Campbell Scientific HFP01 Open Path Eddy Covariance (OPEC) - Page 14

Program Configuration, 3.1.1 Sonic Azimuth

Get Campbell Scientific HFP01 PDF manuals and user guides View all Campbell Scientific HFP01 manuals
Add to My Manuals
Save this manual to your list of manuals

Page 14 highlights

OPEC Open-Path Eddy-Covariance System as a line item on the order, contact Campbell Scientific to purchase the appropriate datalogger program for your open-path eddy-covariance system. The program covers a variety of sensors and is continuously growing. If your system uses sensors that are not currently supported by the program, add the appropriate measurement and processing instructions to the program or contact Campbell Scientific for assistance. Campbell Scientific charges for custom datalogger programming with a one hour minimum and one hour resolution; call for current Application Engineering time rates. The datalogger program aligns the measurements in time from the CSAT3, IRGASON, KH20, and FW05 before computing online fluxes. The IRGASON delay is a function of the user programmed bandwidth setting. The delay as a function of bandwidth is given in the IRGASON manual. The sensor delays are removed before the data is used to compute the online fluxes. These fixed delays are computed automatically by the datalogger program, based in the IRGASON bandwidth setting. The default IRGASON bandwidth is 20 Hz. The sensor delays are not removed from the high frequency time series data saved to Final Storage. Depending on the system configuration, the datalogger programs compute carbon dioxide flux, latent heat flux, sonic sensible heat flux, sensible heat flux, momentum flux, and friction velocity, along with all the second moment covariances, standard deviations, and means. The program will also compute a sensible heat flux using the sonic temperature corrected for the effects of water vapor. This sensible heat flux can also be found from the sonic sensible heat flux and latent heat flux in post processing (see Appendix B). 3.1 Program Configuration The site attendant must enter unique calibration coefficients or site-specific information into the datalogger program. This information includes, but is not limited to, the calibration coefficients for the net radiometer and soil heat flux plates, or site pressure. To find the section of the program where these changes are made, search for the text "Unique". These values are added to the program before it is downloaded into the datalogger. 3.1.1 Sonic Azimuth The example programs report the wind direction in both the sonic coordinate system (a right-handed coordinate system) and in the compass coordinate system (a left-handed coordinate system). The sonic coordinate system is relative to the sonic itself and does not depend on the sonic's orientation (azimuth of the negative x-axis). The compass coordinate system is fixed to the earth. In order for the program to compute the correct compass wind direction, the azimuth of the sonic negative x-axis must be entered into the program. The program default value for the variable "sonic_azimuth" is 0. This assumes that the prevailing wind is from the North, e.g., the sonic is mounted such that the negative x-axis points to the North. The variable "sonic_azimuth" can be changed on the fly using the CR3000 keyboard display or via LoggerNet. Once a "sonic_azimuth" is entered, the value is saved in the CPU. The program default "sonic_azimuth" is used only if a site specific value has not been entered using the keyboard or through LoggerNet. 6

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
OPEC Open-Path Eddy-Covariance System
as a line item on the order, contact Campbell Scientific to purchase the
appropriate datalogger program for your open-path eddy-covariance system.
The program covers a variety of sensors and is continuously growing.
If your
system uses sensors that are not currently supported by the program, add the
N
given in the IRGASON manual.
The sensor delays
are removed before the data is used to compute the online fluxes.
These fixed
ensible heat
flux, momentum flux, and friction velocity, along with all the second moment
eviations, and means.
The program will also compute a
g the sonic temperature corrected for the effects of water
3.1
Program C
on coefficients or site-specific
information into the datalogger program.
This information includes, but is not
ed to, the calibration coefficients for the net radiometer and soil heat flux
s, or site pressure.
To find the section of the program where these changes
3.1.1 Sonic Azimu
ate
ystem is fixed to
the earth.
In order for the program to compute the correct compass wind
The variable “sonic_azimuth” can be changed on the fly using the CR3000
ly
appropriate measurement and processing instructions to the program or contact
Campbell Scientific for assistance.
Campbell Scientific charges for custom
datalogger programming with a one hour minimum and one hour resolution;
call for current Application Engineering time rates.
The datalogger program aligns the measurements in time from the CSAT3,
IRGASON, KH20, and FW05 before computing online fluxes.
The IRGASO
delay is a function of the user programmed bandwidth setting.
The delay as a
function of bandwidth is
delays are computed automatically by the datalogger program, based in the
IRGASON bandwidth setting.
The default IRGASON bandwidth is 20 Hz.
The sensor delays are not removed from the high frequency time series data
saved to Final Storage.
Depending on the system configuration, the datalogger programs compute
carbon dioxide flux, latent heat flux, sonic sensible heat flux, s
covariances, standard d
sensible heat flux usin
vapor.
This sensible heat flux can also be found from the sonic sensible heat
flux and latent heat flux in post processing (see Appendix B).
onfiguration
The site attendant must enter unique calibrati
limit
plate
are made, search for the text “Unique”. These values are added to the program
before it is downloaded into the datalogger.
th
The example programs report the wind direction in both the sonic coordin
system (a right-handed coordinate system) and in the compass coordinate
system (a left-handed coordinate system).
The sonic coordinate system is
relative to the sonic itself and does not depend on the sonic’s orientation
(azimuth of the negative x-axis).
The compass coordinate s
direction, the azimuth of the sonic negative x-axis must be entered into the
program.
The program default value for the variable “sonic_azimuth” is 0.
This assumes that the prevailing wind is from the North, e.g., the sonic is
mounted such that the negative x-axis points to the North.
keyboard display or via LoggerNet. Once a “sonic_azimuth” is entered, the
value is saved in the CPU.
The program default “sonic_azimuth” is used on
if a site specific value has not been entered using the keyboard or through
LoggerNet.
6