AIRBORNE LIDAR
INVESTIGATIONS OF OZONE AND AEROSOLS DURING THE NASA TRACE-P
FIELD EXPERIMENT
Edward V. Browell,
PI; William B. Grant, Co-PI; Johnathan W. Hair, Co-I
Large-scale distributions
of ozone (O3)
and aerosols will be investigated in the western Pacific troposphere
as part of the NASA TRACE-P mission to be conducted from March-April
2001. During this
investigation, we specifically propose to study the vertical
and horizontal distributions of O3 and
aerosol concentrations at high northern latitudes over the western
Pacific in the spring. An
airborne differential absorption lidar (DIAL) system will be
flown on the NASA DC-8 as part of a comprehensive airborne field
experiment. The
airborne DIAL data will provide high-resolution cross sections
of O3 (300
m in the vertical and 70 km in the horizontal) and aerosols (60
m in the vertical and 470 m in the horizontal) from the ocean
surface to the tropopause along the DC-8 flight track. The two
major objectives of this mission are to determine the chemical
composition of the Asian outflow over the western Pacific in
spring and the chemical evolution of this air. By
measuring the tropospheric cross section of O3 and
aerosols from the DC-8 during TRACE-P, both of these objectives
can be met. In addition,
by combining these data with in situ and, in some cases, remote
measurements of temperature, trace gases, and water vapor, a
better picture can be obtained regarding the composition and
evolution as well as determining the types of air masses encountered. Air
mass types will be examined to estimate the relative impact of
each air mass type on the tropospheric O3 budget
over the western Pacific Ocean as a result of photochemical production/destruction
and transport of O3. Natural
processes related to aerosol production and transport will also
be investigated.
The remote lidar
measurements of O3 and
aerosol distributions will be correlated to several factors. Those
of primary concern are the atmospheric structure, the vertical
transport of gases and aerosols between the marine mixed layer
and the free troposphere, exchange between the troposphere and
stratosphere, and the subsequent long-range advection of gases
and aerosols in the free troposphere. Aerosol
optical properties will be derived from the multiple-wavelength
lidar data and the depolarization ratios. The
O3 and
aerosol data will also be used to provide information on the
physical and chemical structure of the troposphere for each comprehensive
set of in situ aircraft measurements.
During the first
year of this 3-year research program, we will participate in
the detailed planning for the TRACE-P field mission, prepare
our UV DIAL system for the field, and make measurements of O3 and
aerosols using the airborne DIAL system during March-April 2001. Real-time
(preliminary) data reduction of DIAL O3 and
aerosol measurements will be provided in the field and posted
on our web site after each flight. We
will also begin the data reduction process. In
the second year, the data reduction and interpretation of the
DIAL data will be conducted as they pertain to the sources, sinks,
and dynamics of O3 and
aerosols over the western Pacific Ocean. The
integration of these data with the other in situ and remotely-sensed
data during TRACE-P will also be completed and archived in the
second year, which will lead to an improved understanding of
O3 and
aerosol budgets in the troposphere as well as being useful in
making the air mass characterizations. Also,
atmospheric transport of gases and aerosols will be studied using
the O3 and
aerosol data. In
the third year, we will complete our collaborations with other
science team members, prepare manuscripts related to the TRACE-P
mission, and submit these joint papers for publication.
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