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Institution Dataset ID
   set  data   graph     PMEL Atmospheric Chemistry ATOMIC CCN 10 second data    ?   F   I   M   background (external link) RSS Subscribe
NOAA PMEL Atmosph...  ?

The Dataset's Variables and Attributes

Row Type Variable Name Attribute Name Data Type Value
attribute NC_GLOBAL _NCProperties String version=2,netcdf=4.7.4,hdf5=1.10.6
attribute NC_GLOBAL cdm_data_type String Trajectory
attribute NC_GLOBAL cdm_trajectory_variables String trajectory_id
attribute NC_GLOBAL comment String Unless otherwise noted, ambient aerosol particles were sampled at 18 m above sea level through a heated mast. The mast extended 5 m above and forward of the aerosol measurement container. The inlet was a rotating cone-shaped nozzle that was automatically positioned into the relative wind to maintain nominally isokinetic flow and minimize the loss of supermicrometer particles. Air entered the inlet through a 5 cm diameter hole, passed through a 7 degree expansion cone, and then into the 20 cm inner diameter sampling mast. The flow through the mast was 1 m3 min-1. The transmission efficiency of the inlet for particles with aerodynamic diameters less than 6.5 um (the largest size tested) is greater than 95% [Bates et al., 2002].

The bottom 1.5 m of the mast were heated to establish a stable reference relative humidity (RH) for the sample air of in the controlled range of 55 to 60 %RH. Twenty one 1.6 cm inner diameter stainless steel tubes extending into the heated portion of the mast were connected to downstream aerosol instrumentation with either conductive silicon tubing or stainless steel tubing for analysis of organic aerosol.

A Droplet Measurement Technologies CCN Counter (DMT CCNC) was used to determine CCN concentrations of sub-1 um particles at supersaturations ranging from 0.1 to 0.62%. A multijet cascade impactor with a 50% aerodynamic cut-off diameter of 1.1 um was upstream of the CCNC. The sampled air was dried prior to reaching the CCNC. Details concerning the characteristics of the DMT CCN counter can be found in Roberts and Nenes [2005] and Lance et al. [2006]. The CCN counter was calibrated before and during the experiment as outlined by Lance et al. [2006]. The uncertainty associated with the CCN number concentration is estimated to be less than +/- 10% [Roberts and Nenes, 2005]. Uncertainty in the instrumental supersaturation is less than +/- 10% for the operating conditions of this experiment [Roberts and Nenes, 2005].

The data are in 10 second time intervals and include CCN concentration (in n/cm^3), CCN/CN ratio, and Supersaturation (in %).

Lance, S., J. Medina, J.N. Smith, and A. Nenes, Mapping the operation of the DMT continuous flow CCN counter, Aer. Sci. Tech., 40, 242 - 254, 2006.

Roberts, G.C. and A. Nenes, A continuous-flow streamwise thermal gradient CCN chamber for atmospheric measurements, Aer. Sci. Tech., 39, 206 - 221, 2005.
attribute NC_GLOBAL contributor_name String Coffman, Derek;Johnson, James;Quinn, Patricia;Bates, Tim;Upchurch, Lucia
attribute NC_GLOBAL Conventions String CF-1.6, COARDS, ACDD-1.3
attribute NC_GLOBAL creator_email String james.e.johnson at
attribute NC_GLOBAL creator_name String Johnson, James
attribute NC_GLOBAL creator_url String (external link)
attribute NC_GLOBAL date_created String 2020-11-30T17:19:26Z
attribute NC_GLOBAL Easternmost_Easting double -50.9246
attribute NC_GLOBAL featureType String Trajectory
attribute NC_GLOBAL geospatial_lat_max double 15.8652
attribute NC_GLOBAL geospatial_lat_min double 12.7865
attribute NC_GLOBAL geospatial_lat_units String degrees_north
attribute NC_GLOBAL geospatial_lon_max double -50.9246
attribute NC_GLOBAL geospatial_lon_min double -59.6588
attribute NC_GLOBAL geospatial_lon_units String degrees_east
attribute NC_GLOBAL history String file created by NOAA/PMEL/ACG
attribute NC_GLOBAL infoUrl String (external link)
attribute NC_GLOBAL institution String NOAA PMEL Atmospheric Chemistry
attribute NC_GLOBAL keywords String aerosol, air, atmospheric, atomic, ccn, ccn_cn_ratio, chemistry, cloud, cloud cover, cloudiness, concentration, condensation, cover, data, environmental, identifier, laboratory, latitude, longitude, marine, noaa, nuclei, number, number_concentration_of_aerosol_particles_at_stp_in_air, number_concentration_of_cloud_condensation_nuclei_at_stp_in_air, pacific, particles, pmel, ratio, ratio_of_number_concentration_of_cloud_condensation_nuclei_to_number_concentration_of_aerosol_particles_at_stp_in_air, second, statistics, stp, supersaturation, time, trajectory, trajectory_id
attribute NC_GLOBAL keywords_vocabulary String GCMD Science Keywords
attribute NC_GLOBAL license String The data may be used and redistributed for free but is not intended for legal use, since it may contain inaccuracies. Neither the data Contributor, ERD, NOAA, nor the United States Government, nor any of their employees or contractors, makes any warranty, express or implied, including warranties of merchantability and fitness for a particular purpose, or assumes any legal liability for the accuracy, completeness, or usefulness, of this information.
attribute NC_GLOBAL Northernmost_Northing double 15.8652
attribute NC_GLOBAL platform String RHBrown
attribute NC_GLOBAL product_version String 2
attribute NC_GLOBAL project String ATOMIC
attribute NC_GLOBAL sourceUrl String (local files)
attribute NC_GLOBAL Southernmost_Northing double 12.7865
attribute NC_GLOBAL standard_name_vocabulary String CF Standard Name Table v55
attribute NC_GLOBAL subsetVariables String trajectory_id
attribute NC_GLOBAL summary String ATOMIC (Atlantic Tradewind Ocean Atmosphere Mesoscale Interaction Campaign) 2020 Field campaign: Surface meteorological and ship navigation collected from the RV Ronald H. Brown by the National Oceanic and Atmospheric Administration (NOAA) Pacific Marine Environmental Laboratory (PMEL) Atmospheric Chemistry Group in the tropical North Atlantic ocean from 2020-01-09 to 2020-02-13
attribute NC_GLOBAL time_coverage_end String 2020-02-11T23:59:50Z
attribute NC_GLOBAL time_coverage_start String 2020-01-07T18:00:00Z
attribute NC_GLOBAL title String PMEL Atmospheric Chemistry ATOMIC CCN 10 second data
attribute NC_GLOBAL Westernmost_Easting double -59.6588
attribute NC_GLOBAL Westernnmost_Easting double -59.6588
variable time   double  
attribute time _CoordinateAxisType String Time
attribute time actual_range double 1.57842E9, 1.58146559E9
attribute time axis String T
attribute time calendar String gregorian
attribute time colorBarMaximum double 1.582E9
attribute time colorBarMinimum double 1.578E9
attribute time ioos_category String Time
attribute time long_name String Time
attribute time standard_name String time
attribute time time_origin String 01-JAN-1970 00:00:00
attribute time units String seconds since 1970-01-01T00:00:00Z
variable trajectory_id   String  
attribute trajectory_id cf_role String trajectory_id
attribute trajectory_id ioos_category String Identifier
attribute trajectory_id long_name String trajectory id
variable latitude   double  
attribute latitude _CoordinateAxisType String Lat
attribute latitude _FillValue double -1.0E34
attribute latitude actual_range double 12.7865, 15.8652
attribute latitude axis String Y
attribute latitude colorBarMaximum double 90.0
attribute latitude colorBarMinimum double -90.0
attribute latitude comment String In the one minute files the position is treated somewhat differently from all the other data. The position given is the ship's position at the start of the one minute 'averaging' period. All other data are a true average. The PMEL GPS was the primary source. The Ship's GPS was used when there were missing data in the PMEL record
attribute latitude epic_code String 500
attribute latitude instrument String GPS
attribute latitude ioos_category String Location
attribute latitude long_name String Latitude
attribute latitude standard_name String latitude
attribute latitude units String degrees_north
attribute latitude valid_max double 90.0
attribute latitude valid_min double -90.0
variable longitude   double  
attribute longitude _CoordinateAxisType String Lon
attribute longitude _FillValue double -1.0E34
attribute longitude actual_range double -59.6588, -50.9246
attribute longitude axis String X
attribute longitude colorBarMaximum double 180.0
attribute longitude colorBarMinimum double -180.0
attribute longitude comment String In the one minute files the position is treated somewhat differently from all the other data. The position given is the ship's position at the start of the one minute 'averaging' period. All other data are a true average. The PMEL GPS was the primary source. The Ship's GPS was used when there were missing data in the PMEL record
attribute longitude epic_code String 502
attribute longitude instrument String GPS
attribute longitude ioos_category String Location
attribute longitude long_name String Longitude
attribute longitude standard_name String longitude
attribute longitude units String degrees_east
variable cn   double  
attribute cn _FillValue double -1.0E34
attribute cn actual_range double 73.4832, 46337.1
attribute cn colorBarMaximum double 100.0
attribute cn colorBarMinimum double 0.0
attribute cn epic_code String 1853
attribute cn instrument String TSI 3010 (sn: 2470)
attribute cn ioos_category String Statistics
attribute cn long_name String Number Concentration of Particles
attribute cn missing_value double -999.0
attribute cn source String surface observation
attribute cn standard_name String number_concentration_of_aerosol_particles_at_stp_in_air
attribute cn units String cm-3
attribute cn valid_max double 50000.0
attribute cn valid_min double 0.0
variable ss   double  
attribute ss _FillValue double -1.0E34
attribute ss actual_range double 0.06, 0.66
attribute ss colorBarMaximum double 100.0
attribute ss colorBarMinimum double 0.0
attribute ss epic_code String 6201
attribute ss instrument String DMT CCNC (sn: 0805-0021)
attribute ss ioos_category String Unknown
attribute ss long_name String Supersaturation
attribute ss missing_value double -999.0
attribute ss source String surface observation
attribute ss units String percent
attribute ss valid_max double 1.6
attribute ss valid_min double 0.0
variable ccn   double  
attribute ccn _FillValue double -1.0E34
attribute ccn actual_range double 0.0, 5495.11
attribute ccn colorBarMaximum double 100.0
attribute ccn colorBarMinimum double 0.0
attribute ccn epic_code String 6200
attribute ccn instrument String DMT CCNC (sn: 0805-0021)
attribute ccn ioos_category String Statistics
attribute ccn long_name String Number Concentration of Cloud Condensation Nuclei
attribute ccn missing_value double -999.0
attribute ccn source String surface observation
attribute ccn standard_name String number_concentration_of_cloud_condensation_nuclei_at_stp_in_air
attribute ccn units String cm-3
attribute ccn valid_max double 50000.0
attribute ccn valid_min double 0.0
variable ccn_cn_ratio   double  
attribute ccn_cn_ratio _FillValue double -1.0E34
attribute ccn_cn_ratio actual_range double 0.0, 29.8666
attribute ccn_cn_ratio colorBarMaximum double 100.0
attribute ccn_cn_ratio colorBarMinimum double 0.0
attribute ccn_cn_ratio epic_code String 6202
attribute ccn_cn_ratio instrument String DMT CCNC (sn: 0805-0021); TSI 3010 (sn: 2470)
attribute ccn_cn_ratio ioos_category String Statistics
attribute ccn_cn_ratio long_name String Ratio of CCN to CN
attribute ccn_cn_ratio missing_value double -999.0
attribute ccn_cn_ratio source String surface observation
attribute ccn_cn_ratio standard_name String ratio_of_number_concentration_of_cloud_condensation_nuclei_to_number_concentration_of_aerosol_particles_at_stp_in_air
attribute ccn_cn_ratio units String 1
attribute ccn_cn_ratio valid_max double 2.0
attribute ccn_cn_ratio valid_min double 0.0

The information in the table above is also available in other file formats (.csv, .htmlTable, .itx, .json, .jsonlCSV1, .jsonlCSV, .jsonlKVP, .mat, .nc, .nccsv, .tsv, .xhtml) via a RESTful web service.

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