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Campbell Open Path Eddy Covariance System Instruction Manual

Summary of Open Path Eddy Covariance System

  • Page 1

    Open path eddy covariance system operator’s manual csat3, li-7500, and kh20 9/06 c o p y r i g h t © 2 0 0 4 - 2 0 0 6 c a m p b e l l s c i e n t i f i c , i n c ..

  • Page 2: Warranty and Assistance

    Warranty and assistance the open path eddy covariance (opec) sytem is warranted by campbell scientific, inc. To be free from defects in materials and workmanship under normal use and service for twelve (12) months from date of shipment unless specified otherwise. Batteries have no warranty. Campbell...

  • Page 3: Table of Contents

    I open path eddy covariance system table of contents pdf viewers note: these page numbers refer to the printed version of this document. Use the adobe acrobat® bookmarks tab for links to specific sections. 1. System description .....................................................1 1.1 opec (csat3 o...

  • Page 4

    Open path eddy covariance system table of contents ii a. Csat3 orientation .................................................. A-1 a.1 determining true north and sensor orientation................................ A-1 a.2 online magnetic declination calculator.............................................

  • Page 5

    Open path eddy covariance system table of contents iii 31. Default edire processing list created by the interpreter......................36 32. Output file location as part of the processing list ...............................37 33. Output file location as part of the processing list .................

  • Page 6

    Open path eddy covariance system table of contents iv this is a blank page..

  • Page 7: 1.  System Description

    1 open path eddy covariance system this document will serve as a guide to properly install and operate a campbell scientific, inc. Open path eddy covariance system (opec). The opec is composed of various products, e.G. Dataloggers, fast response turbulence sensors, slow response meteorological senso...

  • Page 8

    Open path eddy covariance system 2 one or two tcav averaging soil temperature probes, and one or two cs616 soil moisture reflectometers. 1.4 additional fast response sensors if the application requires a direct measurement of sensible heat flux, a fw05 can be added to the system. In the absence of a...

  • Page 9

    Open path eddy covariance system 3 figure 1. Eddy covariance sensors mounted on a cm10 tripod; the datalogger enclosure is on a separate tripod (not pictured) 2.1 fetch and sensor height the eddy covariance sensors must be mounted at some height to ensure that the measurements are made within the lo...

  • Page 10

    Open path eddy covariance system 4 particularly between the eddy covariance sensors and the interface between the corn and soybean field. 2.2 mounting the csat3, li-7500, and hmp45c are mounted to a tripod or tower using a horizontal mounting arm, several nu-rail crossover fittings, and short length...

  • Page 11

    Open path eddy covariance system 5 figure 2. Side view of the csat3 and li-7500 (mounted underneath csat3) figure 3. Side view of the csat3 and li-7500 (mounted beside csat3) cm204 crossarm with bracket, 1.3 m (4 ft) p/n 18048 0.75 inch diameter by 30.48 cm (12 inch) long aluminium pipe p/n 6332 0.7...

  • Page 12

    Open path eddy covariance system 6 figure 4. Cm110 enclosure mounting hardware (p/n 17716 configured for enc 10/12) attached to the li-7500 electronics box figure 5. Close up view p/n 17716, configured for enc 10/12, locking mechanism.

  • Page 13

    Open path eddy covariance system 7 figure 6. Csat3 electronics box and p/n 17813 enclosure hanger kit on cm110 tripod body figure 7. Csat3 and li-7500 electronics boxes mounted on the cm110 tripod body.

  • Page 14

    Open path eddy covariance system 8 figure 8. Enc12/14 enclosure mounted on the cm110 tripod base figure 9. Hmp45c 10-plate radiation shield mounted on the body of the cm110 (left) and on the cm204 horizontal crossarm (right).

  • Page 15

    Open path eddy covariance system 9 2.2.1 measure csat3 azimuth to compute the correct compass wind direction, the station operator must enter the negative x-axis azimuth of the csat3 into the datalogger program. If the csat3 is installed such that it points into the prevailing wind, the negative x-a...

  • Page 16

    Open path eddy covariance system 10 the csat3 and li-7500 are powered by an external battery. Typically, so is the datalogger. If a cr3000/cr5000 is to be powered from a base with a sealed rechargeable battery, connect the datalogger ground lug to the negative post of the external battery. Ensure th...

  • Page 17

    Open path eddy covariance system 11 the library of programs covers a variety of sensors and is continuously growing. If your system has sensors that are not part of any program in the library, simply add the appropriate measurement and processing instructions to the program or contact campbell scien...

  • Page 18

    Open path eddy covariance system 12 3.1 generic program flowchart false false (disable_flag_on(3) = false) enable count of warning flags (disable_flag_on(3) = true) disable count of warning flags true is the csat3 warning not a diagnostic code? False (disable_flag_on(1) = false) enable covariance pr...

  • Page 19

    Open path eddy covariance system 13 false scan_count+1 scan_count = call flux data table false - calculate the oxygen correction - calculate a computed sensible heat flux - calculate webb et al. Term - compute the fluxes from the covariance values - calculate the csat3 wind direction - calculate the...

  • Page 20

    Open path eddy covariance system 14 3.2.1 csat3 azimuth the example programs report the wind direction in both the csat3 coordinate system (a right-handed coordinate system) and in the compass coordinate system (a screwball left-handed coordinate system). The csat3 coordinate system is relative to t...

  • Page 21

    Open path eddy covariance system 15 wind vane wind vector y x north figure 12. Compass coordinate system, compass wind direction is 140 degrees 3.2.2 sensor configuration the csat3 and li-7500 communicate with campbell scientific, inc. Dataloggers using a proprietary digital communication protocol c...

  • Page 22

    Open path eddy covariance system 16 if you loan a csat3 or li-7500 to a colleague, verify that the addresses are 3 and 7, respectively, before deploying the system into the field. 3.3 loading a program to the datalogger before the datalogger can begin to make measurements, a program must be transfer...

  • Page 23

    Open path eddy covariance system 17 use only sandisk industrial grade or silicon systems pc/cf cards. Although consumer versions of pc/cf cards will fit into the card slot and operate, for a short time, only the sandisk industrial grade or silicon systems pc/cf cards have passed our temperature and ...

  • Page 25

    Open path eddy covariance system 19 the datalogger programs are protected under u.S. And international copyright laws. Do not distribute the datalogger programs. See the end user license agreement (eula) shipped with the programs for more information on your rights and obligations. Data is saved on ...

  • Page 26

    Open path eddy covariance system 20 practical if the pc will be located at the site and is continuously polling the datalogger because the volume of data is such that it takes about 8% to 25% of real time to download 10 hz time series data. Transferring data using the pc/cf card is relatively fast; ...

  • Page 27

    Open path eddy covariance system 21 figure 13. Loggernet station setup for the “flux” table figure 14. Loggernet station setup for the “ts_data” table in the “schedule” tab, configure the station’s data collection as shown in figure 15. Modify the primary retry interval, number of primary retries, a...

  • Page 28

    Open path eddy covariance system 22 figure 15. Loggernet station data collection schedule to enable loggernet’s data collection, click on the status monitor button in the toolbar. Select the station and click on the “toggle on/off” button. The time of the next data collection will appear in the “nex...

  • Page 29

    Open path eddy covariance system 23 4.1.2 file management with baler the data is collected by loggernet and placed in the loggernet cache. Two instances of the baler, one for the time series data and the other for the flux data, will pull the data from the cache and “bale” it into a user specified f...

  • Page 30

    Open path eddy covariance system 24 figure 18. Baler station setup for the “ts_data” table 4.1.3 remote data retrieval via a pc/cf card to transfer data manually from the pc/cf card to the pc, remove the card from the datalogger following the proper card removal procedure (see the appropriate datalo...

  • Page 31

    Open path eddy covariance system 25 never remove a pc/cf card from the datalogger or turn off power to the datalogger without first shutting down the card. With a cr3000 or cr1000, press the “removal button” on the cfm100 compact flash/nl115 ethernet/compact flash module. With a cr5000 select the pc...

  • Page 32

    Open path eddy covariance system 26 toa5 ascii file with header array compatible asci arrays without header tob1 binary file tob3 file from pc/cf card figure 19. File format flow start the cardconvert utility. When cardconvert is started, a summary of its current settings is displayed in the lower r...

  • Page 33

    Open path eddy covariance system 27 figure 20. Destination file option screen to create an edire raw format file list using the interpreter, save the data in the tob1 file format. If another format is needed at a later date, convert the tob1 files into the other file format (see figure 19). • set th...

  • Page 34

    Open path eddy covariance system 28 figure 21. Fully configured cardconvert start up screen the converted files will look something like the 20 hz files shown in figure 22. Each file name with consist of a user specified file name and the time stamp of the first record in each file with a one minute...

  • Page 35

    Open path eddy covariance system 29 4.1.4.1 collecting data with one card if a single card is used to collect the data and the data on the card is not deleted after copying it to the pc, the datalogger will append the data collected since the card was removed to the data file on the card. This means...

  • Page 36

    Open path eddy covariance system 30 figure 24. List of files where the duplicate files are renamed to *.Bak 4.1.4.2 collecting data with two cards data can be collected using two cards. The card in the datalogger is removed and replaced with an empty one. The data from the original card is copied to...

  • Page 37

    Open path eddy covariance system 31 figure 25. List of files collected the first time using two cards figure 26. List of files collected the second time using two cards 4.2 data processing there are several ways to process the raw time series data collected by the system. Some of these are considere...

  • Page 38

    Open path eddy covariance system 32 4.2.1 online processing the eddy covariance datalogger programs perform the processing listed below online and in real time. In many cases, no further processing of the data is required. • thirty minute statistics for the turbulence and meteorological variables, t...

  • Page 39

    Open path eddy covariance system 33 • wavelet analysis. • webb et al. (1980) term for latent heat flux and co 2 flux. This term is separated into its components due to temperature and to vapor density fluctuations. • wind direction and wind speed from the csat3. • kh20 krypton hygrometer oxygen corr...

  • Page 40

    Open path eddy covariance system 34 figure 27. Interpreter settings to read a campbell scientific, inc. Tob1 data file figure 28. Folder that contains the raw tob1 time series data files.

  • Page 42

    Open path eddy covariance system 36 the processing steps list has the default instructions needed to extract the data from the tob1 file (figure 31). Additional instructions can be found in the “processing items” list. To configure the instruction, select the instruction parameter and enter values e...

  • Page 43

    Open path eddy covariance system 37 figure 32. Output file location as part of the processing list figure 33. Output file location as part of the processing list.

  • Page 44

    Open path eddy covariance system 38 figure 34. Processing u z and co 2 with 1 chn statistics instruction figure 35. Computing co 2 flux with 2 chn statistics and graphing u z statistic with plot value instruction.

  • Page 45

    Open path eddy covariance system 39 5. Eddy covariance theory 101 figure 36. Ideal vertical profiles of virtual potential temperature and specific humidity depicting all the layers of the atmospheric boundary layer. The surface layer (figure 36) is comprised of approximately the lower 10% of the atm...

  • Page 46

    Open path eddy covariance system 40 where f c is the carbon dioxide flux, ρ′ c is the instantaneous deviation of the carbon dioxide density from the mean, z u′ is the instantaneous deviation of vertical wind speed from the mean, le is the latent heat flux, l v is the latent heat of vaporization, ρ′ ...

  • Page 47

    A-1 appendix a. Csat3 orientation a.1 determining true north and sensor orientation the orientation of the csat3 negative x-axis is found by reading a magnetic compass and applying the site-specific correction for magnetic declination; where the magnetic declination is the number of degrees between ...

  • Page 48

    Appendix a. Sensor orientation a-2 declination angles are always subtracted from the compass reading to find true north. A declination angle east of true north is reported as positive a value and is subtracted from 360 (0) degrees to find true north as shown figure a-2. A declination angle west of t...

  • Page 49

    Appendix a. Sensor orientation a-3 a.2 online magnetic declination calculator the magnetic declination calculator web calculator published by noaa’s geophysical data center is available at the following url http://www.Ngdc.Noaa.Gov/seg/geomag/jsp/struts/calcdeclination. After the web page loads, ent...

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    Appendix a. Sensor orientation a-4 this is a blank page..

  • Page 51: A Fw05

    B-1 appendix b. Sensible heat flux without a fw05 b.1 speed of sound and sonic temperature in the following section the speed of sound will be expressed as a sonically measured temperature. The effects of humidity, on the speed of sound, will be combined into this temperature. This temperature, t s ...

  • Page 52

    Appendix b. Sensible heat flux without a fw05 b-2 ( ) ( ) ( ) c c c q q r t q p v d d d 2 1 0 84 1 0 94 1 0 61 = + + + . . . (b-6) expand and collect terms. ( ) ( ) c c c r t q q q p v d d d 2 2 1 145 0 5124 1 0 94 = + + + . . . (b-7) multiply the above by ( ) ( ) 1 0 94 1 0 94 − − . . Q q and ignor...

  • Page 53

    Appendix b. Sensible heat flux without a fw05 b-3 expand equation (b-14). T t t t t q tq t t q t q s s s = + ′ = + + ′ + ′ + ′ + ′ ′ 0 51 0 51 0 51 0 51 . . . . (b-15) b.3 sensible heat and specific humidity flux in the following section write the sonic sensible heat flux as a function of sensible a...

  • Page 54

    Appendix b. Sensible heat flux without a fw05 b-4 ( ) ′ ′ = ′ ′ + ′ ′ + ′ ′ = ′ ′ + + ′ ′ w t w t q w t t w q w t q t w q s 0 51 0 51 1 0 51 0 51 . . . . (b-23) multiply the first term on the right hand side by t t and recall that ( ) t t q s = + 1 0 51 . . ′ ′ = ′ ′ + ′ ′ w t w t t t t w q s s 0 51...

  • Page 55

    Appendix b. Sensible heat flux without a fw05 b-5 multiply equation (b-28) by ρ c p and the second term on the right hand side by l l v v . Where l v is the latent heat of vaporization (l v = 2.45 × 10 6 j kg -1 @ 20 °c). H h t t c r t p le l s s p d v = + ρ 0 51 2 . (b-29) solve equation (b-29) for...

  • Page 56

    Appendix b. Sensible heat flux without a fw05 b-6 this is a blank page..

  • Page 57: Appendix C.  References

    C-1 appendix c. References brutsaert, w.: 1982, evaporation into the atmosphere, d. Reidel publishing co., dordrecht, holland, 300. Buck, a. L.: 1976, “the variable-path lyman-alpha hygrometer and its operating characteristics”, bull. Amer. Meteorol. Soc., 57, 1113-1118. Campbell, g. S., and tanner,...

  • Page 58

    Appendix c. References c-2 tanner, c. B. And thurtell, g. W.: 1969, anemoclinometer measurements of reynolds stress and heat transport in the atmospheric surface layer, final report, united states army electronics command, atmospheric sciences laboratory, fort huachuca, arizona. Tanner, b. D.: 1988,...

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    Campbell scientific companies campbell scientific, inc. (csi) 815 west 1800 north logan, utah 84321 united states www.Campbellsci.Com info@campbellsci.Com campbell scientific africa pty. Ltd. (csaf) po box 2450 somerset west 7129 south africa www.Csafrica.Co.Za cleroux@csafrica.Co.Za campbell scient...