SGP/EBBR/E26 - AEM Home Signals Incorrect, Surface Fluxes Incorrect

During a preventative maintenance visit to perform the 6-month
calibrations, the home15 and home30 outputs began reading the
same as one another.  A fuse replacement and lubrication of the 
AEM sprockets on 11/13 corrected the problem.

During the interval specified, the home15, home30, and sensible
and latent heat fluxes are incorrect.

• rh_right_mv
• temp_air_right
• temp_air_left
• temp_trh_right_rr
• rh_left_mv
• temp_trh_left_rr

• temp_air_bottom
• temp_trh_bottom
• vapor_pressure_bottom
• rh_bottom_fraction
• temp_air_top
• rh_top_fraction
• home_signal
• vapor_pressure_top
• temp_trh_top

• vapor_pressure_bottom
• temp_air_top
• vapor_pressure_top
• latent_heat_flux
• rh_bottom_fraction
• bowen_ratio
• rh_top_fraction
• temp_air_bottom
• temp_trh_top
• home_signal_30
• sensible_heat_flux
• home_signal_15
• temp_trh_bottom

SGP/EBBR/E26 - 6 Month Checks

Many measurements were incorrect while the AEM was positioned with both aspirators at the 
same height for comparison checks.

• rh_right_mv
• temp_air_right
• temp_air_left
• temp_trh_right_rr
• rh_left_mv
• temp_trh_left_rr

• temp_air_bottom
• temp_trh_bottom
• vapor_pressure_bottom
• rh_bottom_fraction
• temp_air_top
• rh_top_fraction
• vapor_pressure_top
• temp_trh_top

• vapor_pressure_bottom
• temp_air_top
• vapor_pressure_top
• latent_heat_flux
• rh_bottom_fraction
• bowen_ratio
• rh_top_fraction
• temp_air_bottom
• temp_trh_top
• sensible_heat_flux
• temp_trh_bottom

SGP/EBBR/E26 - Spark Gap Bad, Pressure Incorrect

In a trip to E26, I found that a bad spark gap through which the barometer was powered was 
causing pressure measurements to be incorrect.  The pressure readings oscillated with 
the voltage of the EBBR battery.  During daytime the voltage and thus the pressure would 
increase and vice versa during dark hours.

Apparently only the positive side of the power supply was properly connected through the 
spark gap and thus the voltage received by the pressure sensor was lower than required to 
power it properly.  Under this condition the perssure measurement varies with voltage 
level.  The pressure measurements therefore had a diurnal signature and usually were 
incorrect.  

The decreased pressure during most times would cause latent heat flux to be slightly 
overestimated and sensible heat flux to be slightly underestimated.

• atmos_pressure_mv

• Barometric Pressure(atmos_pressure)

• sensible_heat_flux
• Barometric Pressure(atmos_pressure)
• latent_heat_flux
• bowen_ratio

SGP/EBBR/E26  - Wind Speed Sensor Frozen By Ice Storm

The wind speed sensor was frozen stopped by ice from a storm.  The wind speed 
and residual wind speed measurements are incorrect.

• wspd_arith_mean

• wspd_arith_mean
• wspd_vec_mean

• wspd_arith_mean
• wspd_vec_mean

SGP/EBBR/E26  - Wind Direction Sensor Frozen By Ice Storm

The wind direction sensor was frozen stopped by ice from a storm.  
The wind direction, sigma_wd, and residual wind speed measurements 
are incorrect.

• wdir_vec_mean_mv

• wdir_vec_std
• wdir_vec_mean
• wspd_vec_mean

• wdir_vec_std
• wspd_vec_mean
• wdir_vec_mean

SGP/EBBR/E26  - Wind Speed Frozen Stopped By Ice

An ice storm froze the wind speed sensor to a stopped condition.

The wind speed and residual wind speed measurements are incorrect.

This sensor failure does not affect the sensible and latent heat fluxes.

• wspd_arith_mean

• wspd_arith_mean
• wspd_vec_mean

• wspd_arith_mean
• wspd_vec_mean

SGP/EBBR/E26  - Wind Direction Frozen Stopped By Ice

The wind direction sensor was frozen stopped by ice from a storm.  
The wind direction, sigma_wd, and residual wind speed measurements 
are incorrect.

• wdir_vec_std
• wdir_vec_mean
• wspd_vec_mean

• wdir_vec_std
• wspd_vec_mean
• wdir_vec_mean

SGP/EBBR/E26 - Soil Temperature #4 and Soil Heat Flow #4 Incorrect

The soil temperature and soil heat flow probes for set #4 was pulled 
partially out of the ground.  This caused soil temperature #4 to be too high and soil heat 
flow #4 to be too low.  The error is not so great as to cause a large error in the 
sensible and latent heat fluxes.

• corr_soil_heat_flow_4
• sensible_heat_flux
• soil_temp_4
• energy_storage_change_4
• soil_heat_flow_4
• latent_heat_flux
• soil_heat_capacity_4
• surface_soil_heat_flux_4

SGP/EBBR/E26 - Spark Gap Bad, Pressure Incorrect

In a trip to E26, I found that a bad spark gap through which the barometer was powered was 
causing pressure measurements to be incorrect.  The pressure readings oscillated with 
the voltage of the EBBR battery.  During daytime the voltage and thus the pressure would 
increase and vice versa during dark hours.

Apparently only the positive side of the power supply was properly connected through the 
spark gap and thus the voltage received by the pressure sensor was lower than required to 
power it properly.  Under this condition the perssure measurement varies with voltage 
level.  The pressure measurements therefore had a diurnal signature and usually were 
incorrect.  

The decreased pressure during most times would cause latent heat flux to be slightly 
overestimated and sensible heat flux to be slightly underestimated.

• Retrieved pressure profile(pres)

• atmos_pressure_mv

• sensible_heat_flux
• Barometric Pressure(atmos_pressure)
• latent_heat_flux
• bowen_ratio

SGP/EBBR/E26 - 6 Month Checks

Many measurements were incorrect while the AEM was positioned with both aspirators at the 
same height for comparison checks.

• rh_right_mv
• temp_air_right
• temp_air_left
• temp_trh_right_rr
• rh_left_mv
• temp_trh_left_rr

• temp_air_bottom
• temp_trh_bottom
• vapor_pressure_bottom
• rh_bottom_fraction
• temp_air_top
• rh_top_fraction
• vapor_pressure_top
• temp_trh_top

• vapor_pressure_bottom
• temp_air_top
• vapor_pressure_top
• latent_heat_flux
• rh_bottom_fraction
• bowen_ratio
• rh_top_fraction
• temp_air_bottom
• temp_trh_top
• sensible_heat_flux
• temp_trh_bottom

SGP/EBBR/E26 - Low Battery Voltage - Many Measurements Incorrect

During low battery voltage conditions (< 10.5 V especially) many measurements are 
incorrect.

• soil_temp_2_rr
• temp_air_right
• soil_heat_flow_5_mv
• wspd_arith_mean
• soil_temp_1_rr
• soil_temp_4_rr
• soil_moisture_4_rr
• soil_temp_3_rr
• soil_moisture_2_rr
• wdir_vec_mean_mv
• soil_moisture_1_rr
• soil_temp_5_rr
• temp_air_left
• soil_moisture_3_rr
• rh_right_mv
• soil_heat_flow_3_mv
• soil_heat_flow_4_mv
• soil_moisture_5_rr
• atmos_pressure_mv
• rh_left_mv
• soil_heat_flow_1_mv
• temp_trh_left_rr
• net_radiation_mv
• temp_reference_rr
• soil_heat_flow_2_mv
• home_signal
• temp_trh_right_rr

• temp_air_bottom
• temp_trh_bottom
• temp_trh_top
• Barometric Pressure(atmos_pressure)
• home_signal
• wdir_vec_mean
• wdir_vec_std
• wspd_arith_mean
• vapor_pressure_top
• temp_reference
• rh_top_fraction
• net_radiation
• vapor_pressure_bottom
• rh_bottom_fraction
• temp_air_top
• wspd_vec_mean

• soil_temp_4
• latent_heat_flux
• corr_soil_heat_flow_3
• bowen_ratio
• wdir_vec_std
• soil_moisture_4
• soil_heat_capacity_3
• temp_air_bottom
• wdir_vec_mean
• soil_moisture_1
• sensible_heat_flux
• soil_heat_flow_1
• surface_soil_heat_flux_5
• vapor_pressure_top
• energy_storage_change_5
• soil_heat_capacity_4
• corr_soil_heat_flow_5
• rh_bottom_fraction
• soil_heat_flow_3
• soil_heat_flow_4
• surface_soil_heat_flux_4
• rh_top_fraction
• corr_soil_heat_flow_2
• soil_heat_flow_2
• surface_soil_heat_flux_1
• surface_soil_heat_flux_3
• soil_heat_capacity_5
• soil_temp_5
• corr_soil_heat_flow_4
• surface_soil_heat_flux_avg
• soil_moisture_2
• soil_temp_2
• soil_temp_3
• soil_heat_capacity_2
• home_signal_15
• soil_heat_capacity_1
• soil_moisture_3
• vapor_pressure_bottom
• corr_soil_heat_flow_1
• net_radiation
• wspd_arith_mean
• surface_soil_heat_flux_2
• Barometric Pressure(atmos_pressure)
• energy_storage_change_1
• temp_reference
• energy_storage_change_2
• energy_storage_change_3
• soil_heat_flow_5
• temp_trh_top
• temp_trh_bottom
• temp_air_top
• wspd_vec_mean
• energy_storage_change_4
• soil_temp_1
• soil_moisture_5
• home_signal_30

SGP/EBBR/E26 - Most Measurements Incorrect

Most of the measurements became either too large or too small.
The cause is not known.

• soil_temp_2_rr
• temp_air_right
• soil_heat_flow_5_mv
• wspd_arith_mean
• soil_temp_1_rr
• soil_temp_4_rr
• soil_moisture_4_rr
• soil_temp_3_rr
• soil_moisture_2_rr
• wdir_vec_mean_mv
• soil_moisture_1_rr
• soil_temp_5_rr
• temp_air_left
• soil_moisture_3_rr
• rh_right_mv
• soil_heat_flow_3_mv
• soil_heat_flow_4_mv
• soil_moisture_5_rr
• atmos_pressure_mv
• rh_left_mv
• soil_heat_flow_1_mv
• temp_trh_left_rr
• net_radiation_mv
• temp_reference_rr
• soil_heat_flow_2_mv
• home_signal
• temp_trh_right_rr

• temp_air_bottom
• temp_trh_bottom
• temp_trh_top
• Barometric Pressure(atmos_pressure)
• home_signal
• wdir_vec_mean
• wdir_vec_std
• wspd_arith_mean
• vapor_pressure_top
• temp_reference
• rh_top_fraction
• net_radiation
• vapor_pressure_bottom
• rh_bottom_fraction
• temp_air_top
• wspd_vec_mean

• soil_temp_4
• latent_heat_flux
• corr_soil_heat_flow_3
• bowen_ratio
• wdir_vec_std
• soil_moisture_4
• soil_heat_capacity_3
• temp_air_bottom
• wdir_vec_mean
• soil_moisture_1
• sensible_heat_flux
• soil_heat_flow_1
• surface_soil_heat_flux_5
• vapor_pressure_top
• energy_storage_change_5
• soil_heat_capacity_4
• corr_soil_heat_flow_5
• rh_bottom_fraction
• soil_heat_flow_3
• soil_heat_flow_4
• surface_soil_heat_flux_4
• rh_top_fraction
• corr_soil_heat_flow_2
• soil_heat_flow_2
• surface_soil_heat_flux_1
• surface_soil_heat_flux_3
• soil_heat_capacity_5
• soil_temp_5
• corr_soil_heat_flow_4
• surface_soil_heat_flux_avg
• soil_moisture_2
• soil_temp_2
• soil_temp_3
• soil_heat_capacity_2
• home_signal_15
• soil_heat_capacity_1
• soil_moisture_3
• vapor_pressure_bottom
• corr_soil_heat_flow_1
• net_radiation
• wspd_arith_mean
• surface_soil_heat_flux_2
• Barometric Pressure(atmos_pressure)
• energy_storage_change_1
• temp_reference
• energy_storage_change_2
• energy_storage_change_3
• soil_heat_flow_5
• temp_trh_top
• temp_trh_bottom
• temp_air_top
• wspd_vec_mean
• energy_storage_change_4
• soil_temp_1
• soil_moisture_5
• home_signal_30

SGP/EBBR/E26  - Wind Speed Frozen Stopped By Ice Storm

An ice storm froze the wind speed sensor to a stopped condition.

The wind speed and residual wind speed measurements are incorrect.

This sensor failure does not affect the sensible and latent heat fluxes.

• wspd_arith_mean

• wspd_arith_mean
• wspd_vec_mean

• wspd_arith_mean
• wspd_vec_mean

SGP/EBBR/E26  - Wind Direction Frozen Stopped By Ice Storm

The wind direction sensor was frozen stopped by ice from a storm.  
The wind direction, sigma_wd, and residual wind speed measurements 
are incorrect.

• wdir_vec_mean_mv

• wdir_vec_std
• wdir_vec_mean
• wspd_vec_mean

• wdir_vec_std
• wspd_vec_mean
• wdir_vec_mean

SGP/EBBR/E26 - Aging Pressure Sensor Output Changes
With Supply Voltage

The E26 EBBR pressure sensor experienced the poor internal voltage regulation problem 
experienced at other sites last year.  Aging of the internal voltage regulator caused the 
pressure output to drop by 1-2 kPa (0.1-0.5 kPa is normal) when the Sun rose and the solar 
panel goosed the battery voltage up.  

The sensible and latent heat fluxes were not significantly affected.

• atmos_pressure_mv

• Barometric Pressure(atmos_pressure)

• Barometric Pressure(atmos_pressure)

SGP/EBBR/E26 - Incorrect soil type coefficients used

The soil type coefficents for soil moisture were incorrect from the day
of the system installation on, making soil moisture values too large.

As a result, soil heat flows were overmeasured, and sensible and latent heat fluxes were 
underestimated.

• surface_soil_heat_flux_5
• corr_soil_heat_flow_1
• energy_storage_change_4
• latent_heat_flux
• energy_storage_change_5
• soil_heat_capacity_4
• corr_soil_heat_flow_5
• soil_moisture_5
• surface_soil_heat_flux_2
• energy_storage_change_1
• corr_soil_heat_flow_3
• surface_soil_heat_flux_4
• energy_storage_change_2
• energy_storage_change_3
• soil_heat_capacity_3
• soil_moisture_4
• corr_soil_heat_flow_2
• surface_soil_heat_flux_1
• surface_soil_heat_flux_3
• soil_heat_capacity_5
• soil_moisture_1
• corr_soil_heat_flow_4
• sensible_heat_flux
• surface_soil_heat_flux_avg
• soil_moisture_2
• soil_heat_capacity_2
• soil_heat_capacity_1
• soil_moisture_3

SGP/EBBR/E26 - Improved EBBR CR10 Program

Effective 20050331.1700, the EBBR.E26 CR10 program was revised to improve 
the quality of the primary measurements as follows:
   
1) An RMS procedure is used to determine max and min limits of acceptable
soil heat flow.  This is applied to the individual soil sets.  Measurements
outside the limits are rejected and the measurements within the limits are
used to calculate the average soil heat flow.
   
2) Max and min limits are used to determine incorrect values of net
radiation, sensible heat flux (h), latent heat flux (e), and automatic
exchange mechanism (AEM) signal.  If AEM signal is outside the limits, h 
and e are set to 999s.  If net radiation is outside the limits, h and e are 
set to 999s. If h or e are outside the limits, h and e are set to 999s.
   
Virtually no incorrect soil measurement will affect the primary 
measurements of h and e.
   
By setting h and e to 999s, it can be easily seen that the primary 
variables are incorrect; no other interpretation is possible.
   
Prior to 20050331, the improved CR10 program was NOT in effect.  DQRs have
been submitted for known instances of incorrect soil measurements which
affected the quality of the primary measurements of h and e.
   
Note: the DQR begin date is the begin date of the sgp30ebbrE26.b1 data
stream.  The earlier version of the CR10 program was also used on previous
EBBR datastream names (e.g. sgp30ebbrE26.a1).
~

• sensible_heat_flux
• surface_soil_heat_flux_avg
• latent_heat_flux

SGP/EBBR/E26 - Average Soil Heat Flux Incorrect

A typo in the version 9 EBBR program caused average soil heat flow to be zero, resulting 
in both sensible and latent heat fluxes being approximately 20 watts per meter squared too 
large during the middle of the day.

• sensible_heat_flux
• surface_soil_heat_flux_avg
• latent_heat_flux

SGP/EBBR/E26 - metadata corrections

On 20050723, a series of metadata corrections and additions were completed.  These 
metadata changes apply to all EBBR.E26 data collected by ARM back to the installation of the 
instrument in June 1992. Please see the current metadata for correct information.  These 
changes do not affect data values or quality.	

The changes are summarized below:
1) Update of "sensor location" information
2) Addition of installation dates for the systems
3) Correction of soil moisture units (from "by volume" to "gravimetric")

• base time(base_time)

• base time(base_time)

• base time(base_time)

SGP/EBBR/E26 - Data Suspect During Low Supply Voltage

Low battery supply voltage resulted in high home signals and questionable data at times.
Data for battery voltage <10.5 volts should be considered to be incorrect.

• soil_temp_2_rr
• temp_air_right
• soil_heat_flow_5_mv
• wspd_arith_mean
• base time(base_time)
• soil_temp_1_rr
• soil_temp_4_rr
• soil_moisture_4_rr
• soil_temp_3_rr
• soil_moisture_2_rr
• wdir_vec_mean_mv
• soil_moisture_1_rr
• Dummy altitude for Zeb(alt)
• lat(lat)
• soil_temp_5_rr
• temp_air_left
• Time offset of tweaks from base_time(time_offset)
• soil_moisture_3_rr
• rh_right_mv
• soil_heat_flow_3_mv
• soil_heat_flow_4_mv
• lon(lon)
• soil_moisture_5_rr
• atmos_pressure_mv
• rh_left_mv
• soil_heat_flow_1_mv
• temp_trh_left_rr
• battery_voltage
• net_radiation_mv
• temp_reference_rr
• soil_heat_flow_2_mv
• home_signal
• temp_trh_right_rr

• temp_air_bottom
• temp_trh_bottom
• Dummy altitude for Zeb(alt)
• base time(base_time)
• time(time)
• temp_trh_top
• Barometric Pressure(atmos_pressure)
• lon(lon)
• home_signal
• wdir_vec_mean
• wdir_vec_std
• wspd_arith_mean
• vapor_pressure_top
• temp_reference
• rh_top_fraction
• Time offset of tweaks from base_time(time_offset)
• net_radiation
• vapor_pressure_bottom
• lat(lat)
• rh_bottom_fraction
• temp_air_top
• wspd_vec_mean

• soil_temp_4
• latent_heat_flux
• Dummy altitude for Zeb(alt)
• corr_soil_heat_flow_3
• bowen_ratio
• wdir_vec_std
• soil_moisture_4
• soil_heat_capacity_3
• temp_air_bottom
• wdir_vec_mean
• soil_moisture_1
• sensible_heat_flux
• soil_heat_flow_1
• base time(base_time)
• surface_soil_heat_flux_5
• vapor_pressure_top
• energy_storage_change_5
• corr_soil_heat_flow_5
• soil_heat_capacity_4
• rh_bottom_fraction
• soil_heat_flow_3
• soil_heat_flow_4
• lat(lat)
• surface_soil_heat_flux_4
• rh_top_fraction
• corr_soil_heat_flow_2
• soil_heat_flow_2
• surface_soil_heat_flux_1
• surface_soil_heat_flux_3
• soil_heat_capacity_5
• soil_temp_5
• corr_soil_heat_flow_4
• lon(lon)
• surface_soil_heat_flux_avg
• soil_temp_2
• soil_moisture_2
• soil_temp_3
• soil_heat_capacity_2
• home_signal_15
• soil_heat_capacity_1
• soil_moisture_3
• vapor_pressure_bottom
• corr_soil_heat_flow_1
• net_radiation
• Time offset of tweaks from base_time(time_offset)
• surface_soil_heat_flux_2
• wspd_arith_mean
• energy_storage_change_1
• Barometric Pressure(atmos_pressure)
• temp_reference
• energy_storage_change_2
• energy_storage_change_3
• soil_heat_flow_5
• temp_trh_top
• temp_trh_bottom
• temp_air_top
• energy_storage_change_4
• wspd_vec_mean
• soil_temp_1
• soil_moisture_5
• home_signal_30

SGP/EBBR/E26 - Measurements Incorrect

Most measurements were incorrect during low battery voltage conditions.

• soil_temp_2_rr
• temp_air_right
• soil_heat_flow_5_mv
• wspd_arith_mean
• base time(base_time)
• soil_temp_1_rr
• soil_temp_4_rr
• soil_moisture_4_rr
• soil_temp_3_rr
• soil_moisture_2_rr
• wdir_vec_mean_mv
• soil_moisture_1_rr
• Dummy altitude for Zeb(alt)
• lat(lat)
• soil_temp_5_rr
• temp_air_left
• Time offset of tweaks from base_time(time_offset)
• soil_moisture_3_rr
• rh_right_mv
• soil_heat_flow_3_mv
• soil_heat_flow_4_mv
• lon(lon)
• soil_moisture_5_rr
• atmos_pressure_mv
• rh_left_mv
• soil_heat_flow_1_mv
• temp_trh_left_rr
• battery_voltage
• net_radiation_mv
• temp_reference_rr
• soil_heat_flow_2_mv
• home_signal
• temp_trh_right_rr

• temp_air_bottom
• temp_trh_bottom
• Dummy altitude for Zeb(alt)
• base time(base_time)
• time(time)
• temp_trh_top
• Barometric Pressure(atmos_pressure)
• lon(lon)
• home_signal
• wdir_vec_mean
• wdir_vec_std
• wspd_arith_mean
• vapor_pressure_top
• temp_reference
• rh_top_fraction
• Time offset of tweaks from base_time(time_offset)
• net_radiation
• vapor_pressure_bottom
• lat(lat)
• rh_bottom_fraction
• temp_air_top
• wspd_vec_mean

• soil_temp_4
• latent_heat_flux
• Dummy altitude for Zeb(alt)
• corr_soil_heat_flow_3
• bowen_ratio
• wdir_vec_std
• soil_moisture_4
• soil_heat_capacity_3
• temp_air_bottom
• wdir_vec_mean
• soil_moisture_1
• sensible_heat_flux
• soil_heat_flow_1
• base time(base_time)
• surface_soil_heat_flux_5
• vapor_pressure_top
• energy_storage_change_5
• corr_soil_heat_flow_5
• soil_heat_capacity_4
• rh_bottom_fraction
• soil_heat_flow_3
• soil_heat_flow_4
• lat(lat)
• surface_soil_heat_flux_4
• rh_top_fraction
• corr_soil_heat_flow_2
• soil_heat_flow_2
• surface_soil_heat_flux_1
• surface_soil_heat_flux_3
• soil_heat_capacity_5
• soil_temp_5
• corr_soil_heat_flow_4
• lon(lon)
• surface_soil_heat_flux_avg
• soil_temp_2
• soil_moisture_2
• soil_temp_3
• soil_heat_capacity_2
• home_signal_15
• soil_heat_capacity_1
• soil_moisture_3
• vapor_pressure_bottom
• corr_soil_heat_flow_1
• net_radiation
• Time offset of tweaks from base_time(time_offset)
• surface_soil_heat_flux_2
• wspd_arith_mean
• energy_storage_change_1
• Barometric Pressure(atmos_pressure)
• temp_reference
• energy_storage_change_2
• energy_storage_change_3
• soil_heat_flow_5
• temp_trh_top
• temp_trh_bottom
• temp_air_top
• energy_storage_change_4
• wspd_vec_mean
• soil_temp_1
• soil_moisture_5
• home_signal_30