To address the science goals of the Landsat Data Continuity Mission (LDCM), the Landsat Science Team has been selected to investigate and advise the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA) on issues critical to the success of this endeavor. With that in mind, we would like to take the opportunity to introduce you to some of these people.
On July 23, 2007, the Landsat Program celebrated the 35th anniversary of the launch of its first satellite, ERTS-1 (Earth Resources Technology Satellite-1). Renamed Landsat 1 in 1975, it was followed by two very similar satellites: Landsat 2, launched on January 22, 1975, and Landsat 3, launched on March 5, 1978. The legacy continues today with Landsats 5 and 7, two operational satellites that augment a global archive that is maintained at the U.S. Geological Survey's Center for Earth Resources Observation and Science (EROS). The Landsat Data Continuity Mission is currently developing a new satellite with a planned launch date of 2011.
This 35-year legacy of land imaging reveals how land changes over time, whether caused by forces of nature or humans. USGS scientists can estimate timber removal from the Amazon rainforest, monitor regrowth after wildfires or volcanic eruptions, document the expansion of our world's largest cities, or evaluate how policies affect changes in agriculture. The Landsat project is a key tool for understanding our changing world.
Year-to-year we expect the price of bread to remain relatively stable, but rarely do we realize the complex interactions and activities that are responsible for that price stability. And even less often do we realize that Landsat satellite data are behind the accurate global crop production estimates that enable such price stability.
Stable food prices are the result of a delicate balance between food supply and demand. To drastically simplify: if agricultural supply is too high, prices fall to a level where farmers cannot afford to plant; if supply is too small, food prices can soar. So, an unstable agricultural commodities market can lead to wild food price fluctuations—much like the gas price fluctuations caused by recent oil market swings.
To read the full story, visit http://www.nasa.gov/centers/goddard/news/gnews_detail.html and click on the Volume 3, Issue 7 link.
USGS LDCM, in conjunction with the USGS Office of Budget and Performance, conducted a customer satisfaction survey to measure how satisfied Landsat users are and to identify key product characteristics and data delivery strategies. The survey was sent to non-Federal users who had purchased data from the USGS Center for Earth Resources Observation and Science (EROS). (Federal users were surveyed in a separate effort.) We received 243 viable responses, providing a response rate of 48 percent.
What did the survey find?
Users were asked to rate the importance and satisfaction of several things related to Landsat data. Ratings were from 1 to 5, with 1 being high and 5 low. Most of the satisfaction indicators were rated fairly high, but the factors that users rated lower in satisfaction, but higher in importance were:
More than 55 percent of users indicated that cost is at least somewhat of a barrier, and many said why, including:
Cost: USGS is moving toward “Web enabling” or downloading Landsat data. A pilot study began on June 4 to “Web-enable” Landsat 7 terrain corrected data over the United States—this is the first step toward what will be standard practice in the LDCM era.
The approach LDCM is planning at the moment is to deliver the LDCM “standard” product in the preferred projection (UTM), datum (WGS84), and format (GeoTIFF) with a goal of web enabled download via File Transfer Protocol (FTP). The results of this survey seem to confirm that this approach will meet the bulk of the Landsat data users’ needs and will reduce the barriers that the current cost of the data imposes on small business, educational and nonprofit institutions, large-scale studies, and exploratory analyses.
Much more information from this survey is available. You are welcome to contact Ann Krause at email@example.com for more survey results, or to provide your own thoughts.
The USGS Landsat project provides links to many educational sites!
Landsat’s Educational page: http://landsat.usgs.gov/links/educational_links.php
Landsat’s education and outreach program has spawned many educational resources. To enable educators’ seamless access to all of these resources, Landsat and LDCM education are united into one program. Their goal is to enable you to access and use the entire Landsat Program’s data, imagery, and associated science content for your own purposes.
We hope you enjoy exploring these myriad free educational and interpretive resources, images, classroom activities, modules, tutorials, and more.
Landsat Educational Links:
Three Gorges Dam in China
When completed, the $25 billion Three Gorges Dam on the Yangtze River will be the largest hydroelectric dam in the world, more than five times the size of the Hoover Dam in the United States. Spanning more than two kilometers (km) across and 185 meters (m) above the world’s third longest river, its reservoir will stretch more than 600 km upstream.
Construction began in 1994, with the dam itself completed in May 2006. Several generators still have to be installed, and the dam is not expected to become fully operational until approximately 2013.
Although there are economic benefits from flood control and hydroelectric power, the project has been plagued by massive corruption problems, spiraling costs, technological problems, human rights violations, and resettlement difficulties.
In addition, there is concern about the displacement of residents; as of 2006 nearly one million people had lost their homes. Many are living under poor conditions with no recourse to address outstanding problems with compensation or resettlement. It is estimated that more than two million people will be displaced by the time of completion.
The loss of many valuable archaeological and cultural sites, as well as the effects on the environment, is also plaguing the project. It is believed that the dam is a contributing factor in the extinction of the Yangtze River dolphin.
The dam is located at a latitude of 30.83° North and a longitude of 111.01° East (30.827778° N 111.009167° E).
USGS Ground Stations
Sites in both South Dakota and Australia capture data from the Landsat satellites. The Landsat Ground Station (LGS) is located at the USGS EROS in Sioux Falls, South Dakota. The Alice Springs (ASN) site is located at the ACRES facility (http://www.ga.gov.au/acres/) in Alice Springs, Australia. These sites receive both science data (via X-band Radio Frequency [RF] link) and spacecraft health and safety data (via S-band RF link). LGS also provides tracking services and a command link to the spacecrafts. LGS and ASN send all S-band data to the Mission Operations Center (MOC) in real-time for immediate health and safety monitoring. Science data collected at ASN are sent to EROS where the Landsat 7 Processing System (LPS) or the Landsat Archive Conversion System (LACS) processes either the Landsat 7 or Landsat 5 data, respectively. The NASA Tracking Data and Relay Satellite System (TDRSS) (http://msl.jpo.nasa.gov/Programs/tdrss.html) is also used to provide S-band support for Landsat 7.
Ground sites in Poker Flat, Alaska (DataLynx), and Svalbard, Norway (SGS), are used as backup sites during times when extra ground resources are necessary to fulfill mission objectives.
The LGS has one main 10 meter antennae for both X-band and S-band and a 5.4 meter antennae for backup, when necessary. The 10 meter antennae downlinks two X-band frequencies so the LGS can downlink international data stored onboard the spacecraft and live data as it passes over the U.S. This capability is not needed for Landsat 5 as it does not have onboard storage. To see live passes over the United States, go to EarthNow!. http://earthnow.usgs.gov
In the next newsletter: a look at the International Ground Station (IGS) Network