Atmospheric Radiation Measurement Climate Research Facility US Department of Energy

rnccn > Retrieved Number concentration of CCNVAP Type(s) > Evaluation

The objective of the Retrieved Number concentration of Cloud Condensation Nuclei value-added product (RNCCN VAP) is to provide the vertical distribution of cloud condensation nuclei (CCN) number concentrations to better represent aerosol indirect effects in climate models. The RNCCN VAP allows for collecting a large number of independent samples of vertical CCN measurements at various water supersaturation values from the ground. This helps to avoid the high cost of routine airborne measurements and increases the temporal distribution of retrieved CCN at the ARM sites. The VAP method is based on parameterizations proposed by Ghan and Collins (2004) and Ghan et al. (2006) that retrieve the vertical profiles of CCN directly from the ground-level CCN, humidification factor, and in situ lidar measurements. The VAP uses quality-controlled and harmonized datastreams of Raman lidar profiles and CCN data products.

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The first available RNCCN data set, from the Southern Great Plains atmospheric observatory, allows for comparisons with in situ CCN data from the 2016 Holistic Interactions of Shallow Clouds, Aerosols, and Land-Ecosystems (HI-SCALE) field campaign. The VAP uses a filtered data set that passed atmospheric stability and aerosol feature mask tests. Additional quality tests related to well-mixed conditions in the boundary layer are planned to develop the best-estimate RNCCN VAP. Plots for this data are visible here.

For any comments or questions, please contact VAP associate translator Gourihar Kulkarni, VAP developer Chitra Sivaraman, and ARM aerosol translator John Shilling.

Primary Derived Measurements


  • Fixed
  • AMF1
  • AMF2
  • AMF3