Data collection begins on satellite observatory project's latest phase

The applied research from the Purdue Terrestrial Observatory, a real-time satellite remote sensing receiving station, will be used to develop initiatives directed toward homeland security, the environment and ecology, meteorology and climatology, and economic development.

The observatory is operated by the Rosen Center for Advanced Computing, which is part of Information Technology at Purdue (ITaP). The Rosen Center, through its role in the grid-computing project TeraGrid, provides advanced computing resources and services to support computationally intensive research nationwide. It also operates the Envision Center for Data Perceptualization at Purdue.

The first phase of the Purdue Terrestrial Observatory project began operating 15 months ago and receives satellite imagery 24 hours a day, said observatory director Gilbert Rochon.

The initial ground station established in Phase I contains a 3.7-meter geostationary operational environmental satellite receiving station dish located in the communications "dish farm" on campus, said Rochon, who also is associate vice president for collaborative research and chief scientist at the Rosen Center.

"It's a geostationary meteorological station. The satellites are in sync with the Earth's orbit, so the dish itself doesn't move," he said.

The observatory's Phase II includes a tower-mounted tracking ground station with a 30-foot tower located near the Purdue Airport. On top is a 4.5-meter dish that tracks satellites as they orbit the Earth.

"Phase II offers more and higher-level applications — not just meteorology," Rochon said. "The dish activates when directed by a software-generated schedule and tracks when it senses one of the designated satellites in orbit a mere one degree above the horizon and will track that satellite all the way until it clears the horizon."

The powerful Phase II equipment is capturing real-time, remotely sensed data from the National Oceanic and Atmospheric Administration's AVHRR satellite (advanced very high resolution radiometer); NASA's polar-orbiting Terra and Aqua MODIS (moderate resolution imaging spectroradiometer sensors), and also is collecting data from the Chinese Space Agency's Feng Yun (wind and cloud) satellite, Rochon said.

"The terrestrial observatory ground station knows to track these satellites per designated priority settings and daily updated schedules," said terrestrial observatory systems manager Larry Biehl. "The receiving dish rotates to the expected starting position of requested paths of the satellites along the horizon shortly before the pass starts, and then locks onto the satellite because it has elements in the receiving dish that pick up the signal for those specific satellites."

Phase II also is providing multiple modes of data from the AVHRR satellite: global area coverage that can show a large area in 4-kilometer resolution, and local area coverage that can show large and more focused areas in 1-kilometer resolution.

"You want to see both modes," Rochon said. "The global area coverage will let you see a storm approaching, for example, while the local area coverage will allow you to look more locally for impact."

Rochon said establishing and funding the observatory was the result of a collaboration involving ITaP; the Purdue colleges of agriculture, science and engineering; the Purdue departments of agronomy, agricultural and biological engineering, earth and atmospheric sciences, and nuclear engineering.

Also, the Polis Center at Indiana University-Purdue University Indianapolis, a multi-year grant from U.S. Geological Survey AmericaView program, and staff and graduate students, coordinated by Biehl, also played critical roles, Rochon said.

While technologically sophisticated, the observatory also is a catalyst for bringing people together to solve problems, Rochon said.

"There are 35 faculty members at Purdue from 20 different departments who are affiliated with the terrestrial observatory," he said. "It's very interdisciplinary in that the data can be used for a host of different applications."

Examples include precision agriculture, monitoring environmental pollution, studying deforestation and urban sprawl, detecting forest fires and flooding, analyzing natural disasters, and predicting a variety of meteorological conditions.

Rochon said other groups that can access the remotely sensed data include Purdue graduate students working on dissertations and theses; faculty affiliated with Purdue's Laboratory for Applications of Remote Sensing; faculty partners within the Indiana View Consortium of 10 universities in the state; the Indiana Geographic Information Council; the Indiana Geological Survey; the Indiana State Climatologist; members of the Coalition of Universities for Spatial Information Science; and partners within the Indiana Higher Educational Telecommunications System, which includes K-12 schools, libraries and museums.

Also, AmericaView partners representing 25 states and researchers at other supercomputing institutions involved in the TeraGrid can access the data.

The TeraGrid is particularly important, Rochon said, because three of the member institutions have ground stations: Purdue, the University of Texas at Austin and the Scripps Institution of Oceanography at the University of California, San Diego.

Launched in 2001, the TeraGrid is a grid-computing project for building a large, comprehensive distributed infrastructure for open scientific research. Purdue and Indiana University joined the project together in 2003. They received a $3 million National Science Foundation grant to create their portion of the network to extend the grid to IU-Bloomington, IUPUI and Purdue's West Lafayette campus.

"We are non-competitive and have different footprints as to what portions of the Earth can be seen through our ground stations," he said. "Through the TeraGrid, we extend our footprints to see a much larger view of the United States, and even Canada, the Caribbean, Central America and the northern coast of South America.

"Phase II established us within a group of peers that have the regional-scale resolution data and, therefore, we're in a position to barter and share data and provide data to others. Not only does the observatory ground station receive raw data in real time, it also distributes data products in near real time."

Potential future users include members of the Northwest Indiana Computational Grid, which links Purdue West Lafayette with Purdue Calumet, the University of Notre Dame and Argonne National Laboratory in Chicago. In January, the Purdue Terrestrial Observatory's offices and research facilities will be located in the Discovery Park's Gerald D. and Edna E. Mann Hall (formerly known as the e-Enterprise Center). Rochon said they anticipate that it will play a vital role in research there, as well as in collaboration with the Cyber Center, the Center for the Environment and the Purdue Climate Change Research Center.

Rochon said future plans include a growing international role. The observatory plans to serve as the ground station for a hyperspectral satellite from Belgium, South Africa and Nigeria, the THEOS satellite (Thai Earth Observation System) from Thailand, potentially for Canada's radar satellite, and ideally when launched, Digital Globe's WorldView, a commercial high-spatial resolution satellite with a 50-centimeter-by-50-centimeter resolution that could be seen clearly from space.

"Remote sensing is potentially an equal-opportunity technology," Rochon said. "It provides the same high-resolution data for the Third World as it does for the industrialized countries, and for poor, inner-city and rural areas as it does for the economic center of the country. As a result, it's a potential means of empowerment for sub-regions in the United States and throughout the world to become masters of their own destiny and have access to data about their own individual communities."

Writer: Amy Page Christiansen, freelance writer, (765) 463-2644, dlcapc@aol.com

Sources: Gilbert Rochon, (765) 496-2274, rochon@purdue.edu

Larry Biehl, (765) 494-3529, biehl@purdue.edu

Purdue News Service: (765) 494-2096; purduenews@purdue.edu

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