3.14.2. LAS150

3.14.2.1. Introduction

The LAS 150 is a large aperture scintillometer, manufactured by Kipp and Zonen. A scintillometer measures turbulence over a path, which can then be used to calculate heat flux, cross wind and evapotranspiration. The LAS 150 consists of two main parts for observations: a transmitter and a receiver. These are placed between 100m and 4500m apart. The transmitter transmits visible light towards the receiver, which uses the principle of modulation of light by atmospheric refractive index fluctuations in air, known as scintillation, to determine atmospheric turbulence over the path. The main benefit of scintillometry is the greater spatial representation achieved compared to point sensors. The 150 is an older version of the LASMKII.

3.14.2.2. Manufacturer and Model

Model	Brand	Type
LAS150	Kipp & Zonen	Large Aperture Scintillometer

3.14.2.3. Output definitions

Ouput definition ID	File Identifier	Level Number	QAQC notes	File time resolution
LAS150	LAS_Fast_%SITE	0	No_QC	1min
LAS150	LAS_Fast_%SITE	0	No_QC	15min
LAS150	LAS_Fast_%SITE	0	No_QC	30min
LAS150	LAS_Fast_%SITE	1	Thresholds	1min
LAS150	LAS_Fast_%SITE	1	Thresholds	15min
LAS150	LAS_Fast_%SITE	1	Thresholds	30min

3.14.2.4. Processing code

Code used to process raw data: https://github.com/Urban-Meteorology-Reading/Operations-LAS

3.14.2.5. Variables measured by instrument

Table 3.12 Variables measured - sorted alphabetically

Variable ID	Full Name	Unit	Lower Threshold	Upper Threshold	Files present (Output definition ID,Level No,Time resolution)
Cn2	refractive_index_structure_parameter	m-2/3			LAS150,0,1min LAS150,0,15min LAS150,0,30min LAS150,1,1min LAS150,1,15min LAS150,1,30min
Cn2_RAW	refractive_index_structure_parameter_RAW	m-2/3			LAS150,1,1min LAS150,1,15min LAS150,1,30min
Cn2Max	maximum_refractive_index_structure_parameter	m-2/3			LAS150,0,1min LAS150,0,15min LAS150,0,30min LAS150,1,1min LAS150,1,15min LAS150,1,30min
Cn2Min	minimum_refractive_index_structure_parameter	m-2/3			LAS150,0,1min LAS150,0,15min LAS150,0,30min LAS150,1,1min LAS150,1,15min LAS150,1,30min
Cn2Sig	refractive_index_structure_parameter	m-2/3			LAS150,0,1min LAS150,0,15min LAS150,0,30min LAS150,1,1min LAS150,1,15min LAS150,1,30min
CT2	temperature_structure_parameter	K-2m^2/3			LAS150,1,1min LAS150,1,15min LAS150,1,30min
Demod	demodulated_signal	mV			LAS150,1,1min LAS150,1,15min LAS150,1,30min
DemodSig	demodulated_signal_sig	mV			LAS150,1,1min LAS150,1,15min LAS150,1,30min
DeviceTemp	device_temperature	Celsius			LAS150,0,1min LAS150,0,15min LAS150,0,30min LAS150,1,1min LAS150,1,15min LAS150,1,30min
Hfree	upward_turbulent_sensible_heat_flux_free_convection_method	W.m-2			LAS150,0,1min LAS150,0,15min LAS150,0,30min LAS150,1,1min LAS150,1,15min LAS150,1,30min
nSamples	nSamples	samples/interval			LAS150,0,1min LAS150,0,15min LAS150,0,30min LAS150,1,1min LAS150,1,15min LAS150,1,30min
Q_H	upward_turbulent_sensible_heat_flux	W.m-2			LAS150,1,1min LAS150,1,15min LAS150,1,30min
Q_H_db	upward_turbulent_sensible_heat_flux_de_bruin_method	W.m-2			LAS150,1,1min LAS150,1,15min LAS150,1,30min
Q_H_fc	upward_turbulent_sensible_heat_flux_free_convection_method	W.m-2			LAS150,1,1min LAS150,1,15min LAS150,1,30min
SatCorrFactor	Saturation_Correction_Factor	dimensionless			LAS150,1,1min LAS150,1,15min LAS150,1,30min
Srt	maximum_refractive_index_structure_parameter	K-2m^2/3			LAS150,0,1min LAS150,0,15min LAS150,0,30min LAS150,1,1min LAS150,1,15min LAS150,1,30min
UDemod	demodulated_signal	mV			LAS150,0,1min LAS150,0,15min LAS150,0,30min
UdemodSig	demodulated_signal_sig	mV			LAS150,0,1min LAS150,0,15min LAS150,0,30min

3.14.2.6. Serials

Serial	Suffix
60029	A

3.14.2.7. Deployments

3.14.2.7.1. Serial number: 60029

Site ID	Start date	End date
BTT	2010-03-09 00:00	2011-09-23 00:00
NTT	2011-10-12 00:00	2011-11-03 00:00
NGT	2012-01-11 00:00	2012-09-21 00:00

3.14.2.8. Photos

Fig. 3.32 Transmitter from KGG to BTT 05-08-2011.

Fig. 3.33 Reciever at NGT 25-05-2012.

Fig. 3.34 Receiver at NGT 06/01/2012.

Fig. 3.35 Receiver at NDT 11/01/2012.

3.14.2.9. Data acquisition

Data can be requested from Prof. Sue Grimmond (c.s.grimmond@reading.ac.uk).

Tip

1. Stuck? the user guide is a useful place to start.

2. Please report issues at GitHub Issues. Go from the page with the problem - an automatic link will be inserted. Thanks.