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Appendix C. EasyFlux

DL CR6KH20

C-36

TABLE C-22. Data Fields in the Flux_Notes Output Table

Data Field Name

Units

Description

Data Field

Included

shfp_cal_fail_x_1_1

none

Result of TRUE indicates HFP01SC

returned an invalid number or the

calibrated sensitivity was not within

80%-105% of the original sensitivity

If HFP01SC

used

process_time

Average processing time for each scan

Always

process_time_Max

Maximum processing time for a scan

Always

buff_depth_Max

Number

Maximum number of records stored in

the buffer

Always

C.4.5 Program Sequence of Measurement and Corrections

The following are the main correction procedures and algorithms implemented

in the program. The oxygen correction is unique to the KH20; see Appendix

Equations and Algorithms of Water Vapor Density and Water Flux in KH20

Eddy-Covariance Systems

(p. D-1)

. For the other corrections, more details about

the theory and implementation may be found in the appendices of the

EasyFlux

DL CR6OP

manual.

Despike and filter 10 Hz data using sonic and KH20 diagnostic codes.

Coordinate rotations with an option to use the double rotation method

(Tanner and Thurtell 1969), or planar fit method (Wilczak et al.

2001).

Lag CO

and H

O measurements against sonic wind measurements for

maximization of CO

and H

O fluxes (Horst and Lenschow 2009,

Foken et al. 2012), with additional constraints to ensure lags are

physically possible.

Apply oxygen correction to covariances with water density from the

KH20. (See Appendix

Equations and Algorithms of Water Vapor

Density and Water Flux in KH20 Eddy-Covariance Systems

(p. D-1)

Frequency corrections using commonly used cospectra (Moore 1986,

van Dijk 2002a, Moncrieff et al. 1997) and transfer functions of block

averaging (Kaimal et al. 1989), line/volume averaging (Moore 1986,

Moncrieff et al. 1997, Foken et al. 2012, van Dijk 2002a), time

constants (Montgomery 1947, Shapland et al. 2014, Geankoplis

1993), and sensor separation (Horst and Lenschow 2009, Foken et al.

2012).

A modified SND correction (Schotanus et al. 1983) to derive sensible

heat flux from sonic sensible heat flux following the implementation

as outlined in van Dijk 2002b. Additionally, fully corrected real

sensible heat flux computed from fine-wire thermometry may be

provided.

Correction for air density changes using WPL equations (Webb et al.

1980).

Содержание KH20

Страница 2: ...6 Installation 3 6 1 Siting 3 6 2 Mounting 3 6 2 1 Parts and Tools Needed for Mounting 3 6 2 2 Mounting the KH20 Sensor 3 6 2 3 Mounting the Electronics Box 4 6 3 Wiring 6 6 4 Data Logger Programming...

Страница 3: ...orrections C 36 C 5 References C 37 D Equations and Algorithms of Water Vapor Density and Water Flux in KH20 Eddy Covariance Systems D 1 D 1 Fundamental Equation D 1 D 2 Working Equation D 2 D 3 Eddy...

Страница 4: ...s C 10 C 13 Default Wiring for Soil Heat Flux Plates Self Calibrating C 11 C 14 Station Variables with Descriptions C 15 C 15 microSD Flash Card Fill Times with 10Hz Measurement Rate C 19 C 16 Data Ou...

Страница 5: ...ormation against the shipping documents to ensure the correct product and cable length are received see Section 3 1 Components p 1 3 1 Components The KH20 sensor consist of a sensor head with 2 m 6 ft...

Страница 6: ...sensor head comes with cables that connect the sensor to the electronics a power signal cable and mounting hardware Discussion on the principles and theory of measurement is included in Appendix A Cal...

Страница 7: ...od CM115 standard or tower 2 Campbell Scientific crossarm CM204 standard 3 3 4 inch IPS Aluminum Pipe 12 inches long 4 3 4 inch by 1 inch Nu Rail Crossover Fitting 5 Small Phillips and flat head screw...

Страница 8: ...inch nut holding the bottom U bolt is located inside the rain shield 2 Before mounting the rain shield to a tripod first mount the electronics box inside the rain shield Remove the four pan head screw...

Страница 9: ...ill block the position of the connectors 3 Mount the rain shield onto the tripod or tower mast using the U bolt provided Make sure that the distance between the KH20 sensor head and the rain shield is...

Страница 10: ...in place 6 Gather any loose cables and tie them up using cable ties onto the tripod or tower mast 6 3 Wiring TABLE 6 1 Wire Color Function and Data Logger Connection Wire Wire Label Data Logger Conne...

Страница 11: ...e water vapor absorption coefficient kw is entered into the data logger program for the KH20 the following decisions must be made Will the windows be allowed to scale What vapor range is appropriate f...

Страница 12: ...om Campbell Scientific and send the unit in for repair Check the voltage signal output from the KH20 If the voltage output reading is below 50 mV you may have problems with either the source tube or t...

Страница 13: ...little resistance if the window is not scaled If you determine the window is scaled you can clean it with a wet cotton swab Use distilled water and a clean cotton swab to clean the scaled window After...

Страница 14: ...h length for the KH20 sensor and w is the water vapor density w wx k e T A 1 If we express the transmissivity T in terms of the light intensity before and after passing through the material as measure...

Страница 15: ...cientific performs the calibration twice for each KH20 once with the window cleaned and again with the window scaled We then break up the vapor density range into dry and wet ranges and compute the kw...

Страница 16: ...20 A 3 TABLE A 2 Final Calibration Values for KH20 Vapor Range g m3 Slope xkw Y Intercept ln V0 Coefficient kw Full Range 1 74 19 25 0 205 3087 0 144 Dry Range 1 74 9 20 0 216 3259 0 151 Wet Range 7 9...

Страница 17: ...H20 Unit Definitions Units Description ln_mV ln mV natural log of the KH20 millivolts mV millivolts rho_w g m 3 Wiring ANALOG INPUT 1H KH20 signal white 1L KH20 signal black gnd KH20 shield clear EXTE...

Страница 18: ...verage 2 kh 1 IEEE4 False EndTable Raw time series data DataTable ts_data True 1 DataInterval 0 SCAN_INTERVAL mSec 100 Sample 1 kh_mV IEEE4 EndTable Program BeginProg Scan SCAN_INTERVAL mSec 3 0 data...

Страница 19: ...mometer qty 1 Temperature Relative Humidity RH Probe qty 1 Supported Models o HMP155A o EE181 OPTIONAL SENSORS CS106 Barometer qty 0 to 1 FW3 Fine Wire Thermocouple qty 0 to 1 GPS16X HVS GPS Receiver...

Страница 20: ...he function of an altered program C 3 Wiring When wiring the sensors to the data logger or VOLT116 the default wiring schemes along with the number of instruments EasyFlux DL CRKH20 supports should be...

Страница 21: ...Power Red Red 12 V Power Ground Black None G3 1 Wire a user supplied jumper from U4 to 2 Wire colors for the HMP155A are shown in normal font while colors for the EE181 are italicized 3 Due to termina...

Страница 22: ...ack G Trigger not used Green G C 3 2 3 Fine Wire Thermocouple A fine wire thermocouple is recommended for a more accurate and direct measurement of sensible heat flux If no fine wire thermocouple is u...

Страница 23: ...with EasyFlux DL CR6KH20 The program can support a combination of the sensors described in TABLE C 5 Alternatively it can support one of the three types of four way radiometers described in TABLE C 6...

Страница 24: ...Flux DL CR6KH20 however only one may be used at a given time The default wiring for each of the four way radiometers is shown in TABLE C 6 TABLE C 6 Default Wiring for Radiation Measurements Option 2...

Страница 25: ...e VOLT116 Diff 4H Thermistor V Excite Red VOLT116 X1 Thermistor Reference Black VOLT116 Shields Clear VOLT116 1 Jumper to with user supplied wire A CNF4 Ventilation and Heater Unit may be used with th...

Страница 26: ...y REL2 Com to REL 3 COM 1 For the A21REL 12 power connections connect 12V and G to a system or external power supply Do not connect to the 12V or G terminals on the CR6 or VOLT116 TABLE C 8 CNF4 Wirin...

Страница 27: ...d any TCAV measurements TABLE C 10 Default Wiring for Soil Thermocouple Probes Sensor Quantity Wire Description Color VOLT116 Terminal TCAV 1 1 Signal Purple Diff 1H Signal Reference Red Diff 1L Shiel...

Страница 28: ...Black G Shield Clear G Not Used Orange CS650 CS655 SDI 12 address 2 1 SDI 12 Data Green U9 SDI 12 Power Red 12 V SDI 12 Reference Black G Shield Clear Not Used Orange G CS650 CS655 SDI 12 address 3 1...

Страница 29: ...er Reference Purple Diff 13L Shield Clear Heater Power Red SW12 11 Power Reference Black G HFP01SC 2 1 Signal White Diff 6H Signal Reference Green Diff 6L Shield Clear Heater Signal Yellow Diff 14H He...

Страница 30: ...ok for the text comments on the right side of each line of code for more explanation of the constant Generally the constants fall into four categories 1 Program Function Constants These are constants...

Страница 31: ...ular sensor have been grouped together and have the sensor selection constant at the beginning such that if the sensor selection constant is set to FALSE the other constants for that sensor may be ign...

Страница 32: ...tem Menu If no CR1000KD is available these same variables may be viewed and edited using the LoggerNet connect screen numeric display of variables from the Public table FIGURE C 2 Custom keypad menu a...

Страница 33: ...t Surf Type none GRASS Type of surface at the measurement site Options are CROP GRASS FOREST SHRUB BARELAND and WATER This is used to estimate displacement height surface_type 1 CROP 2 GRASS 3 FOREST...

Страница 34: ...d loads the appropriate diameter For FW05_DIA FW1_DIA and FW3_DIA the diameters are 1 27 x 10 5 2 54 x 10 5 and 7 62 x 10 5 m respectively If no fine wire thermocouple is being used this variable is o...

Страница 35: ...e used to rotate the wind when the mean horizontal wind is blowing from the sector of 190 to 300 degrees in the sonic coordinate system wind blowing from the sector right and behind sonic head 1 alpha...

Страница 36: ...eight z Recall that z is the difference between the measurement height and displacement height dist_intrst_60_300 Footprint Dist of Interest 60 170 m 100z The upwind distance of interest from the stat...

Страница 37: ...th required sensors only Fill time with required sensors FW CS106 and biomet energy balance sensors 1 2 GB 41 days 35 days 8 GB 170 days 141 days 16 GB 339 days 281 days 1 Biomet and energy balance se...

Страница 38: ...ctronic delays SCAN_INTERVAL default 100 ms Auto Allocate typically less than 1 hour See TABLE C 15 for total days Data broken into daily files Diagnostic Reports most recent diagnostic flags from sel...

Страница 39: ...ction applied respectively TABLE C 17 Data Fields in the Time_Series Data Output Table Data Field Name Units Description Data Field Included Ux m s 1 Wind speed along sonic x axis Always Uy m s 1 Wind...

Страница 40: ...he calibrated sensitivity it not within 80 105 of the original sensitivity x is an index identifying the HFP01SC of concern If HFP01SC used TABLE C 19 Data Fields in the Monitor_CSAT3B Output Table Da...

Страница 41: ...ux plates during the averaging interval If energy balance sensors used FETCH_MAX m Distance upwind where the maximum contribution to the footprint is found Always FETCH_90 m Upwind distance that conta...

Страница 42: ...NIC_SIGMA deg C Standard deviation of sonic temperature Always PBLH m Estimated planetary boundary layer height Always SWC_x_1_1 Soil water content x is an index for the number of soil sensors If CS65...

Страница 43: ...calculation of H_FW If FW05 FW1 or FW3 is used NETRAD W m 2 Average net radiation corrected for wind If NR LITE2 SN500SS NR01 or CNR4 used G W m 2 Heat flux at the ground surface If energy balance se...

Страница 44: ...Average ambient air pressure from CS106 if used otherwise the nominal air pressure entered by user Always VPD kPa Vapor pressure deficit Always Ux m s 1 Average Ux Always Ux_SIGMA m s 1 Standard devia...

Страница 45: ...diation If SN500SS NR01 CNR4 CS301 or CS320 used SW_OUT W m 2 Average outgoing short wave radiation If SN500SS NR01 or CNR4 used LW_IN W m 2 Average incoming long wave radiation If SN500SS NR01 or CNR...

Страница 46: ...ge volumetric soil water content for each CS650 or CS655 x is an index for the number of sensors If CS650 or CS655 used TS_CS65X_x_1_1 deg C Average soil temperature from CS65X probe x is an index for...

Страница 47: ...r applicable atmospheric conditions else the model of Kormann Meixner 2001 is used Always TABLE C 22 Data Fields in the Flux_Notes Output Table Data Field Name Units Description Data Field Included Ux...

Страница 48: ...e rotations and frequency corrections Always VW_Cov_fc m2 s 2 Covariance of cross and vertical wind after coordinate rotations and frequency corrections Always WT_SONIC_Cov_fc m C s 1 Covariance of ve...

Страница 49: ...Cov g m 2 s 1 Covariance of streamwise wind and H2O density after coordinate rotations and covariance maximization without O2 correction Always VH2O_Cov g m 2 s 1 Covariance of crosswind and H2O densi...

Страница 50: ...tations and covariance maximization If FW05 FW1 or FW3 is used WFW_Cov_fc deg C m s 1 Covariance of vertical wind and fine wire thermocouple temperature after coordinate rotations covariance maximizat...

Страница 51: ...ns for recalculating Monin Obukhov length and frequency factors Always latitude decimal degrees Latitude positive for Nothern hemisphere negative for Southern hemisphere Always longitude decimal degre...

Страница 52: ...ata relative to sonic data to account for separation along axis of oncoming wind and wind velocity If FW05 FW1 or FW3 is used time_const_FW m Calculated time constant of the fine wire thermocouple If...

Страница 53: ...NR01 used cnr4_fan_secs s Number of seconds CNR4 fan was powered in interval If CNR4 used cnr4_fan_freq_max Hz Maximum frequency of CNR4 fan in interval If CNR4 used cnr4_fan_freq_min Hz Minimum freq...

Страница 54: ...e rotations with an option to use the double rotation method Tanner and Thurtell 1969 or planar fit method Wilczak et al 2001 3 Lag CO2 and H2O measurements against sonic wind measurements for maximiz...

Страница 55: ...1993 Transportation Processes and Unit Operation 3rd Edition PTR Prentice Hall New Jersey pp 114 131 and Appendix Horst T W and D H Lenschow 2009 Attenuation of scalar fluxes measured with spatially d...

Страница 56: ...meter near the surface by Kristensen and Fitzjarrald Journal of Atmospheric and Ocean Technology 19 80 19 van Dijk A 2002b The Principle of Surface Flux Physics Research Group of the Royal Netherlands...

Страница 57: ...V01 from wavelength 1 and voltage V02 from wavelength 2 both of which sum up one voltage output as V0 V0 V01 V02 from the sensor for air free of water vapor and oxygen Given water vapor density w in...

Страница 58: ...l 1993 considered as universal for all KH20 sensors with x around 1 3 cm Co is the mole fraction of oxygen that is considered as a constant of 0 2095 in ecosystems Tanner et al 1993 Mo is the molar ma...

Страница 59: ...er Bessel function of the first kind that makes the integration of the transfer function over the frequency domain in need of more computation time Moene 2003 used a simple function to approximate equ...

Страница 60: ...tuations and use of the krypton Hygrometer in surface flux measurement Management of Irrigation and Drainage Systems Sponsored by the Irrigation and Drainage Division ASCE Park City Utah van Dijk A 20...

Страница 61: ...ther manufacturer s products that are resold by Campbell Scientific are warranted only to the limits extended by the original manufacturer Refer to www campbellsci com terms warranty for more informat...

Страница 62: ...shipping container Campbell Scientific s shipping address is CAMPBELL SCIENTIFIC INC RMA _____ 815 West 1800 North Logan Utah 84321 1784 For all returns the customer must fill out a Statement of Prod...

Страница 63: ...ng on or around tripods and towers Do not climb tripods or towers at any time and prohibit climbing by other persons Take reasonable precautions to secure tripod and tower sites from trespassers Use o...

Страница 64: ...nfo campbellsci fr www campbellsci fr Germany Location Phone Email Website Bremen Germany 49 0 421 460974 0 info campbellsci de www campbellsci de India Location Phone Email Website New Delhi DL India...

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