Aerosol Activation in Radiation Fog at the Atmospheric Radiation Program Southern Great Plains Site
Abstract
Environmental supersaturation is a key parameter in the formation of fog and clouds, yet it cannot be measured directly and must be inferred. Calculating the ambient supersaturation in fog requires knowledge of the aerosol hygroscopicity as well as particle size distribution, and relatively few values have been reported in the literature. Here we use κ‐Köhler theory to derive aerosol activation properties based on particle hygroscopicity and dry particle size distributions, and then estimate the effective peak supersaturation during eight cases of radiative fog at the Southern Great Plains site in rural north‐central Oklahoma, USA. The mean hygroscopicity parameter κ of particles likely to act as cloud condensation nuclei varied from 0.14 to 0.43. Ambient effective peak supersaturation during the fog episodes was between 0.01%–0.07%, with most values below 0.04%. The minimum 50% dry activation diameter generally ranged between 300–400 nm with little activation of particles with diameters below 300 nm.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 12, 2021
- Source ID
- 10.1029/2021jd035358
Entities
People
- Charlotte E Wainwright
- David H Richter
- Rachel Chang
Organizations
- Dalhousie University
- Office of Naval Research
- University of Notre Dame