Central California Ozone Study (CCOS) - Desert Research Institute

CCOS Field Operations Plan Version 2: 5/31/00
8. For model evaluation, it is desirable to have measurement stations along the line running
from the San Francisco Bay Area through Sacramento to the foothills of the Sierra
Nevada and along the San Joaquin valley. The model predicts that ozone concentrations
show strong variations over this region due to transport, deposition and chemistry.
Measurement stations to measure ozone concentrations and the concentrations of
precursors and other photochemical products placed along the west–east line will help to
determine if the models represent a scientifically reasonable description of ozone
formation and transport. The same can be said of an array of measurements through the
San Joaquin valley.
9. It is also important to have measurement stations to the north and south of the
Sacramento area because of the bifurcation in typical meteorological situations, where the
flow fields from the west diverges toward the north and south. The ozone concentrations
show several ozone hot spots one directly east of the San Francisco Bay Area with two
more directly to the north and south. Measurements to the north and south in this area
will help determine if the model predicted patterns are real. High ozone concentrations
along and directly east and south of the San Joaquin valley. Measurement stations are
required in this area as well.
10. The SAQM model predicts a rather complex vertical structure in ozone concentrations.
The vertical structure of ozone concentrations along a north–south cross-section through
the center of central California near Sacramento show that ozone is lost and transported
to the north and south leaving an arc of ozone that extends aloft and to the east and west
by midnight. The vertical structure of the ozone concentrations along the west–east cross
section through central California along the line running from the San Francisco Bay
Area through Sacramento to the foothills of the Sierra Nevada is similar in its overall
behavior to the north–south line. The plots show evidence of transport of ozone and NOx
from the west to the east. Ozone is lost in the lower levels and remains relatively high
aloft as the time progresses from noon to midnight. Some of the parcels of high ozone are
seen to travel from west to east in this sequence. Ozonesondes near San Francisco and
Sacramento and aircraft measurements of ozone over the Sierra Nevada foothills and the
western boundary are required to observe this complex ozone structure predicted by the
models.
1.4 Guide to the CCOS Field Operations Plan
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. Section 2 specifies the
CCOS measurement parameters, methods, locations, averaging times, calibration methods.
Section 3 describes the meteorological conditions associated with ozone episodes and transport
scenarios of interests, and specifies the daily forecast and intensive operational period (IOP)
decision-making protocols. Sections 4 and 5 describe the quality assurance and data management
activities for the study, respectively. Section 6 summarizes the efforts to develop a temporally
and spatially resolved emission inventory for the CCOS modeling domain, and Section 7
specifies the program schedule and budget.
Chapter 1: INTRODUCTION 1-11