MANE-VU
Mid-Atlantic/Northeast Visibility Union
Combined Aerosol Trajectory Tool, CATT
An Analytical Tool Extending VIEWS Data System
Final Report Prepared by
Center for Air Pollution Impact and Trend Analysis (CAPITA)
Washington University in St. Louis
to the
MARAMA contract on behalf of
Mid-Atlantic/Northeast Visibility Union (MANE-VU)
and the
Inter-RPO Data Analysis Workgroup
Supplemental funding from
Environmental Protection Agency, OAQPS Agreement # 83114101-0
National Science Foundation, Grant #0113868
ACKNOWLEDGEMENTS
MARAMA gratefully acknowledges the funding support provided by the United States
Environmental Protection Agency under agreements with the Mid-Atlantic/Northeast Visibility
Union and the Midwest Regional Planning Organization.
Numerous individuals provided directions guiding the project, reviewed the drafts of this
report and gave insightful comments including:
Donna Kenski, LADCO
Serpil Kayin, MARAMA
Gary Kleiman, NESCAUM
Rich Poirot, Vermont DEC
Susan Wierman, MARAMA
Paul Wishinski, Vermont DEC
Kristi Gebhart, National Parks Service/CIRA
Bret Schichtel, National Parks Service/CIRA
Final Interim Report
ii
January 2003
A. Introduction
The Visibility Information Exchange Web System (VIEWS) is an online exchange of visibility
data, research, and ideas. The VIEWS web system contains an array of visibility related data for
use by the Regional Planning Organizations (RPOs). The evolving VIEWS system also performs
extensive data summarization, calculations and delivers the raw and processed data through a
simple, user-friendly web interface. The main application of VIEWS is to aid RPOs and the
states in the implementation of regional haze regulations over the next years. The VIEWS system
is operated at Colorado State University, Cooperative Institute for Research in the Atmosphere
(CIRA), under contract from RPOs.
The Center for Air Pollution Impact and Trend Analysis (CAPITA) at Washington University in
St. Louis has been developing a number of software tools for the analysis, exploration, and
presentation for air quality data. Most recently, with support from NSF and NASA, CAPITA has
developed the DataFed (Data Federation) infrastructure for web-based sharing, browsing, and
processing of distributed air quality data. One of the applications built on the DataFed
infrastructure is tool for Combined Aerosol Trajectory Tool (CATT) for the exploration of
airmass transport pattern under specified chemical conditions. The CATT tool received initial
funding from the Mid-Atlantic/Northeast Visibility Union/Midwest Regional Planning
Organization (MANEVU/MRPO) RPOs. This project is an extension of the initial CATT
residence time analysis tool.
A key feature of the expanded CATT tool is the applicability to all RPOs. The extensions include
spatial coverage of the entire US and also incorporation of all chemical parameters in the
VIEWS aerosol chemistry database. With CATT, investigators in any of the RPOs or states can:
a.
Explore the airmass histories associated with any chemical conditions.
b.
Render the associated residence times as contours or trajectories.
c.
Superimpose the transport data on other spatial data sets (emissions, satellites)
CATT is designed and implemented as a community tool. Both the data as well as the processing
routines are contributed by the air quality analysis community.
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Figure 1 CATT as a community tool.
Based on experience in developing the prototype CATT tool the software consists of two rather
independent components:
1. Chemical filter component. This component is accomplished through queries to
chemical data sets. The output of this step is a list of “qualified” dates for a specific
receptor location.
2. Trajectory aggregator component. This component receives the list of dates for a
specific location and performs the trajectory aggregation, residence time calculation and
other spatial operations to yield a transport pattern for specific receptor location and
chemical conditions.
The two software components have substantial utility individually as well as linked as a single
tool.
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Figure 2. CATT components
B. Summary Report on Contract Tasks
The main goal of the project was to develop an analysis tool for exploring the geographic origin
of airmasses with specific chemical composition. This necessitated combining the aerosol
chemistry and air transport data in practical web based tool and making it accessible to the air
quality analyst community.
The specific contractual tasks for this phase of the CATT project consist of four major tasks:
 Connecting the CATT tool to the VIEWS aerosol chemistry database
 Implementing spatial rendering (trajectory/grid/contour) of transport data
 Implementing superposition of multiple GIS map layers
 Maintenance of the CATT web server for one year.
In this section the results of these contractual task are summarized.
Connecting the CATT tool to the VIEWS aerosol chemistry database
The connection of the CATT tool to the VIEWS database has been completed. The CATT tool
has been connected to the SQL server VIEWS database at CIRA. The relevant VIEWS data
tables have also been transferred to the DataFed server and repackaged for fast access,
processing, and rendering. The resulting VIEWS “data cubes” allow easy browsing of the
connected chemical and trajectory data. The CATT data analysis services are delivered through a
separate web server hardware/software system dedicated for this purpose, as shown in Figure 3.
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Figure 3. Networking connection between the DataFed Analytical Server (blue middle) to VIEWS and
CAPITA servers.
The integration of the proposed data analysis tools with the VIEWS system was the subject of
numerous discussions between the system designers at CIRA and CAPITA. The above design
and implementation has the benefit that it eliminates intrusive, low level interaction between the
two systems. Instead, the CIRA and CAPITA systems can be developed independently, but
connected through standard web-links. This design simply requires that the CIRA-VIEWS data
sets and the CAPITA software be routinely updated in the new server by their respective
custodians.
Implementing spatial rendering (trajectory/grid/contour) of transport data
The trajectory/residence time rendering is now implemented is ready for user feedback. The two
major transport display modes are trajectory and residence time grid. Both trajectory rendering
approaches are illustrated below. A more detailed explanation of trajectory and grid rendering is
given in section C. Illustrated Instruction Manual for CATT.
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The trajectory rendering includes weight functions representing the (1) chemical concentration
associated with the trajectory and (2) distance (age) of the trajectory point from the receptor. The
trajectory color is linked to the concentration weight and the point size is proportional to the
distance (age) weight.
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Figure 4. Rendering of ensemble trajectories. Weights are represented by color and point circle size.
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Figure 5. User input screen for the CATT chemical filter
The spatial density of the ensemble trajectories is d
The trajectory end points are summed for each grid and the total number of endpoints in a grid
represents the residence time map. For sake of uniformity, the residence time grid is normalized
by the total number of endpoints. Note that trajectory endpoints are also weighed by chemical
concentrations and distance.
Figure 6. Contour plot of the CATT residence time distribution for specific chemical conditions.
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Transport Probability Metrics
The transport metric is calculated from two residence time grids, one for all trajectories and
another for trajectories on selected (filtered days). Both residence time grids are normalized by
the sum of all residence times in all grid cells:
pijf=rij/ rij
pija=rij/ rijpijf,
is the filtered and pija is the unfiltered residence time probability that an air masses passes
through a specific grid. There is a choice of transport probability metrics:
The Incremental Residence Time Probability (IP) proposed by Poirot et al., 2001 is obtained by
subtracting the chemically filtered grid from the unfiltered residence time grid,
IRTP = pijf – pija
The other metric is the Potential Source Contribution Function (PSCF) proposed by Hopke et al.,
which is the ratio of the filtered and unfiltered residence time probabilities,
PSCF = pijf / pija
Implementing superposition of multiple GIS map layers
The Visibility Information Exchange Web System, VIEWS is an online exchange of visibility
data, research, and ideas to support the Regional Haze Rule. The VIEWS system also provides
spatio-temporal summaries of key haze parameters. The DataFed data browser has a flexible
mapping module that can be incorporated into the VIEWS delivery system. For the past year, B.
Schichtel of CIRA/VIEWS and R. Husar/CAPITA have been planning the mapping module
transfer but the resources were not available.
The CATT-VIEWS extensions enhance the current image-based VIEWS spatial data delivery
system by a dynamic mapping module for flexible presentation of spatial data. For example,
DataFed trajectory rendering for specific locations and dates can be delivered to VIEWS as a
dynamic image, suitable for incorporation into the VIEWS query/presentations system.
Figure 8. Trajectory data layer provided to VIEWS through standard web-based GIS (OGC compliant)
query
The DataFed distributed environmental data browser facilitates access, overlay and rendering of
spatial data from multiplicity of web sources. Distributed DataFed was developed at CAPITA
with funding from NSF, NASA and EPA. Using distributed browser, the spatial images are
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generated at use time. Dynamic mapping also allows GIS data layers to be navigated (zoom, pan,
point) by the user. Figure 7 illustrates the superposition of VIEWS and other data using the
dynamic mapping
facility.
Figure 9. Illustration of dynamic mapping using VIEWS data.
Maintenance of the CATT web server for one year.
As part of this project, the functionality of the CATT was transferred to a dedicated server
located in the Washing University School of Engineering Computing Center. The CATT server
is part of the DataFed server cluster composed of 4 advanced multi-processor DELL servers.
These servers are being maintained professionally, 24/7 by the Engineering School.
The Data Content of the new CATT server is maintained by periodic updates of the respective
databases (CIRA) and software (CAPITA). The updates are initiated manually, since they occur
only several times a year.
The above described tools for data analysis need to be accessible from standard web browsers.
This means that the tools will have to reside on an appropriately reconfigured web server.
The extension of CATT consists of three components:
a) Include all chemical species that are measured or calculated from the IMPROVE
monitoring sites;
b) Incorporate all IMPROVE sites for the CATT analysis;
c) Perform “on-the-fly” trajectory aggregation.
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The benefit of a) is that it will allow residence time analysis for individual chemical species, e.g.
potassium or nitrate. Extension b) will facilitate exploration of transport to IMPROVE sites
anywhere in conterminous US.
C. CATT Instruction Manual
The CATT manual is contained in a separate document
Combined Aerosol Trajectory Tool, CATT Illustrated Instruction Manual
http://capita.wustl.edu/capita/capitareports/0411CATTReport/Tutorial/CATT_Manual.doc
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