Instrumentation in Environmental Physics

-- Is Factory Calibration Reliable?

EPSCoR Project Supported by NSF

Wenguang Zhao & Richard G. Allen

October 24, 2011, Xi’an, China

Instrumentation in Environmental Physics

-- Is Factory Calibration Reliable?

EPSCoR Project Supported by NSF

Wenguang Zhao & Richard G. Allen

October 24, 2011, Xi’an, China

AuthorsAuthors

University of Idaho – Wenguang Zhao and Richard G. Allen

Idaho State University –Matt Germino

Boise State University – Sridhar V.

University of Idaho – Wenguang Zhao and Richard G. Allen

Idaho State University –Matt Germino

Boise State University – Sridhar V.

BackgroundBackground

1. Most people believe the factory calibration. 2. Representation of H and ET measured by

traditional methods (EC and BR etc) is limited, especially for heterogeneous fields.

3. Large aperture scintillometry (LAS) is an alternative method to estimate H from a relatively large footprint (source) area.

1. Most people believe the factory calibration. 2. Representation of H and ET measured by

traditional methods (EC and BR etc) is limited, especially for heterogeneous fields.

3. Large aperture scintillometry (LAS) is an alternative method to estimate H from a relatively large footprint (source) area.

QuestionsQuestions

1. How can we accurately calculate H from the LAS measurement, structure function constant of refractive index fluctuations for the wavelength used by the LAS (Cn

2)?

2. How does the H calculated by the LAS measurement compare to the traditional EC measurement result?

1. How can we accurately calculate H from the LAS measurement, structure function constant of refractive index fluctuations for the wavelength used by the LAS (Cn

2)?

2. How does the H calculated by the LAS measurement compare to the traditional EC measurement result?

4-way net radiometers4-way net radiometers

(A) (B)

Intercomparison of 5 NR01 4-way net radiometers in 2009Intercomparison of 5 NR01

4-way net radiometers in 2009

260

280

300

320

340

360

380

400

7/14/09 9:00 7/14/09 15:00 7/14/09 21:00 7/15/09 3:00 7/15/09 9:00 7/15/09 15:00 7/15/09 21:00 7/16/09 3:00 7/16/09 9:00At

mos

pher

ic Lo

ng W

ave

Radi

ation

(Wm-2

)

Date & Time (m/d/yy h:mm)

Atmospheric Long Wave Radiation(used factory calibration coefficients)

SN: 1083 (UI)SN: 1084 (UI)SN: 1087 (UI)SN: 1148 (BSU)SN: 1158 (ISU)

260

280

300

320

340

360

380

400

7/14/09 9:00 7/14/09 15:00 7/14/09 21:00 7/15/09 3:00 7/15/09 9:00 7/15/09 15:00 7/15/09 21:00 7/16/09 3:00 7/16/09 9:00

Atm

osph

eric

Long

Wav

e Ra

diati

on (W

m-2

)

Date & Time (m/d/yy h:mm)

Atmospheric Long Wave Radiation(used user modified coefficients)

SN: 1083 (UI)SN: 1084 (UI)SN: 1087 (UI)SN: 1148 (BSU)SN: 1158 (ISU)

Measured atmospheric

long wave radiation by

using factory

calibration coefficients

of each NR01’a

Measured atmospheric

long wave radiation by

using the modified

calibration coefficients

of ourselves

Intercomparison

in summer 2009

Intercomparison of 10 4-way net radiometers (8 NR01s & 2 CNR1s) in 2010

Intercomparison of 10 4-way net radiometers (8 NR01s & 2 CNR1s) in 2010

280

300

320

340

360

380

400

420

8/16/10 0:00 8/16/10 12:00 8/17/10 0:00 8/17/10 12:00 8/18/10 0:00 8/18/10 12:00

Atm

osph

eric

Long

wave

Radi

ation

(W/m

-2)

Date & Time (m/d/yy H:mm)

CNR1_71524CNR1_71528NR01_1084NR01_1148NR01_1280NR01_1281NR01_1282NR01_1298NR01_1300NR01_1301

280

300

320

340

360

380

400

420

8/16/10 0:00 8/16/10 12:00 8/17/10 0:00 8/17/10 12:00 8/18/10 0:00 8/18/10 12:00At

mos

pher

ic Lo

ngwa

ve Ra

diati

on (W

/m-2

)

Date & Time (m/d/yy H:mm)

CNR1_71524CNR1_71528NR01_1084NR01_1148NR01_1280NR01_1281NR01_1282NR01_1298NR01_1300NR01_1301

Used factory calibration Coef.

Measured atmospheric

long wave radiation by

using factory

calibration coefficients

of each NR01’a

Measured atmospheric

long wave radiation by

using the modified

calibration coefficients

of ourselves

Intercomparison

in summer 2010

Used self calibration Coef.

Intercomparison of 8 4-way net radiometers (6 NR01s, a CNR1 & a CNR4) in 2011

Intercomparison of 8 4-way net radiometers (6 NR01s, a CNR1 & a CNR4) in 2011

Intercomparison

in summer 2011

Used factory calibration coefficient

Used self calibration coeficient (from day+night data)

Used self calibration coefficient (from

night data) + about 2.3% (from 2.0% to

2.5%) short wave radiation correction

3-D Sonic anemometers3-D Sonic anemometers

3 sets of EC systems (RM Young 8000 3D sonic + LI-7500)

-3.54 mm

-1.77 mm

-3.68 mm

-50

0

50

100

150

200

250

9/25/09 0:00 9/25/09 6:00 9/25/09 12:00 9/25/09 18:00 9/26/09 0:00 9/26/09 6:00 9/26/09 12:00 9/26/09 18:00 9/27/09 0:00

ET (W

/m2 )

Data &Time (m/d/yy h:mm)

BSU SystemUI System1UI System2

Comparison of the 3 EC systems

BLS 9000 Boundary Layer Scintillometers

BLS 9000 Boundary Layer Scintillometers

Transmitter

Receiver

Intercomparison of 3 receivers and their SPU with the same transmitter

0.0E+00

2.0E-13

4.0E-13

6.0E-13

8.0E-13

1.0E-12

1.2E-12

5/30/09 0:00 5/30/09 6:00 5/30/09 12:00 5/30/09 18:00 5/31/09 0:00 5/31/09 6:00 5/31/09 12:00 5/31/09 18:00 6/1/09 0:00

Stru

ctur

e Fun

ction

Cn2

(m-2

/3)

Date & Time

Cn2 (SN:T-E-0112)Cn2 (SN:T-E-0114)Cn2 (SN:T-E-0115)

T1 T2

R1R2

Intercomparison of 2 independent sets of BLS 9000 scintillometers with the opposite light transmiting

directions

-50

0

50

100

150

200

250

6/3/09 0:00 6/3/09 6:00 6/3/09 12:00 6/3/09 18:00 6/4/09 0:00 6/4/09 6:00 6/4/09 12:00 6/4/09 18:00 6/5/09 0:00

Se

nsi

ble

He

at

Flu

x (

Wm

-2)

Date & Time (m/d/yy h:mm)

H_T-E-0112

H_T-E-0114

H_T-E-0115 SN:T-E-0112 measured a lower sensible heat flux (H) than SN: T-E-0115

0

20

40

60

80

100

120

140

160

180

200

6/9/09 0:00 6/9/09 6:00 6/9/09 12:00 6/9/09 18:00 6/10/09 0:00 6/10/09 6:00 6/10/09 12:00 6/10/09 18:00 6/11/09 0:00

Se

nsi

ble

He

at

Flu

x (

Wm

-2)

Date & Time (m/d/yy h:mm)

H_T-E-0112

H_T-E-0114 SN:T-E-0112 measured a lower sensible heat flux (H) than SN: T-E-0114

REBS HFT-3.1 Heat Flow Transducer

Multiple Depths of Plates

(~4 and 8 cm)

Soil Temperature profile

TCs @1,2,3 and 6cm)

LAS: Transmitter A & Receiver B

-200

-150

-100

-50

0

50

100

150

200

250

300

5/20/10 0:00 5/20/10 6:00 5/20/10 12:00 5/20/10 18:00 5/21/10 0:00 5/21/10 6:00 5/21/10 12:00 5/21/10 18:00 5/22/10 0:00

Tota

l SH

F (W

/m2 )

Date (m/d/yy)

Stat#1_4cm TotalStat#1_10cm TotalStat#2_4.5cm TotalStat#2_10cm TotalStat#3_5cm TotalStat#3_10cm TotalStat#3 HFP01SC Total

-200

-150

-100

-50

0

50

100

150

200

250

300

5/20/10 0:00 5/20/10 6:00 5/20/10 12:00 5/20/10 18:00 5/21/10 0:00 5/21/10 6:00 5/21/10 12:00 5/21/10 18:00 5/22/10 0:00

Tota

l SH

F (W

/m2 )

Date (m/d/yy)

Stat#1_4cm TotalStat#1_10cm TotalStat#2_4.5cm TotalStat#2_10cm TotalStat#3_5cm TotalStat#3_10cm TotalStat#3 HFP01SC Total

ConclusionsConclusions

1. Good agreement was obtained between H

measured by CSAT3 and RM Young 81000 3-D

sonic anemometers

2. H measured by Scintec BLS900 compared well

with both EC systems (CSAT3 and RM Young).

Thank you!

1. Good agreement was obtained between H

measured by CSAT3 and RM Young 81000 3-D

sonic anemometers

2. H measured by Scintec BLS900 compared well

with both EC systems (CSAT3 and RM Young).

Thank you!

Questions?Questions?

Do I need to STOP here?

Do I need to STOP here?