Methodology to determine the coupling of continental clouds with surface and boundary layer height under cloudy conditions from lidar and meteorological data
<p>The states of coupling between clouds and surface or boundary layer have been investigated much more extensively for marine stratocumulus clouds than for continental low clouds, partly due to more complex thermodynamic structures over land. A manifestation is a lack of robust remote sensing...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-01-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/22/1453/2022/acp-22-1453-2022.pdf |
| Summary: | <p>The states of coupling between clouds and
surface or boundary layer have been investigated much more extensively for
marine stratocumulus clouds than for continental low clouds, partly due to
more complex thermodynamic structures over land. A manifestation is a lack
of robust remote sensing methods to identify coupled and decoupled clouds
over land. Following the idea for determining cloud coupling over the ocean,
we have generalized the concept of coupling and decoupling to low clouds
over land, based on potential temperature profiles. Furthermore, by using
ample measurements from lidar and a suite of surface meteorological
instruments at the U.S. Department of Energy's Atmospheric Radiation
Measurement Program's Southern Great Plains site from 1998 to 2019, we have
developed a method to simultaneously retrieve the planetary boundary layer
(PBL) height (PBLH) and coupled states under cloudy conditions during the
daytime. The new lidar-based method relies on the PBLH, the lifted
condensation level, and the cloud base to diagnose the cloud coupling. The
coupled states derived from this method are highly consistent with those
derived from radiosondes. Retrieving the PBLH under cloudy conditions, which
has been a persistent problem in lidar remote sensing, is resolved in this
study. Our method can lead to high-quality retrievals of the PBLH under
cloudy conditions and the determination of cloud coupling states. With the
new method, we find that coupled clouds are sensitive to changes in the PBL
with a strong diurnal cycle, whereas decoupled clouds and the PBL are weakly
related. Since coupled and decoupled clouds have distinct features, our new
method offers an advanced tool to separately investigate them in climate
systems.</p> |
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| ISSN: | 1680-7316 1680-7324 |