United States
Environmental Protection
Agency
Environmental Sciences Research
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S3-84-040 Apr 1984
&EPA Project Summary
Regional Acid Deposition:
Design and Management
Plan for a Comprehensive
Modeling System
This companion report to Regional
Acid Deposition: Models and Physical
Processes presents a design and man-
agement plan for the development of an
Eulerian regional acid deposition model.
It first reviews the fundamental physical
processes relevant to acid deposition
and then describes the proposed model
system. The principal components are
discussed in detail with special empha-
sis on model initialization and subsys-
tem validation. The total system inte-
gration and full validation are presented
separately. The management plan sec-
tion focuses on internal structure,
external interactions, and special facility
needs. Strongly managed interdiscipli-
nary interactions and intensive "hands-
on" working groups for external inter-
actions are suggested.
This Project Summary was developed
by EPA's Environmental Sciences Re-
search Laboratory, Research Triangle
Park, NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).
Introduction
This document presents a design and
management plan for developing of a
state-of-the-art Eulerian model for region-
al acid deposition. This plan is based on
the companion document Regional Acid
Deposition: Models and Physical Proces-
ses, the key conclusions of which are:
• Existing models of regional acid deposi-
tion contain fundamental weaknesses,
particularly by not accounting for
upper-air transport and dispersion,
omitting detailed chemical reactions,
neglecting cloud physics, and inade-
quately treating terrain and surface
effects.
• Marked improvements in acid deposi-
tion modeling are now possible be-
cause of recent advances in mesoscale
meteorology and tropospheric chemis-
try; a comprehensive regional acid
deposition model can thus be con-
structed.
• The development of such a compre-
hensive model requires a clearjy
focused, multidisciplinary group effort
under strong scientific leadership.
• The Eulerian framework is most suit-
able for representing the essential
physical and chemical processes in
regional acid deposition
Conclusions and
Recommendations
A plan is presented for integrating
recent advances in mesoscale meteorol-
ogy, tropospheric chemistry, and ad-
vanced computing into a scientifically
defensible, state-of-the-art regional acid
deposition modeling system. A model
system developed according to this plan
would differ from current models in the
following ways:
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It would be based on an established,
proven, mesoscale meteorological
model and its analysis techniques.
It would use fundamental chemical
process equations to predict the rele-
vant transformations; thus, our under-
standing of thefundamental processes
could be tested by comparison with
observed data.
It would incorporate the details of both
wet and dry deposition.
Effort would be focused on analyzing
the sensitivity of model predictions to
uncertainties in chemical initialization
and parametenzations.
Effort would also be focused on the
proper statistical interpretation and
application of the model results.
It would be modular and highly flexible
and would thus allow the easy incor-
poration of new research results.
This Project Summary was authored by staff of The NCAR Acid Deposition
Modeling Project, National Center for Atmospheric Research, Boulder, CO
80307.
Kenneth L. Demerjian is the EPA Project Officer (see below).
The complete report, entitled "Regional Acid Deposition: Design and Management
Plan for a Comprehensive Modeling System," (Order No. PB 84-116 003; Cost:
$8.50, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Sciences Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
•fa U S GOVERNMENT PRINTING OFFICE, 1984 — 759-015/7641
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Environmental Protection
Agency
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