Instrumentation in Environmental Physics -- Is Factory Calibration Reliable? 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 – University of Idaho – Wenguang Zhao and Richard G. Allen Idaho State University – Idaho State University – Matt Germino Boise State University – Boise State University – Sridhar V. University of Idaho – University of Idaho – Wenguang Zhao and Richard G. Allen Idaho State University – Idaho State University – Matt Germino Boise State University – Boise State University – Sridhar V.

BackgroundBackground 1. Most people believe the factory calibration. 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. 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. 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. 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. 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. 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 (C n 2 )? 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 (C n 2 )? 2. How does the H calculated by the LAS measurement compare to the traditional EC measurement result? 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 (C n 2 )? 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 (C n 2 )? 2. How does the H calculated by the LAS measurement compare to the traditional EC measurement result? 2. How does the H calculated by the LAS measurement compare to the traditional EC measurement result?

4-way net radiometers

(A)(B) Intercomparison of 5 NR01 4-way net radiometers in 2009

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

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

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 Intercomparison Used self calibration Coef.

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

Intercomparison in summer 2011 Intercomparison 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 anemometers

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

-3.54 mm mm mm

Comparison of the 3 EC systems

BLS 9000 Boundary Layer Scintillometers

Transmitter Receiver Intercomparison of 3 receivers and their SPU with the same transmitter Intercomparison of 3 receivers and their SPU with the same transmitter

T1T1T1T1 T2T2T2T2 R1R1R1R1 R2R2R2R2 Intercomparison of 2 independent sets of BLS 9000 scintillometers with the opposite light transmiting directions

SN:T-E-0112 measured a lower sensible heat flux (H) than SN: T-E-0115 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 and 6cm)

LAS: Transmitter A & Receiver B

ConclusionsConclusions Good agreement was obtained between H measured by CSAT3 and RM Young D sonic anemometers 2. H measured by 2. H measured by Scintec BLS900 compared well with both EC systems (CSAT3 and RM Young). Thank you! Good agreement was obtained between H measured by CSAT3 and RM Young D sonic anemometers 2. H measured by 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?