Index Geophysics

Developing and bounding ice particle mass- and area-dimension expressions for use in atmospheric models and remote sensing

Ice particle mass- and projected area-dimension (<i>m</i>-<i>D</i> and <i>A</i>-<i>D</i>) power laws are commonly used in the treatment of ice cloud microphysical and optical properties and the remote sensing of ice cloud properties. Although there has long been evidence that a single <i>m</i>-<i>D</i> or <i>A</i>-<i>D</i> power law is often not valid over all ice particle sizes, few studies have addressed this fact. This study develops self-consistent <i>m</i>-<i>D</i> and <i>A</i>-<i>D</i> expressions that are not power laws but can easily be reduced to power laws for the ice particle size (maximum dimension or <i>D</i>) range of interest, and they are valid over a much larger <i>D</i> range than power laws. This was done by combining ground measurements of individual ice particle <i>m</i> and <i>D</i> formed at temperature <i>T</i>  &lt;  −20 °C during a cloud seeding field campaign with 2-D stereo (2D-S) and cloud particle imager (CPI) probe measurements of <i>D</i> and <i>A</i>, and estimates of <i>m</i>, in synoptic and anvil ice clouds at similar temperatures. The resulting <i>m</i>-<i>D</i> and <i>A</i>-<i>D</i> expressions are functions of temperature and cloud type (synoptic vs. anvil), and are in good agreement with <i>m</i>-<i>D</i> power laws developed from recent field studies considering the same temperature range (−60 °C  &lt;  <i>T</i>  &lt;  −20 °C).

Erfani, Ehsan

Mitchell, David L.

2018-09-10

Text

application/pdf

10.5194/acp-16-4379-2016

https://acp.copernicus.org/articles/16/4379/2016/

eISSN: 1680-7324

eng