Landsat-7 Science Team Meeting

-- Darrel Williams (darrel@ltpsun.gsfc.nasa.gov), Landsat-7 Project Scientist

The Landsat-7 Science Team held its third semi-annual team meeting October 21-23, 1997 at the NASA Goddard Space Flight Center. Participants from the 14 research teams, as well as NASA, NOAA, and USGS attended the meeting, which was co-chaired by Landsat Project Scientist, Darrel Williams, and Landsat-7 Science Team Leader, Samuel Goward.

The first morning was dedicated to a briefing on the status of the Landsat platform, the ETM+ instrument, and the EOS Data and Information System (EOSDIS). At that time, Phil Sabelhaus, Landsat Project Manager, reported that development problems with the ETM+ instrument had delayed significantly its delivery to Lockheed Martin such that the launch date had to be pushed back from late May to July 9, 1998. [NOTE: A status update, as this report goes to press in mid-February 1998, is that ETM+ power supply problems encountered during instrument thermal vacuum testing have caused further delays in the launch date. A new launch date will not be set until the instrument comes out of thermal vacuum testing successfully, but a launch before early October 1998 is unlikely.] Progress on the Landsat ground system continues, despite major hail damage to the new X-band receiving antenna at the EROS Data Center in Sioux Falls, South Dakota.

James Ellickson of NOAA gave a brief report on NOAA's plans for Landsat-7 operations. Following a 90-day post-launch checkout, operations of the Landsat-7 satellite transfer to NOAA. Ellickson outlined plans to utilize licensing fees collected from international ground stations to help off-set NOAA's day-to-day operating costs. It was also announced that Landsat Level 0R data (uncalibrated, no geometric correction) will cost users $475 per scene, roughly an order of magnitude cheaper than current prices for non-governmental users. Level 1 data (calibrated, geometrically corrected) will cost no more than $600 per scene.

Anthony Janetos (Landsat Program Scientist at NASA Headquarters) detailed interactions between non-governmental organizations (NGOs) and NASA. Janetos emphasized that many NGOs could make good use of satellite data, but lack the resources and experience to handle the data. He solicited participation of Landsat-7 Science Team members as "mentors" for these organizations.

The second day was devoted to team-member presentations on recent research activities. Landsat-7 Science Team projects cover diverse areas of Earth System Science, including agricultural applications, deforestation, glacier dynamics, volcanic hazards, coastal processes, and cloud characterization. In addition, several team members are working to improve the radiometric calibration and atmospheric correction of the ETM+ data. The following gives a brief synopsis of each science presentation:

• Robert Bindschadler (NASA GSFC) illustrated how Antarctic ice-stream motion could be mapped from multitemporal Landsat-TM imagery.

• Robert Cahalan (NASA GSFC) discussed the uses of Landsat for cloud studies, including the creation of cloud masks and the scaling of cloud properties.

• Luke Flynn (U. Hawaii) illustrated how Landsat-TM infrared data could be used to ascertain the volume and plume geometry of Hawaiian volcanoes.

• Alexander Goetz (U. Colorado) presented on-going research into landcover change in the Great Plains and its relation to climate variability.

• Samuel Goward and Jeffrey Masek (U. Maryland) discussed plans for an automated mass processing center for landcover change analysis.

• Susan Moran (USDA) presented recent work on the integration of SAR and Landsat-TM data for monitoring soil moisture and agriculture.

• Frank Muller-Karger (U. South Florida) discussed expanding the coverage of the Landsat-7 Long-term Acquisition Strategy for coastal regions.

• John Price (USDA, Ret.) discussed calibration/validation strategies for the EOS MODIS sensor using Landsat TM/ETM+ data.

• John Schott (Rochester Institute of Technology) presented on-going research into improved thermal calibration of the ETM+ using airborne sensors.

• Dave Skole (Michigan State University) presented recent work on tropical deforestation monitoring, and outlined priorities for the International Geosphere­Biosphere Program for landcover analysis.

• Kurtis Thome (University of Arizona) discussed field programs at Lunar Lake to establish cross-calibration with other EOS science teams.

• James Vogelman (USGS EROS Data Center) presented new approaches for filtering memory effects and coherent noise from Landsat imagery.

• Curtis Woodcock (Boston University) discussed the scaling of information content within satellite imagery and its relationship to ecosystem properties.

Joanne Gabrynowicz (University of North Dakota), an expert in space law, gave an informative overview of the new Commercial Space Act of 1997 (HR 1702) currently before Congress. The act, designed to facilitate commercial satellite launches and streamline licensing procedures, could have major implications for scientific remote sensing. Of some concern to the science team is a mandate that NASA turn to commercial data providers for future scientific missions whenever possible. It was not clear how this proposal meshed with the current requirement for the creation of a long-term, permanent archive of high-resolution satellite imagery for global change research.

Terry Arvidson (Lockheed Martin) and Jonathan Haskett (University of Maryland) presented an update on the Landsat-7 Long-Term Acquisition Plan (LTAP). Based on the recommendations of the Landsat Science Working Group (1991-1994), the Landsat Project is developing the LTAP which will, as much as possible, ensure seasonally refreshed acquisition of Landsat scenes for all land scenes on the globe. Determination of acquisition frequency based on vegetation state has been finished, with recent work concentrating on minimizing cloud contamination and optimizing ETM+ gain settings. An informal science team review of the LTAP was suggested, and Goward took the action to organize this review.

Team member Robert Cahalan (GSFC) gave a presentation on recent calibration activities at the DoE/ARM site in Oklahoma. This led to splinter discussions on atmospheric correction algorithms for Landsat-7 (led by Kurt Thome, University of Arizona) and precision georegistration techniques (led by Curtis Woodcock, Boston University). Thome noted that a variety of atmospheric correction algorithms are currently in use, ranging from simple dark-object subtraction methods to full radiative-transfer modeling. There was agreement that the Landsat-7 Science Team needed access to a single set of atmospheric correction algorithms, packaged in a user-friendly format.

Woodcock also noted that precision georegistration was a vital part of Landsat analysis, but the team had no provision for creating georegistered products and no library of ground-control points. James Irons (NASA GSFC) noted that only a few ground-control points were required for each swath of Landsat data, provided that entire orbits were processed. While there was general consensus that image-to-image coregistration (using pattern matching techniques) was important, some members suggested that precision georegistration should be left to individual team investigations.

The next Landsat-7 Science Team meeting will be held April 14 - 16, 1998, at Goddard.