TWP/SMET/C1 - Reprocess: Miscalibrated windspeed2 data

A replacement anemometer (WSP2) was installed but the new anemometer calibration 
coefficients were not put into the logger. The multiplication factor was 0.09708 when it should 
have been 0.09763 (very small difference)the offset was 0.36 when it should have been 0.3 
(a difference 0.06 m/s).

• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• Wind #2 speed minimum(wind2_spd_min)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Wind #2 speed maximum(wind2_spd_max)

• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• Wind #2 speed maximum(wind2_spd_max)
• Wind #2 speed minimum(wind2_spd_min)
• Wind #2 speed maximum gust(wind2_spd_max_gust)

TWP/SMET/C1 - Reprocess: Lower Wind Speed incorrect

The lower wind speed sensor (sensor #2) was reporting values 10 times above the actual 
value.  During an update to the logger configuration file the calibration multiplier was 
incorrectly entered.  The multiplier inserted was .97630 when it should have been .09763.  
This caused the readings from this sensor to be incorrect.

• lo_spd_max
• lo_spd_vec_avg
• lo_spd_min
• lo_spd_arith_avg
• lo_spd_sd

• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• wind2_spd_sd
• Wind #2 speed maximum(wind2_spd_max)
• Wind #2 speed minimum(wind2_spd_min)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Wind #2 speed vector average(wind2_spd_vec_avg)

TWP/SMET/C1 - Tower Lowered for Cal Activities

Tower lowered for instrument calibration

• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• Relative humidity minimum(relh_min)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Precipitation maximum(precip_max)
• Relative humidity maximum(relh_max)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• Mean Air Temperature or Hardware Error(temp_mean)
• Precipitation minimum(precip_min)
• Wind #1 speed minimum(wind1_spd_min)
• relh_sd
• Wind #2 speed minimum(wind2_spd_min)
• Wind #1 direction vector average(wind1_dir_vec_avg)
• Wind #2 speed maximum(wind2_spd_max)
• Temperature minimum(temp_min)
• Relative humidity mean(relh_mean)
• vappress_sd
• wind1_spd_sd
• wind1_dir_sd
• precip_sd
• temp_sd
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Wind #2 speed vector average(wind2_spd_vec_avg)
• Temperature maximum(temp_max)
• Precipitation mean(precip_mean)
• wind2_dir_sd
• wind2_spd_sd
• Wind #1 speed maximum(wind1_spd_max)
• Vapor pressure mean(vappress_mean)

• Raw data stream - documentation not supported

TWP/SMET/C1 - Poor Performing Sensor

On 4/23/2004 condensation was found inside the target area of the ORG lens. A spare was 
sent and installed but did not solve the problem of high background voltage values causing 
rainrate values to be recorded during no rainfall.  Values range anywhere from 0.06 to 
0.12 mm/hr.  

A new Optical Rain Gage was installed on 01/19/2005 @ 13:30 GMT alleviating the high 
background voltage values that lead to consistent rainfall rates of around 0.11 to 0.15 mm/hr 
on a consistent basis.  

The formula used to calculate rainfall rates from the new Optical Rain Gage is:  RR 
(mm/hr) = 25(V^1.87) - 0.15.

Older model formula = 20(V^2) - 0.05

The two formulas result in comparable data.

• Precipitation minimum(precip_min)
• Precipitation maximum(precip_max)
• precip_sd
• Precipitation mean(precip_mean)

TWP/SMET/C1 - Incorrect rainrate equation used

There are two different Optical Raingages in use at the TWP sites.  The incorrect equation 
was used at this site.  The incorrect equation is (25*(V^1.87)) - 0.15.
The correct equation is (20*(V^2)) - 0.05.  The correct equation was installed.

• Precipitation minimum(precip_min)
• Precipitation maximum(precip_max)
• precip_sd
• Precipitation mean(precip_mean)

TWP/SMET/C1 - 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.  New loggers were installed 03/09/2004 @ 2243 GMT.

• Precipitation minimum(precip_min)
• Precipitation maximum(precip_max)
• precip_sd
• Precipitation mean(precip_mean)

TWP/SMET/C1 - Upper wind sensor failure

The upper wind speed sensor was binding at low wind speeds.  Comparison to the lower wind 
sensor showed that the upper sensor flat-lines for long periods of time.  The upper 
anemometer was replaced.

• up_dir_sd
• up_spd_max
• up_spd_sd
• up_dir_vec_avg
• up_spd_vec_avg
• up_spd_arith_avg
• up_spd_min

TWP/SMET/C1 - Reprocess: Tipping bucket rain gauge added

A tipping bucket rain gauge was added to the TWP.C1 SMET suite of instruments on 20061017. 
 Effective 20060926, two new variables (count and rain amount) were added to the end of 
the twpsmet60sC1.b1 datastream.  Between 9/26 and 10/17, the data for these two variables 
are filled with zeros.  Users should not use the data during this period as the zeros 
are not representative of the rain fall at the site.  When reprocessing of this datastream 
occurs these variables will be added for the 19961009-20060926 and data from 
19961009-20061017 will be filled with -9999 (missing).

• base_time

TWP/SMET/C1 - Upper winds failure

The upper wind instrument was inoperative resulting in constant wind direction and speed.  
A failed cable was replaced.

• up_dir_sd
• up_spd_max
• up_spd_sd
• up_dir_vec_avg
• up_spd_vec_avg
• up_spd_arith_avg
• up_spd_min

TWP/SMET/C1 - Reprocess: ORG Data has very small rainrate values

The ORG data is collected via analog signal and not digital.  Therefore, we continuously 
collect data even when no rain is occurring.  We also capture small events such as leaves, 
large bugs, dust, etc blowing through the measurement path.  Because this discrete event 
occurs quickly the value is usually captured for 1 or 2 seconds.  This value is then 
averaged to the minute producing rainrate on the order of .009 mm/hr or less.  These values 
are not indicative of rain and should be removed from the record or summing over long 
periods can bias the climate record.  We are reprocessing the data to remove these small 
values and are adjusting the collection program to remove them before ingest.

• Precipitation minimum(precip_min)
• Precipitation maximum(precip_max)
• precip_sd
• Precipitation mean(precip_mean)

TWP/SMET/C1 - ORG Precip Data Incorrect

Moisture intrusion into the sensor body allowed condensation on the lens of the ORG.  
Continual and long-term precipitation was reported during this time.

• Precipitation minimum(precip_min)
• Precipitation maximum(precip_max)
• precip_sd
• Precipitation mean(precip_mean)

TWP/SMET/C1 - Missing data

Data are missing and unrecoverable.

• up_dir_sd
• lo_spd_vec_avg
• up_spd_max
• lo_dir_vec_avg
• logger_temp
• Precipitation maximum(precip_max)
• up_dir_vec_avg
• time_offset
• up_spd_min
• Mean Air Temperature or Hardware Error(temp_mean)
• Precipitation minimum(precip_min)
• time
• relh_sd
• internal_voltage
• lat
• alt
• lo_spd_sd
• base_time
• lo_spd_max
• lo_spd_min
• Relative humidity mean(relh_mean)
• vappress_sd
• up_spd_sd
• Barometric Pressure(atmos_pressure)
• tbrg_count_total
• precip_sd
• up_spd_arith_avg
• tbrg_total
• temp_sd
• Precipitation mean(precip_mean)
• lo_spd_arith_avg
• lon
• lo_dir_sd
• Vapor pressure mean(vappress_mean)
• up_spd_vec_avg

TWP/SMET/C1 - 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.

• lo_spd_max
• up_spd_max
• lo_spd_vec_avg
• lo_spd_min
• lo_spd_arith_avg
• up_spd_sd
• up_spd_vec_avg
• up_spd_arith_avg
• up_spd_min
• lo_spd_sd

TWP/SMET/C1 - Optical Rain Gage Inoperative

Beginning on 02/07/2009, the trending between the TBRG and ORG began to look poor, one 
recording precip when the other was not and vice versa.  After a while the ORG quit 
registering any precip at all.  ORG was replaced.

• Precipitation minimum(precip_min)
• Precipitation maximum(precip_max)
• precip_sd
• Precipitation mean(precip_mean)

TWP/SMET/C1 - Reprocess: Barometric pressure data scaled incorrectly

The barometer data was scaled incorrectly when a new program was loaded into the 
datalogger.  The pressure data was reported as mb (hPa) instead of the standard kPa.  So, in 
essence the value was a factor of ten to large.

• Barometric Pressure(atmos_pressure)

TWP/SMET/C1 - Missing RH, Barometer, and ORG data

Atmos_pressure data suddenly went missing on 03/02 at 07:34 UTC and consequently, the 
relative humidity data flatlined. 

Furthermore, after a sudden precipitation event when the max precip rate flag was tripped 
the TBRG total has not agreed with the comparison ORG or the precip rate plot. 

A loose wire connection was fixed 3/22 restoring RH and barometer data.  A damaged cable 
was repaired 5/11 restoring ORG data.

• Relative humidity mean(relh_mean)
• Precipitation minimum(precip_min)
• relh_sd
• Barometric Pressure(atmos_pressure)
• Precipitation maximum(precip_max)
• precip_sd
• Precipitation mean(precip_mean)

TWP/SMET/C1 - Aux (lower) wind sensor failed

The lower wind direction sensor on the C1 site was flatlining at 270 degrees throughout 
most of the daylight hours of the day. During the night the sensor appeared to be working 
fine.

• lo_spd_max
• lo_spd_vec_avg
• lo_spd_min
• lo_spd_arith_avg
• lo_dir_vec_avg
• lo_dir_sd
• lo_spd_sd