SGP/THWAPS/C1 - THWAPS C1 miscalibrated

Power outages apparently led to the THWAPS HMP233 temperature and RH sensor
being replaced at C1.  The power went out at 0340 on 3/9 was restored at
0635 and went out again at 2025.

The new HMP233 appears to be incorrectly calibrated and all temperature
data since its installation are wrong.  If I am correct about the nature
of the calibration problem, the true average temperature can be recovered
from that recorded by a linear conversion, but I don't think its worth the
trouble.

• Pressure, vapor, 25-m height, 1-min intervals(vap_pres)
• Humidity, relative, 30-min intervals, standard deviation(sd_rh)
• Temperature, air, 30-min intervals, standard deviation(sd_temp)
• Humidity, relative, at 21-m height, 30-min avg(rh)
• Temperature, air, at altitude, RUC model output(temp)

SGP/THWAPS/B1/B5/B6/C1 - Missing data due to Ice storm and clock problems

Data are missing due to power failures caused by an ice storm
and resulting system/instrument clock problems.

• Altitude above mean sea level(alt)
• time_offset
• Wind speed, surface, 1-min avg(wspd)
• Pressure, vapor, 25-m height, 1-min intervals(vap_pres)
• sd_pres
• sd_vap_pres
• Humidity, relative, at 21-m height, 30-min avg(rh)
• East longitude(lon)
• vbat
• sd_wdir
• base_time
• North latitude(lat)
• Humidity, relative, 30-min intervals, standard deviation(sd_rh)
• Temperature, air, 30-min intervals, standard deviation(sd_temp)
• Pressure, atmospheric, constant value of model level, RUC model output(pres)
• Temperature, air, at altitude, RUC model output(temp)
• Wind speed, W-to-E component, at altitude, derived from ETA model(wdir)

SGP/THWAPS/C1 - RH Sensor Calibration

The analog output for the T/RH probe was incorrectly calibrated.  This
caused excessively high readings of RH.

• Pressure, vapor, 25-m height, 1-min intervals(vap_pres)
• Humidity, relative, 30-min intervals, standard deviation(sd_rh)
• sd_vap_pres
• Humidity, relative, at 21-m height, 30-min avg(rh)

SGP/THWAPS/C1 - Minor bias in humidity

The THWAPS humidity sensor output was scaled so that the instrument output
voltage range (0-1VDC) represented 0-100 %RH. Comparisons with the
co-located chilled mirror sensor at the CF suggested that the THWAPS RH
sensor was reading artifically low at high humidities because of this 100
%RH maximum. 
   
The scaling of the system was changed so that 0-1 VDC now represents 0-110
%RH. This resulted in a slight loss of precision in the measurements, but
since the RH measurement is only accurate to 2-3 %RH at best, this isn't a
significant problem.

• Humidity, relative, at 21-m height, 30-min avg(rh)

SGP/THWAPS/C1 - Minor bias in saturation vapor pressure

The saturation vapor correction when temps are below 0C contained an error
in the multiplier.  The incorrect multiplier only equates to an error of
0.01 kPa which is less than the stated uncertainty of the measurement (+/-
0.035 kPa).

• Pressure, vapor, 25-m height, 1-min intervals(vap_pres)

SGP/THWAPS/C1 - RH Data Incorrect

The RH data was incorrect during the times listed.  Reason unknown.  The sensor recovered 
on its own.

• Pressure, vapor, 25-m height, 1-min intervals(vap_pres)
• Humidity, relative, 30-min intervals, standard deviation(sd_rh)
• sd_vap_pres
• Humidity, relative, at 21-m height, 30-min avg(rh)

SGP/THWAPS/C1 - Barometer intermittent

Intermittent dropouts on the barometer data were occurring, with data reading low or 
missing.  Loose wiring was the probable culprit.

In most instances, only 1 minute of data was missing. Linear interpolation between the 
last known good point and the first good point following the dropout can be accomplished.

• Pressure, atmospheric, constant value of model level, RUC model output(pres)

SGP/THWAPS/C1 - Time stamp of data record incorrect

Due to problems with the collector system, the datalogger was being time synched 
inappropriately.  This problem was intermittent and did not affect every time stamp.  The worst 
case time adjustments were approximately +/- 7 minutes.  These were infrequent and most of 
the time adjustments were less than 7 minutes.

• time_offset
• base_time

SGP/THWAPS/C1 - Wind speed incorrect

The wind sensor was reporting 0 m/s winds for excessive periods of time and appeared to 
measure lower wind speeds than nearby co-located wind sensors.  Sensor was replaced.

• Wind speed, surface, 1-min avg(wspd)

SGP/THWAPS/C1 - T/RH sensor failure

Storm damage caused failure of the temperature/humidity sensor.  Sensor replaced.

• Pressure, vapor, 25-m height, 1-min intervals(vap_pres)
• Humidity, relative, 30-min intervals, standard deviation(sd_rh)
• sd_vap_pres
• Temperature, air, 30-min intervals, standard deviation(sd_temp)
• Humidity, relative, at 21-m height, 30-min avg(rh)
• Temperature, air, at altitude, RUC model output(temp)

SGP/THWAPS/C1 - RH too high

The T/RH sensor was reporting much higher humidity than the sonde station and nearby 
sensors for some sonde launches.

• Pressure, vapor, 25-m height, 1-min intervals(vap_pres)
• Humidity, relative, 30-min intervals, standard deviation(sd_rh)
• sd_vap_pres
• Humidity, relative, at 21-m height, 30-min avg(rh)

SGP/THWAPS/C1 - Incorrect T/RH data

There was a power issue with the T/RH sensor.

• Pressure, vapor, 25-m height, 1-min intervals(vap_pres)
• Humidity, relative, 30-min intervals, standard deviation(sd_rh)
• sd_vap_pres
• Temperature, air, 30-min intervals, standard deviation(sd_temp)
• Humidity, relative, at 21-m height, 30-min avg(rh)
• Temperature, air, at altitude, RUC model output(temp)

SGP/THWAPS - RH values low by factor of 1.1

Because of instrument mentor stupidity, all C1 THWAPS RH data collected
from the begin date of this DQR are low by a factor of 1.1.  This error
also will affect the vapor pressure data.  The problem is that the CSI
data logger is expecting the data to be scaled 0-100%RH on the range 0-1V,
but it is now being scaled 0-110%RH on the range 0-1V.

• Pressure, vapor, 25-m height, 1-min intervals(vap_pres)
• Humidity, relative, 30-min intervals, standard deviation(sd_rh)
• sd_vap_pres
• Humidity, relative, at 21-m height, 30-min avg(rh)