Characteristics of CCN activation and cloud microphysics over the east coast of India during the Northeast Monsoon onset

Research output: Contribution to journalArticle

Abstract

Airborne observations conducted during the Northeast Monsoon onset as part of the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX 2011) are used to link the activation properties of aerosols with the observed cloud microphysics. This study illustrates the significant spatial variability in the aerosol spectrum, cloud condensation nuclei (CCN) activation characteristics, and the cloud droplet spectral properties over a coastal and an inland location. High concentrations of Aitken mode and black carbon aerosols were observed in the free troposphere and are attributed to the convectively transported smoke and aerosols from the coastal boundary layer. The assumption of an internally mixed organic and inorganic aerosol composition provided a better CCN closure over assumptions of either purely organic or purely inorganic aerosols. The coastal clouds were equally polluted as the inland clouds with high cloud droplet number concentrations near the cloud base. The vertical distribution of cloud droplet spectral characteristics was similar in both coastal and inland clouds. An increase in droplet number concentration up to 2 km above the cloud base indicated a prominent influence of submicron particles on the cloud microphysical parameters. Evidence for an enhanced concentration of supercooled drops above the freezing level up to temperatures below −12 °C is documented. The secondary ice production was evident through observations of graupel and snow particles. Heavy loading of aerosols near the cloud base leads to enhanced mixed-phase processes in these clouds.

Details

Authors
  • Mercy Varghese
  • Thara V. Prabha
  • Sachin Patade
  • Gayatri K
  • P. D. Safai
  • Duncan Axisa
Organisations
External organisations
  • Indian Institute of Tropical Meteorology (IITM)
  • University of California, San Diego
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Meteorology and Atmospheric Sciences

Keywords

  • BC, Biomass plume, CAIPEEX, CCN closure, Mixed-phase clouds
Original languageEnglish
Article number105589
JournalAtmospheric Research
Volume257
Publication statusPublished - 2021
Publication categoryResearch
Peer-reviewedYes