19 Sep 2023
 | 19 Sep 2023
Status: a revised version of this preprint is currently under review for the journal AMT.

Identifying the seeding signature in cloud particles from hydrometeor residuals

Mahen Konwar, Benjamin Werden, Edward C. Fortner, Sudarsan Bera, Mercy Varghese, Subharthi Chowdhuri, Kurt Hibert, Philip Croteau, John Jayne, Manjula Canagaratna, Neelam Malap, Sandeep Jayakumar, Shivsai A. Dixit, Palani Murugavel, Duncan Axisa, Darrel Baumgardner, Peter F. DeCarlo, Doug R. Worsnop, and Thara Prabhakaran

Abstract. Cloud seeding experiments for modifying cloud and precipitation have been underway for nearly a century; yet practically all the attempts to link precipitation enhancement or suppression to the presence of seeding materials remained inclusive. In 2019, the Cloud-Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) implemented a novel method to detect seeded clouds during its operations in Solapur, India. In this experiment, residuals of cloud hydrometeors in seeded and non-seeded clouds were analyzed with an airborne mini-Aerosol Mass Spectrometer (mAMS). The mAMS instrument was utilized in conjunction with a counterflow virtual impactor (CVI) inlet, which had a cutoff diameter size of approximately 7 µm. Upon traversing the CVI inlet, the cloud droplets underwent a drying process, enabling the subsequent examination of cloud residuals through the mAMS instrument to identify potential seeding signatures. The Chlorine (Cl) associated with hygroscopic materials, i.e., Calcium Chloride (CaCl2) and potassium (K), which serve as the oxidizing agents in the flares, is found in relatively higher concentrations in the seeded clouds compared to the non-seeded clouds. After seeding, small-size cloud droplet concentrations increased in the convective and stratus clouds. In the convective clouds, flare particles propagated to higher cloud depths (≈ 2.25 km, vertical distance from cloud base) and modulate cloud microphysical properties to initiate warm rain. This new technique help to trace activated flare particles in seeded clouds and identify the post-seeding chain of cloud microphysical processes.

Mahen Konwar et al.

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-2023-171', Anonymous Referee #1, 07 Oct 2023
  • RC2: 'Comment on amt-2023-171', Anonymous Referee #2, 12 Oct 2023

Mahen Konwar et al.

Mahen Konwar et al.


Total article views: 308 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
242 53 13 308 19 4 3
  • HTML: 242
  • PDF: 53
  • XML: 13
  • Total: 308
  • Supplement: 19
  • BibTeX: 4
  • EndNote: 3
Views and downloads (calculated since 19 Sep 2023)
Cumulative views and downloads (calculated since 19 Sep 2023)

Viewed (geographical distribution)

Total article views: 306 (including HTML, PDF, and XML) Thereof 306 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 06 Dec 2023
Short summary
In a warm cloud seeding experiment hygroscopic particles are released to alter cloud processes to induce early raindrops. During Cloud Aerosol Interaction and Precipitation Enhancement Experiment, airborne mini-Aerosol Mass Spectrometers analyze the particles on which clouds form. The seeded clouds showed higher concentrations of Chlorine (Cl) and potassium (K), the oxidizing agents of flares. Small cloud droplet concentrations increased, and seeding particles were detected in deep cloud depths.