Kipp&Zonen LAS MkII User Manual
Instruction Manual
LAS MkII • Scintillometer
Important User Information
.
Dear customer, thank you for purchasing a Kipp & Zonen instrument. It is essential that you read this manual completely for a
full understanding of the proper and safe installation, use, maintenance and operation of your new LAS MkII Scintillometer.
We understand that no instruction manual is perfect, so should you have any comments regarding this manual we will be
pleased to receive them at:
Kipp & Zonen B.V.
Delftechpark 36, 2628 XH Delft, - or
P.O. Box 507, 2600 AM Delft,
The Netherlands
T: +31 (0) 15 2755 210
F: +31 (0) 15 2620 351
support@kippzonen.com
www.kippzonen.com
Warranty and liability
Kipp & Zonen guarantees that the product delivered has been thoroughly tested to ensure that it meets its published specifications.
The warranty included in the conditions of delivery is valid only if the product has been installed and used according to the
instructions supplied by Kipp & Zonen.
Kipp & Zonen shall in no event be liable for incidental or consequential damages, including without limitation, lost profits, loss
of income, loss of business opportunities, loss of use and other related exposures, however incurred, rising from the faulty and
incorrect use of the product.
Modifications made by the user may affect the instrument performance, void the warranty, or affect the validity of the CE
declaration or other approvals and compliances to applicable International Standards.
Copyright © 2012 Kipp & Zonen B.V.
All rights are reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form
or by any means, without authorisation by Kipp & Zonen.
Kipp & Zonen reserves the right to make changes to this manual, brochures, specifications and other product documentation
without prior notice.
Manual document number: V1207
st
Publication date: 1
July 2012
Instruction Manual - LAS MkII Scintillometer
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Instruction Manual - LAS MkII Scintillometer
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Declaration of Conformity
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We Kipp & Zonen B.V.
Delftechpark 36, 2628 XH Delft
P.O. Box 507, 2600 AM Delft
The Netherlands
Declare under our sole responsibility that the products:
Model LAS MkII
Type Large Aperture Scintillometer
to which this declaration relates are in conformity with European Harmonised Standards as published in:
Official Journal of the EC, Issue: C288 (30-09-2011)
The compliance of the product has been based on:
Emissions EN 61326-1:2006
Immunity EN 61326-1:2006
following the provisions of the directives (if applicable):
EMC-directive 2004/108/EC
st
Delft, 1
B.A.H. Dieterink
President
Kipp & Zonen B.V.
July 2012
Instruction Manual - LAS MkII Scintillometer
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Instruction Manual - LAS MkII Scintillometer
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Table of Contents
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Important User Information
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Declaration of Conformity
Table of Contents
1. Introduction
1.1 Product overview
1.2 Key parts of the LAS MkII Scintillometer
1.2.1 Transmitter and receiver
1.2.2 Transmitter rear panel
1.2.3 Receiver rear panel
2. Installation
2.1 Included with the product
2.1.1 The transmitter
2.1.2 The receiver
2.1.3 Alignment telescopes
2.1.4 Sun shields
2.1.5 Aperture restrictors
2.1.6 Power cables
2.1.7 Signal cables with 4-pin plugs
2.1.8 Signal cable with 8-pin plug
2.1.9 Allen keys
2.1.10 CD-ROM
2.1.11 Desiccant packs
2.2 tools required
2.3 Location and support base
2.3.1 Path orientation and avoiding direct sunlight
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2.3.2 Minimum installation height to prevent saturation
2.3.3 Effective beam height
2.3.4 Operation in the constant flux layer
2.4 Mounting
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2.5 Electrical and data connections
2.5.1 Power connector
2.5.2 Transmitter signal output connector
2.5.3 Receiver Analogue signal connector
2.5.4 Receiver digital interface connector
2.5.5 Receiver meteorological sensor kit connector
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2.6 Aperture restrictors for short range applications
2.7 Using the display and key-pad
2.8 Configuration for measurement
2.8.1 Setting parameters to measure C
2.8.2 Setting parameters to measure sensible heat flux
2.8.3 External sensors
2.8.4 Data Logger
2.8.5 Interface
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2.9 Installation and optical alignment
2.9.1 Preparation for installation
2.9.2 Installing the transmitter and receiver
2.9.3 Power up transmitter
2.9.4 Power up receiver
2.9.5 Transmitter optical alignment
2.9.6 Receiver optical alignment
2.9.7 Finalise optical alignment
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3. Accessories
3.1 Meteorological sensor kit
3.2 CVP 1 LAS MkII power supply
3.3 Transit case
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3.4 Adjustable heavy-duty tripod package
3.5 Tripod floor stand
3.6 Height extension tube
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4. Software installation and configuration
4.1 Installing the EVATION software package
4.1.1 System requirements
4.1.2 Installation procedure
4.1.3 Using EVATION for the first time
4.1.4 Selecting a data folder
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4.2 Configuring the EVATION software package
4.2.1 Scintillometer type
4.2.2 Communication
4.2.3 Installation
4.2.4 Roughness length and zero displacement height
4.2.5 Instrument
4.2.6 Data processing
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5. Operation and measurement
5.1 Collecting digital data
5.1.1 Real-time data display data using EVATION
5.1.2 Downloading data from the internal data logger
5.1.3 Data logger memory capacity
5.2 Data file format
5.3 Collecting analogue data
5.4 Processing data files
5.4.1 Setting input parameters
5.4.2 Setting output parameters
5.4.3 Selecting a text viewer
5.4.4 Executing data processing
5.5 Diurnal patterns
5.5.1 Diurnal C
5.5.2 Diurnal energy flux patterns
2
patterns
n
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6. Maintenance and recalibration
6.1 Internal calibration features
6.1.1 Checking C
6.1.2 Electronics offset noise check
6.2 Maintenance and inspection intervals
6.3 Inspecting and replacing desiccant cartridge
7. Specifications
7.1 Specifications of LAS MkII transmitter
7.2 Specifications of LAS MkII receiver
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processing
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7.3 Specifications of LAS MkII scintillometer system
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8. Trouble shooting
8.1 Communication problems
8.2 Receiver status and error messages
8.3 Receiver has no signal
9. Customer support
Appendix A. Theory of the scintillation technique
Appendix B. List of symbols and abbreviations
Appendix C. LAS MkII menu structure
Appendix D. Configuration error messages
Appendix E. Effective height calculator
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Using this table
Click on any item in the table of contents to be taken directly to the relevant page.
Click on the Kipp & Zonen logo at the bottom of any page to be taken back to the table of contents.
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1. Introduction
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Throughout this manual the following symbols are used to indicate to the user important information.
General warning about conditions, other than those caused by high voltage electricity, which may result in physical
injury and/or damage to the equipment or cause the equipment to not operate correctly.
Note Useful information for the user
1.1 Product overview
The LAS MkII Large Aperture Scintillometer is an optical instrument with a 150 mm diameter beam that is designed for measuring
2
the path-averaged structure parameter of the refractive index of air (C
the supplied 100 mm diameter aperture restrictors are fitted, the path length can be from 100 m to 1 km
LAS MkII uses a transmitter and receiver horizontally separated by several kilometres to measure intensity fluctuations in the
air known as scintillations. This is the same effect, but of much smaller amplitude, as the ‘shimmering’ of air over very hot or
cold surfaces that causes a mirage.
The scintillations seen by the instrument can be expressed as the structure parameter of the refractive index of air (C
light source of the LAS MkII transmitter operates at a near-infrared wavelength of 850 nm. At this wavelength the observed
scintillations are primarily caused by turbulent temperature fluctuations.
) over horizontal path lengths from 250 m to 4.5 km1. When
n
1
.
2
). The
n
2
Therefore, C
observations of air temperature, wind speed and air pressure to derive the free convection sensible heat flux (H
measurements obtained with the LAS MkII can be combined with temporally and spatially coherent meteorological
n
). An accessory
free
meteorological sensor kit is available for this purpose, which connects to the LAS MKII receiver.
The LAS MkII is self-contained. The system can be locally configured at the receiver with a display and menu keys and has
internal digital signal and data processing and data storage. When the data is exported to the included EVATION software
package running on a computer the surface sensible heat flux (H) can be calculated.
Compared to traditional point measurement systems, the LAS MkII operates at spatial scales comparable to the grid box size of
numerical models and the pixel size of satellite images used in meteorology, hydrology and water management studies. The LAS MkII
has important applications in energy balance and water balance studies, because the surface flux of sensible heat is linked to latent
heat flux (L
E) and evapotranspiration (ET). For these measurements a complete LAS MkII ET System is available.
v
This manual provides information related to the installation, maintenance, calibration, product specifications and applications
of the scintillometer.
If any questions should remain, please contact your local Kipp & Zonen representative or e-mail the Kipp & Zonen customer and
product support department at: support@kippzonen.com
Please go to www.kippzonen.com for information about other Kipp & Zonen products, or to check for any updates to this manual
or software.
1
The maximum usable path length depends upon the atmospheric conditions, the path lengths given are for ‘clear’ conditions (visibility 10-20 km). In general, it is
best to use the scintillometer at full aperture at path lengths down to 250 m, and the aperture restrictors for shorter paths. However, for field-scale measurements
at a range of distances up to 1 km it may be convenient to leave the restrictors fitted.
Instruction Manual - LAS MkII Scintillometer
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1.2 Key parts of the LAS MkII Scintillometer
1.2.1 Transmitter and receiver
The drawing shows the key common parts of the LAS MkII transmitter and receiver:
1
Sun shield fitted to the mounting for the alignment telescope
2
Tilt (vertical) adjustment screws
3
Pan (horizontal) adjustment screws
4
Transmitter window, with heater and Fresnel lens behind
5
Drying cartridges
6
Baseplate
1
4
2 22
3 3
1.2.2 Transmitter rear panel
The drawing shows the key parts of the LAS MkII transmitter rear panel:
1
Power indicator (red)
2
Transmitter power adjustment knob (remove screw-on cover)
3
Signal output connector (4-pin)
4
Power input connector (12 VDC)
5 5
66
1
2
3 4
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1.2.3 Receiver rear panel
The drawing shows the key parts of the LAS MkII receiver rear panel:
Display
1
2
Power and status indicator (green)
3
Menu navigation keys
4
Meteorological sensor kit connector (8-pin)
5
Analogue signal connector (4-pin)
6
Power input connector (12 VDC)
7
Digital interface connector (8-pin)
12
3
4
7
5
6
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2. Installation
.
Please follow the instructions in this section carefully for the mechanical and electrical installation of the LAS MkII scintillometer.
Do not turn on power to the transmitter or receiver until instructed to do so.
Ensure that fixings and mountings are securely tightened when instructed to do so.
2.1 Included with the product
Check the contents of the shipment for completeness (see below) and note whether any damage has occurred during transport. If
there is damage, a claim should be filed with the carrier immediately. In the case of damage and/or the contents are incomplete,
contact your local Kipp & Zonen representative or e-mail the Kipp & Zonen customer and product support department at:
support@kippzonen.com
Note The LAS MkII is rugged, but it contains sensitive optical and electronic parts. Please keep the original packaging
to safely transport the scintillometer to measurement sites or for other shipments.
The following items are included with the LAS MkII scintillometer:
LAS MkII transmitter with pan and tilt adjuster and baseplate
LAS MkII receiver with pan and tilt adjuster and baseplate
2 × alignment telescope with detachable mounting, adjusted for each transmitter and receiver
2 × sun shield with two fixing screws
2 × 100 mm diameter aperture restrictor with fixing kit, for transmitter and receiver
2 × 10 m cable with 4-pin plug for transmitter signal output and receiver analogue connections
1 x 10 m cable with 8-pin plug for receiver digital communication connections
2 x 10 m cable with 4-pin connector for 12 VDC power input
2 x 3 mm hexagonal Allen keys, for fitting the sun shields
2 x 4 mm hexagonal Allen keys, for fitting the telescopes
1 x CD-ROM containing EVATION software and a pdf file of this LAS MkII instruction manual
8 x spare desiccant packs
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2.1.1 The transmitter
The transmitter housing contains a very efficient, eye-safe LED operating at 850 nm wavelength in the near-infrared region. The
LED mounting is axially adjustable to position it at the focus of a Fresnel collimating lens. The near-parallel beam is output
through a glass window with an aperture diameter of 150 mm. There is a self-regulating heater for the window that can disperse
rain, dew, frost and snow. Electronics pulse the LED at 6.5 - 7 kHz and the drive signals can be monitored on the signal output
connector.
There is a baseplate with rugged and easy to use pan and tilt adjustment. A mounting rail on the top of the housing is used to
fit the alignment telescope or the white heat shield. There are two drying cartridges containing desiccant to keep the transmitter
dry internally.
The transmitter is powered by 12 Volts DC.
Instruction Manual - LAS MkII Scintillometer
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2.1.2 The receiver
The beam from the transmitter enters the receiver through a glass window with an aperture diameter of 150 mm. There is a
self-regulating heater for the window that can disperse rain, dew, frost and snow. A Fresnel lens focusses the 6.5 - 7 kHz pulsed
radiation onto a very sensitive large-area photodiode detector with a thin-film optical filter that only transmits radiation in a
waveband around 850 nm, blocking ambient light from reaching the detector. The detector and filter assembly are axially
adjustable to position the detector at the focus of the lens.
Analogue electronics are tuned to the 6.5 - 7 kHz carrier wave and to the scintillation frequency band of 0.2 Hz to 400 Hz. These
signals are rectified and are available at the analogue signal connector. All the remaining electronics are digital. The system can
be locally configured at the receiver with a display and menu navigation keys and has internal signal and data processing and
storage. It can calculate and log Cn2 measurements and, with the accessory meteorological sensor kit connected, the sensible
heat flux (H) can be calculated and stored. External communication is via the digital interface connection.
There is a baseplate with rugged and easy to use pan and tilt adjustment. A mounting rail on the top of the housing is used to
fit the alignment telescope or the white heat shield. There are two drying cartridges containing desiccant to keep the receiver
dry internally.
The receiver is powered by 12 Volts DC.
Instruction Manual - LAS MkII Scintillometer
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2.1.3 Alignment telescopes
Each transmitter and receiver has a telescope, individually adjusted to align with its optical axis, and each telescope is labelled
accordingly. These telescopes attach by clamps to mounting rails on the tops of the transmitter and receiver housings and enable
alignment of the transmitter and receiver at long path lengths. They are not completely weatherproof and should be removed after
alignment and replaced by the sun shields. A 4 mm hexagonal Allen key is supplied for the mounts of each telescope.
2.1.4 Sun shields
After alignment of the transmitter and receiver the telescopes should be removed and replaced by the sun shields. These are each
attached by two screws to mounting rails on the tops of the transmitter and receiver housings. A 3 mm hexagonal Allen key is
supplied for the fixing screws of each sun shield.
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2.1.5 Aperture restrictors
The full beam aperture of 150 mm enables operation over path lengths from 250m to 4.5 km, depending upon the atmospheric
conditions. For shorter path lengths, from 100m to 1 km, restrictors with apertures of 100 mm are fitted in front of the windows of
the transmitter and receiver.
2.1.6 Power cables
Two 10 m long cables with 4-pin waterproof plugs are provided for the transmitter and receiver 12 Volt DC power inputs.
2.1.7 Signal cables with 4-pin plugs
Two 10 m long cables with 4-pin waterproof connectors are provided. One for the transmitter signal outputs, the other for the
receiver analogue signal connection.
2.1.8 Signal cable with 8-pin plug
One 10 m long cable with an 8-pin waterproof plug is provided for the receiver digital interface connection.
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2.1.9 Allen keys
Two 3 mm hexagonal Allen keys are supplied for fitting the transmitter and receiver telescopes and two 4 mm hexagonal Allen keys
for fitting the sun shields.
2.1.10 CD-ROM
The supplied CD-ROM contains the EVATION software package and this manual as a pdf file.
2.1.11 Desiccant packs
Eight spare packs of self-indicating silica gel desiccant are supplied for the drying cartridges of the transmitter and receiver.
2.2 tools required
In addition to the items supplied with the LAS MkII scintillometer, the following equipment is required for performing the installation:
• At least two people
• Stable mounting bases for the transmitter and receiver or tripods
• Printed copy of the manual, from the supplied CD-ROM
• Tape measure for determining the installation height
• 2 x radios or mobile ‘phones for communication between transmitter and receiver operators
• 2 x sets of mounting bolts and suitable wrenches
• 2 x sources of 12 Volts DC power
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2.3 Location and support base
When choosing the location for scintillometer measurements care has to be taken that certain requirements are met.
2.3.1 Path orientation and avoiding direct sunlight
Avoid locating the transmitter and receiver where direct sunlight may be in their views. The Fresnel lenses will focus the light onto
the transmitting LED and the receiving optical filter and photodiode and there is a risk of damage due to overheating.
It is recommended to select a path that is approximately parallel to the Earth’s surface (i.e. horizontal) and has a north-south
orientation to avoid any problems caused at low sun angles. If this is not possible, pick an orientation where some obstruction in
the background (buildings, trees) blocks the direct sun.
Direct sunlight close to the optical axes of the transmitter and receiver may permanently damage optical parts.
In order to maximise the footprint of the measurement, it is recommended to select a path between the transmitter and receiver
which is perpendicular to the predominant wind direction.
Ensure that the optical path between the transmitter and receiver is free of any obstructions.
2.3.2 Minimum installation height to prevent saturation
When the scintillation intensity rises above a certain limit the theory, on which the scintillation measurement method is based,
2
is no longer valid. When this occurs, the relationship between the measured amount of scintillations (σ
2
parameter of the refractive index of air (C
In order to prevent saturation, C
2
must stay below a certain saturation criterion (S
n
only under weakly scintillating conditions. The dependence of C
measurement height (z
) and the path length (L) can be written as follows:
LAS
C
) fails. This phenomenon is known as saturation.
n
), i.e. the scintillometer can measure well
max
2
(λ, D, z
n
2
on the optical wavelength (λ), the aperture diameter (D), the
n
, L) S
LAS
max
The path length and the measurement height are the only variables that can be adjusted in order to keep C
) and the structure
lnI
2
below the saturation
n
criterion. A scintillometer installed at a height close the Earth’s surface; will see more scintillations than a scintillometer
installed high above the surface. As the path length increases more scintillation will be observed.
.
This means that over long distances (several kilometres) the scintillometer must be placed high above the surface in order to
prevent saturation. Over shorter distances (several hundred meters) the scintillometer can be installed closer to the surface.
2
Over dry areas the surface sensible heat flux is large, resulting in higher C
heat flux is small.
The graphs below show the minimum height of the LAS MkII for different surface conditions as a function of the path length. The
area above the curves in the figure is the so-called non-saturation zone. Below the curves saturation will occur. Based on the
user’s preferred path length, and the surface conditions of the area of interest, the user must install the LAS MkII scintillometer
at a height that lies in the non-saturation zone.
values than over wet surfaces where the sensible
n
Instruction Manual - LAS MkII Scintillometer
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Full 150 mm aperture
60
50
40
30
Height LAS [m]
20
10
0
0 500 1000 1500 2000 2500 3000 3500 4000 4500
Restricted 100 mm aperture
7
6
5
4
LAS [m]
h = 50 W/m²
h = 100 W/m²
h = 150 W/m²
h = 250 W/m²
h = 300 W/m²
h = 400 W/m²
No saturation
Saturation
Path length LAS [m]
h = 50 W/m²
h = 100 W/m²
h = 150 W/m²
h = 250 W/m²
h = 300 W/m²
h = 400 W/m²
No saturation
0.1 m-
3
Height
2
1
Saturation
0
0 100 300 500 700 900200 400 600 800 1000
Path length
0.1 m-
LAS [m]
.
For example, a LAS MkII installed over a relatively wet area (h ~ 100 W/m²) and a path length of 3 km must be installed at a
height of at least 12 m.
Ensure that the LAS MkII is operating in the ‘non-saturation’ zone.
Instruction Manual - LAS MkII Scintillometer
20
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2.3.3 Effective beam height
Determine the effective height of beam of the LAS MkII (z
from the structure parameter data is very sensitive to the height (see Appendix A). When the area is relatively flat and the beam
is parallel to the surface the effective height is easy to determine (z
The path-weighting function is symmetrical and bell-shaped having a centre maximum and tapering to zero at the transmitter
and receiver end. This means that the LAS MkII is most sensitive in the middle of its path. For situations where the area is not
flat, or for slanted paths, it is recommend to measure the height of the beam at several points along the path.
The figure below shows how the weighting function must be used in order to estimate the precise height of the beam above the
surface for non-flat areas. The effective height calculator in the EVATION software package can be used to find the effective
height, as described in Appendix E. For more information see Hartogensis et al, 2003
) along the path precisely. The surface sensible heat flux (H) derived
LAS
transmitter
= z
receiver
= z
).
LAS
1
.
70
60
Transmitter
50
Receiver
surface
beam - LAS
40
Height [m]
30
20
10
weighting function - LAS
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Normalised position [-]
0.015
0.01
Weight [%]
0.005
0
The graphs above illustrate a LAS MkII path (beam) over a non-flat area. Based on the elevation map (surface) and the LAS
path-weighting function, an effective beam height of 46 m was calculated.
1
Hartogensis, O.K., Watts, C.J., Rodriguez, J-C. and De Bruin, H.A.R.: 2003, ‘Derivation of an Effective Height for Scintillometers: La Poza Experiment in Northwest Mexico’, J. Hydro-Meteorol. 4, 915-928.
.
2.3.4 Operation in the constant flux layer
2
In order to derive the surface fluxes of sensible heat from the scintillometer measurements (C
) we use the Monin-Obukhov Similarity
n
Theory (MOST) (see Appendix A). MOST is widely used in meteorology and is usually applied to the Surface Layer (SL) and hence is
sometimes called the Surface Layer Similarity. The SL is roughly the lowest 10% of the Planetary Boundary Layer (PBL).
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The PBL is directly influenced by the earth’s surface and its depth varies between roughly 100m and 2 km. In general the PBL
increases during the day, when the Earth’s surface is heated by the sun, and decreases again during the night. Within the SL the
variation of fluxes (such as the sensible heat flux H and latent heat flux L
value at the surface.
Therefore, fluxes measured at a certain elevation in the SL can be considered as being representative of the exchange processes
occurring between the Earth’s surface and the atmosphere above. The SL can be further divided into the Roughness Sub-layer
(RS), influenced by the structure of the roughness elements (e.g. plants, trees, buildings etc.), and the Constant Flux Layer
where fluxes are assumed to be horizontally and vertically constant (due to turbulent mixing). This means that measurement
techniques that apply MOST for estimating surface fluxes can be applied only in the Constant Flux Layer.
Therefore the LAS MkII must be installed at a height such that it is located above the Roughness Sub-layer and is measuring
within the Constant Flux Layer.
The depth of the SL typically varies between 20 m and 100 m. The upper level strongly depends on the diurnal cycle of surface
heating and cooling and the presence of clouds. Like the PBL, the SL increases during the day as the surface is heated by the sun
and is maximum at sunset (~100 m), before it decreases again due to cooling of the surface at night (~20 m).
The height of the Roughness Sub-layer, and thus the lower level of the Constant Flux Layer, depends strongly upon the size, form
and distribution of the roughness elements. Usually, over tall vegetation, the height of the Roughness Sub-layer is taken to be
equal to three times the obstacle height (or roughness elements h).
E) is negligible with respect to the magnitude of their
v
In case the estimated height of the Roughness Sub-layer is below the minimum height to avoid saturation, use a height that
ensures the LAS MkII is in the non-saturation zone.
Ensure that the LAS MkII is measuring in the Constant Flux Layer and in the non-saturation zone.
Note More detailed information about the theory of the scintillation technique can be found in Appendix A.
Note A list of symbols and abbreviations can be found in Appendix B.
Instruction Manual - LAS MkII Scintillometer
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2.4 Mounting
The LAS MkII can only function properly when the transmitter and receiver are precisely optically aligned. By mounting the
scintillometer on a stable support, signal loss and regular re-alignment procedures will be avoided. Vibrations in the mounting
2
structure must be prevented, which can lead to overestimated C
bend and vibrate in the wind.
Mount the LAS MkII transmitter and receiver on stable and vibration-free supports.
Adjustable tripods are only suitable for short-term measurements. Where they are not on hard surfaces, a board should be used
to prevent the tripod legs sinking in and affecting the beam alignment.
If tripods are used, ensure that they cannot easily fall over and possibly damage the transmitter or receiver.
The pan and tilt adjusters of the transmitter and receiver have a baseplate. This has a central M16 thread to fit the mounting
bolts of industrial tripods, such as the accessory adjustable heavy-duty tripod package for the LAS MkII.
The baseplate has 4 slots for 10 mm bolts, on 184.2 mm diameter, which can be used for fixing the transmitter and receiver to a
customer-supplied support or to the accessory Kipp & Zonen tripod floor stand and/or height extension tube. The bottom view
of the baseplate is shown below.
values. This particularly applies to masts or towers that can
n
M16 threaded hole
Mounting slots for
4 x 10 mm bolts on
184.2 mm diameter
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2.5 Electrical and data connections
There are two waterproof connectors located on the rear panel of the transmitter and four on the rear panel of the receiver.
2.5.1 Power connector
The transmitter and receiver are each provided with a 4-pin waterproof plug fitted to a 10 m long cable that is terminated in
tinned wires, for 12 Volts DC (nominal) power to the instrument and heater.
Transmitter and receiver power connector and cable
Pin number Wire colour Function Value
1 red instrument power + 9.6 to 18 VDC
2 orange heater power + 9.6 to 18 VDC
-
3 brown heater return
4 black instrument return
shield thick black cable screen housing ground
The LAS MKII transmitter and receiver must be grounded through the shield of the power connector (also connected
to pin 4) for protection against lightning and electrical interference.
0 V
-
0 V
The LAS MKII transmitter and receiver power inputs should be protected by fuses.
Instrument power +, 1 A normal or slow-blow type. Heater power +, 4 A slow-blow type.
2.5.2 Transmitter signal output connector
The transmitter is provided with a 4-pin plug for signal outputs, fitted to a 10 m long yellow cable that is terminated in tinned wires.
Transmitter signal connector and cable
Pin number Wire colour Function Value
1 red not connected
2 blue 6.5 - 7 kHz pulse + 0 to 8 V
0.5 duty cycle
3 green 6.5 - 7 kHz LED pulse + 0 to 2 V
0.5 duty cycle proportional to LED
power setting
-
4 yellow signal
shield thick black cable screen housing ground
0 V
Instruction Manual - LAS MkII Scintillometer
24
.
2.5.3 Receiver Analogue signal connector
The receiver is provided with a 4-pin plug for analogue signal outputs, fitted to a 10 m long yellow cable that is terminated in
tinned wires.
Receiver analogue signal connector and cable
Pin number Wire colour Function Value Impedance
2
1 red Log UC
10
2 blue 6.5 to 7 kHz AC 0 to 1 V RMS 120 Ω
carrier signal + 100 % = 152 mV RMS 4700 pF
3 green demodulated carrier 0 to 2 V 680 Ω
signal (U
4 yellow signal
shield thick black cable screen housing ground
2.5.4 Receiver digital interface connector
The receiver is provided with an 8-pin waterproof plug for the digital communication interface, fitted to a 10 m long yellow cable
that is terminated in tinned wires.
signal + 0 to 2 V 680 Ω
n
) + 100 %= 606 mV 4700 pF
demod
-
0 V
-17
to 10
-12 m-2/3
4700 pF
Two communication modes can be selected, RS-232 or 4-wire RS-422 (default). The desired mode can be selected using the LAS MkII
configuration menu or by the control software.
Receiver digital interface connector and cable
Pin number Wire colour RS-232 function RS-422 function
1 red RXD RXD- (A)
2 blue CTS RXD+ (B)
3 green DSR do not connect
4 yellow RTS TXD+(Z)
5 grey TXD TXD- (Y)
6 brown DTR do not connect
7 white DCD do not connect
8 black digital ground digital ground
shield thick black cable screen cable screen
For permanent connection to a computer always use optically or galvanicly isolated adapters or converters at the
computer serial port to protect against damage caused by lighting.
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.
2.5.5 Receiver meteorological sensor kit connector
The 8-pin connector marked ‘Sensors’ must only be used with the accessory meteorological sensor kit. The 12 VDC
output must not be used to supply other equipment.
Receiver meteorological sensor kit connector
Pin number Wire colour Function Value
1 red not connected
2 blue not connected
3 green not connected
4 yellow power supply 12 VDC output
for sensor kit do not ground!
5 grey temperature input 4 to 20 mA
6 brown air pressure input 4 to 20 mA
7 white wind speed input 4 to 20 mA
8 black sensors ground 0 V
shield thick black cable screen housing ground
The accessory meteorological sensor kit is supplied pre-wired with a 10 meter long yellow cable and waterproof connector and
will be automatically powered and recognised when plugged into the LAS MkII receiver.
Wind speed
Temperature
Pressure
Do not connect a computer to the sensor connector using the digital interface plug and cable. The 12 V power
output for the sensors may damage the computer serial port.
Junction Box
Instruction Manual - LAS MkII Scintillometer
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