The Science Working Group for the AM Platform (SWAMP) meeting was held at the University of Maryland, in College Park, on November 13-14, 1997. Summaries of the presentations are given below
EOS AM-1 Spacecraft and Instrument Status
Chris Scolese, EOS Project Manager, summarized the status. He said we are still on schedule (but a tight schedule) for launch on June 30, 1998. The spacecraft is in good shape except for one anomaly with the solid-state recorder. Timing interrupts are conflicting when the memory is asked to simultaneously record and playback at the maximum data rate. This mode would only be used in contingency mode, and Lockheed-Martin is working to fix the problem. MOPITT has to fix some EPROM software to correct a data interface problem. Otherwise, the instruments and spacecraft are looking very good. The thermal vacuum test will start in late December.
Instrument Status Reports
Vince Salomonson, MODIS Team Leader, reported that MODIS was delivered to Valley Forge and is now on the spacecraft. He stated that Bands 5, 6, 7, and 26 have a spectral light leak from 5-µm thermal radiation. This light leak appears to be similar to the leak seen on the TRMM VIRS instrument and can be 1-5 percent of the signal. The leak has been spectrally characterized and will be handled during post-launch processing. This problem will also exist in the EOS PM-1 MODIS instrument.
Salomonson noted that sub 1-km spectral bands differ in response for even and odd samples across the focal plane. This problem too will be handled in post-processing.
There is crosstalk between spectral bands 30 and 31 (10-11µm and the lowest sounding 15-µm carbon dioxide channel). This problem was found in ground calibration and will be verified and corrected in post-launch processing. This problem should be eliminated in the EOS PM-1 MODIS instrument.
MODIS' scan mirror angle-dependent reflectance in the thermal infrared will be determined in orbit using the data from the Calibration Attitude Maneuver (CAM).
Dave Diner, MISR Team Leader, reported that the MISR instrument was delivered to Lockheed-Martin in Valley Forge on May 26, 1997. Subsequent to delivery, a new start-up ROM was installed in the flight computer. Additionally, the MISR firmware was reprogrammed due to an incompatibility between the spacecraft and MISR utilization of the 1553 communications bus. MISR is installed on the spacecraft and the instrument has been successfully operatedgood high rate science data have been collected. Currently, an issue regarding occasional failure of the instrument to start properly is being investigated. The working hypothesis is that the flight computer is sensitive to excessive traffic on the 1553 bus during the start-up period, and testing is underway to gain deeper insight. Generally, a retry of the start-up is successful and, once started, the instrument operates properly.
The AirMISR instrument is now flight qualified for flights on the NASA ER-2 aircraft. Flights in August and November 1997 collected high-quality, multi-angle, multi-spectral imagery over Moffett Field, California. Following the August flight, an issue arose regarding interference between the airflow behind the instrument (which is mounted in the ER-2 nose) and the aircraft pitot tubes (used for airspeed indication). This has subsequently been corrected by the addition of standoffs to the pitot tubes. Currently, flight operations are suspended while the NASA aircraft are moved from Ames to Dryden.
MOPITT and MISR indicated substantial performance problems with their instrument support toolkit (IST) software (developed by ECS) (MISR) and supplied data network links (MOPITT). Fixes are in progress and a working group will be formed to foster improvements in this area. ECS software development has not been as responsive as desired by several of the instrument teams.
JGR Special Issue
Any papers for the Journal of Geophysical Research special issue should be submitted by November 30, 1997. The papers should be submitted to JGR Atmospheres with a cover letter indicating preference to publish in the EOS AM-1 special issue. Note that if you do not get revised paper versions in to JGR by July 1, 1998, your paper(s) will not be included in the EOS AM-1 special issue scheduled for Sept. 30, 1998. If late, your paper will be put in a later JGR issue. EOS is planning to pay JGR to print extra copies of the special issue with an EOS AM-1 cover.
EOS Funding
While all of the EOS instrument teams had been forced to use only one-month forward funding into FY98, by the middle of November, little or no FY98 money had been sent to the teams and both MISR and CERES were out of money and borrowing from other programs or delaying essential activities due to a lack of funds. A letter from the SWAMP to this effect was sent to the EOS Project Office to indicate the need to increase transitional funding next year to at least cover the experienced delays we have seen in FY98. Most teams are expecting to get funding by the end of November, roughly two months after the start of the fiscal year. As of November 20, the CERES instrument investigation had still not received any funds.
EOS Validation Plan Concerns
David Starr, EOS validation scientist, reviewed the concepts and responsibilities for validating EOS data products, as well as the results of the recent EOS Validation NRA selections. Detailed information is available from the Validation Homepage. He noted that the Instrument Science Teams (ITs) are primarily responsible for validating their data products. He challenged the ITs to work toward quantitative and systematic definition of the geographical, seasonal, and phenomenological dependencies of the data product uncertainties. Starr noted the importance of forging the necessary connections between the IT activities and those of the new investigations. Toward this end, Tom Charlock (CERES) and Dave Woods (SAGE III) organized the recent Workshop for Atmospheric Validation in EOS AM-1 and SAGE III (WAVES). In addition to CERES and SAGE III, the MISR, MODIS, ASTER, and MOPITT teams participated, as did more than twenty of the new investigators. A smaller meeting concerning ocean-related investigations was held at the recent MODIS meeting, and a Land Validation meeting is planned for December 3-5, 1997, in the GSFC area under the leadership of Chris Justice. Establishing the needed collaborations and data access will be critical for rapid validation results. There will be great pressure for solid results by 18 months after launch.
Starr finished by noting some concerns. He stated that while a tremendous amount of progress has been made by the ISTs over the last two years, the presently-available validation plans were not all up to date. Moreover, the plans could still be markedly improved. Experience indicates that a strong implementation plan leads to a more highly focused effort and more rapid scientific progress. The science and strategy must be tightly interwoven. In particular, improvements could be made in documentation of accuracy goals and error budgets, both for the data products as well as for correlative measurements, and in the definition of the approach or path to validating specific data products. Starr recommended that the teams make serious efforts to develop and implement strategies for managing the validation data and communicating the status and results of their validation work. Functionality and currency are key elements in this respect. Starr also recommended that the teams develop formal plans for comparison of related data products in order that this fundamental activity occur at the earliest opportunity. Lastly, concern was expressed about resources, especially scientists' time, to get the job done. Aircraft resources will also be extremely tight.
EOS AM Outreach Efforts
David Herring, AM Outreach Coordinator, reported that the AM Project Science Office is forming an Executive Committee for Science Outreach (ECSO). Letters of invitation have been sent to the nine desired ECSO members.
The EOS AM-1 brochure is complete and, pending final review, waiting to be printed. You can see a draft of it at http://modarch.gsfc.nasa.gov/EOS-AM.
Digital Elevation Model (DEM)
A SWAMP working group on DEM summarized current status and plans. EDC and MISR have completed 1 km resolution DEM models for the globe. RMS elevation difference between the two maps is 80 m (1 sigma). Validation against the ERS-1 radar altimeter with 2.5-km spatial resolution verifies an accuracy of 40-80 m.
The SWAMP working group recommended that EOS use a merged 1-km DEM which uses the EDC map but replace Greenland with the MISR DEM and replace Australia with the AUSLIG DEM. EDC will merge this optimal data set before launch. The EOS DEM will include land/water mask, water types (e.g., deep ocean, coastal shelf ocean, shallow ocean, large lake, etc), terrain type, and shadow. Format is HDF, data volume is roughly 2- GBytes.
A 100 meter DEM will be available for use only at the GSFC, JPL, and EDC DAACs. This is based on a classified DoD DEM. It will be improved using Shuttle radar data in 2001. Total data volume will be 300-Gbytes.
Questions regarding the DEM/SWG should be referred to Thomas Logan via e-mail, at tom.logan@ jpl.nasa.gov.
Ground Control Points Update
Bryan Bailey, Land Processes DAAC Project Scientist, presented the final report from the SWAMP Ground Control Point (GCP) Working Group. The GCPWG was formed by Piers Sellers in 1996 to facilitate cooperation and minimize duplication of effort in addressing GCP-related issues facing the "land" instruments on AM-1 (ASTER, MISR, and MODIS) and Landsat-7. GCPWG objectives included documenting IT requirements for ground control information, defining the characteristics of suitable GCPs for each instrument, identifying existing sources of ground control information, and converging on an approach to meet GCP requirements as efficiently as possible.
Instrument Team requirements for GCPs relate to various geometric calibrations of the instruments and geometric correction of subsets of data or products. For the most part, these can be met by: 1) a series of GCPs positioned along the orbital track of the sensors; and 2) by either a dense concentration of GCPs over a relatively small area or a broader distribution of GCPs over a substantially larger area. In the case of MODIS and MISR, larger spatial features such as lakes or shorelines are needed as GCPs, whereas the higher spatial resolution sensors, ASTER and ETM+, require features such as road intersections or bridges.
The working group developed a consolidated strategy for GCP development that pairs MODIS with MISR and ASTER with ETM+ and involves GCPs along orbital tracks over Eastern Europe/Africa and South America and more randomly distributed GCPs in the U.S. and Australia. In all cases, precision-processed Landsat thematic mapper (TM) data will serve as the chip image base for GCPs required by MODIS and MISR, and U.S. Geological Survey (USGS) digital orthophoto quadrangles (DOQs) or National Imagery and Mapping Agency (NIMA) control image base (CIB) will serve as the chip image base for most GCPs required by ASTER and ETM+. Locational information required to locate the GCPs will come from USGS and NIMA control point databases or map and other sources. Some of the image data and locational data have already been acquired, but much remains to be obtained or produced.
The Working Group concluded that it is completely feasible to meet the vast majority of AM-1 and Landsat 7 GCP requirements prior to launch, and they recommended an approach for achieving that goal. Two primary tasks are required to meet the GCP requirements of MODIS and MISR: 1) purchase or produce remaining required precision-processed TM reference images, and 2) subset those images into the appropriate size, number, and format of GCP image chips. The Working Group recommends that the remaining U.S. TM scenes be purchased by the MODIS and MISR Teams, and that MODIS and MISR each take on the responsibility for extracting their required GCP image chips from those scenes.
The Working Group recommends that the USGS EROS Data Center be given the responsibility for producing precision-processed TM reference images over the foreign locations identified by MODIS and MISR and that the work be funded by SWAMP. Completed scenes would immediately be sent to MODIS and MISR for extraction of the required GCP images chips. Three primary tasks are required to meet the GCP requirements identified by ASTER and ETM+: 1) purchase remaining required DOQs; 2) "tag" GCP ground features in DOQ and CIB images with locational information, as needed; and 3) subset those images into the appropriate size, number, and format of GCP image chips. The Working Group recommends that the remaining required DOQs be purchased with funds provided by SWAMP. The responsibility for tagging the DOQs with appropriate locational information and for extracting the final image chips should be borne by the ASTER and Landsat-7 Instrument Teams. Nearly all required existing CIB data for production of foreign GCPs already have been provided by NIMA. The USGS EDC will secure those few CIBs that have not yet been received. All CIBs and related NIMA CPDB information will be sent to the ASTER and Landsat 7 Teams for ground feature tagging and/or extraction of final image chips. Finally, the GCPWG recommends that GCPs developed by this activity should be sent to the Land Processes DAAC for archive and general distribution.
The total "out-of-pocket" expenses required to complete production of the required GCPs is estimated at approximately $85,000. SWAMP has accepted the responsibility to identify the required funds, and the effort to complete GCP development prior to launch(es) is underway.
Instrument Data System Backup Plans and Science Software
CERES will select seasonal months and validation sites. MISR will sub-sample pixels for global and select U.S. for full resolution. ASTER will back off to ten level 1B scenes per day, and four level 2 scenes. ASTER will include, at launch, surface temperature, and emissivity.
Edward Masuoka, SDST leader, presented the status of MODIS science software deliveries, and development and testing of the MODIS Emergency Backup System (MEBS). The MEBS completed an "Hour in the Life" test in September with MODIS Version 1 software. In this test, two hours of synthetic Level 0 data was processed by MODIS Level 1 and Level 2 PGEs, producing more than 50 Gbytes of science products. Data were written to the Ampex tape library from the data server at 15 Mbytes/sec and moved between the data server and the science processing systems at 50 Mbytes/sec. There was also an overhead of 25 seconds per tape mount and additional time required to position the tape to the desired file, which reduced the end-to-end performance of writing a file to the archive to 9 Mbytes/sec, and retrieving a file to 7 Mbytes/sec. If the system does need to serve as a backup for EOSDIS, the goal is to produce all MODIS products. Level 1 products will be produced globally and Level 2 and higher products will be produced at limited resolution (ocean products), limited times (1 week a month, atmosphere products), or for limited regions of the world (land products).
MODIS delivered 34 PGEs in Version 1 from June through September. The PGEs were tested with both the SCF and DAAC versions of the SDP Toolkit. These PGEs ran successfully in the ECS system and production threads were run at the DAACs. In Version 2, MODIS plans to deliver 18 PGEs for the EOS Ground System certification tests and 43 at-launch PGEs. The at-launch PGEs will generate all MODIS products but not in all formats nor for all time periods. In particular, most Climate Modeling Grid (CMG) products and most products which are monthly, quarterly, or yearly will not be delivered until post-launch.
Moshe Pniel gave a presentation on the status of ASTER's emergency backup system, being developed jointly by JPL and EDC. The EDC component of the system will receive the Level 1A and 1B tapes from Japan; it will ingest and catalog them and provide JPL with the catalog information. The JPL component of the system will coordinate and prioritize the requests from EDC for the Level 1 data (up to ten Level 1 scenes per week can be requested from EDC), generate up to four Level 2 scenes per week, and provide them to the ASTER Science Team for calibration and validation activities. The status of the system is as follows: the task leads are in place both at JPL and EDC, the requirements have been reviewed and agreed upon by both sides, the hardware has been procured and is in place, the Level 1 metadata catalog has been agreed upon, and the design review is scheduled for December 1997 at EDC. The system will become operational on June 1, 1998.
Pniel also discussed the status of the science software. The Version 2 software is on track for the February 1998 integration at the EDC DAAC. The algorithm developers delivered their updates to the Version 2 algorithms. The software development team has made all but one of the Version 2 science software deliveries to the algorithm developers for their testing and verification. Japan has delivered updates to the Level 1 interface. An updated (delta) software delivery (version 2.1) is planned for July 1998.
Graham Bothwell, MISR team member, reported that MISR's Version 1 science software delivery to the LaRC DAAC included PGE 1 (Level 1 science data products) and PGE 9 (Level 2 Aerosol/Surface products.) These are two of the larger MISR PGEs. During November and December, early Version 2 system integration and testing is occurring at the Hughes Landover facility for PGE 2 (engineering data), PGE 5 (on-board calibrator data), and PGE 7 (geometric parameters). This is using an early form of the Version 2 ECS for purposes of assisting in ECS development. Formal Version 2 deliveries of MISR PGEs will occur at the LARC DAAC in March-April 1998.
MISR's emergency capability will be a limited one, primarily to support the science team's certification and validation of products, and to support early mission science. System throughput will include approximately one partial orbit per day of Level 2 products, which will allow repeat coverage in a 16-day cycle of a significant representative area such as the continental U.S., or Western Europe and North Africa.
Release of Early EOS Data
The official policy on public release of the EOS data was a nominal instrument checkout period of 90 days, with up to 6 months or more if justified to the Project in writing. This is for at-launch production products. CERES is planning to produce routine ERBE-like top-of-the-atmosphere fluxes within 6 months after launch.
Concern was expressed, however, in the potential misuse of early data by scientists unfamiliar with the preliminary nature of the data and the details of validation of each individual product and parameter. It was generally recognized that many researchers do not look for "flags." It was felt that Principal Investigators should avoid hoarding the data, yet be careful not to release "preliminary garbage" results.
Suggestions for helping users understand data product maturity (or lack thereof) included:
As it stands right now, only the data quality flags in the data products are useful for assessing data quality level.
EOSDIS Review Group (ERG)
The ERG met in April and October of 1997. They defined success criteria (46) for the August EOSDIS demo. They also reviewed the demo and called it a qualified success (the main issue was performance). At the October meeting, they recommended killing the Alternative Data System plans, but continuing the emergency plans. ECS should deliver software to the DAACs as soon as possible to begin interaction, and should not wait until they think everything is ready. There is a $40-$65 million run out budget problem for ECS. The ERG wanted it to be known that they did NOT recommend the 25 percent/50 percent/75 percent data volume cutonly that this cut be evaluated as a cost-saving measure. They also did not recommend elimination of all inter-DAAC network transfers for Level 2 data products, but again that its impact should be studied. Both of these actions have been taken, however, and now we must live with them.
(Note: CERES will work with the GSFC DAAC to get the MODIS Level 1b data transferred to the LaRC DAAC by DLT tape [roughly 3-4 tapes per day]. There may also be capacity on an existing T3 line that can be utilized.)
The ERG is concerned about how much of ECS will exist at launch, but clearly some of its capability will be available. The ERG is working on finishing their report from the October meeting and should have it finalized in the next few weeks.
On-Orbit Calibration Attitude Maneuvers
Lisa Shears, of the EOS AM Project, reported that LMMS submitted a final report in June 1997 on the evaluation of feasible technical approaches for implementing the following calibration maneuvers: MODIS Lunar View via Space View Port, Deep Space View Maneuver, and MODIS Solar Diffuser Scattered Light Mapping Maneuver. In October 1997, the EOS Project Office gave authorization to proceed with the LMMS proposal. Implementation of the proposal is scheduled to begin in January 1998, and will be completed prior to launch.