SGP/CO2FLX/C1 - Reprocessing User Notes

Format Changes:
  To comply with archive standards, the name of the unlimited dimention variable in the 
cdf level b1 files was changed from 'record' to 'time'. This does not affect data quality.

• height of base of instrument tower(site_elevation)
• h(h)
• latitude of instrument tower(site_latitude)
• mean IRGA pressure(mean_p)
• variance of c(var_c)
• Date and time in alternate form(yyyydddhhmmss)
• Virtual temperature (T)(mean_t)
• mean horizontal wind speed(mean_rot_u)
• Time offset of tweaks from base_time(time_offset)
• variance of q(var_q)
• variance of v(var_rot_v)
• fractional day of the year(doy)
• Vertical angle of wind(phi)
• variance of w(var_rot_w)
• Monin-Obukhov length scale(Lmoni)
• variance of u(var_rot_u)
• Unit Vector Wind Direction(wdir)
• Friction velocity(ustar)
• additive WPL LE correction to c flux(fc_wpl_le)
• additive WPL H correction to c flux(fc_wpl_h)
• base time(base_time)
• rotation to zero w(theta)
• longitude of instrument tower(site_longitude)
• mean co2 concentration (c)(mean_c)
• height of instument from tower base(zm)
• variance of t(var_t)
• WPL corrected CO2 flux(fc_corr)
• Water vapor density (q)(mean_q)
• Latent heat flux(le)

• mean IRGA pressure(mean_p)
• variance of c(var_c)
• variance of t(var_t)
• Latent heat flux(le)
• mean horizontal wind speed(mean_rot_u)
• Vertical angle of wind(phi)
• Monin-Obukhov length scale(Lmoni)
• variance of q(var_q)
• height of instument from tower base(zm)
• longitude of instrument tower(site_longitude)
• additive WPL LE correction to c flux(fc_wpl_le)
• Virtual temperature (T)(mean_t)
• Water vapor density (q)(mean_q)
• h(h)
• additive WPL H correction to c flux(fc_wpl_h)
• Date and time in alternate form(yyyydddhhmmss)
• Unit Vector Wind Direction(wdir)
• mean co2 concentration (c)(mean_c)
• variance of w(var_rot_w)
• base time(base_time)
• variance of u(var_rot_u)
• variance of v(var_rot_v)
• rotation to zero w(theta)
• WPL corrected CO2 flux(fc_corr)
• latitude of instrument tower(site_latitude)
• Time offset of tweaks from base_time(time_offset)
• Friction velocity(ustar)
• height of base of instrument tower(site_elevation)
• fractional day of the year(doy)

• base time(base_time)
• Monin-Obukhov length scale(Lmoni)
• Latent heat flux(le)
• variance of t(var_t)
• variance of u(var_rot_u)
• Date and time in alternate form(yyyydddhhmmss)
• variance of v(var_rot_v)
• Vertical angle of wind(phi)
• Unit Vector Wind Direction(wdir)
• longitude of instrument tower(site_longitude)
• latitude of instrument tower(site_latitude)
• WPL corrected CO2 flux(fc_corr)
• height of instument from tower base(zm)
• variance of q(var_q)
• Friction velocity(ustar)
• variance of c(var_c)
• additive WPL LE correction to c flux(fc_wpl_le)
• mean IRGA pressure(mean_p)
• variance of w(var_rot_w)
• Virtual temperature (T)(mean_t)
• fractional day of the year(doy)
• mean co2 concentration (c)(mean_c)
• rotation to zero w(theta)
• mean horizontal wind speed(mean_rot_u)
• height of base of instrument tower(site_elevation)
• h(h)
• additive WPL H correction to c flux(fc_wpl_h)
• Water vapor density (q)(mean_q)
• Time offset of tweaks from base_time(time_offset)

• average of four lower soil moisture sensors(mean_m_soil_lower)
• standard error of mean_t_soil_middle note maximum of two values used in
  calculation(stderr_mean_t_soil_middle)
• average of two middle soil temperature sensors(mean_t_soil_middle)
• Time offset of tweaks from base_time(time_offset)
• h(h)
• additive WPL H correction to c flux(fc_wpl_h)
• variance of v(var_rot_v)
• Hourly precipitation(precip)
• additive WPL LE correction to c flux(fc_wpl_le)
• variance of u(var_rot_u)
• rotation to zero w(theta)
• standard error of mean_t_soil_lower note maximum of two values used in
  calculation(stderr_mean_t_soil_lower)
• fractional day of the year(doy)
• WPL corrected CO2 flux(fc_corr)
• depth of soil heat flux probes(z_g_soil)
• height of radiation instruments(zrad)
• net solar radiation (NR-lite)(r_net)
• depth of lower m soil probesp(z_m_soil_lower)
• standard error of mean_m_soil_upper(stderr_mean_m_soil_upper)
• mean co2 concentration (c)(mean_c)
• height of lower RH/T sensor(z_lower)
• Date and time in alternate form(yyyydddhhmmss)
• Water vapor density (q)(mean_q)
• variance of c(var_c)
• depth of middle t soil probesm(z_t_soil_middle)
• height of instument from tower base(zm)
• photosynthetic photon flux density (PAR)(ppfd)
• barometric pressure(bar_pres)
• upwelling longwave hemispheric irradiance t_rad corrected(r_up_long_hemisp)
• latitude of instrument tower(site_latitude)
• mean air temperature, upper level(t_air_upper)
• average of two lower soil temperature sensors(mean_t_soil_lower)
• Unit Vector Wind Direction(wdir)
• standard error of mean_t_soil_upper note maximum of two values used in
  calculation(stderr_mean_t_soil_upper)
• mean horizontal wind speed(mean_rot_u)
• Virtual temperature (T)(mean_t)
• upwelling shortwave hemispheric irradiance t_rad corrected(r_up_short_hemisp)
• mean relative humidity, lower level(rh_lower)
• mean air temperature, lower level(t_air_lower)
• variance of w(var_rot_w)
• Latent heat flux(le)
• mean IRGA pressure(mean_p)
• downwelling shortwave hemispheric irradiance t_rad corrected(r_down_short_hemisp)
• Friction velocity(ustar)
• base time(base_time)
• height of upper RH/T sensor(z_upper)
• height of base of instrument tower(site_elevation)
• variance of q(var_q)
• standard error of mean_g_soil(stderr_mean_g_soil)
• radiometer body temperature (for longwave correction)(t_rad)
• longitude of instrument tower(site_longitude)
• variance of t(var_t)
• downwelling longwave hemispheric irradiance t_rad corrected(r_down_long_hemisp)
• average of four upper soil moisture sensors(mean_m_soil_upper)
• average of up to four soil heat flux sensors(mean_g_soil)
• total downwelling shortwave radiation (LI-200 sensor)(r_tot)
• depth of upper t soil probesm(z_t_soil_upper)
• depth of upper m soil probesm(z_m_soil_upper)
• Vertical angle of wind(phi)
• depth of lower t soil probesm(z_t_soil_lower)
• mean relative humidity, upper level(rh_upper)
• standard error of mean_m_soil_lower(stderr_mean_m_soil_lower)
• average of two upper soil temperature sensors(mean_t_soil_upper)
• Monin-Obukhov length scale(Lmoni)

SGP/CO2FLX/C1 - Reprocessing User Notes

A subset of the radiation measurements had an incorrect gain applied to raw data in period 
from 20021218-20031218.  To correct for this, a multiplicative correction factor of 1.11 
were applied to raw data used for the following variables:

r_down_short_hemisp
r_down_long_hemisp
r_up_short_hemisp
r_up_long_hemisp

Note that the long wave variables are computed by adding the black body thermal radiation 
from the radiometer body to each of the long wave signals.  Hence, the multiplicative 
correction is applied to the raw long wave fluxes before adding in the flux from the 
radiometer body.

• downwelling shortwave hemispheric irradiance t_rad corrected(r_down_short_hemisp)
• upwelling longwave hemispheric irradiance t_rad corrected(r_up_long_hemisp)
• upwelling shortwave hemispheric irradiance t_rad corrected(r_up_short_hemisp)
• downwelling longwave hemispheric irradiance t_rad corrected(r_down_long_hemisp)

SGP/CO2FLX/C1 - Longwave Radiation Incorrect

Long wave radiation values (r_up_long_hemisp, r_down_long_hemisp) are bad 
due to correction with bad radiometer body temperature (t_rad) resulting
from a wiring issue.

• radiometer body temperature (for longwave correction)(t_rad)
• upwelling longwave hemispheric irradiance t_rad corrected(r_up_long_hemisp)
• downwelling longwave hemispheric irradiance t_rad corrected(r_down_long_hemisp)

SGP/CO2FLX/C1 - Reprocess: Units

Mean CO2 density units are incorrectly labeled as umol m-3. Units should be labeled as 
mmol m-3.

• mean co2 concentration (c)(mean_c)

• mean co2 concentration (c)(mean_c)

• mean co2 concentration (c)(mean_c)

SGP/CO2FLX/C1 - Mean CO2 density incorrect, CO2 flux suspect

A problem was identified with the calibration of the instrument over the time period 
October 12, 2004 to October 20, 2004. The offset of the instrument is known to be incorrect 
over this time frame, and a study of the gain of the instrument is underway.

• mean co2 concentration (c)(mean_c)
• WPL corrected CO2 flux(fc_corr)

SGP/CO2FLX/C1 - Reprocessed: User Notes

Replacement of LI-200 sensor (total downwelling shortwave radiation, variable r_tot) by a 
new LI-190 sensor (upwelling photosynthetic photon flux density, variable ppfd_up).

The new LI-190 sensor was:
- installed on December 9, 2004. 
- being tested from December 9, 2004 to December 22, 2004.
- operational after December 22, 2004.

Consequently:
1. variable "r_tot" is filled with missing values (qc_r_tot = 1) after December 9, 2004,
2. variable "ppfd_up" is filled with missing values (qc_ppfd_up = 1) prior December 22, 
2004.

• photosynthetic photon flux density (PAR)(ppfd_up)
• total downwelling shortwave radiation (LI-200 sensor)(r_tot)

SGP/CO2FLX/C1 - downwelling longwave hemispheric irradiance incorrect

A problem was identified with the downwelling longwave hemispheric irradiance (variable 
"r_down_long_hemisp") calibration of our Kipp & Zonen CNR1 radiometer. The offset of the 
instrument is believed to be incorrect over the specified time frame, and a correction of 
the problem is underway.

• downwelling longwave hemispheric irradiance t_rad corrected(r_down_long_hemisp)

SGP/CO2FLX/C1 - Soil Temperature measurements

Current data quality check (qc) procedure does not catch spikes in soil temperature 
measurements. A new qc procedure is being tested and will improve the current procedure.

• average of two lower soil temperature sensors(mean_t_soil_lower)
• average of two middle soil temperature sensors(mean_t_soil_middle)
• average of two upper soil temperature sensors(mean_t_soil_upper)

SGP/CO2FLX/C1 - downwelling longwave hemispheric irradiance incorrect

Downwelling longwave radiation measurements (variable "r_down_long_hemisp") are bad due to 
a wiring issue. Users should not use the downwelling longwave hemispheric irradiance 
during this period. The downwelling shortwave and longwave radiation at CF is also available 
from the Broadband Radiometer Station (BRS).

• downwelling longwave hemispheric irradiance t_rad corrected(r_down_long_hemisp)

SGP/CO2FLX/C1 - Reprocess: 4m instruments height

The height of the 4m instruments is 4.8 m and not 4.65 m as shown in b1 datastream

• height of instument from tower base(zm)