SGP/EBBR - EBBR E12 Anemometer Cups Frozen, Wind Speed Incorrect

The anemometer cups were frozen stalled during this period.

The following values were therefore incorrect:

5 minute:  wind_s, res_ws
15 minute: wind_s
30 minute: wind_s, res_ws

• Wind speed, lower, 1-min avg(wspd_arith_mean)
• Wind speed vector mean(wspd_vec_mean)

SGP/EBBR - EBBR E12 Net Radiation Incorrect

Condensation inside the domes (possibly water in the bottom dome also) 
during the period made daytime net radiation values as much as 50% too 
large and nighttime net radiations as much as 100% too small.  

The affected data are:

5 minute:  q
15 minute: mv_q
30 minute: q, h, e

• Net radiation(net_radiation)

SGP/EBBR - EBBR E12 Net Radiation Incorrect

The net radiometer top dome was broken and water had entered.  Net 
radiation values are therefore incorrect during the period.

The affected data are:

5 minute:  q
15 minute: mv_q
30 minute: q, h, e

• Net radiation(net_radiation)

SGP/EBBR/E12 - EBBR E12 Wind Speed Iced

The anemometer was frozen stopped by freezing rain; the indicated data is incorrect.

• Wind speed, lower, 1-min avg(wspd_arith_mean)
• Wind speed vector mean(wspd_vec_mean)

SGP/EBBR/E12 - EBBR E12 Wind Speed Iced

The anemometer was frozen stopped by freezing rain; the indicated data is incorrect.

• Wind speed, lower, 1-min avg(wspd_arith_mean)
• Wind speed vector mean(wspd_vec_mean)

SGP/EBBR/E12 - E12 EBBR Wind Direction Incorrect

The wind direction vane was frozen stopped in one direction by icing.

• wdir_vec_std
• Wind speed vector mean(wspd_vec_mean)
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - E12 EBBR Wind Speed Incorrect

The wind speed sensor cups were frozen stopped by icing.

• Wind speed, lower, 1-min avg(wspd_arith_mean)
• Wind speed vector mean(wspd_vec_mean)

SGP/EBBR/E12 - E12 EBBR AEM Stuck - Data Incorrect

The AEM became stuck between levels, causing all gradient measurements to be incorrect, 
and thus the latent and sensible heat fluxes and Bowen ratio.

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

SGP EBBR E12 - E12 EBBR Data Incorrect During 6 Month Checks

The data was incorrect during the 6 month checks.

• Wind speed, lower, 1-min avg(wspd_arith_mean)
• rh_top_fraction
• wdir_vec_std
• temp_air_top
• Atmospheric pressure(atmos_pressure)
• temp_trh_top
• rh_bottom_fraction
• Net radiation(net_radiation)
• temp_trh_bottom
• vapor_pressure_bottom
• Wind speed vector mean(wspd_vec_mean)
• temp_reference
• vapor_pressure_top
• temp_air_bottom
• Wind direction vector mean(wdir_vec_mean)

SGP EBBR E12 - E12 EBBR Data Incorrect From AEM In One Position

The AEM kept stopping in one position. Offset biases are not removed from the 
gradient data in this situation and the data indicated is therefore incorrect.

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

SGP/EBBR/E12 - 3-month Check

During EBBR 3 month checks the Automatic Exchange Mechanism is disabled
(reflected by home signals near zero) so that the two aspirator units can be
placed at the same height.  The measurements during this period, at least,
do not produce correct outputs of bowen ratio (bowen), sensible heat flux (h),
or latent heat flux (e), nor do the air temperature and relative humidity
measurements indicate gradients.  Checks performed before or after the AEM
is disabled also lead to some incorrect data.

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

SGP/EBBR/E12 - T/RH Check

During the month of November 1994, site operations personnel conducted
field comparisons of the temperature and relative humidity sensors in the
EBBRs and the HMI31 portable T/RH meter (with the removable probe).  As is
reflected in the home signal output, the automatic exchange mechanism was
disabled in order to conduct the checks.

Measurements were taken every 5 minutes, for a half hour each in the
aspirated radiation shields (the HMI31 was inserted into the EBBR aspirated
radiation shield to provide the same aspiration as the EBBR sensors
received).  Measurements of aspirator flow were also recorded.  This
information was provided to the mentor.  The mentor then compared the field
checks with the data recorded by the EBBRs.

The periods of data and data fields that are incorrect because of the checks
are listed below.  Times are those at which the data are reported.


Data Fields
5 minute:  tair_top, tair_bot, thum_top, thum_bot, hum_top, hum_bot,
           vp_top, vp_bot
15 minute: rr_thum_r, rr_thum_l, mv_hum_r, mv_hum_l, tair_r, tair_l
30 minute: tair_top, tair_bot, thum_top, thum_bot, hum_top, hum_bot,
           vp_top, vp_bot, bowen, e, h

5 minute:  1515, 1520, 1525, 1530, 1535, 1540, 1545, 1550, 1555,
           1600, 1605, 1610
15 minute: 1515, 1530, 1545, 1600, 1615
30 minute: 1530, 1600, 1630

(EDITOR'S NOTE:  The following analysis refers to all EBBRs installed in Nov 1994)

Results of the T/RH comparisons:
The combined accuracy of the HMI31 and EBBR temperature sensors
(thermocouples or PRTDs) is +/- 0.4 degrees C.  The combined accuracy of the
HMI31 and EBBR RH sensors is +/- 4% for RH less than 80%, and +/- 6% for RH
greater than 80%.  The combined accuracy for each pair of EBBR sensors of
the same type is essentially the same as the quantities stated above.

All of the pairs of EBBR sensors show differences that fall within the
stated combined accuracies.  Although this sounds wonderful, a few of the
differences are close to the combined accuracy, which, because of the small
differences in temperature being measured (normally smaller than the
magnitude of the combined accuracy) could lead to some incorrect estimation
of sensible and latent heat flux.  However, unless there would be substantial
differences of calibration slope of two sensors in a pair, the switching of
height of the sensors every 15 minutes by the automatic exchange mechanism
will remove the offset between the sensors.

The comparisons between the EBBR sensors and the HMI31 T/RH meter showed
much larger differences.  The range of differences were: -2.4 to 0.0 degrees
for the thermocouples, -2.1 to 0.1 degrees for the RH probe PRTDs, and -6.6 to
6.7 percent for the RH sensors.  Six Thermocouples indicated differences from
the HMI31 greater than the combined accuracy.  Seven PRTDs indicated
differences from the HMI31 greater than the combined accuracy.  Four RH
sensors indicated differences from the HMI31 greater than the combined
accuracy.  The temperature differences (for both thermocouples and PRTDs)
were nearly all of one sign; the HMI31 indicated the greater temperature,
which may suggest a bias in the HMI31 temperature measurement, even though
a dozen differences of +/- 0.2 degrees were measured.  Four differences of
zero and only one positive difference (out of 40) were measured.  Thirteen of
the 20 RH differences were positive (HMI31 indicating the lower
RH), with the differences near the level of the combined accuracies being
approximately 50% positive and 50% negative.  It does not appear that the
HMI31 has a RH bias.

Plots of EBBR sensor/HMI31 differences as a function of time from the
installation of the individual sensors (a range of 10 to 30 months in the
field) shows no obvious pattern of sensor drift with time.  This is encouraging.

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

SGP/EBBR/E12 - 6 Month Checks

The indicated measurements were incorrect during the 6 month checks.

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

SGP/EBBR/E12 - AEM Hung

The automatic exchange mechanism did not exchange properly, causing other measurements to 
be incorrect.

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

SGP/EBBR/E12 - Measurements Incorrect

All measurements were incorrect or offscale for an unknown reason.

• home_signal
• Wind speed, lower, 1-min avg(wspd_arith_mean)
• rh_top_fraction
• wdir_vec_std
• temp_air_top
• Atmospheric pressure(atmos_pressure)
• temp_trh_top
• rh_bottom_fraction
• Net radiation(net_radiation)
• temp_trh_bottom
• vapor_pressure_bottom
• Wind speed vector mean(wspd_vec_mean)
• temp_reference
• vapor_pressure_top
• temp_air_bottom
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Resistance Measurements Incorrect

All sensors that depend on resistance measurements are incorrect.
Average soil heat flow, sensible heat flux, and latent heat flux are incorrect as a 
result.

This condition normally occurs when the reference temperature sensor is disconnected or 
bad.

• temp_air_top
• temp_trh_bottom
• vapor_pressure_bottom
• temp_trh_top
• temp_air_bottom
• vapor_pressure_top

SGP/EBBR/E12 - Wind Direction Incorrect

The wind direction measurement was zero, in the 50s, or always less than 180 degrees.

A DQPR has been issued to resolve the problem.

• Wind speed, lower, 1-min avg(wspd_arith_mean)
• wdir_vec_std
• Wind speed vector mean(wspd_vec_mean)

SGP/EBBR/E12 - Data Incorrect during 6 month checks

Some of the measurements are incorrect during the 6 month checks.

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

SGP/EBBR/E12 - Resistance-based Measurements Incorrect

When the Reference Temperature in the EBBR 
enclosure is not reported correctly, it
affects all resistance-based measurements
that are adjusted with the temperature of 
the reference junction.

• temp_air_top
• vapor_pressure_bottom
• temp_reference
• temp_air_bottom
• vapor_pressure_top

SGP/EBBR/E12 - Wind Direction Incorrect

The wind direction and residual wind speed measurements are incorrect.

• wdir_vec_std
• Wind speed vector mean(wspd_vec_mean)
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Data zero following Logger Restart

Most of the measurements were zero, which normally happens after a 
datalogger restart.  The restart on 08/16/02 occurred after an EBBR
unit changeout.

• home_signal
• Wind speed, lower, 1-min avg(wspd_arith_mean)
• rh_top_fraction
• wdir_vec_std
• temp_air_top
• Atmospheric pressure(atmos_pressure)
• temp_trh_top
• rh_bottom_fraction
• Net radiation(net_radiation)
• temp_trh_bottom
• vapor_pressure_bottom
• Wind speed vector mean(wspd_vec_mean)
• temp_reference
• vapor_pressure_top
• temp_air_bottom
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Battery Voltage Low

Normally, when Battery Voltage drops below 10.5 volts, most 
measurements are suspect and some are often incorrect.
In this particular case, some of the data is suspect when
the battery voltage is below 11.0 volts.

Soil Heat Flow #3 is normally affected first, with other 
measurements following at lower voltages.

• home_signal
• rh_top_fraction
• wdir_vec_std
• temp_air_top
• Atmospheric pressure(atmos_pressure)
• temp_trh_top
• rh_bottom_fraction
• Net radiation(net_radiation)
• temp_trh_bottom
• vapor_pressure_bottom
• Wind speed vector mean(wspd_vec_mean)
• temp_reference
• vapor_pressure_top
• temp_air_bottom
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Reprocess: Net Rad Calibration Coefficients

The Net Radiometer coefficients were incorrect in the CR10
program when the replacement EBBR unit was installed on
08/16/02.

The data can be easily corrected; see the Suggestion area below.

• Net radiation(net_radiation)

SGP/EBBR/E12 - Data Mostly Zero Following Logger Restart

Most of the measurements were zero, which normally happens after a 
datalogger restart.

The restart on 12/10/02 occurred after a CR10
program change of net radiometer coefficients 
and subsequent restart of the CR10.

• home_signal
• Wind speed, lower, 1-min avg(wspd_arith_mean)
• rh_top_fraction
• wdir_vec_std
• temp_air_top
• Atmospheric pressure(atmos_pressure)
• temp_trh_top
• rh_bottom_fraction
• Net radiation(net_radiation)
• temp_trh_bottom
• vapor_pressure_bottom
• Wind speed vector mean(wspd_vec_mean)
• temp_reference
• vapor_pressure_top
• temp_air_bottom
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - AEM Hung Inbetween Home Positions

The AEM was hung inbetween home positions, causing many measurements to be incorrect.

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

SGP/EBBR/E12 -  6 Month Checks

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

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

SGP/EBBR/E12  - Water in Net Radiometer, Surface Fluxes Incorrect

The net radiometer top dome was punctured by migrating birds.  This alone does not cause 
incorrect net radiation measurements.  However, when it subsequently rains, water collects 
in the bottom dome, causing the net radiation measurements to be too large during the 
day and too small at night.

• Net radiation(net_radiation)

SGP/EBBR/E12 - Pressure Sensor Measurement Scales With Battery Voltage

The barometer output was scaling with supply voltage (i.e. it 
               followed the charging of the battery by the solar panel).

               NOTE: The barometer was replaced later than the end date of 
               this DQR.  Why the problem ended on 26 Nov 2003 is unclear; 
               there was no site ops intervention on that date.

               The problem did not affect the sensible and latent heat flux 
               calculations beyond the expected system error.

• Atmospheric pressure(atmos_pressure)

SGP/EBBR/E12 - 6 Month Checks

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

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

SGP/EBBR/E12 - Pressure Sensor Measurement Scales With Battery Voltage

The barometer output scaled with supply voltage (it followed the charging of the battery 
by the solar panel).

The problem did not affect the sensible and latent heat flux calculations
beyond the expected system error.

• Atmospheric pressure(atmos_pressure)

SGP/EBBR/E12  - 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.

• Wind speed, lower, 1-min avg(wspd_arith_mean)
• Wind speed vector mean(wspd_vec_mean)

SGP/EBBR/E12  - 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.

• Wind speed, lower, 1-min avg(wspd_arith_mean)
• Wind speed vector mean(wspd_vec_mean)

SGP/EBBR/E12  - 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
• Wind speed vector mean(wspd_vec_mean)
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Incorrect Times

The ntpd server (time adjustment) stopped working on Feb. 19th at 22:12:16 GMT, and the 
clock was corrected by -5600.177269 seconds on March 10th at 22:47 GMT. The recorded times 
for observations are off by amounts ranging from 0 seconds on Feb. 19th to 5600 seconds 
on March 10th.

• home_signal
• rh_top_fraction
• Wind speed, lower, 1-min avg(wspd_arith_mean)
• wdir_vec_std
• temp_air_top
• Atmospheric pressure(atmos_pressure)
• temp_trh_top
• time_offset
• rh_bottom_fraction
• Net radiation(net_radiation)
• temp_trh_bottom
• vapor_pressure_bottom
• base_time
• Wind speed vector mean(wspd_vec_mean)
• time
• temp_reference
• vapor_pressure_top
• temp_air_bottom
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - 6 Month Checks

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

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

SGP/EBBR/E12 - AEM home_15 Incorrect, Flux Measurements not affected

The home_15 measurement was incorrect during much of the stated period.
The AEM was exchanging however, and thus the flux measurements were not affected.

• home_signal

SGP/EBBR/E12  - 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.

• Wind speed, lower, 1-min avg(wspd_arith_mean)
• Wind speed vector mean(wspd_vec_mean)

SGP/EBBR/E12  - 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_std
• Wind speed vector mean(wspd_vec_mean)
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12  - 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.

• Wind speed, lower, 1-min avg(wspd_arith_mean)
• Wind speed vector mean(wspd_vec_mean)

SGP/EBBR/E12  - 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
• Wind speed vector mean(wspd_vec_mean)
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Wind Speed and Direction Frozen by Ice Storm

The wind speed and direction sensors were frozen by ice from and ice storm.

• Wind speed, lower, 1-min avg(wspd_arith_mean)
• wdir_vec_std
• Wind speed vector mean(wspd_vec_mean)
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - metadata corrections

On 20050723, a series of metadata corrections and additions were completed.  These 
metadata changes apply to all EBBR.E12 data collected by ARM back to the installation of the 
instrument in August 1993. 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 type
4) Correction of soil moisture units (from "by volume" to "gravimetric")

• base_time

SGP/EBBR/E12 - Multiplexer failure

Sensible and latent heat fluxes are incorrect during a period when multiplexer #2 
experienced a failure.

• rh_top_fraction
• temp_air_top
• vapor_pressure_bottom
• Atmospheric pressure(atmos_pressure)
• rh_bottom_fraction
• Net radiation(net_radiation)
• temp_air_bottom
• vapor_pressure_top

SGP/EBBR/E12 - Fluxes and Gradient Measurements Incorrect

The AEM hung in one position; therefore the fluxes and gradient measurements were 
incorrect.

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

SGP/EBBR/E12 - Net Radiation, and Sensible and Latent Heat Fluxes Incorrect

Rain entered into the net radiometer through a broken top dome.  Most of the net radiation 
values during the period are much too large, thus sensible and latent fluxes are also 
too large.

• Net radiation(net_radiation)

SGP/EBBR/E12 - Wind Speed Incorrect

The wind speed sensor was stopped by freezing rain.

• Wind speed, lower, 1-min avg(wspd_arith_mean)
• Wind speed vector mean(wspd_vec_mean)

SGP/EBBR/E12 - Wind Speed Sensor Frozen Stopped by Icing

Icing stopped the wind speed sensor cups and resulted in the measurement of wind speed 
being equivalent to the sensor offset.

• Wind speed, lower, 1-min avg(wspd_arith_mean)
• wdir_vec_std
• Wind speed vector mean(wspd_vec_mean)
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Intermittent data loss

The datalogger at E12 EBBR reset it's time to Dec 3, 1999 on a periodic basis.  This 
occurred on 5/3, 5/15, 5/17, 5/18, 5/27, 6/5 and 6/6 of 2010. Each time this occurred we lost 
1-2 hours of data.

The datalogger was apparently at fault.  The problem has not re-occurred since the 
datalogger was replaced on 6/8/2010.

• home_signal
• rh_top_fraction
• North latitude(lat)
• Wind speed, lower, 1-min avg(wspd_arith_mean)
• wdir_vec_std
• temp_air_top
• Atmospheric pressure(atmos_pressure)
• temp_trh_top
• time_offset
• rh_bottom_fraction
• Net radiation(net_radiation)
• East longitude(lon)
• temp_trh_bottom
• vapor_pressure_bottom
• base_time
• Wind speed vector mean(wspd_vec_mean)
• time
• Altitude above mean sea level(alt)
• temp_reference
• vapor_pressure_top
• temp_air_bottom
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Sensible and Latent Heat Fluxes and Other Measurements Incorrect

The power supply leads for the combined temperature probe shorted somehow, resulting in 
several measurements from the probe and for the multiplexer that it was connected to, to be 
incorrect.

• temp_air_top
• temp_trh_bottom
• temp_trh_top
• temp_reference
• temp_air_bottom

SGP/EBBR/E12 - Net radiation too high

Net radiation was too high, resulting in overestimated sensible and latent heat fluxes. 

Net rad domes replaced.

• Net radiation(net_radiation)

SGP/EBBR/E12 - Net rad too high

The net radiometer measurements were too large and therefore resulted in incorrect 
sensible and latent heat flux measurements.

• Net radiation(net_radiation)

SGP/EBBR/E12 - Missing Data

All data missing for these periods.

• home_signal
• rh_top_fraction
• North latitude(lat)
• Wind speed, lower, 1-min avg(wspd_arith_mean)
• wdir_vec_std
• temp_air_top
• Atmospheric pressure(atmos_pressure)
• temp_trh_top
• time_offset
• rh_bottom_fraction
• Net radiation(net_radiation)
• East longitude(lon)
• temp_trh_bottom
• vapor_pressure_bottom
• base_time
• Wind speed vector mean(wspd_vec_mean)
• time
• Altitude above mean sea level(alt)
• temp_reference
• vapor_pressure_top
• temp_air_bottom
• Wind direction vector mean(wdir_vec_mean)

SGP ALL INSTRUMENTS - Icing Event

An icing event (winter storm Cara) passed slowly through the area during this time frame.  
Instruments at the SGP may have been affected by ice accumulation.

• home_signal
• Wind speed, lower, 1-min avg(wspd_arith_mean)
• rh_top_fraction
• temp_air_top
• wdir_vec_std
• Atmospheric pressure(atmos_pressure)
• temp_trh_top
• rh_bottom_fraction
• Net radiation(net_radiation)
• temp_trh_bottom
• vapor_pressure_bottom
• Wind speed vector mean(wspd_vec_mean)
• temp_reference
• vapor_pressure_top
• temp_air_bottom
• Wind direction vector mean(wdir_vec_mean)

SGP Site Power Outage Due to Winter Storm

On Saturday and Sunday, December 26 and 27th a powerful winter storm (Goliath) brought 
sleet and freezing rain to much of Oklahoma with wind gusts of 45 MPH at times. The result 
was very very slick roads and mass power outages.
 
The SGP central facility lost power at 8:55 PM CDT on Sunday, December 27th.  
The power was restored on 7:56 PM CDT on Wednesday, December 30th
 
Site Emergency procedures were activated and Technicians drained water out of instrument 
reservoirs and other measures as needed, early Monday morning.
 
On Wednesdays as roads and power started was restored to much of the areas east of I-35 , 
Site Technicians performed maintenance on several Extended Facilities.

During this period, data are potentially missing, incorrect, or suspect.  Carefully 
inspect the data before use.

• home_signal
• North latitude(lat)
• rh_top_fraction
• Wind speed, lower, 1-min avg(wspd_arith_mean)
• temp_air_top
• wdir_vec_std
• Atmospheric pressure(atmos_pressure)
• time_offset
• temp_trh_top
• rh_bottom_fraction
• Net radiation(net_radiation)
• East longitude(lon)
• temp_trh_bottom
• vapor_pressure_bottom
• base_time
• Wind speed vector mean(wspd_vec_mean)
• time
• Altitude above mean sea level(alt)
• temp_reference
• vapor_pressure_top
• temp_air_bottom
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Invalid data due to blown AEM fuse at E12

On December 20, 1993, before 0730 GMT, the fuse in the AEM (Automatic
Exchange Mechanism) of Pawhuska, OK (E12) EBBR blew out.  The AEM remained
nonfunctional until the fuse was replaced just before 1500 GMT on
December 22, 1993.  This situation resulted in the following invalid data:

5 minute: tair_top, tair_bot, thum_top, thum_bot, hum_top, hum_bot,
          vp_top, vp_bot, home

15 minute: rr_thum_r, rr_thum_l, mv_hum_r, mv_hum_l, mv_home, tair_r,
           tair_l

30 minute: tair_top, tair_bot, thum_top, thum_bot, hum_top, hum_bot,
           vp_top, vp_bot, bowen, e, h, home_15, home_30

Bowen, h, and e can not be recalculated from the 15 minute and/or 5 minute data
since we cannot determine the position of the sensors on the AEM from the home
signal; home signal is near zero when there is no power to the AEM.

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

SGP/EBBR/E12 - Wind Direction

For much of the period above, a malfunction in the E12 EBBR wind direction
sensor (insect larvae shorting out the circuit board) caused incorrect
values for 5 minute res_ws, wind_d, and sigma_wd, 15 minute mv_wind_d, and
30 minute res_ws, wind_d, and sigma_wd.  Wind direction normally indicated
north (near 0 or 360 degrees); there were some times during the period when
wind directions looked good, but the lack of variation in direction and sigma
implies that the data is suspect.  Therefore, it would be wise to flag all
of the values listed above during the entire time period as incorrect.
The wind direction sensor (S/N 3081) was replaced with S/N 3042 at 1515 GMT
on June 8, 1994.

• wdir_vec_std
• Wind speed vector mean(wspd_vec_mean)
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Aspirator Failure

On June 18, 1994 the aspirator fan in the EBBR at E12, Pawhuska stopped
working.  This situation was not discovered until a Preventative
Maintenance visit by site operations personnel on June 22, 1994.  I
determined the time of the beginning of the malfunction from close
inspection of the sensible and latent heat flux data.  There is no aspiration
status output for the EBBRs, nor is one presently possible.  Wind speeds during
most of the period listed were sufficient to provide some (although
inadequate) aspiration to the temperature and relative humidity probes, making
it difficult for most users of the data to be able to tell (except in a few
circumstances) that the sensible and latent heat flux values produced were
incorrect.  All of the data fields listed below are incorrect for the period
listed above.  Latent and Sensible heat fluxes cannot be recomputed, as the
measurements that they are based on are what was corrupted.

30 minute: tair_top, tair_bot, thum_top, thum_bot, hum_top, hum_bot,
           vp_top, vp_bot, bowen, e, h

15 minute: rr_thum_r, rr_thum_l, mv_hum_r, mv_hum_l, tair_r, tair_l

5 minute:  tair_top, tair_bot, thum_top, thum_bot, hum_top, hum_bot,
           vp_top, vp_bot

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

SGP/EBBR/E12 - Stopped Ventilation Fan

On August 4, 1994, a site operator discovered the ventilation fan of the
EBBR to be stopped; the fan guard was clogged with animal remains.
Inspection of the EBBR data from Pawhuska, OK, E12 indicates that this
condition occurred from July 22 through August 4.  Lack of ventilation of
the temperature and relative humidity sensors attached to the AEM results
in questionable measurements of air temperature, relative humidity, and all
quantities calculated from them, including sensible and latent heat fluxes.
The quantities that are questionable for the period indicated are:

5 minute:  tair_top, tair_bot, thum_top, thum_bot, hum_top, hum_bot,
           vp_top, and vp_bot

15 minute: rr_thum_r, rr_thum_l, mv_hum_r, mv_hum_l, tair_r, tair_l

30 minute: tair_top, tair_bot, thum_top, thum_bot, hum_top, hum_bot,
           vp_top, vp_bot, bowen, e, h

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

SGP/EBBR/E12 - Miscellaneous Problems Affecting Data

Three hardware problems occurred at E12, Pawhuska, OK in late August 1994.

On August 12 the wind direction sensor malfunctioned.  Therefore, all wind
direction, sigma, and resultant wind speed values for the period above are
incorrect.  The wind direction sensor was replaced on August 31.  Affected
data are:

        5 minute:  wind_d, sigma_wd, res_ws
        15 minute: mv_wind_d
        30 minute: wind_d, sigma_wd, res_ws.

Water accumulated in the AEM motor box and apparently caused a reduction in
the voltage level of the home signal (battery condition was very good and so
was not the cause); by late August 27 the hom30 level had fallen below the
minimum qc check level.  The AEM continued to exchange properly.  The minimum
qc level check is intended to help detect either a non-operating AEM or low
battery condition.  The Campbell CR10 software operates properly unless the
hom30 signal is thirty-five or greater.  So the low hom30 values do not
result in any incorrect data!!!.  I point this out because this situation
demonstrates a condition flagged by the qc checks, even though no effect on
the data has occurred.  The AEM box was dried out and new dessicant placed
in it on August 31.

On August 28, 1994 the left AEM housing ventilation fan ceased to operate
because of clogging of the ventilation system with debris.  Fifteen minute
data seems to indicate that the fan stopped operating just before 1245 GMT.
This is at least the third such incidence of clogging this summer at different
EBBRs.  The clog was removed and ventilation restored on August 31.  The lack
of ventilation caused improper measurements of temperature and
relative humidity in the left housing (these are quite obvious in the 15
minute data but difficult to detect in the 30 minute data) and therefore
incorrect values of sensible and latent heat.  Affected data are:

        5 minute:  tair_top, tair_bot, thum_top, thum_bot, hum_top,
                   hum_bot, vp_top, vp_bot
        15 minute: rr_thum_l, mv_hum_l, tair_l
        30 minute: tair_top, tair_bot, thum_top, thum_bot, hum_top,
                   hum_bot, vp_top, vp_bot, bowen, e, h.

• rh_top_fraction
• wdir_vec_std
• temp_air_top
• temp_trh_bottom
• vapor_pressure_bottom
• temp_trh_top
• Wind speed vector mean(wspd_vec_mean)
• rh_bottom_fraction
• temp_air_bottom
• vapor_pressure_top
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Net Radiometer Hemisphere Changes

The upper hemisphere of the net radiometer at the site was punctured
allowing water to collect in the lower (and sometimes upper) section of the sensor. The 
punctures are most likely the result of migratory birds (a problem that we have experienced 
almost every year here at ANL also). The punctures (and water in some net radiometers) 
did not result in obvious invalidation of the data.

Whether there is water in the lower hemisphere or not, a small puncture of the upper 
hemisphere would not have a major effect on the net radiation measurement.  Significant 
amounts of water in the lower
hemisphere should have a major effect on nighttime measurements particularly, although 
that effect is hard to detect in the data. 
The date when the puncture occurred is approximate - but is certainly 
no more than two weeks before the hemisphere was replaced.

• Net radiation(net_radiation)

SGP/EBBR/E12 - Low home_15 Values

The home signal values for the EBBR system installed at E12, Pawhuska, OK have
generally been lower than for the other EBBR systems.  However, during the
period above the home_15 value was often lower than 35, which is then
improperly interpreted by the CR10 software.  A home_15 value less than 35 is
interpreted as meaning that the AEM aspirated housings (which hold the
temperature and relative humidity sensors) are in the opposite orientation to
what they actually are.  The AEM continues to exchange properly, but the
resulting calculations of Bowen ratio, latent heat flux, and sensible heat
flux are incorrect.  On September 15, 1994 Site Operations personnel
refurbished the wiring for the left housing and the home_15 signal returned
to proper levels.

When 30 minute home_15 values are below 35, the data fields listed below are
incorrect.

5 minute:  home, tair_top, tair_bot, thum_top, thum_bot, hum_top, hum_bot,
           vp_top, vp_bot

15 minute: mv_home

30 minute: home_15, tair_top, tair_bot, thum_top, thum_bot, hum_top,
           hum_bot, vp_top, vp_bot, Bowen, e, h

It is possible to recalculate the Bowen ratio, e, and h by using the 15
minute data to compute the correct gradients of temperature and relative
humidity (two 15 minute periods are averaged to give a half hour value); the
orientation of the AEM is obvious in the 15 minute data, based on the home
signal (which is largest for the first 15 minutes of the half hour).  More
information on performing this recalculation can be obtained from the
mentor.

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

SGP/EBBR/E12 - Wind Direction Malfunction

For most of the period above, a malfunction in the E12 EBBR wind direction
sensor caused the following data values to be incorrect:

5 minute: res_ws, wind_d, and sigma_wd
15 minute: mv_wind_d
30 minute: res_ws, wind_d, and sigma_wd.

Wind direction normally indicated near north or 135 degrees (the latter
indicates a malfunction).

The wind direction sensor (S/N 3036) was replaced with S/N 3034 at 1620 GMT
on April 26, 1995.

• wdir_vec_std
• Wind speed vector mean(wspd_vec_mean)
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Wind Direction Malfunction

For the period indicated, a malfunction in the E12 EBBR wind direction
sensor caused the following data values to be incorrect:

5 minute: res_ws, wind_d, and sigma_wd
15 minute: mv_wind_d
30 minute: res_ws, wind_d, and sigma_wd.

Wind direction normally indicated smaller or larger than it should have.
The affected time period was determined from comparison with data from E7,
Elk Falls EBBR, which is located north of E12.

The wind direction sensor (S/N 3034) was replaced with S/N 3039 at 1822 GMT
on June 7, 1995.

• wdir_vec_std
• Wind speed vector mean(wspd_vec_mean)
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Wind Direction Malfunction

For the period indicated, a malfunction in the E12 EBBR wind direction
sensor caused the following data values to be incorrect:

5 minute: res_ws, wind_d, and sigma_wd
15 minute: mv_wind_d
30 minute: res_ws, wind_d, and sigma_wd.

Wind direction normally indicated small values (15 to 25 degrees) from 3 July
1995 at 0600 GMT through 6 July 1995 at 1500 GMT (at which time the sensor
was removed).  No sensor was in place between 6 July 1995 at 1500 GMT and 7
July 1995 at 1605 GMT (at which time a new sensor was installed).
 Old sensor S/N K3039, new S/N K3033.

• wdir_vec_std
• Wind speed vector mean(wspd_vec_mean)
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - AEM Failure

As noted in a previous DQR, the home signal values at E12, Pawhuska, OK
began decreasing in July.  At the beginning of the period listed, the home
30 value dropped below 15; this causes a data quality message to be output in
the site operations log as the stated acceptable range for home 30 is 15 to
34.999999.  No data is incorrect as a result of this condition.

The home 15 value dropped below 35 beginning July 21, 1995, sometime after
2000 GMT; this causes a data quality message to be output in the site
operations log as the stated acceptable range for home 15 is 35 to
70.  Data is incorrect as a result of this condition, that being 30 minute e,
h, and bowen.

The home values frequently dropped below their proper levels until 10 August,
1995, at some time after 1100 GMT, when the set screws in the AEM would no
longer hold and the aspirator units were stranded inbetween the home
positions.  Thereafter, the reported home signals were negative.  All 30
minute e, h, and bowen data are incorrect for this condition.

On August 16, 1995, at about 1600 GMT, site operators determined that they
could not repair the AEM on-site and they determined that the replacement AEM
that they took with them has an electronic short.  Therefore, the AEM was
left in manual mode (no exchange).  Replacement of the AEM will not take
place until a working spare is available and all 30 minute e, h, and bowen
data will be incorrect until then.

I will submit another DQR or addendum when successful replacement of the
AEM is accomplished.

• home_signal

SGP/EBBR/E12 - Wind Direction Malfunction

For the period above, a malfunction in the E12 EBBR wind direction
sensor caused the wind direction to output a constant 212 degrees.  Site
operations replaced the sensor (S/N K3033) with K3042.  The following data
values are incorrect for the period listed:

5 minute: res_ws, wind_d, and sigma_wd
15 minute: mv_wind_d
30 minute: res_ws, wind_d, and sigma_wd.

• wdir_vec_std
• Wind speed vector mean(wspd_vec_mean)
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - AEM replacement

Please see DQR P950816.2, where this problem was first documented.

As noted in a previous DQR, the home signal values at E12, Pawhuska, OK
began decreasing in July.  At the beginning of the period listed, the home
30 value dropped below 15; this causes a data quality message to be output in
the site operations log as the stated acceptable range for home 30 is 15 to
34.999999.  No data is incorrect as a result of this condition.

The home 15 value dropped below 35 beginning July 21, 1995, sometime after
2000 GMT; this causes a data quality message to be output in the site
operations log as the stated acceptable range for home 15 is 35 to
70.  Data is incorrect as a result of this condition, that being 30 minute e,
h, and bowen.

The home values frequently dropped below their proper levels until 10 August,
1995, at some time after 1100 GMT, when the set screws in the AEM would no
longer hold and the aspirator units were stranded inbetween the home
positions.  Thereafter, the reported home signals were negative.  All 30
minute e, h, and bowen data are incorrect for this condition.

On August 16, 1995, at about 1600 GMT, site operators determined that they
could not repair the AEM on-site and they determined that the replacement AEM
that they took with them has an electronic short.  Therefore, the AEM was
left in manual mode (no exchange).  All 30 minute e, h, and bowen data are
incorrect until the end of the period listed above.

On 13 September 1995 site operations personnel replaced the AEM
(old S/N 92005, new S/N 94008).  The new AEM would not exchange when the
right sensor was in the home position: this was confirmed on 14 September
when site operations personnel again visited the site.  However, soon after
the site operations personnel left Pawhuska on 14 September (at 1810 GMT),
the AEM started to exchange properly (data correct for 1900 GMT and after).
The AEM continues to operate properly.

• home_signal

SGP/EBBR/E12 - Wind Speed Cups Frozen

Freezing rain, snow, and below freezing conditions during 18 and 23 January 
1996 caused the wind speed sensor cups to freeze in a stopped state at E12, 
Pawhuska, OK.  The cups were freed up later on 18 January when the wind speed 
rose to above 10 meters per second.  When temperatures rose to above freezing 
on 24 January 1996, the ice thawed and the cups turned freely again. 

Measurements affected by the stalled wind speed sensor include:

5 minute:  wind_s, res_ws

15 minute: wind_s

30 minute: wind_s, res_ws

• Wind speed, lower, 1-min avg(wspd_arith_mean)
• Wind speed vector mean(wspd_vec_mean)

SGP/EBBR/E12 - 3-month check

During EBBR 3 month checks the Automatic Exchange Mechanism is disabled
(reflected by home signals near zero) so that the two aspirator units can be
placed at the same height.  The measurements during this period, at least,
do not produce correct outputs of bowen ratio (bowen), sensible heat flux (h),
or latent heat flux (e), nor do the air temperature and relative humidity
measurements indicate gradients.  Checks performed before or after the AEM
is disabled also lead to some incorrect data.  The period of incorrect
data for the EBBR is listed above; data times affected do not include the
beginning time and do include the ending time (data files are denoted by
the end time).

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

SGP/EBBR/E12 - EBBR 3 Month Checks - 10 EFs

During EBBR 3 month checks the Automatic Exchange Mechanism is disabled 
(reflected by home signals near zero) so that the two aspirator units
can be placed at the same height.  The measurements during these periods 
do not produce correct outputs of bowen ratio (bowen), sensible heat flux (h), 
or latent heat flux (e), nor do the air temperature and relative humidity 
measurements indicate correct gradients.  Checks performed before or after the 
AEM is disabled also lead to some incorrect data.  Incorrect 5, 15 minute and 
half hour data occurs for periods indicated.

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

SGP/EBBR/E12 - Annual Calibration Changeout

On 9 October 1996 the EBBR changeout for annual calibration occurred at 
E12, Pawhuska, OK.  SEBS unit 10 was removed and unit 1 was installed.  Between 
1000 and 1500 GMT no data was collected.  Data for half hours 1530-2000 GMT is 
incorrect; 3 month calibration checks were being performed.

• home_signal
• rh_top_fraction
• Wind speed, lower, 1-min avg(wspd_arith_mean)
• North latitude(lat)
• wdir_vec_std
• temp_air_top
• Atmospheric pressure(atmos_pressure)
• temp_trh_top
• time_offset
• rh_bottom_fraction
• Net radiation(net_radiation)
• East longitude(lon)
• temp_trh_bottom
• vapor_pressure_bottom
• base_time
• Wind speed vector mean(wspd_vec_mean)
• Altitude above mean sea level(alt)
• temp_reference
• vapor_pressure_top
• temp_air_bottom
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Left Air Temperature Thermocouple Incorrect

The left air temperature thermocouple was offscale, for unknown reasons, for 
1715 GMT for 15 minute, and 1730 GMT for 30 minute air temperature values.

The malfunction of the air temperature thermocouple results in incorrect Bowen 
ratio, sensible heat flux, and latent heat flux during the period indicated. 

The data values that are affected are:

5 minute:  tair_top, tair_bot

15 minute: tair_l

30 minute: tair_top, tair_bot, bowen, e, and h

• temp_air_top
• temp_air_bottom

SGP/EBBR/E12 - Battery Voltage Low - Fluxes Affected

The battery condition deteriorated over time so that the solar panel was not 
always able to keep the battery voltage high enough to produce correct home 
signal values.  The home 15 signal was too low much of the period above, 
with home 30 being low also occasionally.  The home signal qc checks should 
be consulted to determine which half hour values of sensible (h) and latent (e)
heat fluxes are incorrect; no other data values were affected.  The first 
occurrence of low home 15 signal appears to be 0630 GMT on 13 July 1996.  
Battery voltage did not drop low enough to cause any sensors to stop 
functioning.  The battery was replaced on 9 October 1996 at 2000 GMT, 
during annual calibration changeout of the entire EBBR unit (the mentor 
assumes that the battery was replaced - no instrument maintenance reports 
are available for that time).

• home_signal

Controlled burn at E12 on 3/20/97 and affected data

DQR No:                               Platforms:  sgpsirosE12
                                                  sgpebbrE12

Subject: Controlled burn at E12 on 3/20/97 and affected data

Date Submitted:  3/31/97
Submitted By: Mike Splitt             ___  Instrument Mentor
                                      ___  EST Member
                                      ___  Science Team Member
                                      _x_  Other _Site_Scientist_Team_
 
For questions or problems, please contact the ARM Experiment Center at
509-375-6898 or via email at problems@arm.gov.

Platform/Measurement:
        What level data: (raw,a0,a1,b1,c1 etc):
             all levels
    What location was the data collected at: sgp E12
 
    Period of time in question
        Begin Date   3/20/97  Time   22:55    (GMT)
        End Date      *       Time     :      (GMT)

* The "end date" is not necessarily in need of definition. The EBBR data
  appears to be directly affected for a period of about one hour. The
  effect on the local shortwave albedo will be longer lasting and could 
  be said to "end" when the vegetative state recovers to being representative
  of similar areas.

 Data should be labeled:
 ___  questionable                      ___  All data fields affected
 ___  incorrect                         ___  Only some data fields affected
 ___  wrong calibration
 _x_  others 
 
 Discussion of Problem:

This report is reflective of a change in environmental conditions thought
to be worth noting at E12, Pawhuska, and does not concern any issue of
substandard sensor performance. 

A contolled burn was conducted at the the Pawhuska Extened Facillity (E12)
by the Tallgrass Prairie Preserve. The Preserve director, Bob Hamilton,
contacted the ARM SGP Site prior to the activity which allowed Site Operations
to take precautionary steps. Danny Nelson reported the following activities by
Site Operations:

1)  Site Ops cut and removed all dried grass within the EF fence and
also to a 10' perimeter around the outside of the fence.  Final grass
height was 1-3".  This was done on Monday the 17th of March.

2)  Tallgrass Prairie Preserve personnel put down a 10' wet line around
our EF prior to the burn on the 20th, so the EF area was not burned.

3)  Site Ops had originally planned to deploy a field crew to inspect
the site on the day following the burn.  TPP director Bob Hamilton had
agreed to call us the morning of the burn, but didn't actually call us
until this morning; the day following the burn.  Due to the short
notification and prior commitment of personnel, Site Ops will not be
able to travel to the site until Monday or Tuesday of next week.

John Shatz was given the following information about the duration of
the burn:

>Bob Hamilton called and indicated that they did a control burn of the
>Tall Grass Prairie yesterday(3-20-97).  He indicated that the fire in
>our area lasted between 4:55 PM to 5:40 PM.  He also said that they
>plan to put this control burning on a two to three year cycle.

Affect on ARM Data:

Review of the EBBR temperature data (the sensor in the lower position)
shows a dramatic increase of temperature from 26 to 37 Celsius in a 
10 minute period.  The temperatures appear to have been affected for 
approximately 1 hour. 

Analysis of the broadband shortwave albedo during this period reveals
changes that appear to be related to the burn. The following is 
a listing of the daily average shortwave albedos (caluclated by running a linear
regression fit on the "curve" created by plotting the upwelling shortwave 
vs. the downwelling shortwave values from the E12 SIROS broadband instrumentation):

    Date        Broadband Shortwave Albedo
    ________   ____________________________

    3-14-97              .171
    3-15-97              .171
    3-16-97              .169
    3-17-97              .166
    3-18-97              .135
    3-19-97              .171
    3-20-97              .174
    3-21-97              .141
    3-22-97              .143
    3-23-97              .148
    3-24-97              .147

The grass cutting activity at the EF does not appear to be responsible
for the abledo change on 3-18; this is likely related to the drizzle
and overcast sky conditions in the area on that day. Note that the albedo
recovers to previous values by the next day. 

The burn occured late on the 20th, and it appears the albedo after the
burn sustained a more long-lasting decrease in value.  Examination of
both the upwelling and downwelling solar irradiance indicates that 
the albedo change was a resultant of the decrease in upwelling irradiance,
as the downwelling values were comparable to other sites.

• home_signal
• rh_top_fraction
• Wind speed, lower, 1-min avg(wspd_arith_mean)
• North latitude(lat)
• wdir_vec_std
• temp_air_top
• Atmospheric pressure(atmos_pressure)
• temp_trh_top
• time_offset
• rh_bottom_fraction
• Net radiation(net_radiation)
• East longitude(lon)
• temp_trh_bottom
• vapor_pressure_bottom
• base_time
• Wind speed vector mean(wspd_vec_mean)
• Altitude above mean sea level(alt)
• temp_reference
• vapor_pressure_top
• temp_air_bottom
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Wind Direction Sensor Malfunctions

For much of the period above, a malfunction in the E12 EBBR wind direction 
sensor (insect larvae shorting out the circuit board) caused incorrect 
values for 5 minute res_ws, wind_d, and sigma_wd, 15 minute mv_wind_d, and 
30 minute res_ws, wind_d, and sigma_wd.  Wind direction normally indicated 
north (near 0 or 360 degrees); there were some times during the period when 
wind directions looked good, but the lack of variation in direction and sigma 
implies that the data is suspect.  Therefore, it would be wise to flag all
of the values listed above during the entire time period as incorrect. 
The wind direction sensor (S/N 3081) was replaced with S/N 3042 at 1515 GMT 
on June 8, 1997.

• wdir_vec_std
• Wind speed vector mean(wspd_vec_mean)
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - EBBR Biannual Checks

During EBBR 3 month checks the Automatic Exchange Mechanism is disabled 
(reflected by home signals near zero) so that the two aspirator units
can be placed at the same height.  The measurements during these periods 
do not produce correct outputs of bowen ratio (bowen), sensible heat flux (h), 
or latent heat flux (e), nor do the air temperature and relative humidity 
measurements indicate correct gradients.  Checks performed before or after the 
AEM is disabled also lead to some incorrect data.  Incorrect 5, 15 minute and 
half hour data occurs for periods indicated.

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

SGP/EBBR/E12- EBBR Frozen Wind Speed

Wind speed cups were frozen during the indicated time periods. All 5,
15, and 30 minute data values indicated  are incorrect for the periods
listed.

• Wind speed, lower, 1-min avg(wspd_arith_mean)
• Wind speed vector mean(wspd_vec_mean)

SGP/EBBR/E12 - EBBR AEMs Not Exchanging (Iced Or Fuse Blown)

The EBBR AEM stopped exchanging because of icing at during this time
period.

The calculations of Bowen ratio, latent heat flux, and sensible heat
flux are incorrect for the time period indicated.  The other
measurements listed  are also incorrect for those times:

Note:  Mentor supplied the end date/time for this DQR after submittal

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

SGP/EBBR/E12 - EBBR Net Radiometer Domes Pierced, Water Inside - Data Affected

The upper dome of the EBBR net radiometers was punctured.
After the puncture, water collected in the top and/or bottom dome.  The
water was removed and the dome was replaced during PM visits. 

 In some cases, the puncture and water resulted in incorrect data. 
Comparison with net radiation values from surrounding EBBR sites and the
SIRS is neccesary to determine if the EBBR net radiation data 
are correct or incorrect.

It is often difficult to tell from the data when the punctures occurred,
but they would have existed for no more than 2 weeks, since the domes
are checked during each two-weekly PM visit.

Incorrect net radiation data results in the latent heat flux and
sensible heat flux also being incorrect.

• Net radiation(net_radiation)

SGP/EBBR/E12 - AEM Failure and Replacement

The E12 AEM did not exchange for most of the period above, yielding small
negative home signals.  The AEM was replaced on 18 December by site
operations personnel.  All 30 minute e, h, and bowen data are incorrect for
the times when the home signal is incorrect, and the temperature, relative
humidity, and vapor pressures do not represent properly switched values.

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

SGP/EBBR/E12 - 3-Month Check

During EBBR 3 month checks the Automatic Exchange Mechanism is disabled
(reflected by home signals near zero) so that the two aspirator units can be
placed at the same height.  The measurements during these periods 
do not produce correct outputs of bowen ratio (bowen), sensible heat flux
(h), or latent heat flux (e), nor do the air temperature and relative 
humidity measurements indicate correct gradients.  Checks performed before 
or after the AEM is disabled also lead to some incorrect data.  Incorrect 5,
15 minute and half hour data occurs for the period above.

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

SGP/EBBR/E12 - Wind Direction Sensor Failure

The wind direction sensor failed, producing zero values.  
The cause is unknown.  Data values affected are below:

 5 minute: res_ws, wind_d, sigma_wd

15 minute: mv_wind_d

30 Minute: res_ws, wind_d, sigma_wd

• wdir_vec_std
• Wind speed vector mean(wspd_vec_mean)
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Six Month Checks

During EBBR 6 month checks (formally called 3 month checks) the Automatic 
Exchange Mechanism is disabled (reflected by home signals near zero) so that
the two aspirator units can be placed at the same height.  The measurements
during these periods do not produce correct outputs of bowen ratio (bowen), 
sensible heat flux (h), or latent heat flux (e), nor do the air temperature
and relative humidity measurements indicate correct gradients.  Checks 
performed just before or after the AEM is disabled also lead to some 
incorrect data.  Incorrect 5, 15 minute and half hour data occurs for the 
period indicated.

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

SGP/EBBR/E12 - Wind Direction Data Incorrect (revised)

The wind direction sensor was iced stopped by freezing rain, 
resulting in the following values being incorrect:

5 minute:  res_ws, wind_d, sigma_wd
15 minute: mv_wind_d
30 minute: res_ws, wind_d, sigma_wd

• wdir_vec_std
• Wind speed vector mean(wspd_vec_mean)
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Wind Speed Data Incorrect

The wind speed sensor was iced stopped by freezing rain, 
resulting in the following values being incorrect:

5 minute:  wind_s, res_ws
15 minute: wind_s
30 minute: wind_s, res_ws,

• Wind speed, lower, 1-min avg(wspd_arith_mean)
• Wind speed vector mean(wspd_vec_mean)

SGP/EBBR - EBBR E12 Wind Speed Data Incorrect

The wind speed sensor was iced stopped by freezing rain, 
resulting in the following values being incorrect:

5 minute:  wind_s, res_ws
15 minute: wind_s
30 minute: wind_s, res_ws,

• home_signal
• rh_top_fraction
• Wind speed, lower, 1-min avg(wspd_arith_mean)
• North latitude(lat)
• wdir_vec_std
• temp_air_top
• Atmospheric pressure(atmos_pressure)
• temp_trh_top
• time_offset
• rh_bottom_fraction
• Net radiation(net_radiation)
• East longitude(lon)
• temp_trh_bottom
• vapor_pressure_bottom
• base_time
• Wind speed vector mean(wspd_vec_mean)
• Altitude above mean sea level(alt)
• temp_reference
• vapor_pressure_top
• temp_air_bottom
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR - EBBR E12 Wind Speed Data Incorrect

The wind speed sensor was iced stopped by freezing rain, 
resulting in the following values being incorrect:

5 minute:  wind_s, res_ws
15 minute: wind_s
30 minute: wind_s, res_ws,

• home_signal
• rh_top_fraction
• Wind speed, lower, 1-min avg(wspd_arith_mean)
• North latitude(lat)
• wdir_vec_std
• temp_air_top
• Atmospheric pressure(atmos_pressure)
• temp_trh_top
• time_offset
• rh_bottom_fraction
• Net radiation(net_radiation)
• East longitude(lon)
• temp_trh_bottom
• vapor_pressure_bottom
• base_time
• Wind speed vector mean(wspd_vec_mean)
• Altitude above mean sea level(alt)
• temp_reference
• vapor_pressure_top
• temp_air_bottom
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Data Incorrect

Most of the data values for just this time (1630 GMT) for the 5, 15, and 30
minute periods are incorrect; this apparently was the result of PM activities.

• home_signal
• rh_top_fraction
• Wind speed, lower, 1-min avg(wspd_arith_mean)
• North latitude(lat)
• wdir_vec_std
• temp_air_top
• Atmospheric pressure(atmos_pressure)
• temp_trh_top
• time_offset
• rh_bottom_fraction
• Net radiation(net_radiation)
• East longitude(lon)
• temp_trh_bottom
• vapor_pressure_bottom
• base_time
• Wind speed vector mean(wspd_vec_mean)
• Altitude above mean sea level(alt)
• temp_reference
• vapor_pressure_top
• temp_air_bottom
• Wind direction vector mean(wdir_vec_mean)

SGP/EBBR/E12 - Temperature, RH, and Vapor Pressure Data Incorrect

The right aspirator housing fell off of the AEM around 1345 GMT, by looking
at the data.  The housing was put back into place later in the day during 
a PM visit.  The following values were affected:

5 minute:  tair_top, tair_bot, thum_top, thum_bot, hum_top, hum_bot, vp_top,
           vp_bot
15 minute: rr_thum_r, mv_hum_r, tair_r
30 minute: tair_top, tair_bot, thum_top, thum_bot, hum_top, hum_bot, vp_top,
           vp_bot, bowen, e, h

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

SGP/EBBR/E12 - All Temperature Measurements Incorrect

Failure of the multiplexer connection for the reference temperature 
thermocouple in the control box or a problem with the Campbell CR10
bridge circuitry caused all air and soil temperature measurements
to be incorrect. Therefore, the computed 30 minute bowen, e, and h were 
also incorrect.

• temp_air_top
• temp_trh_bottom
• temp_trh_top
• temp_reference
• temp_air_bottom