TWP/SMET/C3 - Rain blocked pressure port

Atmospheric pressure values were suspect due to anomolous readings during heavy rain 
events.  Suspect blockage of port due to rainfall.  New logger and enclosure corrected problem.

• Barometric Pressure(atmos_pressure)

TWP/SMET/C3 - Negative rainfall rates

Due to limitations of the Zeno dataloggers all voltage measurements
from the optical rain gauge (ORG) were converted to rainfall rates. 
This resulted in negative values for rain rates.  Any value below
0.10 mm/hr should be considered to be 0 mm/hr.  New dataloggers 
alleviated this problem.

• Precipitation mean(precip_mean)
• Precipitation maximum(precip_max)
• Precipitation standard deviation(precip_sd)
• precipitation minimum(precip_min)

TWP/SMET/C3 - Data non-representative

Tower mast was lowered for inspection.  Data during this time is non-representative.

• Lower sensor, wind speed minimum(lo_spd_min)
• Precipitation maximum(precip_max)
• Lower sensor, wind direction standard deviation(lo_dir_sd)
• precipitation minimum(precip_min)
• Upper sensor, wind speed maximum(up_spd_max)
• Tipping bucket raingauge total(tbrg_total)
• Mean Air Temperature or Hardware Error(temp_mean)
• Upper sensor, wind direction standard deviation(up_dir_sd)
• Vapor pressure mean(vappress_mean)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Barometric Pressure(atmos_pressure)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Vapor pressure standard deviation(vappress_sd)
• Lower sensor, wind speed maximum(lo_spd_max)
• Mean Relative Humidity(relh_mean)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Upper sensor, wind direction vector average(up_dir_vec_avg)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Precipitation mean(precip_mean)
• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• Precipitation standard deviation(precip_sd)
• Upper sensor, wind speed minimum(up_spd_min)
• Tipping bucket raingauge count total(tbrg_count_total)
• Upper sensor, wind speed standard deviation(up_spd_sd)
• Std Dev of Air Temperature(temp_sd)
• Upper sensor, wind speed vector average(up_spd_vec_avg)

TWP/SMET/C3 - Lower wind direction sensor failure

The lower wind direction sensor failed on 4/14 and disagrees significantly with the upper 
wind direction sensor.  The lower wind sensor reports a constant value around 0-15 
degrees since it failed.  Testing showed that excitation channel two on the logger was the 
problem.  Logger was replaced by spare.

• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• Lower sensor, wind direction standard deviation(lo_dir_sd)

TWP/MWR/C3 - Reprocess - Revised Retrieval Coefficients

IN THE BEGINNING (June 1992), the retrieval coefficients used to derive 
the precipitable water vapor (PWV) and liquid water path (LWP) from the 
MWR brightness temperatures were based on the Liebe and Layton (1987) 
water vapor and oxygen absorption model and the Grant (1957) liquid 
water absorption model.

Following the SHEBA experience, revised retrievals based on the more 
recent Rosenkranz (1998) water vapor and oxygen absorption models and 
the Liebe (1991) liquid waer absorption model were developed.  The 
Rosenkranz water vapor absorption model resulted a 2 percent increase 
in PWV relative to the earlier Liebe and Layton model.  The Liebe 
liquid water absorption model decreased the LWP by 10% relative to the 
Grant model.  However, the increased oxygen absorption caused a 
0.02-0.03 mm (20-30 g/m2) reduction in LWP, which was particularly 
significant for low LWP conditions (i.e. thin clouds encountered at 
SHEBA).

Recently, it has been shown (Liljegren, Boukabara, Cady-Pereira, and 
Clough, TGARS v. 43, pp 1102-1108, 2005) that the half-width of the 
22 GHz water vapor line from the HITRAN compilation, which is 5 percent 
smaller than the Liebe and Dillon (1969) half-width used in Rosenkranz 
(1998), provided a better fit to the microwave brightness temperature 
measurements at 5 frequencies in the range 22-30 GHz, and yielded more 
accurate retrievals. Accordingly, revised MWR retrieval coefficients 
have been developed using MONORTM, which utilizes the HITRAN compilation 
for its spectroscopic parameters.  These new retrievals provide 3 
percent less PWV and 2.6 percent greater LWP than the previous 
retrievals based on Rosenkranz (1998).

Although the MWR data will be reprocessed to apply the new monortm-based 
retrievals, for most purposes it will be sufficient to correct the data 
using the following factors:

PWV_MONORTM = 0.9695 * PWV_ROSENKRANZ
LWP_MONORTM = 1.026  * LWP_ROSENKRANZ

The Rosenkranz-based retrieval coefficients was active at TWP.C3 from
inception of the data, 20020227.0151.  The MONORTM-based retrieval
coefficients became active at TWP.C3 20050630.2100.

Note: a reprocessing effort is already underway to apply the 
Rosenkranz-based retrieval coefficients to all MWR prior to April 
2002.  An additional reprocessing task will be undertaken to apply 
the MONORTM retrieval to all MWR data when the first is completed. 
Read reprocessing comments in the netcdf file header carefully to 
ensure you are aware which retrieval is in play.

• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)

• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)

• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)

TWP/SMET/C3 - Data not representative

Tower was lowered for radiometer change and characterization. Data are not representative 
of local conditions.

• Lower sensor, wind speed minimum(lo_spd_min)
• Precipitation maximum(precip_max)
• Lower sensor, wind direction standard deviation(lo_dir_sd)
• precipitation minimum(precip_min)
• Upper sensor, wind speed maximum(up_spd_max)
• Tipping bucket raingauge total(tbrg_total)
• Mean Air Temperature or Hardware Error(temp_mean)
• Upper sensor, wind direction standard deviation(up_dir_sd)
• Vapor pressure mean(vappress_mean)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Barometric Pressure(atmos_pressure)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Vapor pressure standard deviation(vappress_sd)
• Lower sensor, wind speed maximum(lo_spd_max)
• Mean Relative Humidity(relh_mean)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Upper sensor, wind direction vector average(up_dir_vec_avg)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Precipitation mean(precip_mean)
• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• Precipitation standard deviation(precip_sd)
• Upper sensor, wind speed minimum(up_spd_min)
• Tipping bucket raingauge count total(tbrg_count_total)
• Upper sensor, wind speed standard deviation(up_spd_sd)
• Std Dev of Air Temperature(temp_sd)
• Upper sensor, wind speed vector average(up_spd_vec_avg)

TWP/MWR/C3 - New software version (4.15) installed

A problem began with the installation of MWR.EXE version 4.12 in October 2002. The 
software had been upgraded from a "DOS" to a "Windows"-compiled program to address an earlier 
problem.  The software upgrade corrected the earlier problem but introduced a new one that 
caused line-of-sight observing cycles to be skipped, a 15% reduction in the number of tip 
curves, and saturation of CPU usage.  Software versions 4.13 and 4.14 also produced 
these problems.

The new MWR software version (4.15) was installed on 9/20/2005. As a consequence of this 
upgrade, the tip curve frequency increased. The tip cycle time decreased from ~60s to ~50s.

• Sky brightness temperature at 31.4 GHz(tbsky31)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• 23.8 GHz Blackbody signal(bb23)
• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)
• 31.4 GHz blackbody(bb31)
• 31.4 GHz sky signal(sky31)
• 23.8 GHz sky signal(sky23)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Sky Infra-Red Temperature(sky_ir_temp)
• Blackbody kinetic temperature(tkbb)
• Mixer kinetic (physical) temperature(tkxc)
• (tknd)
• Ambient temperature(tkair)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)

• Ambient temperature(tkair)
• Blackbody kinetic temperature(tkbb)
• (tknd)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Temperature correction coefficient at 23.8 GHz(tc23)
• 23.8 GHz sky signal(tipsky23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 31.4 GHz blackbody(bb31)
• 31.4 GHz goodness-of-fit coefficient(r31)
• 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• Mixer kinetic (physical) temperature(tkxc)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• 31.4 GHz sky signal(tipsky31)
• 23.8 GHz goodness-of-fit coefficient(r23)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 23.8 GHz Blackbody signal(bb23)

TWP/MWR/C3 - Instrument failure, Power outage

A lightning strike sent the MWR offline. The radiometer suffered extensive damage, was 
removed from the site and sent to the vendor for repair. A spare radiometer was sent to the 
TWP/C3 site and was installed on 12/07. However, some hardaware communication issues 
prevented data collection until 12/10.

• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• MWR column precipitable water vapor(vap)
• 23.8 GHz Blackbody signal(bb23)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• base time(base_time)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Mixer kinetic (physical) temperature(tkxc)
• Temperature correction coefficient at 23.8 GHz(tc23)
• (tknd)
• Averaged total liquid water along LOS path(liq)
• Dummy altitude for Zeb(alt)
• 31.4 GHz blackbody(bb31)
• lon(lon)
• Ambient temperature(tkair)
• Sky Infra-Red Temperature(sky_ir_temp)
• 23.8 GHz sky signal(sky23)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• lat(lat)
• Time offset of tweaks from base_time(time_offset)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Blackbody kinetic temperature(tkbb)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• 31.4 GHz sky signal(sky31)

• 23.8 GHz blackbody+noise injection signal(bbn23)
• lon(lon)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Time offset of tweaks from base_time(time_offset)
• MWR column precipitable water vapor(vap)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• (tknd)
• Ambient temperature(tkair)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• base time(base_time)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Dummy altitude for Zeb(alt)
• 23.8 GHz Blackbody signal(bb23)
• Averaged total liquid water along LOS path(liq)
• 31.4 GHz blackbody(bb31)
• 31.4 GHz sky signal(sky31)
• 23.8 GHz sky signal(sky23)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• lat(lat)
• Sky Infra-Red Temperature(sky_ir_temp)
• Blackbody kinetic temperature(tkbb)
• Mixer kinetic (physical) temperature(tkxc)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)

• Ambient temperature(tkair)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Temperature correction coefficient at 23.8 GHz(tc23)
• 23.8 GHz sky signal(tipsky23)
• 31.4 GHz blackbody(bb31)
• Time offset of tweaks from base_time(time_offset)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• base time(base_time)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 23.8 GHz Blackbody signal(bb23)
• Blackbody kinetic temperature(tkbb)
• (tknd)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 31.4 GHz goodness-of-fit coefficient(r31)
• 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)
• lon(lon)
• Mixer kinetic (physical) temperature(tkxc)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• 31.4 GHz sky signal(tipsky31)
• 23.8 GHz goodness-of-fit coefficient(r23)
• Dummy altitude for Zeb(alt)
• lat(lat)
• Actual elevation angle(actel)
• Actual Azimuth(actaz)

• null(Raw data stream - documentation not supported)

TWP/SMET/C3 - Upper wind sensor failure

A lightning strike destroyed the upper wind sensor.

• Upper sensor, wind speed maximum(up_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Upper sensor, wind direction vector average(up_dir_vec_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Upper sensor, wind direction standard deviation(up_dir_sd)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind speed standard deviation(up_spd_sd)

TWP/SMET/C3 - RH Values Artificially High

Lightning strike caused RH readings to be higher than reasonable (130%).

• Vapor pressure standard deviation(vappress_sd)
• Mean Relative Humidity(relh_mean)
• Vapor pressure mean(vappress_mean)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)

TWP/SMET/C3 - Instrument failure

A lightning strike caused a failure in the ORG.  Rainfall was being continually recorded.

• Precipitation mean(precip_mean)
• Precipitation maximum(precip_max)
• Precipitation standard deviation(precip_sd)
• precipitation minimum(precip_min)

TWP/MWR/C3 - REPROCESS- Updated retrieval coefficients

The statistical retrieval coefficients currently in use at the Darwin (TWP/C3) site were 
developed using radiosonde RS80 launched from Manus Island during the TOGA-COARE 
experiment.
Data from Manus Island have minimal seasonality, therefore a single, annual set of 
coefficients was used at all three sites. Retrievals using these coefficients are sufficiently 
accurate especially during the local summer months (December-January). However, the Darwin 
site displays a summer/winter seasonality resulting in larger differences during the 
southern winter (May-
June).
Since we now have enough radiosonde soundings (RS80 and RS90) available at the Darwin 
site, the Darwin coefficients were modified to better reflect the local seasonality.

• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)

• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)

TWP/SMET/C3 - ORG data noisy due to degraded ground

SMET Rain Data began to be noisy during December 2005 and the problem slowly became worse 
over time so that in February 2006 the ORG was reporting with a constant background value 
of around 0.10 mm/hr rain rate.  ORG voltage showed a near constant value above the 85mV 
threshold.  The ground for the ORG had become degraded and was lost due to corrosion.

• Precipitation mean(precip_mean)
• Precipitation maximum(precip_max)
• Precipitation standard deviation(precip_sd)
• precipitation minimum(precip_min)

TWP/SMET/C3 - Reprocessed: Lower windspeed sensor calibration error

The lower anemometer was replaced but the calibration coefficients were not changed during 
this period.  The data were reprocessed to apply the correct calibrations and the 
reprocessed data were archived in August 2008.

• Lower sensor, wind speed minimum(lo_spd_min)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Lower sensor, wind speed maximum(lo_spd_max)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)

TWP/MWR/C3 - Site shutdown

On 4/24, the site was shutdown in preparation for a cyclone. Instruments were back up on 
4/25 at 22:59

• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• MWR column precipitable water vapor(vap)
• 23.8 GHz Blackbody signal(bb23)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• base time(base_time)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Mixer kinetic (physical) temperature(tkxc)
• Temperature correction coefficient at 23.8 GHz(tc23)
• (tknd)
• Averaged total liquid water along LOS path(liq)
• Dummy altitude for Zeb(alt)
• 31.4 GHz blackbody(bb31)
• lon(lon)
• Ambient temperature(tkair)
• Sky Infra-Red Temperature(sky_ir_temp)
• 23.8 GHz sky signal(sky23)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• lat(lat)
• Time offset of tweaks from base_time(time_offset)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Blackbody kinetic temperature(tkbb)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• 31.4 GHz sky signal(sky31)

• 23.8 GHz blackbody+noise injection signal(bbn23)
• lon(lon)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Time offset of tweaks from base_time(time_offset)
• MWR column precipitable water vapor(vap)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• (tknd)
• Ambient temperature(tkair)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• base time(base_time)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Dummy altitude for Zeb(alt)
• 23.8 GHz Blackbody signal(bb23)
• Averaged total liquid water along LOS path(liq)
• 31.4 GHz blackbody(bb31)
• 31.4 GHz sky signal(sky31)
• 23.8 GHz sky signal(sky23)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• lat(lat)
• Sky Infra-Red Temperature(sky_ir_temp)
• Blackbody kinetic temperature(tkbb)
• Mixer kinetic (physical) temperature(tkxc)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)

• Ambient temperature(tkair)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Temperature correction coefficient at 23.8 GHz(tc23)
• 23.8 GHz sky signal(tipsky23)
• 31.4 GHz blackbody(bb31)
• Time offset of tweaks from base_time(time_offset)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• base time(base_time)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 23.8 GHz Blackbody signal(bb23)
• Blackbody kinetic temperature(tkbb)
• (tknd)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 31.4 GHz goodness-of-fit coefficient(r31)
• 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)
• lon(lon)
• Mixer kinetic (physical) temperature(tkxc)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• 31.4 GHz sky signal(tipsky31)
• 23.8 GHz goodness-of-fit coefficient(r23)
• Dummy altitude for Zeb(alt)
• lat(lat)
• Actual elevation angle(actel)
• Actual Azimuth(actaz)

• null(Raw data stream - documentation not supported)

TWP/SMET/C3 - Data not representative

The Anemometer readings were incorrect due to the tower being lowered for maintenance.

• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Lower sensor, wind speed minimum(lo_spd_min)
• Lower sensor, wind speed maximum(lo_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Upper sensor, wind direction vector average(up_dir_vec_avg)
• Lower sensor, wind direction standard deviation(lo_dir_sd)
• Upper sensor, wind speed maximum(up_spd_max)
• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Upper sensor, wind direction standard deviation(up_dir_sd)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Upper sensor, wind speed standard deviation(up_spd_sd)
• Upper sensor, wind speed vector average(up_spd_vec_avg)

TWP/SMET/C3 - Reprocess: Barometric pressure units change

Barometric pressure data during this time period is reported in hPa.  After this time, the 
data have been converted to kPa to standardize the measurement units among ARM sites and 
to conform to accepted standard units determined by the scientific community.

• Barometric Pressure(atmos_pressure)

TWP/SMET/C3 - Reprocess: Tipping bucket rain gauge added

A tipping bucket rain gauge was added to the SMET suite of instruments effective 20060926. 
 Two new variables (count and rain amount) were added at the end of the twpsmet60sC1.b1 
datastream.  When reprocessing of this datastream occurs these variables will be added 
with -9999 (missing) as the value for dates prior to gauge installation.

• base time(base_time)

TWP/MWR/C3 - Sun in field of view of radiometer

Each day from approximately 9/15 to 10/9 around local noon, there is an increase in the 
brightness temperature due to the sun being in the field of view of the radiometer.

• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Sky brightness temperature at 23.8 GHz(tbsky23)

• 31.8 GHz sky brightness temperature derived from tip curve(tbskytip31)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• 23.8 GHz sky signal(tipsky23)
• 31.4 GHz sky signal(tipsky31)
• 23.8 GHz sky brightness temperature derived from tip curve(tbskytip23)

TWP/RAIN/C3 - faulty precipitation result from blocked funnel

The funnel was partially blocked and the water was flowing so slowly through the system 
that the timing of precipitation was wrong.

• Rainfall rate(rain_rate)
• Precipitation(precip_tbrg)

TWP/SMET/C3 - Barometer Data Incorrect

The barometer data was incorrect or missing due to water intrusion.

• Barometric Pressure(atmos_pressure)

TWP/SMET/C3 - Water in enclosure

Data became erratic and unreasonable after water intrusion into the enclosure.

• Precipitation mean(precip_mean)
• Vapor pressure standard deviation(vappress_sd)
• Precipitation maximum(precip_max)
• Mean Relative Humidity(relh_mean)
• Mean Air Temperature or Hardware Error(temp_mean)
• Precipitation standard deviation(precip_sd)
• Vapor pressure mean(vappress_mean)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• precipitation minimum(precip_min)
• Std Dev of Air Temperature(temp_sd)

TWP/SMET/C3 - Upper wind speed artificially slow

The upper wind measurement was consistently slower by around 0.5 - 1 m/s than the lower 
wind measurement.  The bearings on the upper wind measurement were binding.

• Upper sensor, wind speed maximum(up_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind speed standard deviation(up_spd_sd)

TWP/SMET/C3 - ORG overestimated rainfall

Optical rain gauge (ORG) measured approximately 10mm higher than two co-located tipping 
bucket rain gauges and a co-located disdrometer.  The ORG is typically higher but usually 
not by an order of magnitude.

• Precipitation mean(precip_mean)
• Precipitation maximum(precip_max)
• Precipitation standard deviation(precip_sd)
• precipitation minimum(precip_min)

TWP/SMET/C3 - Upper Wind Sensor Data Questionable

The wind_up vs. wind_low wind directions diverged, with the differences between the two 
eventually reached 45 degrees. The Upper sensor was found to be mis-aligned and loose.

• Upper sensor, wind speed maximum(up_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind speed standard deviation(up_spd_sd)

TWP/SMET/C3 - Lower Wind Direction Intermittently Wrong

The lower wind sensor cabling had a problem causing an intermittent connection for the 
wind direction data.

• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• Lower sensor, wind direction standard deviation(lo_dir_sd)

TWP/SMET/C3 - Upper wind speed data incorrect

Beginning on 07/08, the upper wind sensor started reporting significantly lower wind 
speeds than the lower wind sensor.  The cable connections weather proofing failed allowing 
corrosion to occur and increasing he resistance of the cables.  This in turn lowered the 
wind speeds artificially.

• Upper sensor, wind speed maximum(up_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind speed standard deviation(up_spd_sd)

TWP/SMET/C3 - Missing data

Data are missing and unrecoverable.

• time(time)
• lat(lat)
• Lower sensor, wind speed minimum(lo_spd_min)
• Time offset of tweaks from base_time(time_offset)
• Precipitation maximum(precip_max)
• Battery Voltage(internal_voltage)
• Logger panel temperature(logger_temp)
• Lower sensor, wind direction standard deviation(lo_dir_sd)
• precipitation minimum(precip_min)
• Upper sensor, wind speed maximum(up_spd_max)
• Tipping bucket raingauge total(tbrg_total)
• Mean Air Temperature or Hardware Error(temp_mean)
• Vapor pressure mean(vappress_mean)
• Upper sensor, wind direction standard deviation(up_dir_sd)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Barometric Pressure(atmos_pressure)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Vapor pressure standard deviation(vappress_sd)
• Mean Relative Humidity(relh_mean)
• Lower sensor, wind speed maximum(lo_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Upper sensor, wind direction vector average(up_dir_vec_avg)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Precipitation mean(precip_mean)
• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• base time(base_time)
• Dummy altitude for Zeb(alt)
• Precipitation standard deviation(precip_sd)
• lon(lon)
• Upper sensor, wind speed minimum(up_spd_min)
• Tipping bucket raingauge count total(tbrg_count_total)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Std Dev of Air Temperature(temp_sd)
• Upper sensor, wind speed standard deviation(up_spd_sd)

TWP/SMET/C3 - Wind Speed data contain offset due to induced voltage

The marine model of the RM Young wind sensor needs twisted pair shielded cable.  The 
manufacturer did not originally supply the pigtail with twisted pair shielded cable.  Use of 
twisted pair shielded cable for the rest of the cable run to the logger was also not 
specified.  This caused an induced voltage in the wind speed line from the wind direction 
excitation.  The induced voltage varied from sensor to sensor and probably changed anytime 
the cable was replaced or parts of the wind sensor were repaired or replaced. The induced 
voltage has been seen to vary from 0.15 m/s to as much as 1.08 m/s.

• Upper sensor, wind speed maximum(up_spd_max)
• Lower sensor, wind speed minimum(lo_spd_min)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Lower sensor, wind speed maximum(lo_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind speed standard deviation(up_spd_sd)

TWP/SMET/C3 - Reprocess: Temperature data biased low

Due to a datalogger problem, the temperature data were biased low by 2.13 degrees C.

The data will be reprocessed.

• Mean Air Temperature or Hardware Error(temp_mean)
• Std Dev of Air Temperature(temp_sd)

TWP/SMET/C3 - Reprocess: Temperature Biased low by 1.06 Degrees

The temperature of the SMET system was biased low by 1.06 Deg C due to a non-precision 
resistor being used int he measurement circuit.  The data will be reprocessed.  Saturation 
Vapor pressure and Vapor pressure will have to be reprocessed also.

Add 1.06 degrees to the temperature data.  

Correct Sat Vap Press using the Buck approximation:
   Es = 6.1121exp((17.502*T)/(240.97 + T) 
where T is the temperature in C.  

Correct Vapor pressure using: E = (RH*Es)/100

• Vapor pressure standard deviation(vappress_sd)
• Mean Air Temperature or Hardware Error(temp_mean)
• Vapor pressure mean(vappress_mean)
• Std Dev of Air Temperature(temp_sd)