Preprints
https://doi.org/10.5194/amt-2021-358
https://doi.org/10.5194/amt-2021-358

  28 Oct 2021

28 Oct 2021

Review status: this preprint is currently under review for the journal AMT.

Estimating cloud condensation nuclei concentrations from CALIPSO lidar measurements

Goutam Choudhury and Matthias Tesche Goutam Choudhury and Matthias Tesche
  • Leipzig Institute for Meteorology (LIM), Leipzig University, Stephanstrasse 3, 04103 Leipzig, Germany

Abstract. We present a novel methodology to estimate cloud condensation nuclei (CCN) concentrations from spaceborne CALIPSO lidar measurements. The algorithm utilizes (i) the CALIPSO-derived backscatter and extinction coefficient, depolarization ratio, and aerosol subtype information, (ii) the normalized volume size distributions and refractive indices from the CALIPSO aerosol model, and (iii) the MOPSMAP optical modelling package. For each CALIPSO height bin, we first select the aerosol-type specific size distribution and then adjust it to reproduce the extinction coefficient derived from the CALIPSO retrieval. The scaled size distribution is integrated to estimate the aerosol number concentration which is then used in the CCN parameterizations to calculate CCN concentrations at different supersaturations. To account for the hygroscopicity of continental and marine aerosols, we use the kappa parameterization and correct the size distributions before the scaling step. We have studied the sensitivity of the thus derived CCN concentration to the effect of variations of the initial size distributions. It is found that the uncertainty associated with the algorithm can range between a factor of 2 and 3. We have also compared our results with the POLIPHON and found comparable results for extinction coefficients larger than 0.05 km−1. An initial application to a case with coincident airborne in-situ measurements for independent validation shows promising results and illustrates the potential of CALIPSO for constructing a global height-resolved CCN climatology.

Goutam Choudhury and Matthias Tesche

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on amt-2021-358', Aristeidis Georgoulias, 23 Nov 2021
  • RC2: 'Comment on amt-2021-358', Anonymous Referee #2, 30 Nov 2021

Goutam Choudhury and Matthias Tesche

Goutam Choudhury and Matthias Tesche

Viewed

Total article views: 360 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
279 72 9 360 1 3
  • HTML: 279
  • PDF: 72
  • XML: 9
  • Total: 360
  • BibTeX: 1
  • EndNote: 3
Views and downloads (calculated since 28 Oct 2021)
Cumulative views and downloads (calculated since 28 Oct 2021)

Viewed (geographical distribution)

Total article views: 380 (including HTML, PDF, and XML) Thereof 380 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 08 Dec 2021
Download
Short summary
Aerosols are tiny particles suspended in the atmosphere. A fraction of these particles can form clouds and are called cloud condensation nuclei (CCN). CCN measurements are necessary to study the aerosol-cloud interactions and reduce the uncertainty in our future climate projections. We present a novel methodology to estimate global height-resolved CCN concentrations from the CALIPSO satellite measurements. The final data will be used to improve the understanding of aerosol-cloud interactions.