Minutes of the Eleventh EOS Investigators Working Group Meeting
-- Renny Greenstone
(renny@ltpmail.gsfc.nasa.gov), Hughes STX Corporation
-- Bill Bandeen
(wbandeen@ltpmail.gsfc.nasa.gov), Hughes STX Corporation
Monday, May 13, 1996
Morning Plenary Session
Michael King, EOS Senior Project Scientist, opened the Investigators Working Group (IWG) meeting and introduced Joe Rothenberg, Director of the Goddard Space Flight Center (GSFC), for a welcoming address.
Rothenberg discussed some developments in regard to Mission to Planet Earth (MTPE). There is good progress leading to the launch, as scheduled, of the AM-1 platform, and TRMM is on schedule for a fall 1997 launch. The protest that was lodged against the award for the contract on the "common spacecraft" has now been resolved. An Announcement of Opportunity (AO) to support the Earth System Science Pathfinder (ESSP) program is due to be released in June.
Rothenberg said that the FY 96 budget has now been signed and MTPE has suffered only minor cuts. Budget cuts are still threatened for FY 97. Finally, he said that the commitment to the 24 MTPE/EOS measurement sets remains firm.
Charles Kennel, Associate Administrator for MTPE, gave an overview of MTPE and EOS. He started with the "State of Health of NASA's MTPE," and said that "the patient is still in critical condition." The approved FY 96 budget is set at $1289.4 M, down by 6%. This is the first NASA budget to be passed since the Congress adopted the balanced budget goal. The FY 97 request is for $1402.1 M. This shows an increase, but the outyear budgets are still ill-defined. Overall, the NASA budget is to decline by FY 00 from $13.8 B to $11.6 B.
If this decline does, in fact, take place, MTPE will surely not go unscathed. Administrator Dan Goldin thinks this decline is negotiable. We have the dual strategy of hoping for the best, but planning for the worst.
The House Science Committee has subtracted $373.7 M from the FY 97 budget. While this loss will not affect the 1998 launch of AM-1, it could lead to delay of the following missions starting with PM-1. The Science Committee added $310 M to NASA's Space Science Budget, but Goldin has said that this is irresponsible, and he opposes it.
MTPE has had a strategy that has gotten us through the last fiscal year reasonably intact:
a. We have paid attention to House Science Committee concerns regarding downsizing spacecraft and providing opportunities for commercial activities.
b. We have appealed to the appropriate House and Senate committees, emphasizing that this is a science program with short-term applications. (This is particularly important to the Senate.)
[On the day following the IWG meeting, May 16, there were to be MTPE presentations to the House Appropriations Committee and to the Senate Authorizing Committee.]
The National Academy of Sciences Board on Sustainable Development (BSD) in its report of last summer came out with spirited support of MTPE. The report said that MTPE science was strong, and that we should go ahead to implement the program without delay. Nonetheless, Kennel said, we can expect the pressures on the program to continue.
He explained that the New Millennium Program (NMP) was strongly directed toward the introduction of new technology and that ESSP is more directed toward the introduction of new science that could be supported by new technology.
There have been 760 downloads from the World Wide Web (WWW) of the draft AO for participation in ESSP. The plan is to choose one candidate each year and not maintain a queue of proposers for the AO. Instead there would be a new competition each year.
Kennel reported on the major challenges of the past two years, the period in which he has been the Associate Administrator for MTPE. It had not been possible to achieve a national consensus on the MTPE budget level, and this had been a chief goal. On the other hand we were able to maintain the 24 measurement sets as a goal.
A MTPE science plan is being developed, showing planned activities vs. time. Bob Harriss has had the lead on the plan, which shows the integration of MTPE's Research and Analysis (R&A) program, modeling program, and EOS. The plan outlines the expected short-term vs. long-term achievements in regard to understanding climate variability and change. It also articulates the science goals and brings out the interrelated network of science problems that are to be addressed. The EOS science plan, being developed by members of the IWG, will contribute to the articulation of the MTPE goals.
There has been an evolutionary approach to the implementation of EOS. The original plan was to have two repeat missions for each member of the first set of EOS missions. In this way there would be economies of scale, and the needed quality of measurements for monitoring of climate change would be maintained. Unfortunately, however, by following this approach, annual costs would have risen monotonically until 2010, and then there would have been a decrease.
A budget profile showing this relentless growth could not be supported. As a result it became clear that implementation of the second and third round could be different from the implementation of the first round. Despite changing the implementation mode, the commitment to the 24 measurement set categories could be maintained and it is up to the scientific community to guard the integrity of the measurement sets.
There has been a new focus on cost saving. Partly, this can be achieved by re-engineering the instruments to cut down on their mass and power requirements. In search of improved instruments, 80% of NMP funding is going to the development of new, re-engineered instruments. The Advanced Land Imager (ALI) is the first example of a NMP development. It is to co-fly with Landsat. If ALI proves successful, then a copy could fly on the AM-2 spacecraft and thereby save system costs.
There are several areas in which we are achieving closer alignment with NOAA with potential for considerable overall savings. We are developing new technology for the National Polar-orbiting Operational Environmental Satellite System (NPOESS). NPOESS is planned to have a 2008 launch. If it operates at a level of accuracy and precision needed for climate change purposes, it will offer an opportunity to save money for EOS. Related to this are plans for linking NOAA and NASA data systems. We are also considering new technology that would be applicable to the geostationary weather satellites. Incidentally, NOAAis still planning a move to the Goddard campus.
Following the BSD recommendations we are developing a new philosophy for data product generation. Creating an EOSDIS "federation" will be the first step toward providing greater flexibility, partly through introducing competitive forces. The federation should be in place by 1999.
MTPE is to have a new management approach -- there will be a major implementation review every two years at Goddard. This will involve "all players," including Congressional staff members.
MTPE is now in the process of drafting a commercialization strategy and has an educational outreach philosophy that says: "teach the teachers." Unfortunately, the education budgets are limited.
An Integrated Global Observing Strategy (IGOS) is being formulated in conjunction with NOAA. The larger question is how would all the relevant agencies collaborate in monitoring the global environment. Currently, systems are being designed for parts of the global system -- atmosphere, land, biodiversity, oceans -- but these sets of programs have no coordinating body.
In March of this year the Committee on Earth Observations Satellites (CEOS) reviewed IGOS. The next step will be taken at the Global Climate Observing System (GCOS) meeting in Geneva, where there is the hope of building an international strategy group that would plan for the post-EOS era. In fact, at this time there is no international plan to cooperate on Earth observing after the CHEM-1 mission has flown.
Kennel said that the "Critical Challenges" are:
Kennel added that relentless technical innovation demands close collaboration among the scientists, engineers, and administrators.
NASA Headquarters (HQ) is shrinking dramatically -- MTPE program implementation has been transferred to Goddard, acting as the lead Center. NASA HQ retains responsibility for the peer review process and the science program. There has to be a proper balance of science and applications of MTPE research. Commercial interactions must be considered.
NASA has been given expanded responsibilities for the full range of related observations to solve its science problems -- this means both space-based and in situ observations.
Kennel brought his presentation to a close with what he called "Personal Remarks." He asked whether global change research is truly sustainable. He said that it is not clear whether we can sustain the program long enough. There surely is no clear-cut end to research. Domestic and international priorities can change drastically. There is an inherent potential for controversy. Research results can provoke anxiety and calls for change in the program. There is no easy road to public confidence; there is no crucial experiment; and there are no widespread economic payoffs foreseen as yet.
But, Kennel said, "global change research must be sustained!" In our generation human impacts on the environment have become quantitatively discernible. We owe it to the next generation to have the ability to think clearly about our global environment. The next generation will have to make the "tough calls" about sustainable development. Kennel's concluding statement was that NASA's basic role is to develop the sciences that require technology to achieve results.
Berrien Moore reported on the "NRC Review and Perspectives on MTPE/EOS." Speaking without viewgraphs he discussed the La Jolla meeting of the National Research Council (NRC) Board on Sustainable Development (BSD) Committee on Global Change Research, which took place last summer. He also discussed the findings of the March of this year follow-on meeting.
At La Jolla there were seen to be four challenges of the USGCRP: seasonal to interannual variations of climate, chemical changes in the atmosphere, eco-terrestrial changes, and climate change on decadal-to-century scales. (Previously, USGCRP had been regarded as just a climate change program.)
The Committee urged that the federal government think about end-to-end information management. They noted that there had been a falling away of the mission agencies, such as Department of Agriculture, Department of Interior, and the Environmental Protection Agency, from participation in the USGCRP activities. At the March meeting they noted that their greatest concern was with the perceived lack of concern for terrestrial and marine ecosystems.
They stressed that the role of human dimensions in global change is essential. There should be a horizontal cut of social sciences across the four USGCRP objectives. There is a need to focus social science within each of the four USGCRP areas.
The Committee also noted that the international linkage is not well integrated in the USGCRP. The Integrated Observing Strategy was not deeply reviewed but it was felt to be extremely important. The status of Earth system modeling in the United states vs. the status of international efforts needs to be reviewed. The U.S. appears to be falling behind in this area.
As important as climate change has been perceived, atmospheric chemistry changes must now be recognized as being very important.
Issues that were summed up included these:
Robert Harriss, director of the Science Division of MTPE, reported on the "MTPE Science Plan and Planning." He referred to the critical challenges ahead that had been discussed by Kennel and said that there now is a logical MTPE plan with scientific substance. This plan is now available on the "net." The EOS plan that is to come will strengthen the MTPE plan by adding implementation insights.
He cautioned that there are still major problems with reaching outsiders -- Congress, the White House, and the general population.
There has been an evolution of science and commerce from the Darwinian competitive world to the 21st-century world without competition. The winners will be those having a co-evolutionary and cooperative approach to problem solving. [He showed a sketch in which advanced technology, core research (R&A), EOS science (Interdisciplinary Science, IDS), academia, and regional applications all fed into sustainable use.]
There is a need to bring local and regional governments into the cooperative effort. Implications of global change for localities must be considered.
Assessments, such as the ozone assessment by the ozone community and the climate change assessments by the Intergovernmental Panel on Climate Change (IPCC), have taught us a lot. The IPCC Working Group II dealt with the climate consequences of global climate change, and Working Group III dealt with the economic consequences, but the quality of these studies is lower than that of Working Group I that dealt only with the assessment of scientific information on climate change.
The hydrologic cycle may be regarded as an instance wherein the relation of global to local change can be studied. There are enormous issues related to the problem of regional water supply. Elements that must be understood include:
We are now building interactions with the Department of Agriculture and the U.S. Geologic Survey (Department of Interior) to pursue these questions, and we have already identified critical regions that should be studied.
We can see the relative impact of key changes in other countries, e.g., using a United Nations Environment Program (UNEP) study we can see the role of land degradation in arid and semi-arid areas that affects both water quality and quantity.
The World Bank looks at the price of water as the population increases in the megacities of the world. It expects the price of delivering water to double or triple in these places by the end of the century! Harriss believes that better science, and anticipating and ameliorating some of the foreseen changes, can lower the costs that may otherwise be incurred.
Around the world issues of the environment are becoming critical to national security in the developed world as a result of problems being encountered in the developing world. Increased environmental scarcity leads to conflicts. Worldwide, population is still increasing, but at a slowing rate.
In the Texas border region there has been a massive migration from Mexico to Texas. Thus about two million people are now living in an area where only about 200,000 people can be supported by the ground water. The wells there will be dry in a decade. Considering factors like those just outlined, Harriss sees many regional applications for MTPE, and he listed just three of these, for which we can supply the needed data:
As an example of what support MTPE might give, he said that we could provide Digital Elevation Model (DEM) data, coming from the Defense Mapping Agency, to Costa Rica. We would provide both slope and aspect data. The problem being faced in Costa Rica is a conflict between hydropower uses and other potential issues of land use. With the right data the hydropower users could have their needs satisfied and yet not infringe unnecessarily on the other users.
Soil composition mapping is another benefit that can be offered by MTPE. For example, he cited the flights of AVIRIS on the ER-2 aircraft . He pointed out that there will soon be AVIRIS-like hyperspectral technology on the Lewis satellite.
Within the EOS program as it stands we have these IDS studies relating to the hydrologic cycle: Sorooshian and Dickinson arid-lands studies, and Dozier's snow-melt study. All of these are relevant to the study of the Mexico/U.S. border region hydrology. The University of Texas at El Paso, under an Equal Opportunity contract, can also contribute useful hydrologic information.
The problem is that in Texas we don't know where the re-charge areas for ground water are located. However, our R&A program has relevant models for this. The growth rates for regions like the Mexico/Texas border are so great that the available census data are invalid. Mark Imhoff has been using city lights from the Defense Meteorological Satellite Program (DMSP) as a basis for quantifying urbanization. He will be applying DMSP city light data to pursue water studies for the mid-East. Danny Rosenfeld of Israel will be using Tropical Rainfall Measuring Mission (TRMM) precipitation data to learn about water availability in the tropics.
Harriss said that there are to be two new NASA opportunities to engage in hydrology-related studies. Two NASA Research Announcements (NRAs) are now going through the approval process and will be on the street within about six weeks.
The first of these NRAs is for Land Use and Land Cover Change Research (LUCC) and will provide support for three years. It calls for:
The expected outcome of these studies will be integrated assessments of the consequences of land-cover and land-use changes in globally important areas of rapid change. The second NRA provides for support of TRMM science in the period from 1997 to 2000.
Ghassem Asrar, EOS Program Scientist, presented "EOS Science Update: IDS Reviews and NRA Selection." Harriss reiterated his feeling that MTPE must do more than develop an understanding of the Earth system; rather we should also show how to apply the knowledge that we gain.
Asrar started by mentioning a recent NRA that had been issued in September of 1995. The focus was on increasing participation, enhancing educational outreach, and improving the communications aspects of the program. There were 328 proposals received, and 123 of these were for IDS investigations. As a result of the NRA, the following numbers of new Team Members have been selected: MODIS - 5, Landsat - 14, AIRS - 2, Multifrequency Passive Microwave Radiometer (MPMR) - 2, and TRMM - 2. Five new investigators have been added to pursue atmospheric chemistry and climate modeling. Five new projects have been selected for education and communication.
Asrar said that the biennial site reviews began in 1990, a second review was held in 1992, and the latest review was held in 1995. He reviewed the mail- and panel-review process. As a result of the process IDS teams were scored in three categories, with these results: 7 teams were rated exemplary (category I); 18 were rated satisfactory (category II); and 4 were rated unsatisfactory (category III). One team did not submit a progress report. Category III investigations are to be phased out over two years, with their budgets reduced by 50%. There is to be a recompetition in the 2000 time frame.
Asrar remarked that there was some outstanding science in some of the category III investigations, but this work should be part of an R&A study and not an IDS study. As a result of the review it was felt that there should no longer be 10-year grants to the investigators. Rather there should be an allowance for re-adjustments every 4-to-5 years.
Plenary Session on Chemistry-Aerosol Climate Processes
Jerry Mahlman, Director of NOAA's Geophysical Fluid Dynamics Laboratory, reviewed "Challenges and Opportunities for Climate Research." He began by acknowledging Charlie Kennel's key role in refocusing NASA's MTPE to make it a science-based program. He then went on to discuss requirements for climate monitoring. He illustrated the problem by showing the equilibrium [[Delta]]T that should have been calculated as a result of greenhouse forcing and showing that it doesn't match what has been observed.
The role of water vapor in the troposphere is a very significant one that needs more study. There is good agreement between a general circulation model (GCM) experiment and measurements of upper troposphere water vapor. This confirms the notion that deep convection leads to moistening of the upper troposphere.
Mahlman devoted much of his to talk to the National Polar-orbiting Operational Environmental Satellite System (NPOESS). Some relevant thoughts were that: climate change predictions must be evaluated; long-term monitoring is very difficult; "clean" monitoring is rare; monitoring from space is critical; and NASA expertise is essential. NPOESS will provide continual measurements over the next 2-to-3 decades.
Mahlman also listed some "barriers" to NPOESS success, including: the current operational focus of the program; the current organizational structure; the current sense of program ownership -- the science community needs to be in there; the limited awareness on the part of key agencies -- NOAA, DOD, NASA, and OSTP are not pushing for serious climate monitoring. NASA should "kick in" financially; and, finally, a research infrastructure is missing as is an arrangement for an "NPOESSDIS."
Mahlman discussed the findings of an integrating panel from an NPOESS climate needs workshop. Among the findings were these: NPOESS represents a major opportunity to obtain climate-relevant operational products; NASA, especially, is in a position to influence the choice of climate products; research support needs to be planned very carefully; a strategy is needed to incorporate new instruments and new technologies; and NPOESS needs to take advantage of EOS knowledge and developments.
Mahlman's conclusion was that understanding climate change requires an inseparable synthesis of appropriate observations, focused analyses, and careful modeling. Kennel added that the White House has to take the lead in adapting NPOESS for climate research.
Mark Schoeberl, Goddard Space Flight Center, described his research on "Comparison of Modeled and Observed Antarctic Ozone Loss." He started with data for the period August 17 to September 17, 1992 from the CLAES instrument onboard the UARS satellite. The intent of the research was to determine the mechanism for Antarctic ozone loss. He found that necessary conditions for the development of the Antarctic ozone hole include high levels of reservoir chlorine species, HCl and ClONO2, sufficiently cold temperatures leading to the formation of polar stratospheric clouds (PSCs) made up of ice and nitrates and isolation of the air by the circumpolar vortex.
He said that his analyses can't explain the year-to-year variations in the ozone hole but do explain the long-term trends. The use of "balanced" winds in his model may be the reason for the discrepancies he found.
Hugh Christian, Marshall Space Flight Center, described his observations with "The Optical Transient Detector (OTD): Initial Results from a pre-EOS Instrument." The OTD was built in just eight months and was launched in April 1995 as a Pegasus payload, along with the GPS/meteorology (GPS/MET) payload. [GPS/MET is the subject of Michael Exner's presentation, which is described later in these minutes.] OTD is a precursor to the LIS instrument, which is part of the TRMM payload. Thirteen months of data have now been obtained. Christian showed data for the one-year period from May 1995 to April 1996. OTD has the special advantage of being able to detect lightning both day and night.
Christian explained that three conditions are necessary to have lightning: a strong updraft is needed (> 13 m/s); there must be ice crystals; and there must be graupel.
Pat McCormick, Langley Research Center, discussed "LITE Cloud and Aerosol Measurements from the Space Shuttle." LITE is the Lidar In space Technology Experiment and was launched on September 9, 1994, providing data from September 10 to September 19 based on 2 million laser shots. LITE was a NASA Office of Space Access & Technology (Code X) program and flew in ten years from its inception.
LITE has a small footprint -- 1 mrad divergence leading to 300 m at the surface from Shuttle altitude. There are 20 to 30 ns pulses, leading to 15 m vertical resolution. The fundamental wavelength is 1020 nm, and there are also doubled and tripled frequencies. Pulses hit the ground at 740 m intervals.
The goal of LITE was to demonstrate the utility of spaceborne lidar. Sixty groups in twenty countries participated in the experiment by providing correlative measurements. Six instrumented aircraft made underflight measurements.
Among visualization products were beautiful three-D images showing slices of observations of aerosols and clouds along the spacecraft path.
Jim Garvin, Goddard Space Flight Center, gave some "Preliminary Results from the Shuttle Laser Altimeter Experiment: Implications for EOS Era Observations of Oceans, Land, and Clouds." The experiment was the successful design and application of a 30 W, 30 kg lidar system for Shuttle mission STS-72. The lidar system is designed to study land cover and geodetic topography, globally. The particular application of the data from such a system is the establishment of ground elevation control points. The particular beneficiary of the work that has been done will be the GLAS instrument which will fly as part of the EOS laser altimetry mission. The next flight of the Shuttle Laser Altimeter is to be on a 57deg. inclination orbit in July 1997.
Michael Exner, University Corporation for Atmospheric Research, gave the last talk of the day: "GPS Sounding of the Atmosphere from Low Earth Orbit: GPS/MET." GPS/MET went from concept to spacecraft flight in six months. It provides 500 atmospheric profiles per day for one receiving satellite. Not only does the system provide meteorological measurements, but also it provides electron density profiles, giving it a space-weather capability. The measurements that have been made show great variabilities in the ionospheric electron density profiles.
There are temperature profile errors in the system at altitudes greater than 50 km, which are due to ionospheric effects. Calculations of temperatures are made ignoring moisture variations. The system offers vertical resolution of about 1 km to within 500 m of the surface. The best resolutions are obtained near the tropopause. The horizontal resolution is 300 km.
Tuesday, May 14, 1996
Session on Global Productivity and the Carbon Cycle
Steve Running, University of Montana, led off a joint presentation (with Alan Strahler and John Townshend) on "Global Land Cover Products from EOS." Running called his part of the presentation "Representation of Terrestrial Vegetation in Global Models." In a series of viewgraphs he illustrated: abrupt changes in vegetation that take place as one crosses the Montana/Canadian border; the effects of land-use changes on plant canopy density; the reduction in evaporation/transpiration (E-T) -- 50 % lower in some places than was expected; and the great differences in land cover classes vs. area covered, as defined by various authors. He noted that terminology for vegetation classes is far from standard and that, until satellite measurements came along, direct measurements have been sorely lacking.
Running has been trying to straighten out the discrepancies in classification and has settled upon six clear-cut classes. He has found that surface temperature is a better classifier than is NDVI. The temperature thresholds he uses are based on maximum temperatures throughout the year and are consistent classifiers. He now has a global 8 km land cover map, based on AVHRR observations, but there is no way to verify the scheme that he used.
John Townshend, University of Maryland, presented the set of products that his investigation is to produce at launch.
Alan Strahler, Boston University, discussed his use of advanced classification technology involving neural nets and decision trees. He said that the IGBP is providing a 1 km database involving 17 "IGBP land cover units." Nine of the units fit the category "natural vegetation," three are in the category "developed lands," two are in "mosaic lands," and three are in "nonvegetated lands." He also pointed out that when MODIS data are available it will be possible to make use of surface reflectance and spatial texture.
As part of his advanced technology approach he illustrated the "change vector" technique. The presence of mixed cover in a 1 km pixel would appear to be a problem, but Strahler feels that it will not be a problem with 30 m pixels. It is subscale variations that are a problem.
Jim Collatz, Goddard Space Flight Center, discussed work on "Radiative and Physiological Effects of Doubled Atmospheric Levels of CO2 on Climate." The goal of the investigation was to develop an Earth system model involving the modeling of the interactions among soils, vegetation, and the atmosphere. The Simple Biosphere Model Version 2 (SiBV2) shows the interaction paths of the canopy and atmosphere. The combined model uses SiBV2 and the Colorado State University general circulation model (GCM), a modified version of the University of California GCM. The FIFE and BOREAS campaigns have served as validation for the modeling efforts.
Collatz showed observations of NDVI from the NOAA satellites and commented that NDVI is affected by changes in the sensors that have occurred during the succession of the satellites.
A question of interest to the investigation is how plant physiology and the atmosphere interact when CO2 is doubled. Collatz pointed out that C3 plants are very sensitive to increases of CO2 , whereas, C4 plants are not sensitive.
A simulation of more than 30 years has been run and shows that the temperature effects vary with latitude. When physiology is introduced into the model there is substantial warming over and above the effects of radiative forcing attributable to the change in CO2 .
Milton Smith, Goddard Space Flight Center, spoke on the subject "Analyzing AVHRR Data Over Amazonia Using Fore-and Background Techniques to Minimize Cloud Effects on Surface Images." He was reporting on changes in Amazonia based on a ten-year AVHRR time series. He has been looking at biogeochemical fluxes derivable from remote-sensing measurements. Challenges to the analysts have been the uncertain instrument calibration and the variable scene illumination. Atmospheric effects are significant and must be taken into account. He has used a Finite Impulse Response (FIR) filter to find components of the observed mixtures. The filters were applied to a single image each day. He gave as his conclusions:
Berrien Moore, as session chairperson, led a "Synthesis and Discussion" period. He said that the straightforward classification schemes of Running and Strahler gave confidence. The Sellers work (reported by Collatz) shows that doubling CO2 shuts down evapotranspiration leading to warm tropics and cool high latitudes. The presentation by Milton Smith shows that some of the previous AVHRR data interpretations have been questionable. It is interesting to ask how much of the changes that have been reported in the past are due to changes in calibration. Will MODIS data get us out of the difficulties we have been having?
Dozier responded that MODIS would help by doing atmospheric corrections directly, and Scolese pointed out that MODIS will still have clouds in its data set. Strahler added that his group uses multi-channel atmospheric correction and gets corrected surface reflectances. View angle effects can be taken into account by correcting to standard angles. Townshend pointed out that it is possible to go back to the old AVHRR data and apply the atmospheric corrections retroactively. His group will be doing this for both 1 and 8 kilometer data. The 8 kilometer data go back to the early 80's.
Moore said that there is an intercomparison group using CO2 flask data to see whether land or ocean has the greatest effect on gross primary productivity (GPP). Moore asked whether information on the bi-directional reflectance distribution function (BRDF) would be available from AVHRR or from MODIS. Strahler replied that the MISR/MODIS teams are converging on semi-empirical models for surface BRDF. POLDER will contribute as well. Global maps of BRDF have been created using AVHRR data, but no global seasonal maps are yet available.
Dozier pointed up the odd situation that as models have been improving the apparent uncertainties have been increasing! We need to be able to explain this to the Congress.
Session on Validation, Calibration, and EOSDIS
Vince Salomonson, Goddard Space Flight Center, led off with a review of some of the calibration/validation issues that he perceives. We have heard a lot about the sensor drift of AVHRR. The 24 EOS instruments have now become the 24 EOS measurement sets, and this allows openings for new instruments to be introduced into the program. The proposed smaller version of MODIS will have the disadvantage of losing some of its internal calibration/characterization devices. Looking to future developments, it is necessary to protect the quality/integrity of the EOS measurements.
David Starr, Goddard Space Flight Center, reviewed the status of validation planning for the early AM-1 timeframe. Recent activities include the October Airborne Instrument Workshop, the March EOS Test Sites Meeting, and May EOS Validation Workshop. The May meeting had substantial Interdisciplinary Science (IDS) and NASA Headquarters (HQ) participation with 15 IDS teams and 12 Program Scientists participating. Starr noted that Jim Dodge has NASA HQ responsibility for calibration/validation activities.
Starr went on to review the Test Sites Meeting report and the Validation Workshop held the prior week. He also introduced the EOS validation homepage. In addition to documentation of validation activities and reports, the contents include the draft Validation Plans from the instrument teams and summaries of their plans, inputs from the IDS teams, and links to descriptions of test sites, field experiments and networks.
The schedule calls for revision of AM-1 timeframe validation plans with a formal review late in the year. There is also to be a NASA Research Announcement (NRA) for correlative measurements later this year. Validation planning activities for missions in the PM-1 timeframe will be initiated this fall. A hierarchical approach to land test sites was established at the Test Sites Meeting. Five "tiers" were defined as follows:
It was recommended that the EOS Validation Program NRA emphasize support for the Tier 3 and Tier 4 sites. A balance between enhancement of existing sites and development of new sites was also recommended. A major focus of the Validation Workshop was further cooperation and integration among activities of the Instrument and IDS teams and with NASA R&A Programs, as well as to identify potential interagency and international partnerships in support of EOS Validation. A unifying theme here is that the overall scientific productivity, quality, and comprehensiveness of EOS validation will strongly benefit from cooperative community efforts. Utilization of common test sites and field experiments, where appropriate, is essential to this end.
Starr summarized the Validation Workshop and highlighted some important issues that had been identified. Working groups considered validation of fundamental geophysical products (radiances) including vicarious calibration activities (joint ASTER/MODIS/MISR activities are underway), atmospheric correction algorithms, and standards and protocols for validation measurements. Validation of higher order geophysical products including radiation, cloud, ocean, land and atmosphere products was also considered.
Issues included the need for well-defined measurement protocols and calibration. An accessible secondary calibration facility is required. Development of a unified EOS Master Aircraft Schedule is needed to facilitate planning and allocation of resources. Efforts are needed to define a standard instrument package for the Tier 3 sites, to determine the suitability of existing tower sites around the globe, and to document existing test sites and networks. Archival of validation data is another key issue that must be addressed. A policy must be implemented that is consistent with providing data access to facilitate progress but is realistic in terms of resources. The role of the DAACs should be clarified. In addition, specific information is needed about the NASA R&A programs and what activities are planned that might provide opportunities for coordination with other validation activities.
Barry noted that the National Snow and Ice Data Center (NSIDC) will look after the Surface Heat Budget of the Arctic (SHEBA) data; the DOE has an archive program for ARM data; and the other discipline DAACs can do more. Running said that four classes of data sets have been identified, but none of the 50 to 60 existing towers that were cited collect all four classes of data. He asked whether we could send sensors of our selection to the tower managers.
Murphy replied that long-term loans have been made in the past.
Goodison asked whether sites like BOREAS will be maintained for the duration of MTPE. He wondered whether Canada was expected to provide the funding.
Jim Butler's subject was "EOS Calibration: Status and Plans." He began by discussing the use of ultra-stable transfer radiometers for radiometric measurement comparisons. A set of four targets has been used as standards for artifact measurement round robins. After each measurement the target was returned for checking to the National Institute of Standards and Technology (NIST). Butler stressed that calibration, validation, and quality analysis are all significant steps in the process.
Fritz Hasler and K. Palaniappan, Goddard Space Flight Center, gave the final presentation of the morning: "Visualization and Analysis of MTPE Datasets Using the Interactive Image Spreadsheet." This was a live presentation involving images that were both static and animated and could be brought up in spreadsheet fashion for manipulating the contents of the various images. Hasler remarked that techniques such as the one demonstrated for dealing with overwhelming amounts of data had been described by Vern Suomi as those that "help us to drink from the fire hose."
One of the examples of visualization had to do with animated renditions of Hurricane Luis. Using the new techniques it has been possible to bring out the previously unrecognized intensification that took place in the northwestern corner of the hurricane "eye." Palaniappan emphasized that in the future the hardware elements that are used to make sophisticated visualizations work will be essentially "free." The significant costs will be associated with the software elements.
Breakout Sessions on Science Implementation Plan
The afternoon was devoted to breakout sessions on the various discipline chapters of the plan.
Wednesday May 15
Yukio Haruyama, NASDA, gave an invited presentation on "NASDA Future Earth Observation Plans." He began by showing plans for the Japanese meteorological satellites including the GMS series and then showed the plans for TRMM and the Advanced Land Observing Satellite (ALOS). TRMM is to be launched in November 1997, and ALOS has a target launch date of 2002. ALOS will feature an L-band SAR called PALSAR. ADEOS is to be launched on August 17 this year, and ADEOS II will launched in 1999. The JERS-1 satellite was launched in 1992.
Longer-range developments include ADEOS III and ADEOS IV. TRMM follow-ons could be ATMOS 1,2, and 3. ADEOS III may be launched in the 2001 time frame. Its mission concept is described as providing a better understanding of global change. It will include sensors for both atmosphere and ocean characteristics.
Atmospheric measurements will include cloud characteristics, temperatures, water vapor, cloud water, precipitation, radiation budget, aerosols, and ozone.
ATMOS-1 could include three versions, A, B, and C. The goal would be to determine seasonal and annual global water cycle elements. With a 55deg. inclination angle and 400-kilometer orbit, ATMOS will give approximately 95% coverage of the world. A dual-frequency precipitation radar (PR) on ATMOS-A will measure lower rain rates than will be possible with the single-frequency version on TRMM. ATMOS-B will carry a cloud lidar.
Session on Seasonal and Interannual Climate
Ted Strub, Oregon State University, addressed "Comparative Studies of Eastern Boundary Currents in the Ocean: A Multi-sensor Approach." Four out of five major bio-activity areas occur in eastern boundary currents. They are rich systems for fisheries and have large fluctuations. Strub discussed a program called Global Ocean System Eco-Dynamics (GLOBEC). He pointed out that there is a natural cycle of about sixty years for sardine/anchovy catches. It is also interesting that there is an out-of-phase variability between Alaska salmon vs. Pacific Northwest salmon.
In studies of the ocean circulation off the coasts of both North and South America he has used satellite altimetry and AVHRR to survey patterns of the formation of a "jet," and the appearance of eddies as the jet moves off shore. In turn he has studied both the California current and then the Chile current. In doing this he has found different patterns between the two currents. He has also taken advantage of CZCS color sampling in these studies.
Studying the dynamics of the maxima in the counter currents he has analyzed the relative influence of local wind frequencies vs. large-scale/basin-scale currents. Strub has not established whether ocean topography affects the observed motions of the jet, such as the pattern of separation from the coast. He will be adding Atlantic upwelling regions to his studies. His models do produce meandering jets.
Eric Wood, Princeton University, gave the final plenary session paper, "Strategy and Initial Testing of the EOS/HPC Large Scale Terrestrial Water and Energy Balance Algorithms." (HPC refers to hydrologic processes and climate.) Wood's studies cover small, medium, and large scales, going from 102to 104 to 106 km2. He uses process models, coupled models, and budget analyses. In his mesoscale hydrologic model he uses four vertical models to account for the water and heat fluxes, including the effects of soil moisture. He makes soil porosity estimates for the underlying bedrock and uses texture data, porosity, and conductivity relations to analyze the first few meters of soil depth. His model for runoff does not include water quality/geochemical content.
Wood said that his group has found errors in reported ground heat fluxes, but has been able to correct them. There is a wide variation in reports of runoff vs. evaporation from many groups. Often there is either too much or too little soil moisture compared to observations. Other errors that he has encountered have to do with modeled sensible heat fluxes. Moore remarked that precipitation-temperature data are needed globally to use as standards for studies such as this.
Wood's strategy for calibration/validation is to work with large-scale data sets, in particular, data from the Red-Arkansas Basin. It was pointed out that the available global precipitation data do not include precipitation in the form of snow, and this could affect studies like Wood's.
Pierre Morel pointed to the need to promote cooperation between the various IDS investigations. For instance, the land surface hydrology people should improve their connections with the CERES Earth radiation team. Wood responded that CERES just offers monthly data and his approach requires daily data. Also, it will be hard to get the necessary 1deg.-to-1.25deg. data from CERES. There are also problems in matching up grids and projections. Similarly, Wood is unable to use GEWEX data, as the data are monthly and suffer from too many inconsistencies. Moore concluded that there is clearly a great need for a technique to down-scale data.
Payload Panel Meeting, Wednesday, May 15, 1996
Following the plenary sessions of the IWG there was a meeting of the Payload Panel, chaired by Mark Abbott. See page 15 for Abbott's full report on that meeting.
Mark Abbott, Oregon State University, in his "Opening Remarks," traced the flow of MTPE elements through science, technology, and requirements as manifested in the R&A program, ESSP, and NMP and on through EOS and NPOESS. In all of these the focus has been on climate research. He said that we can see the EOS focus on technology being adapted by the NPOESS program.
There has been rapid evolution in the MTPE climate research programs, but slow evolution in the developments leading to NPOESS. There is a need to keep science insights in mind. He concluded his introductory remarks by referring to the role of new technology in MTPE with its potential for both scientific benefits and possible risks.
The next few lines of this report indicate just the nature of the other presentations made to the Payload Panel.
Al Diaz, Deputy Director, Goddard Space Flight Center, addressed "Chemistry-1 Study: Objectives." In his talk he described the nature and findings of the NASA Headquarters study that had been headed by Sam Venneri toward the end of last year. The study looked at possible cost savings vs. possible science accomplishments for the Chemistry-1 mission.
Rich Zurek, Jet Propulsion Laboratory, described "Chemistry-1 Study: Results, Science Impacts, and Options." He gave the contents of the interim report of the study and then gave the purpose as addressing: resource reduction, new technology opportunities, and accelerated tropospheric chemistry measurements, all constrained by the need to maintain a 2002 launch schedule.
The various Chemistry mission instrument teams were asked what they could do to reduce costs by fifty percent. [ODUS was not included in this review.] The responses in brief, were as follows:
Zurek showed five potential mission scenarios plus the one he called baseline. In some of the options the launch date for CHEM-1 could be advanced. With the MMIC array, MLS could incorporate vertical profiles in multiple azimuth directions in addition to the baseline along track scanning. Among the three instruments, only MLS is in a position to infuse new technology.
Robert Price, Goddard Space Flight Center, Associate Director of the Mission to Planet Earth Program Office, led a final session devoted to "Chemistry Project Assessment of Technical Risks and Options." Five options, in addition to the current baseline, were presented and are given in the Payload Panel report on the CHEM-1 study in this issue.
Peg Luce, Goddard Space Flight Center, Flight Manager for the CHEM-1 mission, gave the Project assessment. She said that there is only a small cost difference between 200 kg/300 W and 500 kg/500 W payloads. All the options that have been considered will advance the launch dates over the baseline launch date of December 2002.
Abbott brought the Payload Panel meeting to a close, saying that he would have a draft report available in a week or two to be ready for the planned July 29-31 meeting of the Payload Panel.
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