SGP/EBBR - EBBR E19 Changeout, Data Missing/Incorrect

During changeout of the EBBR system at E19, data was missing for the
time period, except for 1815-1830 GMT, when the data was incorrect.

• soil_heat_flow_1_mv
• base_time
• temp_air_left
• atmos_pressure_mv
• rh_left_mv
• time_offset
• soil_heat_flow_3_mv
• soil_heat_flow_4_mv
• net_radiation_mv
• lat
• soil_temp_4_rr
• battery_voltage
• rh_right_mv
• soil_temp_1_rr
• temp_reference_rr
• soil_temp_2_rr
• alt
• temp_trh_right_rr
• home_signal
• soil_temp_3_rr
• soil_moisture_1_r
• Wind speed, lower, 1-min avg(wspd_arith_mean)
• wdir_vec_mean_mv
• soil_moisture_4_r
• soil_moisture_3_r
• soil_moisture_2_r
• soil_temp_5_rr
• soil_moisture_5_r
• temp_trh_left_rr
• soil_heat_flow_5_mv
• lon
• soil_heat_flow_2_mv
• temp_air_right

• temp_trh_top
• Wind speed, lower, 1-min avg(wspd_arith_mean)
• wdir_vec_std
• lon
• temp_trh_bottom
• Barometric Pressure(atmos_pressure)
• lat
• time_offset
• vapor_pressure_top
• home_signal
• vapor_pressure_bottom
• Radiation, net(net_radiation)
• alt
• base_time
• rh_top_fraction
• rh_bottom_fraction
• Wind direction, vector, lower, 1-min avg(wdir_vec_mean)
• temp_air_bottom
• temp_reference
• temp_air_top
• Wind speed vector mean(wspd_vec_mean)

• vapor_pressure_top
• Wind direction, vector, lower, 1-min avg(wdir_vec_mean)
• temp_trh_bottom
• soil_temp_5
• soil_temp_1
• soil_temp_2
• soil_temp_3
• soil_temp_4
• surface_soil_heat_flux_1
• soil_moisture_2
• surface_soil_heat_flux_2
• soil_moisture_1
• soil_moisture_4
• soil_moisture_3
• surface_soil_heat_flux_5
• surface_soil_heat_flux_3
• surface_soil_heat_flux_4
• rh_bottom_fraction
• Average soil heat flow at the surface(surface_soil_heat_flux_avg)
• Wind speed vector mean(wspd_vec_mean)
• Wind speed, lower, 1-min avg(wspd_arith_mean)
• soil_moisture_5
• Heat flux, sensible, at 1.5-m height, 30-min intervals(sensible_heat_flux)
• base_time
• Heat flux, latent, at 1.5-m height, 30-min intervals(latent_heat_flux)
• temp_trh_top
• lon
• home_signal_30
• energy_storage_change_3
• energy_storage_change_2
• energy_storage_change_5
• energy_storage_change_4
• home_signal_15
• energy_storage_change_1
• Radiation, net(net_radiation)
• lat
• soil_heat_capacity_4
• soil_heat_capacity_5
• soil_heat_capacity_2
• soil_heat_capacity_3
• wdir_vec_std
• soil_heat_capacity_1
• bowen_ratio
• Barometric Pressure(atmos_pressure)
• time_offset
• corr_soil_heat_flow_4
• corr_soil_heat_flow_3
• corr_soil_heat_flow_2
• corr_soil_heat_flow_1
• alt
• vapor_pressure_bottom
• soil_heat_flow_4
• soil_heat_flow_5
• temp_air_bottom
• temp_reference
• temp_air_top
• rh_top_fraction
• corr_soil_heat_flow_5
• soil_heat_flow_1
• soil_heat_flow_2
• soil_heat_flow_3

SGP EBBR E19 - E19 EBBR Soil Heat Flow #1 Sign Reversed

The sign was reversed (heat flow plate #1 was installed upside down), causing incorrect 
measurements, as indicated.

The average soil heat flow can be recalculated by using an average of soil sensor sets 
2-5.  The recalculated average soil heat flow can then be used to recalculate latent and 
sensible heat fluxes.

• soil_heat_flow_1_mv

• corr_soil_heat_flow_1
• Heat flux, latent, at 1.5-m height, 30-min intervals(latent_heat_flux)
• Average soil heat flow at the surface(surface_soil_heat_flux_avg)
• soil_heat_flow_1
• Heat flux, sensible, at 1.5-m height, 30-min intervals(sensible_heat_flux)

SGP/EBBR/E19 - Metadata errors

The latitude, longitude and altitude of the El Reno (E19) site were
incorrectly entered into the ARM database.  The correct location
of the EBBR.E19 instrument is:
 Lat: 35.557N
 Lon: 98.017W
 Alt:    421m

• alt
• lon
• lat

• alt
• lon
• lat

• lon
• lat
• alt

SGP/EBBR/E19 - Wind Direction Dependency of Surface Fluxes and General Data Quality 
Information

Beginning in FY2006, Data Quality Reports are not written for missing 
data or for situations when qc flags clearly show that the data is 
incorrect (this is true for most of the conditions listed below).  
DQRs are written for periods when data is incorrect, when the situation 
is not represented by qc flags in the data, and it's not obvious that 
the data should have been flagged as incorrect.

The EBBR data is only useful for particular wind directions at each 
Extended Facility.  Please use the following resources to help in 
interpreting the EBBR data.

1) qc flags in the EBBR data.

2) Instrument Mentor Monthly Summaries (IMMS) at http://www.db.arm.gov/IMMS/

3) SGP EF Surface Conditions Observations (EFSCO) at 
http://198.124.96.210:591/sfc_cond1/default.htm

4) Surface fluxes are valid only for the following wind directions
(in degrees):

0-133, 151-360

Note that there are wind directions at most sites for which the fetch
is insufficient and therefore EBBR data is invalid.  Appropriate 
fetch was determined from a 1/40 measurement height to fetch ratio, 
resulting in a required minimum fetch of 120 m.  Particular attention 
should be paid to the limited valid wind directions for the Central 
Facility EBBR.  The surface vegetation type for the EBBRs is grazed 
or ungrazed grassland (refer to the EFSCO for state).

5) Some conditions that commonly cause the EBBR primary measurements to 
be incorrect or missing follow:

a) Sensible and latent heat fluxes are not accurate during times when 
the Automatic Exchange Mechanism (AEM) is not functioning properly.  
The AEM switches the gradient measuring instrumentation between the 
top and bottom positions every 15 minutes; this reduces the effects of 
instrument offsets.  Sometimes the AEM does not reach it's full extent 
of travel, resulting in the home signal being zero.  

b) Sensible and latent heat fluxes are sometimes incorrect when surface 
soil heat flow is out of range, as seen in the average soil heat flux 
(ave_shf).

c) Very light winds may be seen at nights for brief periods. Wind 
direction flops around a lot during low wind conditions (< 1.5 m/s) 
and is often unreliable during those periods.

d) Missing data periods occur at times; this is usually a site data 
system collection/communication problem; it can also occur during 
replacement of the system with a newly calibrated unit.  Missing data 
is sometimes filled in later from manual or automatic re-collection of 
the data.

• energy_storage_change_3
• energy_storage_change_2
• energy_storage_change_5
• energy_storage_change_4
• vapor_pressure_top
• home_signal_15
• energy_storage_change_1
• Wind direction, vector, lower, 1-min avg(wdir_vec_mean)
• temp_trh_bottom
• soil_temp_5
• Radiation, net(net_radiation)
• soil_temp_1
• soil_temp_2
• soil_temp_3
• soil_temp_4
• lat
• surface_soil_heat_flux_1
• soil_moisture_2
• surface_soil_heat_flux_2
• soil_moisture_1
• soil_heat_capacity_4
• soil_moisture_4
• soil_heat_capacity_5
• soil_moisture_3
• soil_heat_capacity_2
• surface_soil_heat_flux_5
• soil_heat_capacity_3
• surface_soil_heat_flux_3
• wdir_vec_std
• soil_heat_capacity_1
• surface_soil_heat_flux_4
• rh_bottom_fraction
• Average soil heat flow at the surface(surface_soil_heat_flux_avg)
• Wind speed, lower, 1-min avg(wspd_arith_mean)
• Wind speed vector mean(wspd_vec_mean)
• bowen_ratio
• soil_moisture_5
• Heat flux, sensible, at 1.5-m height, 30-min intervals(sensible_heat_flux)
• base_time
• Barometric Pressure(atmos_pressure)
• time_offset
• corr_soil_heat_flow_4
• corr_soil_heat_flow_3
• corr_soil_heat_flow_2
• corr_soil_heat_flow_1
• alt
• vapor_pressure_bottom
• soil_heat_flow_4
• soil_heat_flow_5
• temp_air_bottom
• Heat flux, latent, at 1.5-m height, 30-min intervals(latent_heat_flux)
• temp_reference
• temp_trh_top
• temp_air_top
• rh_top_fraction
• lon
• corr_soil_heat_flow_5
• soil_heat_flow_1
• soil_heat_flow_2
• soil_heat_flow_3
• home_signal_30

SGP/EBBR/E19 - Noisy Sensible and Latent Heat Fluxes

"Noisy" sensible and latent heat fluxes often occur during daytime periods
when the net radiation is smaller (less than 150 watts/m2), but this is not
the only condition under which it occurs.  During this condition especially,
the temperature gradient, RH gradient, and thus the vapor pressure
gradient are near zero; this causes the sensible and latent heat flux gradients
to be inaccurately calculated.  Good examples of these conditions occurred
on 28 December 1997 and 6 January 1998.  However, even when there is
substantial net radiation the problem does sometimes occur; good examples of
this are found during daytime or nighttime variously on 1, 2, 3, and 4
January 1998.  The conditions occur more fequently than at other EBBR sites;
they do occur at other EBBR sites, but less frequently.

• net_radiation_mv

• Radiation, net(net_radiation)

• Heat flux, latent, at 1.5-m height, 30-min intervals(latent_heat_flux)
• Radiation, net(net_radiation)
• Heat flux, sensible, at 1.5-m height, 30-min intervals(sensible_heat_flux)