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OAS accession Detail for 0301002, meta_version: 1. Current meta_version is: 4
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Title: NOAA GML and CIRES/Uni. of Colorado-Boulder Ceilometer Cloud Data Products at Kettle Ponds (CKP) for SPLASH (NCEI Accession 0301002)
Abstract: Overview
The NOAA Global Monitoring Laboratory (GML) Radiation, Aerosols, and Cloud Division (G-RAD) and the Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado Boulder, operated Vaisala CL51 ceilometers at the Kettle Ponds (CKP) and Brush Creek (CBC) observatory field sites during the NOAA Study of Precipitation, Lower Atmosphere, and Surface for Hydrometeorology (SPLASH) experiment. The cloud product files are produced in order to condense the wealth of level 0 data streams and instrument health checks that are produced and logged by Vaisala’s BL View processing system in order to focus on the primary data observations/products these ceilometers produce; namely attenuated backscatter coefficient profiles (aerosol and cloud hydrometeor backscatter) cloud detection status, and cloud base height above ground level. Note, Vaisala’s BL View retrieved boundary layer height estimates are not included in these files; NOAA GML/G-RAD and CIRES researchers are working to produce a value-added data product of boundary layer height retrievals from CL51 attenuated backscatter and additional surface-based observations that will be uploaded as separate data product/data files once completed.

These files are produced daily, from 00:00:00 UTC to 23:59:59 UTC at each location. The ceilometer data products were temporally downscaled to 1 min frequency through a nearest neighbor methodology. Missing days indicate instrument downtime, errors in BL View algorithm processing, or other data issues which inhibited data transfer. If particular days of interest are missing data, please contact the data author via email listed in the global attributes section of the netCDF files to determine if raw data could be recoverable. The CL51 ceilometers were deployed in early- to mid-October 2021, with data collection occurring across the following date ranges:

● CKP: 2021-10-19 through 2023-08-15
● CBC: 2021-10-19 through 2023-08-14

Filename information:
File naming convention example: ‘ckp.cl51.cloud_prod.202211024.nc’ ckp: site identifier (either ‘ckp’ for Kettle Ponds, or ‘cbc’ for Brush Creek) cl51: instrument model
cloud_prod: data product descriptor
20221024: YYYYMMDD
Variables, dimensions, and attributes:
An example dump of the netCDF file contents for one example daily file is found here:
netcdf ckp.cl51.cloud_prod.20221024 { dimensions:
time = 1440 ; range = 1540 ; cloud_layer = 3 ;
variables:
int64 time(time) ;
time:units = "seconds since 1900-01-01T00:00:00+00:00" ; time:calendar = "proleptic_gregorian" ;
int range(range) ;
range:long_name = "Distance from ground" ; range:units = "m" ;
range:standard_name = "distance" ; range:axis = "Z" ;
range:positive = "up" ;
byte cloud_layer(cloud_layer) ;
cloud_layer:long_name = "Cloud layer index" ; cloud_layer:units = "1" ;
cloud_layer:axis = "Z" ;
cloud_layer:positive = "up" ;
float backscatter_profile(time, range) ;
backscatter_profile:_FillValue = NaNf ;
backscatter_profile:long_name = "2-D ceilometer signal backscatter profile." ; backscatter_profile:units = "10e-9 m^-1 sr^-1" ; backscatter_profile:comments = "Range-corrected-scattering" ;
float cloud_status(time) ; cloud_status:_FillValue = NaNf ;
cloud_status:long_name = "Cloud detection status." ;
cloud_status:units = "1" ;
cloud_status:flag_values = "0,1,2,3,4" ;
cloud_status:flag_0 = "No significant backscatter." ;
cloud_status:flag_1 = "One cloud layer detected." ;
cloud_status:flag_2 = "Two cloud layers detected." ;
cloud_status:flag_3 = "Three cloud layers detected." ;
cloud_status:flag_4 = "Full obscuration/vertical visibility mode. First cloud_base will report vertical
visibility and second cloud_base will report highest signal" ;
cloud_status:comments = "When cloud_status=4 there is an optically thick cloud that obscures the signal.
Therefore it is not possible to discern additional cloud layers above it so the vertical visibility and highest signal are reported instead." ;
float cloud_data(time, cloud_layer) ; cloud_data:_FillValue = NaNf ;
cloud_data:long_name = "Cloud base heights." ;
cloud_data:units = "m" ;
cloud_data:comments = "A 2D array containing all three cloud bases at each timestep. -999 if no
significant signal." ;
cloud_data:cloud_base_1 = "First cloud base height or vertical visibility if cloud_status=4" ; cloud_data:cloud_base_2 = "Second cloud base height or highest received signal if cloud_status=4" ; cloud_data:cloud_base_3 = "Third cloud base height" ;
int64 instrumen_reported_time(time) ;
instrumen_reported_time:long_name = "Instrument reported time" ; instrumen_reported_time:comments = "Timestamp that was reported by the instrument. The \"time\"
coordinate was re-indexed to the full minute (see global comments)." ; instrumen_reported_time:units = "seconds since 1900-01-01T00:00:00+00:00" ; instrumen_reported_time:calendar = "proleptic_gregorian" ;
// global attributes:
:title = "Ceilometer cloud product" ;
:version = "1.3.2" ;
:institution = "NOAA/GML/GRAD" ;
:author = "hagen.telg@noaa.gov" ;
:source = "Vaisala CL51 ceilometer" ;
:serial_number = "r1350816" ;
:input_files = "L2_CKP_202210240000_r1350816.nc" ; :Conventions = "CF-1.8" ;

:comments = "The \'time\' coordinate has been re-indexed to the nearest full minute, using the closest valid data value from within 1 minute prior to each timestamp. The data remains unprocessed, except for the default processing by Vaisala\'s software. Quality control is limited to visual checks for implausible values or clear errors." ;
}
Versioning:
:site_name = "ckp" ; :site_latitude = "38.941700" ; :site_longitude = "-106.973099" ;
The current version of this data product is v1.3.2. Details on versioning updates can found on the following GitHub account: https://hagne.github.io/ceilopy/product_cl51_cloud_prod_lev1.html
Date received: 20241218
Start date: 20211019
End date: 20230815
Seanames:
West boundary: 106.973099
East boundary: 106.973099
North boundary: 38.9417
South boundary: 38.9417
Observation types:
Instrument types:
Datatypes:
Submitter: Ballard, Bradley
Submitting institution:
Collecting institutions:
Contributing projects:
Platforms:
Number of observations:
Supplementary information:
Availability date:
Metadata version: 1
Keydate: 2025-01-22 13:02:02+00
Editdate: 2025-01-22 13:04:12+00