluminium |
This range is in continuous development therefore
specifications may change without prior notice.
Accessories
Included with the Wind Research 400 ultrasonic anemometer:
Field Calibration Kit
Transport Case
Mains Adapter
20 m (65 ft) power, data and analogue cable (8 m (26 ft) between the measuring head and electronics box and 12 m (39 ft) from electronics box)
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