Sediment Analysis Network for Decision Support (SANDS) - Landsat Datasets

Sediment Analysis Network for Decision Support (SANDS) Landsat Geological Survey of AL (GSA) Analysis
Sediment Analysis Network for Decision Support (SANDS) Landsat Geotiff

Table of Contents

Introduction

The Sediment Analysis Network for Decision Support (SANDS) project, funded by NASA, focuses on enhancing suspended sediment in satellite imagery related to tropical cyclones in the Gulf of Mexico. Since the year 2000, Eastern Louisiana, coastal Mississippi, Alabama, and the western Florida panhandle have been affected by 28 tropical storms, seven of which were hurricanes. These tropical cyclones have significantly altered normal coastal processes and characteristics in the Gulf region through sediment disturbance. Sediment deposits are changed in very short periods of time by these tropical storms. SANDS will generate decision support products that address the impacts of tropical storms and hurricanes on sediment disturbance, suspension, transport, and deposition in the Alabama and Florida coastal region. NASA satellite observations from MODIS, Landsat and SeaWiFS instruments, using color and infrared reflected bands, will be used to produce these decision support products. Analyzed data from these instruments will be enhanced to show suspended sediment carried out much farther into the Gulf than can be seen in normal true-color images. Increased area of sediment plumes from pre- to post- storm data can be visualized in the enhanced imagery and helps with comparison of pre- and post-storm runoff, sediment suspension, and transport patterns.

The Geological Survey of Alabama (GSA) GeoTIFF products are enhanced images 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. Daytime images from Landsat 5 and Landsat 7 GeoTIFF imagery for Gulf coastal storms were used. Documentation on the analysis methodology is found at Methods-Flow-Chart_Landsat.ppt and specific storm conditions and satellite information is documented in Landsat_and_MODIS_Info.xls.

The following 2000-2008 named storms were included:

The preliminary Landsat GeoTIFF products were produced by the U.S. Geological Survey (USGS) and were the input for the GSA sediment analysis data product. The products used were from the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and the Landsat 5 Thematic Mapper. The Thematic Mapper is a Landsat multispectral scanner designed to acquire data to categorize the Earth's surface. Particular emphasis was placed on agricultural applications and identification of land use. The scanner continuously scans the surface of the Earth, simultaneously acquiring data in seven spectral channels. The ground resolution of the six visible and shortwave bands of the Thematic Mapper is 30 meters, and the resolution of the thermal infrared band is 120 meters. The Enhanced Thematic Mapper Plus (ETM+), on Landsat 7, replicates the capabilities of the highly successful Thematic Mapper instruments on Landsat 4 and 5. The ETM+ also includes new features that make it a more versatile and efficient instrument for global change studies, land cover monitoring and assessment, and large area mapping.

Instrument

Thematic Mapper:

The Thematic Mapper (TM) is an advanced, multispectral scanning, Earth resources sensor designed to achieve higher image resolution, sharper spectral separation, improved geometric fidelity and greater radiometric accuracy and resolution than the MSS sensor. TM data are sensed in seven spectral bands simultaneously. Band 6 senses thermal (heat) infrared radiation. Landsat can only acquire night scenes in band 6. A TM scene has an Instantaneous Field Of View (IFOV) of 30 square meters in bands 1-5 and 7 while band 6 has an IFOV of 120 square meters on the ground. A Thematic Mapper (TM) is still operational aboard Landsat 5 as of  September 2010.

Enhanced Thematic Mapper Plus (ETM+):

The Enhanced Thematic Mapper Plus (ETM+) instrument is a fixed "whisk-broom", eight-band, multispectral scanning radiometer capable of providing high-resolution imaging information of the Earth's surface. It detects spectrally-filtered radiation in VNIR, SWIR, LWIR and panchromatic bands from the sun-lit Earth in a 183 km wide swath when orbiting at an altitude of 705 km. An ETM+ scene has an Instantaneous Field Of View (IFOV) of 30 meters in bands 1-5 and 7 while band 6 has an IFOV of 60 meters on the ground and the band 8 an IFOV of 15 meters.

Satellites

Landsat 5:

On March 1, 1984, NASA launched Landsat 5, the agency’s last originally mandated Landsat satellite. Landsat 5 was designed and built at the same time as Landsat 4 and carried the same payload: the Multispectral Scanner System (MSS) and the Thematic Mapper (TM) instruments. The TM instrument is still in operation, some 26 years after its planned design life. Data are regularly acquired at stations in the U.S. and Australia for entry into the U.S. archive.

Landsat 7:

Built for NASA and launched April 15, 1999, Landsat 7 is a remote sensing spacecraft operated for the United States Geological Survey (USGS). Landsat 7 is the seventh spacecraft in the Landsat series and is dedicated to capturing images of the changing Earth for use in many fields of study and application. Landsat 7 is continually adding to a database containing images of every piece of land on the planet. USGS is responsible for Landsat 7 operations, data processing, archive and distribution.

File Naming Convention

The GSA enhanced Analyzed GeoTIFF data files are zipped containing information files and ARCGIS files that can be read using ESRI software. All data are from year 2008. The file naming convention for the GSA product is as follows:

SE_<Storm>_yyyymmdd_pprr.ext
Zipped_bands_ mmdd_pprr.zip
Zipped_grid_SEyymmdd_pprr.zip

where

SE = Storm Event
<Storm> = storm name, e.g. Dennis, Gustav
yyyy = 4 digit year
mm = 2 digit month
dd= 2 digit day
pp = starting path
rr = starting row
ext = pdf (sediment product), jpg (stacked image), txt

The file-naming convention for the USGS GeoTIFF product is as follows:

Landsat 7:     LMfppprrr_rrrYYYYMMDD_AAA.XXX
Landsat 5:     LMfppprrr_rrrYYYYMMDD_AAA.XXX

where,

L = Landsat
M = Mission: (7 = Landsat 7, 5=Landsat 5)
f = ETM+ format (1 or 2) (data not pertaining to a specific format default to 1)
ppp = Product starting path
rrr_rrr = Product starting and ending rows
YYYYMMDD = Acquisition date of the image
AAA = File type:

B10 = Band 1
B20 = Band 2
B30 = Band 3
B40 = Band 4
B50 = Band 5
B61 = Band 6L
B62 = Band 6H
B70 = Band 7
B80 = Band 8
MTL = L1 metadata
GCP = Ground Control Points
DEM = Digital Elevation Model

XXX = file extension (.TIF or .txt) (Only the MTL and GCP files end with .txt)

Data Format

The enhanced GSA image files are also in the geoTIFF image format as described below. For more in depth information on the GeoTIFF data format, please reference the USGS provided USGS_README.txt.

These USGS image files are in "GeoTIFF" format. "GeoTIFF" refers to TIFF (Tagged Image File Format) files which have geographic (or cartographic) data embedded as tags within the TIFF file. The geographic data can then be used to position the image in the correct location and geometry on the screen of a geographic information display. GeoTIFF is a metadata format, which provides geographic information to associate with the image data. The TIFF file structure allows both the metadata and the image data to be encoded into the same file. GeoTIFF makes use of a public tag structure which is platform interoperable between any and all GeoTIFF-savvy readers. Many web browsers do not handle these files well.

These data sets are provided through the NASA Earth Science Data and Information System (ESDIS) Project and the Global Hydrology Resource Center (GHRC) Distributed Active Archive Center (DAAC). GHRC DAAC is one of NASA's Earth Observing System Data and Information System (EOSDIS) data centers that are part of the ESDIS project.

Reproduction or redistribution of digital datasets or products derived therefrom to a third party organization or entity is not forbidden. Any reproduction or hardcopy use of this data or results derived by using this data should include an acknowledgement of the Geological Survey of Alabama as the originator of the GSA data as a primary reference source for the GSA product in addition to the Information Technology and Systems Center (ITSC) SANDS project funded though the NASA Applied Sciences Program. The ITSC is part of the University of Alabama in Huntsville. The Landsat GeoTIFF product should acknowledge the U.S. Geological Survey (USGS) as the primary reference source.

Additionally each product should acknowledge that the data were obtained from the NASA EOSDIS Global Hydrology Resource Center (GHRC) DAAC, Huntsville, AL. This dataset is to be used as a primary reference source. This is public information and may be interpreted by organizations or others based on needs; however, users are responsible for the appropriate application. Federal, state, or local regulatory bodies are not to reassign to the originators any authority for decisions they make. Examples for general acknowledgments, data set citation in a reference listing, and crediting online web images and information can be found at: http://ghrc.nsstc.nasa.gov/uso/citation.html

Contact Information

The GSA data producer is:

Sandy M. Ebersole, PhD
Sandy Ebersole [SEbersole@gsa.state.al.us]
Geological Survey of Alabama
P.O. Box 869999
Tuscaloosa, Alabama 35486-6999
Office: Mary Harmon Bryant Hall #124

To order these data or for further information, please contact:

Global Hydrology Resource Center
User Services
320 Sparkman Drive
Huntsville, AL 35805
Phone: 256-961-7932
E-mail: ghrcdaac@itsc.uah.edu
Web: http://ghrc.nsstc.nasa.gov/