David Lary (PI)
University of Maryland Baltimore County
dlary@gmao.gsfc.nasa.gov
The Swift Neurological Acceleration of Atmospheric Photochemistry and
Aerosol Calculations [SNAPA]: Development and Application to Atmospheric
Chemistry and Aerosol Simulations With a Focus on UT/LS Ozone
An adequate photochemical mechanism to describe the evolution of ozone
in the upper troposphere and lower stratosphere (UT/LS) in a computational
model involves reactive nitrogen, hydrogen, halogens, hydrocarbons, and
interactions with aerosols. This complex mechanism is computationally
expensive, and applications are limited by the computational burden. Simulations
are made tractable by using coarse horizontal resolution (4º latitude
x 5º longitude or greater) or by greatly reducing the interactions
accounted for in the photochemical mechanism, but these compromises limit
the scientific applications. Neural networks, multi-variate nonlinear
machine learning algorithms, offer a means to obtain a fast, accurate
solution to the stiff ordinary differential equations that comprise the
photochemical calculations, thus making high resolution simulations including
the complete photochemical mechanism possible. This proposal will
implement advanced neural networks to speed up the photochemical solution
and also two other key elements of the Global Modeling Initiative (GMI)
Chemistry and Transport Model (CTM), the photolysis calculation and aerosol
microphysical calculations. In addition to demonstrating that the
neural networks provide improved computational efficiency without sacrificing
accuracy, we will exploit the increased computational efficiency to examine
the ozone budget in the upper troposphere and lower stratosphere (500-50
mb).
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