3.14.1. BLS

3.14.1.1. Introduction

The BLS 900 is a large aperture scintillometer, manufactured by Scintec. A scintillometer measures turbulence over a path, which can then be used to calculate heat flux, cross wind and evapotranspiration. The BLS 900 consists of two main parts for observations: a transmitter and a receiver. These are placed between 250m and 6000m apart. The transmitter transmits visible light towards thereceiver, 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.

3.14.1.2. Manufacturer and Model

Model

Brand

Type

BLS900

Scintec

Large Aperture Scintillometer

3.14.1.3. Output definitions

Ouput definition ID

File Identifier

Level Number

QAQC notes

File time resolution

BLS

BLS_%SITE

0

No_QC

1min

BLS

BLS_%SITE

0

No_QC

15min

BLS

BLS_%SITE

0

No_QC

30min

BLS

BLS_%SITE

1

Thresholds

1min

BLS

BLS_%SITE

1

Thresholds

15min

BLS

BLS_%SITE

1

Thresholds

30min

3.14.1.4. Processing code

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

3.14.1.5. Variables measured by instrument

Table 3.11 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

BLS,0,1min BLS,0,15min BLS,0,30min BLS,1,1min BLS,1,15min BLS,1,30min

cor_c

correlation_of_X_Y

dimensionless

BLS,0,1min BLS,0,15min BLS,0,30min BLS,1,1min BLS,1,15min BLS,1,30min

correctCn2Cov

Cn2_correction_factor_saturation_cov

dimensionless

BLS,0,1min BLS,0,15min BLS,0,30min BLS,1,1min BLS,1,15min BLS,1,30min

correctCn2EO

Cn2_correction_factor_extinction_outer_scale

dimensionless

BLS,0,1min BLS,0,15min BLS,0,30min BLS,1,1min BLS,1,15min BLS,1,30min

correctCn2Sat

Cn2_correction_factor_saturation

dimensionless

BLS,0,1min BLS,0,15min BLS,0,30min BLS,1,1min BLS,1,15min BLS,1,30min

crosswind

crosswind

m.s-1

BLS,0,1min BLS,0,15min BLS,0,30min BLS,1,1min BLS,1,15min BLS,1,30min

CT2

temperature_structure_parameter

K-2m^2/3

BLS,0,1min BLS,0,15min BLS,0,30min BLS,1,1min BLS,1,15min BLS,1,30min

CT2_BLS

BLS_temperature_structure_parameter

K-2m^2/3

BLS,1,1min BLS,1,15min BLS,1,30min

error

error

N/A

BLS,0,1min BLS,0,15min BLS,0,30min

FLAG

Status flag

N/A

BLS,1,1min BLS,1,15min BLS,1,30min

H_convection

Heat_flux_free_convection

W.m-2

BLS,0,1min BLS,0,15min BLS,0,30min BLS,1,1min BLS,1,15min BLS,1,30min

nSamples

nSamples

samples/interval

BLS,1,1min BLS,1,15min BLS,1,30min

numDgnTotal

total_number_of_diagnosis_subperiods_measured

dimensionless

BLS,0,1min BLS,0,15min BLS,0,30min BLS,1,1min BLS,1,15min BLS,1,30min

numDgnValid

num_valid_diagnosis_subperiods_included

dimensionless

BLS,0,1min BLS,0,15min BLS,0,30min BLS,1,1min BLS,1,15min BLS,1,30min

numDgnValidCrosswind

num_valid_diagnosis_subperiods_included_crosswind

dimensionless

BLS,0,1min BLS,0,15min BLS,0,30min BLS,1,1min BLS,1,15min BLS,1,30min

Q_H

upward_turbulent_sensible_heat_flux

W.m-2

BLS,1,1min BLS,1,15min BLS,1,30min

Q_H_db

upward_turbulent_sensible_heat_flux_de_bruin_method

W.m-2

BLS,1,1min BLS,1,15min BLS,1,30min

Q_H_fc

upward_turbulent_sensible_heat_flux_free_convection_method

W.m-2

BLS,1,1min BLS,1,15min BLS,1,30min

sigCrosswind

standard_deviation_crosswind

m.s-1

BLS,0,1min BLS,0,15min BLS,0,30min BLS,1,1min BLS,1,15min BLS,1,30min

sigXn_c

standard_deviation_of_X_intensity

dimensionless

BLS,0,1min BLS,0,15min BLS,0,30min BLS,1,1min BLS,1,15min BLS,1,30min

sigYn_c

standard_deviation_of_Y_intensity

dimensionless

BLS,0,1min BLS,0,15min BLS,0,30min BLS,1,1min BLS,1,15min BLS,1,30min

X_c

average_X_intensity_corrected

dimensionless

BLS,0,1min BLS,0,15min BLS,0,30min BLS,1,1min BLS,1,15min BLS,1,30min

Y_c

average_Y_intensity_corrected

dimensionless

BLS,0,1min BLS,0,15min BLS,0,30min BLS,1,1min BLS,1,15min BLS,1,30min

3.14.1.6. Serials

Serial

Suffix

T-E-0470

A

3.14.1.7. Deployments

3.14.1.7.1. Serial number: T-E-0470

Site ID

Start date

End date

NDT

2011-05-20 00:00

2011-11-23 00:00

NDT

2012-01-11 00:00

2012-03-08 00:00

NDT

2012-03-29 00:00

2012-09-21 00:00

NGT

2012-09-21 00:00

2013-02-26 00:00

BTT

2014-06-29 00:00

2017-03-16 00:00

SWT

2017-04-06 00:00

2020-11-04 00:00

3.14.1.8. Photos

../../../_images/dartrey-bls-setup_23160159424_o.jpg

Fig. 3.27 BLS900 reciever at NDT 24/05/2011

../../../_images/dartrey-bls-view-to-trellick-3_23160155864_o.jpg

Fig. 3.28 View of BLS900 at NDT towards NTT 24/05/2011

../../../_images/work-to-move-bls-davis-and-thermal-cameras-out-of-the-way-of-flue-construction-on-6-jan-2016_23860675819_o.jpg

Fig. 3.29 BLS transmitter at IMU 06/01/2016

../../../_images/after-reinstalled-bls-spu_25610890531_o.jpg

Fig. 3.30 Reciever (left) at BTT 11/02/2016

../../../_images/18-02-2020_(3).JPEG

Fig. 3.31 Reciever (left) at SWT 18/02/2020

3.14.1.9. Supplementary information

Link

Title

Description

BLS manual

BLS manual

Manual from Scintec.

BLS 900 brochure

BLS 900 brochure

Brochure from Scintec.

3.14.1.10. Data acquisition

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

3.14.1.11. References

  1. Crawford, B., Grimmond, C. S. B., Ward, H. C., Morrison, W. and Kotthaus, S. (2017) Spatial and temporal patterns of surface-atmosphere energy exchange in a dense urban environment using scintillometry. Quarterly Journal of the Royal Meteorological Society, 143 (703). pp. 817-833. ISSN 1477-870X doi: https://doi.org/10.1002/qj.2967

  2. Ward, H. C., Evans, J. G., Grimmond, C. S. B. and Bradford, J. (2015) Infrared and millimetre-wave scintillometry in the suburban environment – Part 1: Structure parameters. Atmospheric Measurement Techniques, 8 (3). pp. 1385-1405. ISSN 1867-8548 doi: https://doi.org/10.5194/amt-8-1385-2015

  3. Ward, H. G., Evans, J. G. and Grimmond, C. S. B. (2015) Infrared and millimetre-wave scintillometry in the suburban environment – Part 2: Large-area sensible and latent heat fluxes. Atmospheric Measurement Techniques, 8 (3). pp. 1407-1424. ISSN 1867-8548 doi: https://doi.org/10.5194/amt-8-1407-2015

  4. Ward, H. C., Evans, J. G. and Grimmond, C. S. B. (2014) Multi-scale sensible heat fluxes in the urban environment from large aperture scintillometry and eddy covariance. Boundary-Layer Meteorology, 152 (1). pp. 65-89. ISSN 0006-8314 doi: https://doi.org/10.1007/s10546-014-9916-4

  5. Wood, C. R., Pauscher, L., Ward, H. C., Kotthaus, S., Barlow, J., Gouvea, M., Lane, S. E. and Grimmond, C. S. B. (2013) Wind observations above an urban river using a new lidar technique, scintillometry and anemometry. Science of the Total Environment, 442. pp. 527-533. ISSN 0048-9697 doi: https://doi.org/10.1016/j.scitotenv.2012.10.061

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.