SGP/TSI/C1 - sampling rate change

SGP TSI-880 sampling rate changed from 20-second to
30-second at 20020426.001900 UTC (20020425.1819 SGP
CF local time) per ECR-00226 and BCR-00491.

This change brings all ARM TSIs to the same operational
sampling rate.  Daily SGP TSI data volume will decrease
by about 1/3 due to this change.

• region.horizon.count.opaque
• solar.altitude
• count.mask
• region.zenith.count.thin
• region.zenith.count
• count.unknown
• count.sub.proczen
• North latitude(lat)
• region.zenith.count.opaque
• count.sky
• region.sun.count.opaque
• count.opaque
• region.sun.count.thin
• East longitude(lon)
• solar.azimuth
• region.horizon.count
• region.horizon.count.thin
• count.sub.horz
• Altitude above mean sea level(alt)
• Cloud amount, thin (percent)(percent.thin)
• count.thin
• base_time
• Sunshine Meter(sunny)
• region.sun.count
• count.box
• Cloud amount, opaque (percent)(percent.opaque)
• sun.strength
• time_offset

SGP/TSI/C1 - Metadata Errors in NetCDF Header

The value of "sample_int" reported in the netCDF header is
incorrect.  The correct sampling interval is 30 seconds.

The maximum values for the variable "sunny" is incorrect.  
It should be 1, not 100 as documented in the netCDF header. 
Users should disregard the "qc_sunny" flag during this
period of time and apply their own qc check if desired.

The minimum value for the variable "solar.altitude" is
incorrect. It should be -90, not 10 as documented in the
netCDF header.  Users should disregard the "qc_solar.altitude"
flag during this period of time and apply their own qc check
if desired.

• Sunshine Meter(sunny)
• solar.altitude
• time_offset

SGP/TSI/C1 - Shadowband misaligned

The shadowband and mask were initially misaligned after the re-installation of the TSI.

• region.horizon.count
• region.horizon.count.opaque
• count.sub.horz
• region.horizon.count.thin
• count.mask
• region.zenith.count.thin
• region.zenith.count
• count.unknown
• count.thin
• Cloud amount, thin (percent)(percent.thin)
• count.sub.proczen
• region.zenith.count.opaque
• count.sky
• region.sun.count.opaque
• count.opaque
• region.sun.count
• region.sun.count.thin
• Cloud amount, opaque (percent)(percent.opaque)
• count.box

SGP/TSI/C1 - Metadata errors

The latitude, longitude and altitude of the Total Sky Imager 
(TSI) were incorrectly entered into the ARM database.  The 
correct location of the SGP.C1 TSI is:
   Lat: 36.606N
   Lon: 97.485W
   Alt:    316m

• East longitude(lon)
• Altitude above mean sea level(alt)
• North latitude(lat)

SGP/TSI/C1 - Shadowband Misalignment

The shadowband was slightly misaligned and was corrected by adjusting it +2 degrees.

• count.sky
• count.opaque
• region.sun.count.opaque
• region.sun.count
• region.sun.count.thin
• Cloud amount, opaque (percent)(percent.opaque)
• count.mask
• count.thin
• Cloud amount, thin (percent)(percent.thin)
• count.sub.proczen

SGP/TSI/C1 - Instrument failure

The TSI-880 experienced a power and/or computer failure. It was replaced with a spare 
TSI-440 and data collection resumed 4/5/05.  Note: this is a temporary replacement.

• region.horizon.count.opaque
• solar.altitude
• count.mask
• region.zenith.count.thin
• region.zenith.count
• count.unknown
• count.sub.proczen
• North latitude(lat)
• region.zenith.count.opaque
• count.sky
• region.sun.count.opaque
• count.opaque
• region.sun.count.thin
• East longitude(lon)
• solar.azimuth
• region.horizon.count
• region.horizon.count.thin
• count.sub.horz
• Altitude above mean sea level(alt)
• Cloud amount, thin (percent)(percent.thin)
• count.thin
• base_time
• Sunshine Meter(sunny)
• region.sun.count
• count.box
• Cloud amount, opaque (percent)(percent.opaque)
• sun.strength
• time_offset

SGP/TSI/C1 - Heater problem

The TSI was converted from a model 880 to 660 which requires separate power for the mirror 
heater. The heater was not powered during this period so morning dew and other 
condensation was not quickly evaporated.

• count.opaque
• Cloud amount, opaque (percent)(percent.opaque)
• count.thin
• Cloud amount, thin (percent)(percent.thin)

SGP/TSI/C1 - Missing data

Data are missing and unrecoverable.

• region.horizon.count.opaque
• solar.altitude
• count.mask
• region.zenith.count.thin
• region.zenith.count
• count.unknown
• count.sub.proczen
• North latitude(lat)
• region.zenith.count.opaque
• count.sky
• region.sun.count.opaque
• count.opaque
• region.sun.count.thin
• East longitude(lon)
• solar.azimuth
• region.horizon.count
• region.horizon.count.thin
• count.sub.horz
• Altitude above mean sea level(alt)
• Cloud amount, thin (percent)(percent.thin)
• count.thin
• base_time
• Sunshine Meter(sunny)
• region.sun.count
• count.box
• Cloud amount, opaque (percent)(percent.opaque)
• sun.strength
• time_offset

SGP/TSI/C1 - Contamination of mirror

A persistent bird was landing on and polluting the mirror, multiple times throughout the 
day. Spikes were placed on the corners and top of the instrument (an affective deterrent 
in the past) but this bird had the agility to perch on the top-center of the mirror.

• count.sky
• count.opaque
• Cloud amount, opaque (percent)(percent.opaque)
• region.zenith.count.thin
• region.zenith.count
• count.thin
• Cloud amount, thin (percent)(percent.thin)
• region.zenith.count.opaque

SGP/TSI/C1 - Ingest Problem

A minor error was made with diagnostic metadata attribute sunny_thresh when the TSI ingest 
was updated.

• base_time

SGP/TSI/C1 - Water on lens

After a rain episode, drops of water collected on the lens window causing the cloud 
fraction values to be suspect.

To prevent this, a drip edge was formed around the bottom of the enclosure with thick 
electrical or splicing tape.

• count.sky
• count.opaque
• Cloud amount, opaque (percent)(percent.opaque)
• region.zenith.count.thin
• region.zenith.count
• count.thin
• Cloud amount, thin (percent)(percent.thin)
• region.zenith.count.opaque

SGP/TSI/C1 - Mirror contamination

The surface of the chrome mirror was soiled causing the cloud fraction determination to be 
unreliable.

• count.opaque
• Cloud amount, opaque (percent)(percent.opaque)
• count.thin
• Cloud amount, thin (percent)(percent.thin)

SGP/TSI/C1 - Data processing problem

Values of count_opaque and count_thin are reals but should be integers  (units = pixels).

• count.opaque
• count.thin

SGP/TSI/C1 - Reprocessing Notice (RID 951)

See below for details of reprocessing that was completed on 20140922.  Original 
DQR category: 5 (Transparent - Does not affect quality).

-----------------------------------------------------------

The units of global attributes region_sun_radius and region_zenith_radius should be 
degrees, not pixels.

• base_time

SGP/TSI/C1 - Camera misalignment

The camera was slightly out of alignment causing the west edge of the image to be cropped. 
The position of the camera was adjusted so it was centered over the mirror.

• region.horizon.count
• count.box
• count.sub.horz

SGP/TSI/C1 - Shadowband misalignment

The shadowband was misaligned.

• count.opaque
• region.sun.count.opaque
• region.sun.count.thin
• region.horizon.count.opaque
• Cloud amount, opaque (percent)(percent.opaque)
• region.horizon.count.thin
• sun.strength
• region.zenith.count.thin
• count.thin
• Cloud amount, thin (percent)(percent.thin)
• region.zenith.count.opaque

SGP/TSI/C1 - Icing event

An icing event (winter storm Cara) passed slowly through the area during this time frame.  
The TSI image was affected by ice accumulation on the mirror.

• region.horizon.count
• region.horizon.count.opaque
• count.sub.horz
• region.horizon.count.thin
• count.mask
• region.zenith.count.thin
• region.zenith.count
• count.thin
• Cloud amount, thin (percent)(percent.thin)
• count.sub.proczen
• region.zenith.count.opaque
• count.sky
• Sunshine Meter(sunny)
• region.sun.count.opaque
• count.opaque
• region.sun.count
• region.sun.count.thin
• Cloud amount, opaque (percent)(percent.opaque)
• sun.strength

SGP/TSI/C1 - Ice storm

The TSI images were affected by an ice storm that caused the mirror to be covered with 
ice, the shadowband to stop rotating, and condensation to blur the images.

• Sunshine Meter(sunny)
• count.opaque
• region.sun.count.opaque
• region.sun.count.thin
• region.horizon.count.opaque
• Cloud amount, opaque (percent)(percent.opaque)
• region.horizon.count.thin
• sun.strength
• region.zenith.count.thin
• count.thin
• Cloud amount, thin (percent)(percent.thin)
• region.zenith.count.opaque

SGP/TSI/C1 - power failure

An ice storm caused the SGP site to lose power.

• region.horizon.count.opaque
• solar.altitude
• count.mask
• region.zenith.count.thin
• region.zenith.count
• count.unknown
• count.sub.proczen
• North latitude(lat)
• region.zenith.count.opaque
• count.sky
• region.sun.count.opaque
• count.opaque
• region.sun.count.thin
• East longitude(lon)
• solar.azimuth
• region.horizon.count
• region.horizon.count.thin
• count.sub.horz
• Altitude above mean sea level(alt)
• Cloud amount, thin (percent)(percent.thin)
• count.thin
• base_time
• Sunshine Meter(sunny)
• region.sun.count
• count.box
• Cloud amount, opaque (percent)(percent.opaque)
• sun.strength
• time_offset

SGP/TSI/C1 - Reprocess: Corrupt properties file

The YYYMMDDHHMMSS_tsi.properties files were corrupted when the computer operating system 
was upgraded, causing the ingest to assign incorrect values to attributes opaque_thresh, 
thin_thresh, cam_mir_dist, and center_x. A default properties file from 5/25/2004 was 
briefly used and then a properties file from 10/11/2013 was being concatenated to the current 
properties file before it was moved to the ingest directory, so that the last values 
read were from the earlier date.

• base_time

SGP/TSI/C1 - Reprocess: Global attribute units incorrect for cam_mir_dist

The global attribute cam_mir_dist was converted incorrectly.  The raw 
camera.mirror.distance, in inches, was multiplied by 10 and assigned a unit of mm.

• base_time