Our group studies the climate change implications of transport
phenomena at the meso- to global scale, with emphasis on the upper
troposphere and stratosphere. This region is crucial for climate change,
containing the ozone layer, volcanic aerosol layer, water vapor and other
significant trace gases. We use a variety of satellite and aicraft data,
global meteorological analyses, and numerical models to address problems
ranging from ozone depletion to the influence of the quasibiennial
oscillation (QBO) on tropical convection.
We have enjoyed strong participation on several NASA science teams:
SAGE II, UARS, STRAT, POLARIS, and SOLVE, and have carried out radar
campaigns measuring winds and gravity waves with the
mesosphere-stratosphere-troposphere radar at Jicamarca, Peru. We have a
comprehensive two dimensional model of the
troposphere-stratosphere-mesosphere for studying climate change related to
the ozone and aerosol layers. We have also tailored Prof. Tripoli's UW-NMS
model for application to tropical convection and gravity waves for
ASHOE/MAESA, extratropical synoptic waves for POLARIS, and the influence
of mountain gravity wave-generated polar stratospheric clouds on winter
ozone depletion for SOLVE.
Our climatology of stratospheric aerosol shows that it is primarily
volcanic in nature. Its distribution is very useful in diagnosing
variation in transport among seasons and the phases of the QBO. It also
helps illuminate the nature of transport between the tropics and
extratropics. We have documented the structure of the stratospheric
Aleutian high and described how it is maintained by surges of tropical air
associated with planetary wave breaking. Our Rossby wave breaking
climatology shows that stratosphere-troposphere exchange across the
subtropical tropopause occurs primarily over the summer oceans, downstream
of the tops of monsoon structures. This provides a useful mental model of
stratospheric geography for understanding several issues relevant to
climate change. Our work for POLARIS suggests that changes in net
transport entering summer can explain the observed natural summertime
diminution in column ozone.
Our group comprises myself, three research scientists and four graduate
students. Ongoing work includes further exploration of transport near the
tropopause, analysis of satellite and ER2 data, extending the Rossby wave
breaking climatology, analysis of the effects of the QBO on the upper
troposphere, and high resolution simulations for NASA's aircraft
deployments over Scandinavia this coming winter for SOLVE (Stratospheric
Ozone Loss and Validation Experiment).
See also:
Climate and Climate Change and Large Scale Dynamics
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