Diagnostic and Numerical Studies of Atmospheric
Transport Related to Tropospheric Chemistry
and Global Scale Modeling and Analysis
A Research Project for the
National Aeronautics and Space Administration
Three research tasks will lead to a better understanding of atmospheric chemical transport. Task 1 will improve a
procedure that we recently developed to isolate air that previously had been within the lowest levels of the
troposphere-the source of most pollution. The procedure will be modified in several ways. 1) It will have the option
of utilizing either global scale meteorological data or input from a mesoscale meteorological model. 2) The existing
procedure crudely defines the boundary layer in terms of pressure (e.g., the layer below 850 hPa). We will modify the
scheme to rigorously define the boundary layer using established PBL criteria. 3) We will introduce a parameter that
indicates the time spent within the boundary layer.
As a result of the above improvements, the scheme will identify locations whose air previously was in the boundary
layer, where that boundary layer contact occurred, and the duration of time in the boundary layer. We believe the new
procedure will provide valuable information for the upcoming INTEX field project. We will utilize historical CO data
from MOPITT to verify the procedure and examine the pollutant transport that is expected during INTEX-locating sources
of boundary layer venting for air entering the United States as well as locations for venting within the States.
The second task will document a long range "River of Pollution" that we hypothesize within the Southern Hemisphere. We
recently confirmed a corresponding "river" in the Northern Hemisphere that transports pollution eastward from Asia to
near the coast of California and then back westward to near the coast of Indonesia. Since wind currents in the
Southern Hemisphere are a mirror image of those farther north, we believe that a corresponding "river of pollution"
exists in that hemisphere. Such transport would carry pollutants from widespread biomass burning over southern Africa
and South America eastward where they would recurve due to the southern hemispheric subtropical anticyclone and be
carried back westward by the trade winds. Thus, these aged parcels from southern hemispheric biomass burning would be
juxtaposed near the Intertropical Convergence Zone (ITCZ) with northern hemispheric aged parcels from Asia. Diagnostic
meteorological analyses will be performed to define the "river", and chemical analyses will document the photochemical
aging and dilution that are expected along its path. Finally, we will utilize mesoscale modeling in the vicinity of
the ITCZ to investigate smaller scale inter-hemispheric transport due to the "rivers".
Task 2 will utilize an existing GTE data set (PEM Tropics A). Documenting this hypothesized delivery of middle
latitude pollution to the tropics is important since the abundant sunlight and high humidity in the tropics accelerate
the loss of photochemically sensitive species. Also, the increased vertical mixing due to convective activity in the
tropics leads to more rapid mixing of longer-lived species into the background atmosphere.
Task 3 involves Florida State's participation in the first phase of NASA's Intercontinental Chemical Transport
Experiment-North America (INTEX-A) that was conducted during Summer 2004. "The goals are to understand the transport
and transformation of gases and aerosols on transcontinental/intercontinental scales and their impact on air quality
and climate. A particular focus in this study is to quantify and characterize the inflow and outflow of pollution
over North America". During INTEX-A, NASA's DC-8 instrumented aircraft conducted eighteen research flights
over North America and adjacent portions of the North Atlantic and North Pacific Oceans to sample the atmosphere.
Meteorological conditions exert a major influence on the transport and evolution of various chemical species. The
meteorology must be accurately forecast for flight planning purposes and described in detail to the Science Team
post-mission in order for INTEX-A to meet its objectives. Florida State University (FSU) proposed three major tasks
to address this important issue:
Prof. Henry Fuelberg was Mission Meteorologist during INTEX-A. In that capacity he assisted with flight planning
by providing various meteorological products and expertise that enabled the aircraft to meet the goals of the various
types of flights that were planned.
We calculated our newly derived boundary layer exposure product that is being developed under the current NASA
award. This product was calculated for flight planning and then re-derived for post mission use.
After the mission was completed, we prepared our final meteorological data set for the Science Team that supports
their analysis and publication of results. Those products can be viewed at our