Summary of a 4-Year Fog Field Study in Northern Nanjing, Part 2: Fog Microphysics

Abstract

Comprehensive field observations of fog were conducted during the winters of 2006–2009 at the Nanjing University of Information Science & Technology, in order to study macro- and micro-physical structures and physical–chemical processes of dense fogs in northern Nanjing. The fog boundary-layer structures of different types and their corresponding characteristics are presented in Part I of these twin papers. In this second part, microphysical characteristics and droplet spectrum distributions of different types of fogs, microphysical relationships (among fog droplet concentration, liquid water content, and mean diameter), and microphysics of atmospheric aerosols during haze/fog events are discussed. The results show that there are large differences in microphysical parameters among four types of haze/fog. Many interesting phenomena, including fog burst reinforcement, fog droplet spectrum broadening, fog bimodal or multi-modal drop-size distributions, and critical triggering maxD value of fog coagulation growth, were captured during the 4-year field study.