Central California Ozone Study (CCOS) - Desert Research Institute

CCOS Field Operations Plan Version 2: 5/31/00
(released on 6/11/99 and 9/7/99). The field study plan describes the goals and technical
objectives to be addressed by the study, and describes alternative experimental, modeling, and
data analysis approaches for addressing the study objectives. It presents a summary of the current
knowledge of meteorology, emissions, and chemical and physical processes that affect the
formation and accumulation of ozone in northern and central California. It also reviews the
results from prior SAQM 2 modeling by ARB, and identifies the remaining uncertainties and their
implications for the design of the CCOS field measurement program. The plan describes
requirements for the modeling and data analysis approaches that are proposed to address CCOS
technical objectives and specifies measurements for modeling and data analysis. It considers the
merits of alternative measurement approaches and explains the rationale and criteria for
measurement decisions. The field study plan is available in PDF format on the study web site at
http://www.arb.ca.gov/ccaqs/ccos/ccos.htm.
The field study plan served as the basis for contracts with measurement groups and for
developing the field operations plan for the summer 2000 field study. This field operations plan
specifies the details of the field measurement program that will allow the field study plan to be
executed with available resources. It identifies measurement locations, observables, and
monitoring methods, specifies data management and reporting conventions, and outlines the
activities needed to ensure data quality.
1.1 Basis for the Study Design
The goals of CCOS are to be met through a process that includes analysis of existing
data; execution of a large-scale field study in summer 2000 to acquire a comprehensive database
to support modeling and data analysis; analysis of the data collected during the field study; and
the development, evaluation, and application of an air quality simulation model for northern and
central California. Although air quality simulation modeling may be used to address CCOS
goals, past experience has demonstrated the need for thorough diagnostic analyses and
corroborative data analysis to assess the reliability of outputs from each part of the modeling
system (i.e., emissions, meteorological, and air quality models). Corroborative data analysis is
used to reinforce current understanding, identify gaps and improve the conceptual model of
ozone formation, and to determine if measurement and modeling results are consistent with the
conceptual model as revised by CCOS.
The reliability of model outputs is assessed through operational and diagnostic
evaluations and application of alternative diagnostic tools. Operational evaluations consist of
comparing concentration estimates from the model to ambient measurements. Diagnostic
evaluations determine if the model is estimating ozone concentrations correctly for the right
reasons by assessing whether the physical and chemical processes within the model are
simulated correctly. This broad task also involves reconciliation of the corroborative data
analysis results with modeling results. It includes evaluation of modeling uncertainties,
processes, and assumptions and their effect on observed differences among model results,
measurements, and data analysis results.
2 SARMAP Air Quality Model
Chapter 1: INTRODUCTION 1-2