Record Details

Penetrative elements at the top of the atmospheric mixed layer

ScholarsArchive at Oregon State University

Field Value
Title Penetrative elements at the top of the atmospheric mixed layer
Names Paumier, James (creator)
Mahrt, Larry J. (advisor)
Date Issued 1981-03-05 (iso8601)
Note Graduation date: 1981
Abstract High resolution data of moisture, temperature and wind velocity
collected by aircraft during the 1975 Air Mass Transformation
Experiment (ANTEX '75) provide information for detailed investigations
of the phenomena occurring at the top of a cloud-topped mixed
layer.
Joint frequency diagrams of humidity and temperature reveal that
for parts of the record the coldest temperatures occur in air near
saturation while drier air or air with substantial liquid water is
warmer. This suggests the possible occurrence of cloud-top entrainment
instability (Deardorff, 1980).
Using humidity as an indicator, the flight record is systematically
searched for penetrative mixed layer elements and pockets of
dry air penetrating into cloudy air (wisps). The separate phenomena
are then composited to produce an "average" wisp and penetrating
element. The composites show evidence of net cooling due to evaporation
downstream from the penetrating element and upstream from the
wisps. Sinking motion is associated with the cold temperatures. These
results suggest the interaction of shear, penetrating elements and
wisps, and the existence of cloud-top entrainment instability.
Genre Thesis/Dissertation
Topic Planetary boundary layer
Identifier http://hdl.handle.net/1957/29287

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