2019 journal article

Characterization of Ice-Nucleating Particles Over Northern India

JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 124(19), 10467–10482.

co-author countries: India 🇮🇳 United States of America 🇺🇸
Source: Web Of Science
Added: January 6, 2020

Abstract The sources and concentrations of ice‐nucleating particles (INPs) over India are not well known. Here, INP concentrations in rainwater from Northern India and a dust sample from the Thar Desert are characterized. Rainwater INP concentrations ranged between 10 4 and 3 × 10 7 L −1 water, spanning temperatures between −4 and −28 °C. During the monsoon season, INP concentrations were low and approached those in remote marine air mass. During the winter season, INPs active between −4 to −10 °C were occasionally observed. An increase in INP activity sometimes occurred after the initial onset of rain. The onset freezing temperature of samples active at warmer temperatures was shifted to colder temperature after heat treatment, suggesting that the INP activity stemmed from biological influence. Plating was used to isolate and sequence INP active bacterial strains from some of the rainwater samples, specifically strains of close taxonomic affiliation with the ice nucleating genera Pantoea . The size‐resolved ice nucleation active site density for 200–600‐nm particles of Thar Desert Dust ranged between 10 7 and 10 9 m −2 at −20 °C, values similar to dusts from other regions of the world. The data reported herein may help constrain models that seek to predict the impact of INP on the properties of mixed‐phased clouds over the Indian subcontinent.