SANDS – Sediment Analysis Network for
Decision Support
NASA Contract Number: NNX09AT46G
ROSES 2008 A.28
Semiannual Report Submitted On:
February 9, 2016
PI: Sara Graves Ph.D., sgraves@itsc.uah.edu
Co-I: Sandy Ebersole, sebersole@gsa.state.al.us
1.0 PROJECT OVERVIEW
Since the year 2000, Eastern Louisiana, coastal Mississippi, coastal Alabama, and the western
Florida panhandle have been affected by 28 tropical storms, seven of which were hurricanes.
Although tides, seasonality, and agricultural development influence suspended sediment and
sediment deposition over periods of time, tropical storm activity has the capability of moving the
largest sediment loads in the shortest periods of time for coastal areas.
The SANDS project is addressing sediment redistribution issues by producing a suite of decision
support products, derived from satellite observations from MODIS, Landsat and SeaWiFS for
assessment and monitoring of suspended sediment and sediment deposition in the north central
Gulf of Mexico region. These products will support resource management, planning, and
decision making activities in the Gulf of Mexico. The project will also facilitate delivery of the
resulting products to end users by making them available through a SANDS portal hosted at the
Geological Survey of Alabama (GSA) and through NASA’s Global Hydrology Resource Center.
The Information Technology and Systems Center (ITSC) at the University of Alabama in
Huntsville (UAHuntsville) has acquired Landsat, MODIS, and SeaWiFS data over the Northern
Gulf of Mexico before and after each storm identified for study (Table I). Landsat and MODIS
data have been processed and sent to GSA for further processing and enhancements.
Analysts at GSA are working to create products that highlight suspended sediment in the
imagery (both before and after the storms) through image processing techniques. Image
enhancement methods including false color composites, spectral ratios, and other spectral
enhancements based on the mineral composition of sediments are being applied to combinations
of visible and infrared satellite bands individually for Landsat, MODIS, and SeaWiFS data. The
final processed imagery will be saved in GeoTIFF format for later use by end users. Figure 1
shows a graphical representation of the overall process. The distribution of enhanced SeaWiFS
products will be governed by the SeaWiFS data access and distribution policy.
Figure 1. SANDS Decision Support Product Process Diagram
2.0 SUMMARY OF ACCOMPLISHMENTS THIS PERIOD (MARCH – SEPT. 2010)
Accomplishments from the past six months are summarized in the following list and elaborated
in section 3.
2.1 IMAGE ENHANCEMENTS AND ANALYSIS
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Completed spectral enhancements of Landsat data, including iron oxide enhancements,
clay enhancements, Iterative Self Organized Data (ISODATA) classification, and yellow
and red enhancements
Applied cluster busting techniques to remove high sun-glint areas from selected Landsat
imagery
Finalized production of enhanced imagery, per Landsat scene, for images without
significant sun-glint problem areas
Evaluated and segregated MODIS Aqua data exhibiting striping and data gap problems.
Began land and cloud classification for non-striped MODIS data
Began first-pass ISODATA classification on non-striped MODIS data
Assessed enhancement techniques and methodologies for SeaWiFS data and began
architecting the model for suspended sediment enhancements for SeaWiFS data
Submitted a poster abstract on the remote sensing techniques used in the SANDS project
to the Geological Society of America meeting
2.2 DATA SET PREPARATIONS AND MANAGEMENT
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Completed development of an automated procedure for subsetting MODIS data files and
producing multi-layer GeoTiff files for analyses
Completed subsetting of MODIS data (MYD02 and MOD02) over the region of study for
each of the 11 storm events
Completed extraction of Reflective Solar Bands from MODIS data (MYD02 and
MOD02) producing multi-layer GeoTiff files for all 11 storm events
Populated the GHRC data catalog with metadata for all MODIS HDF-EOS subset files,
corresponding GeoTiff files, and Landsat GeoTiff files
Acquired additional MODIS Terra (MOD02) data for tropical storm Arlene and Landsat
5 TM data for Allison, Barry, Helene and Isidore storm events
Attended the Gulf of Mexico Alliance meeting August 2-5 in Biloxi MS
Submitted abstract to Fall AGU Oceans session
3.0 DESCRIPTION OF ACCOMPLISHMENTS
3.1 IMAGE ENHANCEMENTS AND ANALYSIS
During the first six month period of the SANDS
project, GSA downloaded the GeoTiff imagery
acquired by the UAHuntsville team, and began
analysis of all the Landsat data. Land and cloud
areas were deleted from each scene (Figure 2) to
reduce pixel confusion and improve spectral
enhancement of suspended sediment (cluster
busting). Enhancement analyses continued during
the past six month period resulting in additional
sediment enhancements and sun-glint reduction
techniques. Mineral-specific enhancement
Figure 2 Land and cloud pixels deleted from Landsat
techniques and turbid water coloration
enhancements were incorporated into the
final model for Landsat data. Sun glint
was a problem in some Landsat scenes
(Figure 3 at right, sun glint is displayed
as red-yellow) and interfered with
sediment enhancements (spectral
confusion). To increase the quality of the
final product, identification and deletion
of the glint area was performed before
processing sediment enhancements.
Figure 3 Sun glint displayed as red-yellow.
During this reporting period, GSA completed the
download and pre-assessment of the MODIS data.
One obstacle encountered was striping (Figure 4)
in the MODIS Aqua scenes. Because this is a
functional problem of the satellite sensor itself and
since there are no spectral-value-protecting or
corrective procedures available for data with
severe striping problems, some of the scenes were
set aside and will not be included in the sediment
enhancements. Land and cloud deletion and
ISODATA classifications were begun on the
Figure 4 Example of striping in MODIS Aqua data
remaining MODIS data.
Research review of SeaWiFS data and suspended sediment enhancement techniques was also
conducted during this reporting period. The techniques to be used in sediment enhancements for
SeaWiFS data will be similar to those used for Landsat and MODIS (with respect to wavelength
ranges most useful in enhancing suspended sediments).
3.2 DATA SET PREPARATIONS AND MANAGEMENT
With confirmation from GSA that the
Landsat and MODIS data products held
promise for evaluating sediment
redistribution, the UAHuntsville team
proceeded to complete an automated
processing sequence to subset each of the
MODIS HDF-EOS data files to the
desired region of study (Figure 5) and then
generate multi-layer GeoTiff files from the
Reflective Solar bands. (MODIS data and
Landsat data for all eleven storm events
had been obtained during the first six
Figure 5 SANDS Region of Study
months of the project.) The Landsat data were
already in GeoTiff format requiring no further
processing. The MODIS data was processed by the automated procedure – known as SANDS
Script – for all storm events and the resulting subset HDF-EOS data and GeoTiff data products
were staged to the ftp server at the Global Hydrology Resource Center. The products were also
entered into the GHRC Data Catalog in preparation for publication through the GHRC data
search and order system as well as NASA’s ECHO system.
The MODIS data obtained for SANDS is a combination of MODIS Aqua and MODIS Terra.
Since Aqua was not launched until May 2002 MODIS Terra data were obtained for storms
Helene (Sept., 2000), Allison (June, 2001) and Barry (Aug., 2001). MODIS Aqua data were
obtained for the remaining eight storm events. Following analyses of MODIS Aqua data for
tropical storm Arlene (June, 2005) GSA requested additional data from MODIS Terra. The
UAHuntsville team obtained the data from LAADS and using the SANDS Script procedures
quickly generated the new products. This was a good test of the data access and product
generation procedures. Additional Landsat 5 TM data was also obtained for Allison, Barry,
Helene and Isidore.
One of the goals of the SANDS project is to make all data available from the GHRC. For
provenance we planned to maintain the MODIS HDF-EOS subset files as well as the GeoTiff
files from which GSA conducted the analyses and created new products. Since the MODIS
HDF-EOS subset files and GeoTiff files for all storms were completed the UAHuntsville team
incorporated them into the GHRC as new data products. This involved the specification of
metadata, integrating the data files into the GHRC server and populating the GHRC data catalog
with the full list of granules. This was completed for the MODIS and Landsat data. However,
these data sets will not be made publically visible through the GHRC user interface or the NASA
ECHO system until the decision support products are available as well.
3.3 PRELIMINARY RESULTS
OF SEDIMENT ENHANCEMENTS OF LANDSAT DATA
Sediment enhanced data for Landsat scenes are in an
intermediate format and are not currently ready for
distribution. Corrections for sun glint (Figure 3 in the
previous section) are still being processed, with
completion of final enhanced Landsat imagery expected
within the next two months. The final imagery will be a
compilation of multiple enhancement techniques and
will look similar to the image shown at left (Figure 6)
with suspended sediment (green) in Mobile Bay and
waters south of Morgan Peninsula. Metadata will
accompany each image including a description of the
processing steps taken in producing the final imagery.
The final products will be made available through the
GHRC and GSA.
Figure 6 Suspended sediment in Mobile Bay
3.3 SANDS WEBSITE
An initial website has been developed for the project at http://sands.itsc.uah.edu/ . This website
currently provides basic project information. As the project proceeds, the site will be expanded to
include links to all of the SANDS decision support products as well as the data used to produce
them. During the past six months the SANDS team has started the implementation of automated
scripts which will automatically link the data and imagery to the website.
4.0 WORK PLAN FOR SEPTEMBER 18, 2010 – MARCH 18, 2011
All SeaWiFS data will be processed from its native HDF4 format into GeoTiff format for
analysis by GSA. The UAHuntsville team is employing the SeaDAS 6.0 software developed by
the GSFC Ocean Color team for this effort. The data and software are already resident on the
GHRC computing systems.
Landsat, MODIS and SeaWiFS data have been obtained for all storm events identified in the
proposal. However, it is expected that additional data will be needed to fill in gaps or to extend
the period of observation for one or more storm events. As necessary the team will obtain and
process additional data. Additional Landsat 5 TM data has already been obtained for the Allison,
Barry, Helene and Isidore storm events, and MODIS Terra data has been obtained for Arlene.
For the next six-month period, GSA will finalize corrections and enhancements to the Landsat
data and will deliver the finished products (enhanced imagery and metadata) to the UAHuntsville
team for upload to the SANDS portal. GSA will also complete enhancements for the MODIS
data and the final enhanced MODIS imagery will also be delivered to the Huntsville team for
upload to the SANDS portal.
GSA will begin sharing information on the remote sensing techniques used to create the final
enhanced imagery at the fall 2010 Geological Society of America meeting in Colorado. GSA
will produce a poster (the abstract for which has been accepted) highlighting the SANDS project,
the data used, the analyses and models used, and examples of the final enhanced Landsat
imagery and potential applications for end users.
The development of the SANDS portal will continue during the next six month period. Landsat
and MODIS data are on hand and available to the SANDS team via the GHRC ftp server. The
SANDS portal will provide a better interface to the data by giving the user a calendar like
interface organized by storm event. Automated scripts are under development that will populate
the calendar with links and thumbnail imagery for the GeoTiff data files used in the SANDS
analyses. As decision support products become available they will be posted to the portal as well.
5.0 MILESTONES
The SANDS project has progressed as planned. The acquisition of Landsat, MODIS and
SeaWiFS data for all eleven storm events ranging from 10 days prior to 10 days following
landfall is in house. Subsets of MODIS data over the study region have been produced and
corresponding GeoTiff files generated. All Landsat and MODIS GeoTiff files have been
transferred to GSA for analysis and the GHRC data catalog has been populated with metadata
from these products. A script for subsetting the MODIS data and producing GeoTiff files has
been completed putting SANDS ahead of schedule in automating data access and processing.
While GSA has made great advances in the analysis of the Landsat data, two obstacles have
slowed progress which will delay the publication of the Landsat decision support products by
two months. One obstacle is the time-consuming task of removing sun glint, a phenomenon that
inhibits proper spectral analysis. Techniques have now been created to correct for this issue
however, and progress will resume. The other obstacle to progress at GSA was the Gulf oil spill.
One of GSA’s obligations is to help in response efforts related to natural resources damage
assessment. Some of the time originally allotted to the SANDS project was diverted to response
efforts related to the oil spill.
6.0 FINANCIAL
As of August 31, 2010 the SANDS project has expended $155,774 of which $67,388 has been
expended by GSA. This represents about 40% of the total 24-mo budget of $390,179.
7.0 ISSUES
As reported in the first semi-annual report there are some issues related to the processing of
SeaWiFS data. We originally planned to incorporate the SeaWiFS processing into the same
script as that for MODIS. However, due to the HDF4 format of SeaWiFS this did not work.
(MODIS is in HDF-EOS format.) Instead we are using the SeaDAS 6.0 software to create
GeoTiff files from SeaWiFS.
Issues that have impacted GSA’s remote sensing analyses included sun-glint problems in
Landsat data, striping in MODIS data, and diverted time from the SANDS project to the Deep
Water Horizon oil spill response. Techniques have been developed and applied to correct for the
sun-glint problems. Severely striped MODIS Aqua data cannot be enhanced and will be
discarded, but the remaining less-striped and non-striped data can be used. Oil spill activities
have slowed for GSA staff on SANDS allowing work to continue as planned.
Figure 7. SANDS project schedule and milestones
8.0 CONFERENCE PRESENTATIONS
The SANDS project was promoted through a poster session at the Federation of Earth Science
Information Partners (ESIP Federation) July 6-8, 2010 in Knoxville TN.
Table 1. Storm
Events Included in SANDS Project
Storm Name
Hurricane Helene
Tropical Storm Allison
Tropical Storm Barry
Tropical Storm Isidore
Hurricane Ivan
Tropical Storm Arlene
Tropical Storm Cindy
Hurricane Dennis
Hurricane Katrina
Tropical Storm Fay
Hurricane Gustav
Landfall Date
September 21, 2000
June 5, 2001
August 5, 2001
September 25, 2002
September 15, 2004
June 11, 2005
July 5, 2005
July 10, 2005
August 28, 2005
August 19, 2008
September 1, 2008