SANDS – Sediment Analysis Network for
Decision Support
NASA Contract Number: NNX09AT46G
ROSES 2008 A.28
Semiannual Report Submitted On:
February 6, 2016
PI: Sara Graves Ph.D., sgraves@itsc.uah.edu
Co-I: Sandy Ebersole Ph.D., 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 Landsat and MODIS, 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. Due to the
recent end of the SeaWiFS mission the SANDS team has chosen to work with Landsat and
MODIS data only. This does not hinder the analysis or goals of the project since preliminary
results have shown that suspended sediment can be extracted from Landsat and MODIS data.
Analysts at GSA using image processing techniques have produced preliminary data products
that reveal suspended sediment in the Landsat and MODIS imagery. Image enhancement
methods including false color composites, spectral ratios, and other spectral enhancements based
on the mineral composition of sediments, were applied to combinations of visible and infrared
satellite bands individually for Landsat and MODIS data. The final processed imagery are being
saved in jpeg, pdf and grid formats for later use by end users. Figure 1 shows a graphical
representation of the overall process.
Figure 1 SANDS Decision Support Product Process Diagram
2.0 SUMMARY OF ACCOMPLISHMENTS THIS PERIOD (SEPT. 2010 - MARCH 2011)
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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Because some storms had only one image that was usable in analysis (due to cloud cover
or other problems), additional Landsat imagery was acquired by ITSC to supplement the
analysis. This data was then processed using the same techniques as documented
previously.
GSA reviewed MODIS data analyses from the previous reporting period and identified a
multi-band deletion problem that prevented correct analysis. GSA is going back and
correction this problem.
GSA reviewed SeaWiFS data for one scene acquired by ITSC, but had difficulty
analyzing the data due to a file type difference.
A poster on the remote sensing techniques used in the SANDS was presented by GSA in
October 2010 to the Geological Society of America national meeting in Denver, CO.
2.2 DATA SET PREPARATIONS AND MANAGEMENT
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Completed preparation of Landsat and MODIS data for all eleven storm events
Finalized posting of all MODIS HDF-EOS data files (subset to region of study) to the
SANDS ftp server at ftp://ghrc.nsstc.nasa.gov/pub2/data/SANDS/
Finalized posting of all MODIS GeoTiff formatted data to the SANDS ftp server
Finalized posting of all the Landsat GeoTiff data files to the SANDS ftp server
Added links for all MODIS HDF-EOS subset data, MODIS GeoTiff reformatted data and
Landsat GeoTiff data to the SANDS portal at http://sands.itsc.uah.edu/
Produced a one-page summary of SANDS preliminary results and distributed it to the
user community.
Completed the population of GHRC/NASA catalogs with metadata for all MODIS HDFEOS subset files, MODIS GeoTiff files, and Landsat GeoTiff files
Presented preliminary suspended sediment results at the Fall AGU meeting December 15,
2010
Presented poster at the Gulf of Mexico Alliance meeting December 1-3 in Mobile, AL
Added high resolution imagery of preliminary results showing suspended sediment and
floating surface oil to the SANDS website
Experimented with KML versions of SANDS GeoTiff data for display with Google Earth
3.0 DESCRIPTION OF ACCOMPLISHMENTS
3.1 IMAGE ENHANCEMENTS AND ANALYSIS
During this reporting period, GSA downloaded additional Landsat imagery from the SANDS ftp
server and began analyses of this supplemental data. These additional Landsat data were
gathered to help fill gaps for some storms that had only one or two useable images (mainly due
to cloud cover). The images were enhanced using the same spectral techniques described in
previous reports.
GSA has worked to finalize the Landsat imagery for all storm events and, with ITSC, to develop
a set of data and metadata that will maximize usefulness of the products for end users.
A problem was discovered with the processed MODIS imagery from analyses performed in
previous months. A band deletion problem was identified that impacted the imagery for
suspended sediment enhancements. To address this problem, the GSA staff reviewed the MODIS
analyses and recompiled the bands per image to re-run the spectral analysis and classifications.
SeaWiFS data was downloaded from the SANDS ftp server and a preliminary spectral
assessment of the data was performed. GSA worked with ITSC on the conversion of SeaWiFS
data from HDF4 format to GeoTiff. Problems persisted in developing useful imagery from
SeaWiFS. As described below we have decided to work with MODIS and Landsat data for the
remainder of the SANDS project.
3.2 DATA SET PREPARATIONS AND MANAGEMENT
The ITSC data management team completed preparation of all MODIS data for analysis by
GSA. These data files were produced by subsetting the MODIS (Aqua and Terra) HDF-EOS
data swaths over the SANDS region of study and then converting their format from HDF-EOS to
GeoTiff. Those data along with the Landsat data (which did not require any preparation) were
posted to the SANDS ftp site at the GHRC. The majority of this work was completed by
September 2010 and reported in the SANDS Annual Report of September 18, 2010. During the
past six months some additional data files were obtained and data on the ftp server were
reorganized. In addition, some cleanup of files took place. The SANDS ftp server is now
organized by data type (MODIS, Landsat) instead of by storm which makes for a simpler
structure. The organization by storm event requiring us to have multiple copies of MODIS data
on the server since some storm events overlapped.
With the ftp server structure finalized the MODIS and Landsat data were linked into the SANDS
data portal. The SANDS project utilizes satellite imagery from an approximate three week
window centered over landfall of the storms. This allows comparison of suspended sediments
before and after the storm event. The portal presents the SANDS data through a calendar
interface that gives access to each data file through hyperlinks in the respective calendar cell.
There are currently calendars for Landsat GeoTiff (Fig 2), MODIS GeoTiff (Fig. 3) and MODIS
HDF-EOS (Fig. 4). A calendar interface will also be used to link the suspended sediment
decision support products when they are completed.
Each hyperlink points to a file on the SANDS ftp server. Each calendar also shows the address of
the ftp server for users who prefer to get data that way. Notes on the calendar explain the
shorthand of the links and give notice that these files are quite large. Landsat files are
approximately 50Mbytes each and the MODIS files range from 20 to 50 Mbytes. Potential users
are directed to the GHRC User Services Office for assistance and the GHRC Data Search and
Order System for yet another method of ordering the data. Figure 5 shows the GHRC dataset
order page for SANDS data.
Figure 2 Landsat GeoTiff data files for Hurricane Katrina
Figure 3 MODIS GeoTiff data files for Hurricane Katrina
Figure 4 MODIS HDF-EOS data files for Hurricane Katrina
In the discussion above there is no description of the SeaWiFS data as in previous reports. There
are several reasons for this. The first and foremost is the end of the SeaWiFS mission. As
reported by Gene Feldman in a note on the Ocean Color website dated February 15, 2011 “I am
very sorry to have to report the news that after nearly two months of intensive research and numerous
attempts at communication with the spacecraft, GeoEye has determined that the SeaWiFS mission is no
longer recoverable. While this
is certainly not the outcome
that we were all hoping for, the
international scientific
community certainly could not
have asked for a more
tenacious little spacecraft and
instrument that has served us
so well for the past 13+ years.”
The other reasons are that the
GSA team has shown that
suspended sediments are
extractable from Landsat and
MODIS imagery. Because of
the demise of SeaWiFS the
SANDS team will
Figure 5 SANDS data order page at the GHRC
concentrate on the MODIS and Landsat data. The final reason is that GSA researchers had to
respond to the BP Deepwater Horizon oil spill event which delayed some of their efforts on
SANDS.
3.3 RESULTS OF SEDIMENT ENHANCEMENTS OF LANDSAT DATA
Sediment enhanced iamgery for all Landsat scenes are still being converted to their final format
(pdf, jpeg, grid) and corresponding FGDC-compliant metadata are being generated. During the
generation of these products, GSA identified spatial and spectral correlations previously
undocumented. One was the correlation between fingers of suspended sediment stretching out
from the coast into the Gulf that correlated with sand ridges on the sea shelf floor (Fig. 6).
Another correlation was spectral identification of oil slicks from Hurricane Katrina that
correlated with oil slicks previously identified by others in aerial imagery (Fig. 7).
Figure 6 Suspended sediment (orange) in Mobile Bay derived from Landsat data
Figure 7 (A) Landsat 5 image (path 21, row 39) of the eastern Louisiana Delta and Chandeleur Islands on August 31,
2005 (2 days after Hurricane Katrina made landfall) in true color (bands 1, 2 and 3). (B) The same area with preliminary
spectral identification of oil (yellow) floating on the surface
3.3 SANDS PORTAL
As described above the SANDS portal has been expanded to include links to all MODIS and
Landsat data prepared by ITSC for analysis by GSA. In addition preliminary results from
Landsat data showing suspended sediments and surface oil have been posted on the home page at
http://sands.itsc.uah.edu/ . The page has links to high resolution imagery which show these results
in detail. The portal also has documentation for users who are interested in the MODIS HDFEOS data files. As the decision support products are completed they will be linked to the portal
as well. One of the SANDS deliverables is the data portal. Since it will transition to the GSA the
portal is being constructed such that it can easily transition to the GSA server.
4.0 WORK PLAN FOR MARCH 18, 2011 – JULY 31, 2011
With the end of the SeaWiFS mission the plans for analyzing SeaWiFS data has for all practical
purposes come to an end. It should also be pointed out that the preparation of SeaWiFS data for
analysis requires an order of magnitude more work than that of MODIS. This is due to the
format. The SeaWiFS data are in HDF version 4 while MODIS data are in HDF-EOS. There are
good tools available for working with HDF-EOS data such as the HDF-EOS to GeoTiff (HEG)
conversion tool. Converting SeaWiFS data to GeoTiff requires SeaDAS 6.0 – software
developed by the Ocean Color Group – which works but is more cumbersome to use. The results
from that process have not yielded files that are as workable as those from MODIS and Landsat.
Thus, the plans for the remainder of the contract will center on the MODIS and Landsat data.
Currently all data prepared for analysis are posted to the SANDS ftp server and are available
from the SANDS portal. In the next four months the portal will be completed by adding links to
the decision support products, imagery of the storm events and more documentation.
The decision support products will be entered into the GHRC data catalog and made available
through the GHRC and the NASA Earth Science Data Center search and order systems (ECHO
and WIST).
The SANDS data portal will transition to the Geological Survey of Alabama. The data itself will
reside both at the GHRC and GSA. Metadata for the decision support products will be entered
into state of Alabama data systems including Alabama View and Virtual Alabama.
For the remainder of the contract, GSA will finalize end products for the Landsat data and will
perform corrections and enhancements to the MODIS data. GSA will deliver the finished
products (enhanced imagery and metadata) to the ITSC team for upload to the SANDS portal.
GSA will also share information on the suspended sediment products analyzed in the SANDS
project as a poster presentation at the 2011 Southeastern Geological Society of America meeting
in Wilmington, North Carolina this March. The meeting will be well attended with other
scientific researchers in remote sensing and coastal fields and will be a good way of increasing
interest and knowledge of the SANDS project and available products.
5.0 MILESTONES
The SANDS project has progressed much as planned. The analysis of Landsat and MODIS data
have shown that suspended sediments can be detected from these remotely sensed data. In
addition the analysis technique also clearly revealed the presence of surface oil off the coast of
Louisiana – which was not one of the original SANDS goals. All MODIS, Landsat and SeaWiFS
data have been obtained but only MODIS and Landsat have been analyzed. It is not likely that
SeaWiFS data will be analyzed as explained above. The SANDS data portal is on track and
currently provides access to all MODIS and Landsat data used for analysis. There has been a
delay in the production of suspended sediment decision support products due to the impact of the
BP Deepwater Horizon oil spill on the GSA staff. However, the process is established and
preliminary data products have been produced. The production of jpeg, pdf and grid formatted
decision support products derived from enhanced Landsat imagery along with accompanying
metadata is almost complete. Although there was a delay in progress on the MODIS data due to
the discovery of band deletions from earlier analyses, the problem has been corrected and the
MODIS data will be reanalyzed.
6.0 FINANCIAL
As of February 2011, the SANDS project has expended $241,342 of the $390,179 total budget of
which $124,730 has been expended by GSA. This represents about 62% of the total 24-mo
budget of $390,179.
7.0 ISSUES
As described above the ending of the SeaWiFS mission has resulted in a change of plans for the
SANDS team. This is not seen as a problem however, since it has been demonstrated that
suspended sediments can be extracted from the Landsat and MODIS data. The team will focus
on generating suspended sediment decision support products from the Landsat and MODIS data
for all eleven storm events listed in Table I.
A problem was identified with the MODIS data analysis which has delayed progress on the
MODIS data products. Techniques have been identified to correct the MODIS band deletion
issue however, and progress will resume. Another continuing obstacle is the response to 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. Time required for oil spill tasks however has been
decreasing over time and we are positive that we will be able to complete the objectives of the
SANDS project.
8.0 CONFERENCE PRESENTATIONS
Preliminary results from the SANDS project were presented at the Fall AGU Meeting. The
presentation was part of session OS18 “Estuarine Sediment Dynamics and Fate of Particles,
Contaminants, and Carbon at the Land-Ocean Interface.” The PowerPoint charts are available
from the SANDS website at: http://sands.itsc.uah.edu/documents.html
Preliminary results and methodology of the SANDS remote sensing analyses were presented at
the Geological Society of America national meeting in Denver, Colorado, in October. The
presentation was part of a remote sensing poster session. Results from SANDS will also be
presented at a marine and coastal science poster session at the Southeastern Geological Society
of America Meeting in March 2011 in Wilmington, NC.
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
Landfall Date
September 21, 2000
June 5, 2001
August 5, 2001
September 25, 2002
September 15, 2004
June 11, 2005
July 5, 2005
Hurricane Dennis
Hurricane Katrina
Tropical Storm Fay
Hurricane Gustav
July 10, 2005
August 28, 2005
August 19, 2008
September 1, 2008