GRW/VCEIL/M1 - Receiver failure

The AMF VCEIL had lower-than-normal laser transmitter power, ~84%, so the instrument was 
replaced with a spare on 4/22. The spare VCEIL had just been repaired but began to display 
receiver failure warnings.

Diagnostic information was sent to Vaisala and we discussed either replacing the receiver 
with the one from the original VCEIL (with the degraded transmitter) or replacing the 
transmitter in the original VCEIL with the one from the spare. Vaisala recommended the 
latter because the original VCEIL is a much newer unit.

On 5/16, the site operator replaced the transmitter in the original VCEIL with the one 
from the spare, realigned the optics, recalibrated the laser, and put the instrument back 
into service, successfully correcting the problem.

The data during this period were intermittently incorrect, containing warning flags and 
alarms and unreasonable cloud base heights.

• Vertical visibility(vertical_visibility)
• Lowest cloud base height detected.(first_cbh)
• background_light
• Backscatter(backscatter)
• Third cloud base height(third_cbh)
• Second lowest cloud base height(second_cbh)
• alt_highest_signal

GRW/ECOR/M1 - Reprocessed: ECOR Wind direction offset corrected

The ECOR sonic anemometer was initially aligned to an east declination
instead of a west declination.  For the period stated, ECOR wind direction
was 21 degrees too high.

Data were reprocessed 20090602 and archived 20090619.

• wind_dir

GRW/TSI/M1 - Mirror reflection

A deformity in the mirror produced an anomolous refraction within the mirror surface that 
appeared in the images as a white streak near the top of the mirror and shadowband. The 
mirror was replaced on 6/19.

• region_sun_count
• region_sun_count_thin
• region_sun_count_opaque

GRW/SONDE/M1 - Wind data missing

A GPS problem associated with Vaisala BBSS ground station software issues caused the 
ground stations to enter into an error state when using GPS wind finding. In some instances, 
the flight was aborted due to the error state and no data was collected.  A workaround was 
developed to allow sondes to be launched without collecting wind data.

• Northward Wind Component(v_wind)
• Eastward Wind Component(u_wind)
• wstat
• Mean Wind Speed(wspd)

GRW/MET/M1 - Temperature/RH Aspirator Failure

The aspirator fan on the solar shield failed causing incorrect readings on the temp, RH 
and calculated variables.

• Temperature mean(temp_mean)
• relh_sd
• Vapor pressure mean(vappress_mean)
• Relative humidity mean(relh_mean)
• vappress_sd
• temp_sd

GRW/TSI/M1 - Shadowband Misalignment

The shadowband was intermittently misaligned and not completely masking the sun because 
the mirror became loose from the shaft while being polished. The shadowband was realigned 
on 1/14 but by 1/27 was again slightly misaligned. The instrument was reoriented with true 
north on 1/27 and the shadowband adjusted again on 1/31. The problem was corrected on 
2/2 when the mirror mounting was tightened and the shadowband realigned.

• Cloud decision images, Total Sky Imager, PNG format(png)

• count_sub_horz
• region_sun_count
• region_horizon_count_thin
• region_horizon_count_opaque
• count_mask
• count_thin
• region_sun_count_thin
• region_zenith_count_thin
• region_sun_count_opaque
• Cloud amount, opaque (percent)(percent_opaque)
• count_sky
• Cloud amount, thin (percent)(percent_thin)
• count_sub_proczen
• count_opaque
• count_box
• region_horizon_count
• region_zenith_count
• region_zenith_count_opaque

• JPEG data stream - documentation not yet available

GRW/VCEIL/M1 - Reprocess: Incorrect serial_number and sum_backscatter fields

Attribute serial_number: In most cases, this field is not representative of the actual 
serial number of the instrument because the value did not change when an instrument changed 
locations or was replaced with a spare.
   
Variable sum_backscatter: An out-of-range condition for the "sum of detected and 
normalized backscatter" was reported as 0 instead of missing (-9999). The valid range is 0 - 
0.0999 /srad.

• sum_backscatter

GRW/TSI/M1 - Contamination of mirror

A persistent, agile bird was landing on top of and polluting the mirror, multiple times 
throughout the day, affecting the visible and processed images and cloud fraction data.

• MPEG data stream - documentation not yet available

• Cloud decision images, Total Sky Imager, PNG format(png)

• count_sky
• Cloud amount, thin (percent)(percent_thin)
• sun_strength
• count_thin
• count_opaque
• region_zenith_count_thin
• region_zenith_count
• region_zenith_count_opaque
• Cloud amount, opaque (percent)(percent_opaque)

• JPEG data stream - documentation not yet available

GRW/MET/M1 - 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 will reprocess the data to remove these 
small values.

• precip_rate_sd
• Rain, surface, 1-min avg(precip_rate_mean)
• precip_rate_min
• precip_rate_max

GRW/ECOR/M1 - Effects on ECOR CO2 Flux and Concentration by Aircraft

Aircraft landings, departures, and running aircraft on the airport pad were found to 
produce spikes in the half hourly CO2 flux and small spikes in CO2 concentration on many days 
during the entire deployment of the AMF1 at GRW. This influence sometimes occurred 
multiple periods in a day; this was typical of the year of data.  The spikes range from only 
several micromoles s-1 m-2 to one hundred or more for flux (a typical spike was in the 
twenties) and near zero to 1.0 mmoles m-3 for CO2 concentration (typically around 0.15).

Occasionally an influence on water vapor density was detected, but this was fairly rare 
and usually of very small magnitude.

• variance of variable c(var_c)
• rotated covariance wc(cvar_rot_wc)
• covariance uc(cvar_uc)
• CO2 flux(fc)
• rotated covariance vc(cvar_rot_vc)
• covariance tc(cvar_tc)
• covariance wc(cvar_wc)
• covaraince vc(cvar_vc)
• Mean CO2 density(mean_c)
• rotated covariance uc(cvar_rot_uc)

GRW/TSI/M1 - Shadowband Misalignment

The shadowband was slightly out of alignment because one corner of the instrument stand 
had sunk about 25mm.  The stand was releveled and the TSI re-aligned.

• region_sun_count
• sun_strength
• count_mask
• count_thin
• region_sun_count_thin
• region_zenith_count_thin
• region_sun_count_opaque
• Cloud amount, opaque (percent)(percent_opaque)
• Cloud amount, thin (percent)(percent_thin)
• count_opaque
• count_box
• region_zenith_count
• region_zenith_count_opaque