Victor Zlotnicki (vz@pacific.jpl.nasa.gov), Task Scientist, Jet Propulsion Laboratory
The Users Working Group (UWG) of the EOSDIS Physical Oceanography DAAC (PO DAAC) met May 15-17 at the Jet Propulsion Laboratory, Pasadena, CA. The UWG members are: David Glover, Woods Hole Oceanographic Institution (co-chair); William Emery, University of Colorado (co-chair); David Adamec, Goddard Space Flight Center; Bruce Douglas, Director of NOAA's National Oceanographic Data Center; Robert Evans, University of Miami; Michael Freilich, Oregon State University; Lee Fu, Jet Propulsion Laboratory; Tim Liu, Jet Propulsion Laboratory; C. K. Shum, University of Texas-Austin; Victor Zlotnicki, Jet Propulsion Laboratory (Task Scientist).
The afternoon of May 15 was a closed-door session in which the UWG, the PO DAAC Manager, and Deputy Manager reviewed the UWG Charter of September 1991, and discussed the UWG's internal organization, responsibilities, and mode of operation. The result was not a change in the charter, rather a clarification of issues to all involved and an agreement to work in a collegial fashion.
On May 16 the UWG reviewed all PO DAAC FY 95 activities and heard a detailed assessment of the PO DAAC's progress during that fiscal year from Mary Reph of the Earth Science Data and Information System (ESDIS). UWG members found the DAAC's users were very happy with its service, and ESDIS praised the PO DAAC's technical expertise and technical contributions to EOSDIS Version 0 (V0). ESDIS also suggested improvements in the cost of supporting flight projects, in communications between PO DAAC, ESDIS, and the EOSDIS Version 1 Core System contractor, and in responding to ESDIS requests. During the discussion it became clear that PO DAAC has an operational satellite flying (TOPEX/Poseidon) and one about to launch (NSCAT on ADEOS in August 1996), in distinction to other DAACs except the Alaska SAR Facility. As such, the conflicts imposed by the operational nature of a flying satellite and a developing system, i.e., during V0 to V1 migration, must be considered as prototype "lessons learned" for EOSDIS.
Subsetting data generated considerable discussion. The cost/benefit ratios of two different approaches were compared. One approach involves subsetting data on demand and transporting the subset over the Internet to the recipients. The other approach is based on generating CD-ROMs (or equivalent high-capacity, random-access media) that include all the data and sending it to users for subsetting at their local workstation. It was found that, for TOPEX/Poseidon altimeter data, the cost of central subsetting and electronic delivery was lower only if the networking cost was zero, i.e., was paid out of another budget line, as it is today. For higher volume imaging data sets, such as Pathfinder AVHRR sea surface temperatures, central subsetting can make the difference between a usable dataset or having a user swamped with data, and so is the preferred mode of handling.
Networks generated some concern. William Emery presented some costs of connecting universities to the wide area network. He expressed the concern that funding for networks needed by EOSDIS, for DAACs and users, may be falling through the cracks, even though electronic data delivery is planned for 50% of the data. The installed bandwidth appears to be sufficient, but the cost may be unaffordable to academic institutions.
On May 17 the highlights of the FY 96 workplan were presented to the UWG. Subsequent to the meeting, a formal draft of the plan was mailed to all UWG mem-bers, and their responses were incorporated into the final plan submitted to NASA Goddard on July 1.