Abstract View
Cloud Chemical Speciation Measurements Conducted On-Line with a mini-AMS during the CAIPEEX Seeding Study
SUBHARTHI CHOWDHURI, Edward Fortner, Benjamin Werden, Mahen Konwar, Sachin Patil, Mercy Varghese, Sudarsan Bera, P. Murugavel, Philip Croteau, John Jayne, Manjula Canagaratna, Kurt Hibert, Neelam Malap, Sandeep J., Duncan Axisa, Peter F. DeCarlo, Douglas Worsnop, Thara Prabhakaran, Aerodyne Research, Inc.
Abstract Number: 534
Working Group: Aerosols, Clouds and Climate
Abstract
A mini-AMS (aerosol mass spectrometer) was flown during the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX), a project for examining the effects of seeding on clouds conducted by the Indian Institute of Tropical Meteorology, Pune. Various chemical and meteorological parameters involving cloud condensation nuclei (CCN) and cloud processing were measured during the experiment, during the monsoon season in the rain shadow region of the Western Ghat in Solapur India. The instrumented research aircraft used in the experiment had both isokinetic and CVI inlets to allow for characterizing either total non-activated submicron aerosol in or out of clouds (isokinetic inlet) or alternatively cloud droplet residuals from in-cloud measurements (CVI inlet).
The mini-AMS was operated on the research aircraft from 25 July – 10 September 2019 to examine the chemical speciation of cloud and background aerosols. The mini-AMS acquired data on 37 research flights. During these flights, measurements were focused on cumulus cloud development, stratus clouds, and regional air quality. The mini-AMS provided 1 Hz measurements of various chemical loadings in aerosol including NO3, SO4, Chl and Organics. Cloud seeding was conducted using CaCl2 burn in place hygroscopic flares and the mini-AMS detected chemical signatures in the seeded clouds consistent with CaCl2. Other non-seeded Cl species were also observed in cloud residuals and are compared with the seeded CaCl2 signature. Aircraft passes through both seeded and unseeded clouds provide framework for comparing the variability of chemical composition in these different cloud types. Finally, measurements of aerosol composition and size with the mini-AMS outside of clouds also provide additional comparison points for cloud residual composition.