SGP/EBBR/E13 - Automatic Exchange Mechanism Failure

The AEM was stuck in the home_15 position or reported near zero
home signals during much of the indicated period.

The Bowen ratio and latent and sensible heat fluxes were incorrect 
when the AEM was not operating properly; the periods of incorrect
data can be determined from the home signal values.

On 7/14/04 the AEM was replaced.

• Left air temperature(tair_l)
• Right air temperature(tair_r)

• temperature of the bottom humidity sensor chamber(thum_bot)
• top vapor pressure(vp_top)
• top air temperature(tair_top)
• temperature of the top humidity sensor chamber(thum_top)
• bottom vapor pressure(vp_bot)
• bottom relative humidity(hum_bot)
• top relative humidity(hum_top)
• bottom air temperature(tair_bot)

• bottom relative humidity(hum_bot)
• ratio of sensible/latent heat fluxes (Bowen ratio)(bowen)
• bottom vapor pressure(vp_bot)
• temperature of the bottom humidity sensor chamber(thum_bot)
• temperature of the top humidity sensor chamber(thum_top)
• latent heat flux(e)
• corrected sensible heat flux(h)
• bottom air temperature(tair_bot)
• top air temperature(tair_top)
• top relative humidity(hum_top)
• top vapor pressure(vp_top)

SGP/EBBR/E13 - Improved EBBR CR10 Program

Effective 20050331.2100, the EBBR.E13 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 sgp30ebbrE13.b1 data stream.  The 
earlier version of the CR10 program was also used on previous EBBR datastream names (e.g. 
sgp30ebbrE13.a1).

• average surface soil heat flow at the surface(ave_shf)
• latent heat flux(e)
• corrected sensible heat flux(h)

SGP/EBBR/E13 - metadata corrections

On 20050723, a series of metadata corrections and additions were completed.  These 
metadata changes apply to all EBBR.E13 data collected by ARM back to the installation of the 
instrument in September 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 systems
3) Correction of soil type
4) Correction of soil moisture units (from "by volume" to "gravimetric")

• Time offset from base_time(base_time)

• Time offset from base_time(base_time)

• Time offset from base_time(base_time)