SGP/E9/EBBR - AEM Malfunction

EDITOR'S NOTE:  This DQR refers, in part, to data collected prior to the
begin date of regular ARM data.  During the first month covered by this
DQR, the EBBR.E9 data were not archived with standard ARM names.  The data
are therefore not readily available, but can be made available by special
request.  The total period covered by the problem documented here is
930615.0000-940322.1643.

The AEM at E9 frequently did not function properly during the time period
stated.  Please see the notes in the EBBR platform describing home signal
conditions for which certain of the data fields are suspect.  The newly
installed AEM is performing properly so far.

The files could be flagged, but it is up to the user to read the
platform notes concerning the condition of the home signal and then
view the quality of the data accordingly.  I would be at my terminal full-
time in attempting to list all days and times and data fields that are
affected by the numerous AEM malfunctions.  Furthermore, I have done so
previously in several PIFs that I will reference here for information:
P931101.4, P931115.2, P940105.2, P940211.3

• Temperature of bottom humidity sensor chamber(thum_bot)
• top vapor pressure(vp_top)
• Home signal(home)
• bottom vapor pressure(vp_bot)
• bottom air temperature(tair_bot)
• Temperature of the top humidity chamber(thum_top)
• Bottom humidity(hum_bot)
• top air temperature(tair_top)
• Top humidity(hum_top)

• Exchange mechanism position indicator (0 to 15 min)(home_15)
• bottom air temperature(tair_bot)
• bottom vapor pressure(vp_bot)
• latent heat flux(e)
• top air temperature(tair_top)
• Temperature of the top humidity chamber(thum_top)
• h(h)
• Bottom humidity(hum_bot)
• top vapor pressure(vp_top)
• Top humidity(hum_top)
• Exchange mechanism position indicator (15 to 30 min)(home_30)
• Temperature of bottom humidity sensor chamber(thum_bot)

SGP/EBBR/E9 - Temperature Portion of T/RH Probe

The Temperature portion of the right T/RH probe indicated too high a 
temperature for nearly 11 months.  I twice placed work requests to have the 
probe replaced, but no spares were available.  Spares recently became 
available and I placed a new work request to have the probe changed.  The 
replacement occurred on 18 June 1997; this fixed the problem.  The main 
results of the high temperatures were probe top and bottom temperatures
(used only for the calculation of vapor pressure) and vapor pressures that 
were too large.  Furthermore, this caused latent heat flux to be reported 
to be too large, and therefore sensible heat flux was reported to be too 
small.  Recalculation of the fluxes using thermocouple temperatures to 
calculate vapor pressure would be quite time consuming and would have to
assume that the thermocouple temperature and probe temperature were nearly 
the same.

The EBBR procedures have been changed to include comparison of the 
thermocouple and probe temperatures to make it easier for the site 
operators to detect this condition.

The data affected (and thus incorrect) includes:

15 minute: rr_thum_r 
30 minute: thum_top, thum_bot, vp_top, vp_bot, e, h, bowen.

• Battery(bat)
• Dummy altitude for Zeb(alt)
• Soil heat flow 3(mv_hft3)
• Temperature of right humidity sensor chamber(rr_thum_r)
• Soil heat flow 4(mv_hft4)
• Soil heat flow 5(mv_hft5)
• lon(lon)
• Soil heat flow 1(mv_hft1)
• Soil heat flow 2(mv_hft2)
• base time(base_time)
• lat(lat)

• bottom vapor pressure(vp_bot)
• latent heat flux(e)
• Temperature of the top humidity chamber(thum_top)
• h(h)
• top vapor pressure(vp_top)
• Temperature of bottom humidity sensor chamber(thum_bot)
• ratio of sensible/latent heat fluxes (Bowen ratio)(bowen)