The interdependence of continental warm cloud properties derived from unexploited solar background signals in ground-based lidar measurements
We have extensively analysed the interdependence between cloud optical depth, droplet effective radius, liquid water path (LWP) and geometric thickness for stratiform warm clouds using ground-based observations. In particular, this analysis uses cloud optical depths retrieved from untapped solar bac...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-08-01
|
| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/14/8389/2014/acp-14-8389-2014.pdf |
| Summary: | We have extensively analysed the interdependence between cloud optical
depth, droplet effective radius, liquid water path (LWP) and geometric
thickness for stratiform warm clouds using ground-based observations. In
particular, this analysis uses cloud optical depths retrieved from untapped
solar background signals that are previously unwanted and need to be removed
in most lidar applications. Combining these new optical depth retrievals
with radar and microwave observations at the Atmospheric Radiation
Measurement (ARM) Climate Research Facility in Oklahoma during 2005–2007,
we have found that LWP and geometric thickness increase and follow a
power-law relationship with cloud optical depth regardless of the presence
of drizzle; LWP and geometric thickness in drizzling clouds can be generally
20–40% and at least 10% higher than those in non-drizzling clouds,
respectively. In contrast, droplet effective radius shows a negative
correlation with optical depth in drizzling clouds and a positive
correlation in non-drizzling clouds, where, for large optical depths, it
asymptotes to 10 μm. This asymptotic behaviour in non-drizzling clouds
is found in both the droplet effective radius and optical depth, making it
possible to use simple thresholds of optical depth, droplet size, or a
combination of these two variables for drizzle delineation. This paper
demonstrates a new way to enhance ground-based cloud observations and
drizzle delineations using existing lidar networks. |
|---|---|
| ISSN: | 1680-7316 1680-7324 |