TWP/SMET/C2 - Instrument failure

Upper wind sensor failed. Wind direction was reported at a near constant value of 69 
degrees and was significantly different than the lower wind sensor's direction values. Sensor 
replaced.

• Wind #1 direction standard deviation(wind1_dir_sd)
• Wind #1 direction vector average(wind1_dir_vec_avg)

TWP/VCEIL/C2 - Ceilometer failure

Large data gaps began occurring frequently at the TWP Nauru site 26 February at 06Z.  
Prior to 25 February, optical cross talk errors had been observed.  Beginning on 25 February, 
data errors were observed.  By 26 February, these errors were exhibiting themselves as 
extended data gaps.  These gaps became increasingly frequent between 2/26 and 3/4.  All 
data are missing after 20050304.1550.

The instrument was replaced on 29 March and after some subsequent configuration work, the 
instrument was revived just after 00Z on 1 April.

• Raw data stream - documentation not supported(Raw data stream - documentation not supported)

• Aerosol volume backscattering coefficient at 355 nm(backscatter)
• Time offset of tweaks from base_time(time_offset)
• Warning and alarm status bits(status_string)
• east longitude for all the input platforms.(lon)
• Percentage of nominal factory setting (0 to 999%)(receiver_sensitivity)
• Vertical visibility(vertical_visibility)
• Laser temperature(laser_temperature)
• Altitude of highest signal(alt_highest_signal)
• Second lowest cloud base height(second_cbh)
• 6 character string describing instrument measurement parameters(measurement_parameters)
• Degrees from vertical (-15 to +90)(tilt_angle)
• GPS raw data filename(filename)
• Detection status. See details(detection_status)
• north latitude for all the input platforms.(lat)
• altitude above sea levelaltunits(alt)
• Flag indicating aeri retrieval status(status_flag)
• Third cloud base height(third_cbh)
• Percentage of nominal factory setting (0 to 999%)(laser_pulse_energy)
• Lowest cloud base height detected.(first_cbh)
• Time offset from base_time(base_time)
• distance to center of range bin after correcting for offset in sync(range)
• Millivolts at internal ADC input (0 to 2500)(background_light)
• Millivolts at internal ADC input(window_contamination)
• SUM of detected and normalized backscatter(sum_backscatter)

TWP/MWR/C2 - Heater problem

When the wiring of the air temperature sensor was checked the heater apparently began 
activating too often.

• Water on Teflon window (1=WET, 0=DRY)(wet_window)

• Fraction of data in averaging interval with water on the Teflon window(water_flag_fraction)

• Water on Teflon window (1=WET, 0=DRY)(wet_window)

TWP/SMET/C2 - Upper wind sensor failure

After replacement on 03/03/2005 the upper wind sensor began reporting erroneous values 
again on 03/09/2005 becoming very apparent after 03/17/2005.  Wind speed data appears 
reasonable but the wind direction data do not agree well with the lower wind sensor.

• Wind #1 direction standard deviation(wind1_dir_sd)
• Wind #1 direction vector average(wind1_dir_vec_avg)

TWP/MWR/C2 - mixer temperature

When the wiring of the air temperature sensor was checked the mixer temperature 
unexpectedly decreased 4 degrees. It increased to its normal value when the dielectric window was 
replaced. The problem was probably caused by a loose and/or corroded connection.

• Mixer kinetic (physical) temperature(tkxc)

• Mixer kinetic (physical) temperature(tkxc)

TWP/SMET/C2 - RH failure

The RH values were frequently over MAX value of 104% starting on 7/10/2005 through end of 
period.  Sensor was replaced.

• Relative humidity mean(relh_mean)
• Relative humidity maximum(relh_max)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Relative humidity minimum(relh_min)

TWP/SONDE/C2 - Bad RH sensor

It appears that the RH sensor heating circuit failed during this sounding.  The RH 
oscillates rapidly between low (~0 %RH) and not so low (ambient %RH) and the oscillation seems 
to stop when the temperature is below -50 degC.  According to Vaisala these are symptoms 
of failure in the ASIC (application specific integrated circuit) that controls the heating.

• Relative humidity scaled, by total column amount from MWR(rh)
• Surface dew point temperature(dp)

TWP/SMET/C2 - Instrument maintenance

Instrument calibration and testing were taking place for brief periods.

• Relative humidity mean(relh_mean)
• Wind #1 direction standard deviation(wind1_dir_sd)
• Mean Air Temperature or Hardware Error(temp_mean)
• Wind #1 speed maximum(wind1_spd_max)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Wind #1 speed standard deviation(wind1_spd_sd)
• Max Temperature at lowest Model Level- 1 hr(temp_max)
• Wind #2 speed vector average(wind2_spd_vec_avg)
• Wind #2 direction standard deviation(wind2_dir_sd)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• Vapor pressure mean(vappress_mean)
• Wind #2 speed minimum(wind2_spd_min)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Wind #1 speed minimum(wind1_spd_min)
• Wind #2 speed maximum(wind2_spd_max)
• Temperature standard deviation(temp_sd)
• Min Temperature at lowest Model Level- 1 hr(temp_min)
• Wind #2 speed standard deviation(wind2_spd_sd)
• Relative humidity minimum(relh_min)
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• Vapor pressure standard deviation(vappress_sd)
• Relative humidity maximum(relh_max)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• Wind #1 speed maximum gust(wind1_spd_max_gust)

TWP/SMET/C2 - ORG data incorrect

Data from the ORG was incorrect due to heavy condensation on the lens.

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

TWP/MWR/C2 - New software version (4.15) installed

A problem began with the installation of MWR.EXE version 4.12 in November 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 9/15/2005. As a consequence of this 
upgrade, the tip curve frequency increased. The tip cycle time decreased from ~60s to ~50s.

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

• 31.4 GHz sky signal(tipsky31)
• Noise diode mount temperature(tknd)
• Blackbody kinetic temperature(tkbb)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 31.4 GHz goodness-of-fit coefficient(r31)
• 23.8 GHz goodness-of-fit coefficient(r23)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 23.8 GHz sky signal(tipsky23)
• 31.4 GHz blackbody+noise injection signal(bbn31)
• 31.4 GHz Blackbody signal(bb31)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Mixer kinetic (physical) temperature(tkxc)
• Ambient temperature(tkair)

TWP/SMET/C2 - Tower down for calibration activities

Tower lowered, wind vanes spun at different frequencies, and ORG tested with electronic 
rain.

• Relative humidity mean(relh_mean)
• Wind #1 direction standard deviation(wind1_dir_sd)
• Mean Air Temperature or Hardware Error(temp_mean)
• Wind #1 speed maximum(wind1_spd_max)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Wind #1 speed standard deviation(wind1_spd_sd)
• Max Temperature at lowest Model Level- 1 hr(temp_max)
• Wind #2 speed vector average(wind2_spd_vec_avg)
• Wind #2 direction standard deviation(wind2_dir_sd)
• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• precipitation minimum(precip_min)
• Vapor pressure mean(vappress_mean)
• Wind #2 speed minimum(wind2_spd_min)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Wind #1 speed minimum(wind1_spd_min)
• Wind #2 speed maximum(wind2_spd_max)
• Temperature standard deviation(temp_sd)
• Min Temperature at lowest Model Level- 1 hr(temp_min)
• Relative humidity minimum(relh_min)
• Wind #2 speed standard deviation(wind2_spd_sd)
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• Vapor pressure standard deviation(vappress_sd)
• Precipitation maximum(precip_max)
• Relative humidity maximum(relh_max)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Precipitation mean(precip_mean)
• Precipitation standard deviation(precip_sd)

TWP/SONDE/C2 - Broken temperature sensor

The temperature sensor on this radiosonde broke after launch.  All the temperature-related 
data are incorrect.

• Relative humidity scaled, by total column amount from MWR(rh)
• Dry-Bulb Temperature(tdry)
• Surface dew point temperature(dp)

TWP/VCEIL/C2 - occasional communication fault

Beginning August 30, 2005, the Nauru Ceilometer periodically went into a strange 
operational mode where the backscatter data exhibits vertical stripes.  Looking at the backscatter 
data - there are high amplitude oscillations occuring in the backscatter as a function 
of time at a given height.  The phenomenon appears to be more common at night.  Dates 
include: 30 Aug, 31 Aug, 1 Sep, 9 Sep, 15 Sep, 20 Oct, 22 Oct, 8 Dec, and others.

The fiber optic link to the ceilometer was faulty and causing periodic data corruption. 
The problem was corrected when the fiber optic line was replaced with a hard wired RS232 
link.

• Aerosol volume backscattering coefficient at 355 nm(backscatter)
• Flag indicating aeri retrieval status(status_flag)
• Percentage of nominal factory setting (0 to 999%)(laser_pulse_energy)
• Third cloud base height(third_cbh)
• Time offset of tweaks from base_time(time_offset)
• Time offset from base_time(base_time)
• Lowest cloud base height detected.(first_cbh)
• Warning and alarm status bits(status_string)
• distance to center of range bin after correcting for offset in sync(range)
• east longitude for all the input platforms.(lon)
• Millivolts at internal ADC input (0 to 2500)(background_light)
• Percentage of nominal factory setting (0 to 999%)(receiver_sensitivity)
• Vertical visibility(vertical_visibility)
• Laser temperature(laser_temperature)
• Altitude of highest signal(alt_highest_signal)
• 6 character string describing instrument measurement parameters(measurement_parameters)
• Second lowest cloud base height(second_cbh)
• GPS raw data filename(filename)
• Degrees from vertical (-15 to +90)(tilt_angle)
• Detection status. See details(detection_status)
• north latitude for all the input platforms.(lat)
• altitude above sea levelaltunits(alt)
• Millivolts at internal ADC input(window_contamination)
• SUM of detected and normalized backscatter(sum_backscatter)

TWP/SONDE/C2  - Broken temperature sensor

The temperature sensor on this radiosonde broke after launch.  All the temperature-related 
data are incorrect.

• Relative humidity scaled, by total column amount from MWR(rh)
• Dry-Bulb Temperature(tdry)
• Surface dew point temperature(dp)

TWP/SMET/C2 - Reprocess: Barometric Data Changed from hPa to kPa

Barometric pressure data was converted from hPa to kPa in order to standardize the 
measurement units among ARM sites and to conform to accepted standard units determined by the 
scientific community.

• Atmospheric pressure(atmos_pressure)

TWP/SMET/C2 - 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.

• Time offset from base_time(base_time)