A polar stratospheric cloud parameterization for the global modeling initiative three-dimensional model and its response to stratospheric aircraft

Journal Article · Wed Feb 16 04:00:00 EST 2000 · Journal of Geophysical Research

DOI:https://doi.org/10.1029/1999JD900932· OSTI ID:20216013

Considine, D B ^[1]; Douglass, A R ^[2]; Connell, P S ^[3]; Kinnison, D E ^[3]; Rotman, D A ^[3]

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1. Earth System Science Interdisciplinary Center and Department of Meteorology, University of Maryland, College Park (United States)
2. NASA Goddard Space Flight Center, Greenbelt, Maryland (United States)
3. Lawrence Livermore National Laboratory, Livermore, California (United States)

We describe a new parameterization of polar stratospheric clouds (PSCs) which was written for and incorporated into the three-dimensional (3-D) chemistry and transport model (CTM) developed for NASA's Atmospheric Effects of Aviation Project (AEAP) by the Global Modeling Initiative (GMI). The parameterization was designed to respond to changes in NO{sub y} and H{sub 2}O produced by high-speed civilian transport (HSCT) emissions. The parameterization predicts surface area densities (SADs) of both Type 1 and Type 2 PSCs for use in heterogeneous chemistry calculations. Type 1 PSCs are assumed to have a supercooled ternary sulfate (STS) composition, and Type 2 PSCs are treated as water ice with a coexisting nitric acid trihydrate (NAT) phase. Sedimentation is treated by assuming that the PSC particles obey lognormal size distributions, resulting in a realistic mass flux of condensed phase H{sub 2}O and HNO{sub 3}. We examine a simulation of the Southern Hemisphere high-latitude lower stratosphere winter and spring seasons driven by temperature and wind fields from a modified version of the National Center for Atmospheric Research (NCAR) Middle Atmosphere Community Climate Model Version 2 (MACCM2). Predicted PSC SADs and median radii for both Type 1 and Type 2 PSCs are consistent with observations. Gas phase HNO{sub 3} and H{sub 2}O concentrations in the high-latitude lower stratosphere qualitatively agree with Cryogenic Limb Array Etalon Spectrometer (CLAES) HNO{sub 3} and Microwave Limb Sounder (MLS) H{sub 2}O observations. The residual denitrification and dehydration of the model polar vortex after polar winter compares well with atmospheric trace molecule spectroscopy (ATMOS) observations taken during November 1994. When the NO{sub x} and H{sub 2}O emissions of a standard 500-aircraft HSCT fleet with a NO{sub x} emission index of 5 are added, NO{sub x} and H{sub 2}O concentrations in the Southern Hemisphere polar vortex before winter increase by up to 3%. This results in earlier onset of PSC formation, denitrification, and dehydration. Active Cl{sub y} increases and produces small ({approx}1%) decreases in lower stratospheric vortex O{sub 3} concentrations during the spring relative to the HSCT-free run. (c) 2000 American Geophysical Union.

• OSTI ID: 20216013
• Journal Information: Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Journal Issue: D3 Vol. 105; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AIR POLLUTION
AIR TRANSPORT
ATMOSPHERIC CHEMISTRY
CLOUDS
EXPERIMENTAL DATA
MATHEMATICAL MODELS
STRATOSPHERE
THEORETICAL DATA