Characteristics and Sources of Ice Nucleating Particles in the North-Western Himalayas

SHWETA YADAV, Nathaniel Curtis, Rebecca Venezia, Kiran Kumari, Sunandan Mahant, Ankit Tandon, Bruce Moffett, Ryan Paerl, Markus Petters, Central University of Jammu, India

     Abstract Number: 263
     Working Group: Aerosols, Clouds and Climate

Abstract
The ice nucleating particles (INPs) in rainwater, aerosols and river water samples were measured using the Drop freezing assay. Three different campaigns were carried out in the North Western Himalayas to understand sources and characteristics of INPs. Heat treatment was applied to infer the presence of biological INPs. In the first campaign, time‐resolved precipitation samples were collected in different seasons at Jammu (urban and rural) and urban locations in Dharamshala, Lucknow and New Delhi. Dominance of biologically active INPs and no influence of pollution on INP concentration was observed. In the second campaign, bioaerosol diversity and INP concentration in total suspended particulate matter were studied along a transect. The phyla Firmicutes, Proteobacteria, and Actinobacteria dominated the microbial community but Archaea were rare in aerosols. This work demonstrated the importance of surface sources, land use pattern, and local meteorology on the understanding of bioaerosols and their link with INP concentrations in the atmosphere. In the third campaign, water soluble ionic species using ion chromatography and INP concentrations were measured in surface water samples of three Himalayan rivers. This campaign showed that river water is a potential source of INPs in the Himalayas. The data reported here from the Himalayan region may help to constrain modelling studies that target aerosol‐ice cloud interactions in this region.