Renny Greenstone (rgreenst@pop900.gsfc.nasa.gov), Hughes STX
Note: Direct access to many of the presentations made at this meeting may be achieved by accessing the World Wide Web at the following URL: http://eospso.gsfc.nasa.gov/iwg_presentations/nov97/nov97.html
The 13th meeting of the Investigators Working Group (IWG) of the Mission to Planet Earth/Earth Observing System (MTPE/EOS) took place for three days at the Renaissance Hotel in Atlanta, Georgia, November 4-6, 1997.
Tuesday Morning, November 4
Session on Land Cover and Land Use Change
Michael King, EOS Senior Project Scientist, greeted the attendees and then turned the meeting over to Tony Janetos, who chaired this first session. King explained that EOS Program Scientist, Ghassem Asrar, was unable to attend this meeting.
Janetos remarked briefly that land use/land cover change was an important area of concern for all of us as a nation, not just for us as scientists. He then introduced new interdisciplinary scientist (IDS) principal investigator (PI) Ralph Dubayah (University of Maryland), who gave a spirited presentation of "The Vegetation Canopy Lidar (VCL) ESSP Mission: Implications for MTPE/EOS."
Dubayah explained that VCL was the first project to be selected as part of the recently-established Earth System Science Pathfinder (ESSP) program of MTPE. ESSP was established to provide for low-cost quick- turnaround projects that would be performing research where no adequate Earth Observing System program existed. Two missions are selected every two years for ESSP. These missions operate in the "PI mode," where the PI is responsible for an entire project from "cradle to grave." The mandate is to produce data sets. Science analysis is separate.
The principal goal of VCL is mapping of the Earth's land cover. Dubayah said that we need to know the distribution of biomass around the world. Existing land-cover maps show 74% disagreement.
The VCL spacecraft will orbit at 400 km, using five laser beams in a lidar mode, spaced at 2-km intervals, producing an 8-km swath. (Ultimately, there will be a 2 x 2- km product.) The lidars give both canopy heights and topography of the surface. Dubayah said that prior Shuttle missions have shown the feasibility of this laser method. A 5-to-10 times improvement over existing canopy height estimates is expected. Billions of topographic control points at 1-m vertical accuracy will be provided.
Pegasus XL will be the launch vehicle for VCL. There are to be 290 pulses per second over land, and 60-cm vertical resolution is planned.
Sam Goward (University of Maryland) followed with a discussion of "Landsat 7: Resolving Terrestrial Science Issues." He pointed out that the Landsat program started in 1972 and is now celebrating 25 years of continuous operation. Landsat represented the beginning of land monitoring from space in this country. Now, with Landsat 7, we have the beginning of a new Landsat era. One new aspect is the transfer of management responsibility from the private sector to the government.
Landsat 7 will operate in seven spectral bands. It adds a 15-m panchromatic band and a thermal band with 60-m resolution and, with higher precision, the data volume doubles. There will be a seasonally refreshed global archive with 250 scenes per day.
The long-term acquisition plan has these elements:
Goward also discussed the synergy between Landsat 7 and the AM-1 mission. Another point he made was that Landsat 7 will provide a link between local activities and global phenomena.
According to Goward, Level 0 data will be available at launch, and Level 1 data will be available a year after launch. Berrien Moore expressed great concern with this delay. Tony Janetos added that NASA has been trying to improve this schedule. There is now funding for 100 scenes per day of Level 1 data. One of the unsolved problems is the software for billing for orders for the data. Steve Running pointed out that there will be no processing of standard higher-level products such as Leaf Area Index (LAI). He urged comparison of the standard MODIS products with the relatively raw Landsat products.
Jing Chen (Canada Center for Remote Sensing) discussed ñNorthern Biosphere Observation and Modeling Experiment (NBIOME) Recent Results.î NBIOME is one of the original international land process interdisciplinary investigations. The major goal is to use EOS data to monitor the state of boreal forests and detect changes as they evolve with climate change. So far they have relied heavily upon AVHRR data. They recalculate NDVI and temperatures every ten days.
They have found that use of their contamination mask is very important. Use of a four-scale plant canopy model gives a good fit to observations. It takes the hot spot into account. They have a scheme called Classification by Progressive Generalization (CPG).
They have now achieved the first-ever net primary productivity (NPP) map of Canada. A program called GEOComp II is scheduled to be complete by the end of 1998. It will be made up of 10-day composites and will be acquired by assimilating MODIS data sets.
Jon Foley (University of Wisconsin, Madison) described his project on "Integrating Biogeochemical, Ecological, and Hydrological Processes in a Dynamic Biosphere." He said that it was really a project to study biosphere/atmosphere interactions, looking at past, present, and future. His team has looked at first-order impacts of climate-driven changes on vegetation patterns. They take into account biospheric feedbacks to the atmosphere, which have usually been ignored in other global-change scenarios.
Foley listed classes of biosphere models in order of increasing time scales: land surface models (found in AGCMs), terrestrial biosystem models, and equilibrium vegetation models.
His group has developed the Integrated Biosphere Simulation (IBIS), which incorporates vegetation dynamics as a new feature. In this model it is possible to "seed" an area and see what grows. The model will then follow the development of trees vs. grasses, distinguishing tree types and grass types. The model can be started with nothing but dirt for the whole world, a "dirt world," and then it will trace out, very credibly, the worldwide distribution of tree types. IBIS has also been used to predict hydrological routings.
Biogeophysical feedbacks have been taken into account in modeling highlands and monsoon-affected lands. Effects of increases in CO2 have also been simulated. Foley remarked that if boreal forests extend further north, there will be increased warming.
A stepwise iteration of the effects of coupling vegetation changes with land/atmosphere models has already been performed, and now they have achieved synchronous coupling of vegetation and climate change. Using the GENESIS models without introducing "flux corrections" has led to very promising results. However, the model does have problems with topography. It puts mountains like the Rockies and Andes in the wrong places!
Steve Running pointed out that Foley is the recipient of the "Presidential Young Investigator" award (see Kudos).
Tom Loveland (USGS) reported on what is now a 3-and-1/2-year effort known as the "1-km Land Cover Project." This activity is led by the USGS, with the University of Nebraska serving as a key partner. Many other groups support this effort as well. The origins of this effort go back to 1990. They have been using 1-km AVHRR data for environmental monitoring purposes. The results of this project will constitute the first-ever global land-cover characteristics database. (Soil characteristics are not included in their data set.)
Loveland said that none of the current land-cover data sets have been validated. They typically have 1°x1° resolution, whereas mesoscale modelers want 1-to-40-km resolution.
Loveland's characterization strategy calls for use of NDVI from the AVHRR 1-km data set. They also take advantage of NASA Pathfinder data. Ten-day composites are basic. They have been carrying out their research on a continent-by-continent basis, with continents subdivided into seasonal land-cover regions. Thus, North America has 205 seasonal land-cover regions. Loveland showed a chart bringing out, by continent, the onset of greenness, the peak of greenness, and the end of greenness.
Loveland's team relies on the users to improve the quality of the data sets. A formal validation activity is underway, with Jack Estes as leader. The validation strategy uses a random sample survey based on IGBP DIScover classes with 25 samples per class. They expect to have at least one validation effort completed before the EOS AM-1 launch.
The group has found the conservation applications of their database to be much larger than they had anticipated.
Mark Harmon (Oregon State University) reported on "Estimating Long-Term Carbon Flux Due to Land-Use Change." Using Landsat data, the group is comparing changes in the Pacific Northwest with changes in Russia over a study period from 1972 to 1991. They have found that one-third of the observed carbon increase in the atmosphere is caused by land-use change.
Going from one disturbed system to another is what makes the difference in effects on carbon. Eco-friendly harvesting has the advantage of leading both to more products and to more carbon storage. Housing is a big component of harvested material, but about 50% of harvested material is lost in the manufacturing process. Overall, 80% of harvested carbon is released into the atmosphere. The interaction of climate change with clear-cut harvested areas may be the most significant element in carbon release into the atmosphere.
Tuesday Afternoon, November 4
Session on Integrated Assessments on Climate Variability and Change: Outcomes of U.S. Regional Workshops (chaired by Eric Barron, Pennsylvania State University)
An introductory presentation was given by Eric Barron. He stated that at the time of the Bush administration the USGCRP did not make the connection between global change and national policy. In the present administration, Clinton and Gore have a shared interest in the policy implications of global change. There is a new focus on the human dimension of global change. There is a feeling that we need to do climate-change assessments and take into consideration their impacts.
In a further amplification of this new concern has come the realization that we need to get the elements of society involved in these assessments and their impacts. These elements of society are recognized to be the "stakeholders" in climate change.
Barron outlined three phases in the new process of getting the stakeholders involved with the assessment of climate change and its impacts. In Phase 1 six regional workshops are held. Each workshop is funded by a different agency. White House plus relevant agency representatives meet with local leaders and other people from all walks of life. Typical interests would be fisheries, human health, commerce, industry, recreation, natural hazards, etc. They examine climate-change predictions, consider regional vulnerabilities, and devise mitigation strategies.
In Phase 2, the workshop leaders meet in Washington, DC for a national convenors workshop. About 200 people are expected to attend such a workshop, and they are to show regional assessments leading to a national assessment.
In Phase 3, the first national assessment is to be achieved before 2000, and then there would be follow-ons every five years thereafter.
Barron noted that regional perceptions are becoming stronger as people become aware of such matters as rice paddies serving as a source of methane and thereby having consequences for global warming.
Peter Mouginis-Mark asked about the legal implications of steps that might be taken toward hazard mitigation, and Soroosh Sorooshian replied that the legal field has not shown any interest in this as yet. Berrien Moore noted that he has already taken advantage of some Canadian regional assessment studies.
Berrien Moore (University of New Hampshire) presented the results of the New England Regional Assessments Workshop that was held September 3-5, 1997. He found out that the participants expect information to be available over the next few years. They feel that the currently-available information is not adequate. They are very critical of the information that is available from the EPA. They stress that information needs to be available and be useful. They can use "pragmatic" statementsanything that can be asserted with better than 50% probability will be useful to them. There is a serious need for adult educational materials, not at the K-12 level.
The participants accept the notion that greenhouse gases in the atmosphere will increase for the next 50 years and recognize that the U.S. share of the gases is declining.
Eight sectors were represented at this assessment workshop: natural resources, health, insurance, business/industry, energy/utilities, government resource management, recreation/tourism, and information transfer. Notably, the organizers could not get the banking industry to attend. Of 122 participants, 71 were academics. The final report was almost entirely written by the non-academics.
There were a total of 10 workshop findings in the final report:
A legal issue that arose at this workshop was related to the possible change in the number of severe storms as a consequence of warm or cool El Niño-type events. Would it be legal to change insurance rates because of anticipated increases in severe storm occurrence? Will there be effects on insurance regulatory laws?
Bruce Barkstrom commented that there is a need for data structures using Geographic Information Systems (GIS). Physical data should be coupled to economic models. Generally, it is necessary to determine just what are the public's needs for information.
Moore said that the workshop group was concerned with the interaction between drought periods and the presence of acid rain. The insurance sector would like to have forecasts on a thirty-year scale. They can't put their hands on good data sources. Bob Dickinson suggested that this is the opportunity for private consultants to step in and supply the answers.
Eric Barron addressed the findings of the Mid-Atlantic States Workshop. For the purposes of this workshop, Mid-Atlantic meant all the areas draining into the Chesapeake Bay. The workshop funding came from the EPA.
A general discussion relating to the difficulties in getting scientific information out to the public followed Barron's presentation. Bob Price said that Goddard has developed a strategy to increase public outreach. Cindy Howell of Goddard is taking the lead. Five different communities that should be reached have been identified, including scientists outside of the Earth science community. Spacecraft launches should be used as triggers to get public attention to advances in science. Scientists must take the action to identify results that should be brought to public attention. As an example of the new approach, he stated that Veerabhadran Ramanathan has now been made spokesperson along with Yoram Kaufman for the AM-1 mission.
Price said that he has looked to the Hubble Space Telescope Science Institute as a model for scientific outreach. Out of 300 scientists employed at the Institute, some 50 participate successfully in the outreach program. They have a pattern of announcing one "hot" result each month.
Otis Brown said that he is concerned that performing regional assessments does not truly address global warming.
Jeff Richey said that the University of Washington has been taking the lead in working with its community. They divide problems into appropriate target audiences.
Peter Mouginis-Mark said that the Space-Grant Consortia are already doing the job and invited others to check with him on this. On the other hand, Nancy Maynard, Acting Science Division Director for MTPE, said we haven't yet got a good mechanism for getting the word out.
Ron Ritschard (University of Alabama, Huntsville, MSFC) discussed the Southeast Regional Workshop proceedings. The workshop had been held in June of this year. Notable, he said, was the stakeholders' need for resultsthey want information. They want to know the current climate variability, and they want to know about extreme climate events. In the southeast, agriculture is very sensitive to the occurrence of precipitation at the right time.
At this workshop there were 125 participants and one third of these were stakeholders. The seven sectors represented included agriculture, coastal resources, parks, and public lands. Forestry and agriculture did not participate in the assessment but, independently, they are well advanced in assessment of their problems with climate change. A report of the meeting is now available. Here are some of the findings:
Establishment of a Center for Southeastern Regional Assessments (CSERA) has been proposed. The Center would be a focal point for access to all relevant information and would represent eight sectors of the economy. The Center will support the first National Climate Assessment Report, which is due in December 1999. The Center will also support the IPCC 2001 third assessment, which is to be regional in nature.
Soroosh Sorooshian (University of Arizona) spoke for the Southwest Regional Climate Change Symposium and Workshop. (The workshop concentrated on the Colorado River Basin.) In Arizona the primary water resources are snow melt runoff and ground water. Sorooshian said that water may be the common thread tying together all the U.S. regions.
The reservoir capacity in the Southwest is about four years worth, and 84% of water use is agricultural.
The workshop was conducted by means of the WorldWide Web. There were 199 attendees and 21% were stakeholders. The symposium addressed the question of how climate change affects human activity, and there was a panel discussion on how climate variability and change affect different sectors in the southwest.
The workshop had four primary recommendations as follows: (1) create a regional center; (2) identify how stakeholders use information; (3) incorporate climate data with GIS to produce maps; and (4) the scientists should phrase issues understandably.
Other recommendations had to do with the need to supply climate forecasts and to perform hydrological modeling; the need to provide market information on responses to climate change; the need to address health issues; and the need for sensitivity analyses to change, by sector.
Sorooshian said that traditional climate data are now used in dam development. There has been a correlation between winter precipitation and El Niño, but the correlation has been oversold. Berrien Moore said that it might be a good idea to look at the North Atlantic oscillation for effects in New England. El Niño is not the only driver.
Sorooshian concluded his presentation, saying that hydrological data are scattered among many agencies.
Jeff Dozier (University of California, Santa Barbara) reviewed the California regional assessment activities. The planned workshop has yet to take place, but there is definitely a desire to have an ongoing process. Dozier believes that issues to be addressed should be categorized by more than sectorssystems and then impacts should be added. He has found that the stakeholders are not interested in "Steering Committees." Doug Wheeler, California Secretary for Natural Resources, has agreed to participate in the upcoming workshop. In planning for the workshop Dozier found that a similar assessment was the subject of a book published in 1991, reporting on three workshops: Global Change and California: Potential Impacts and Responses, UC Press, 1991. The book reports on findings and recommendations about water, agriculture, natural ecosystems, human dimensions, climate, and energy.
The upcoming workshop will be called the California Regional Climate Change Workshop and will be held on March 9-11 in Santa Barbara. The issues for the workshop have been categorized as Sectors, Systems, and Impacts. Sectors includes water supply/use, agriculture, forestry, coastal recreation, fisheries, land use, and ports. Systems includes ecosystems, predator/prey, food/migration, hydrologic, air, and economic. Impacts includes endangered species, timing and patterns, insurance, and international.
In the discussion that followed Dozier's presentation, several questions were raised and comments offered. Berrien Moore commented that nonlinear responses to climate change events, such as a shift in the California current, could be significant but unpredictable. In New England small changes in storm tracks could be significant.
Gille suggested that the workshop should be looking at renewable resources such as solar and wind power. Other suggestions were to include population growth and fire among the issues to be addressed.
Wednesday Morning, November 5
This morning was devoted to a poster session and no formal presentations were made.
Wednesday Afternoon, November 5
This session was chaired by Michael King, and the lead speaker was William Townsend (NASA Headquarters, Acting Associate Administrator, Office of Mission to Planet Earth) discussing the MTPE/EOS Program and giving Project Updates.
Townsend said that a decision is due by Christmas on the choice for a permanent Associate Administrator for MTPE. Mr. Goldin has said to wait until the new AA is appointed and let him select a replacement Director of the MTPE Science Division. Bob Harriss, the previous Director, has left for a position at Texas A&M University. Meanwhile, Nancy Maynard is serving as the Acting Science Division Director.
Townsend said that MTPE/EOS is in a more-stable funding environment. The appropriations bill was signed the previous week, and MTPE received the amount requested. Some funds were set aside, partly for the regional assessments discussed here on the previous day. Among conditions that were imposed was a limit of $10 M on the "Federation" experiment. The House Science Committee appears to be supportive of MTPE. They are encouraging full funding of our '98 and '99 requests. The Science Subcommittee is pleased with changes we have made in the direction of applications and commercialization. The full committee is still concerned with our "uncosted" funds. The committee feels that perhaps MTPE may be helpful in providing insights that will be helpful to the U.S. side at the upcoming international Kyoto meeting on climate change.
There is an approved $50 M reduction in the president's budget for MTPE applied research and data analysis, due to data purchase funding of $50 M, which was added to the MTPE budget in '96 as a one-time experiment.
Townsend cited several items under the heading of "current Events."
Townsend showed the MTPE Mission Profile thru 2002 (see page 10), and he commented that MTPE coordination with the Integrated Program Office (IPO) of the National Polar-orbiting Operational Environmental Satellite System (NPOESS) is intensifying. NASA has the lead responsibility for advanced technology. Under current plans, NASA will become dependent on NPOESS for atmospheric sounding. NPOESS may fly the Integrated Multispectral Atmospheric Sounder (IMAS) to satisfy both research and operational requirements.
NASA is looking at adding two additional UV channels to the Total Solar Irradiance Sensor Mission (TSIM) and is also considering modifications to MODIS to meet NPOESS' Visible Infrared Imager Radiometer Suite (VIIRS) requirements.
Townsend next discussed the Integrated Global Observing Strategy (IGOS) as the way to coordinate plans for satellite observations of the Earth. Six prototype projects have been selected by the Strategic Implementation Team (SIT). They include, among others, upper air measurements (satellites vs. radiosondes) and long-term ocean biology (consider reducing the overlap of programs).
Townsend said focused efforts will be made in the area of MTPE outreach. There will be funding for this effort.
MTPE is planning a Biennial Review Results Workshop next year focusing on implementation of MTPE after 2002. There is a general understanding that MTPE should be evolutionary, and that there should be reviews of scientific progress and technological advances biennially. Townsend noted that 19 countries now have programs that complement MTPE. He then went on to summarize the recommendations of the Earth System Science and Applications Advisory Committee (ESSAAC). These recommendations were in the three areas of EOSDIS Core System (ECS), future missions, and program balance. Roughly paraphrasing, the recommendations called for: (1) fundamental changes in EOSDIS having to do with limiting its requirements, using an open architecture, and making the data products largely the responsibility of the PIs; (2) reexamining the EOS missions following the PM-1 mission; and (3) improving the balance of resources within MTPE, shifting away somewhat from "hardware" to provide more support for R&A and mission-oriented science.
Townsend reported on the findings of the Independent External Review Board, chaired by Pamela Matson (University of California, Berkeley). This Biennial Review Board met in June and reported preliminary recommendations. Two of them are as follows (severely shortened here):
Townsend then reported on the decisions made in response to the Biennial Review recommendations (again severely condensed here):
Townsend said that the needs for monitoring versus process study measurements should be distinguished in planning future missions. We will continue to develop international partnerships and commercial opportunities. We expect more than 10% savings through development and deployment of cheaper spacecraft. The average cost per mission will be reduced from $600 M for the second EOS series to about $250 M.
Finally, Townsend listed recent MTPE science results including a number of "firsts":
There were some comments after Townsend's presentation. Dave Glover said that there is an effort to centralize all data processing operations up to Level 3 at the Johnson Space Center. Mark Schoeberl asked about the effect of consolidating aircraft operations at Dryden, and Townsend said that there could be some problemsthere is a shortage of aircraft. Some aircraft time will have to be sought from commercial sources. Townsend also said that the validation program is moving to NASA Headquarters, but the connection between science team validation and Headquarters evaluation is not yet clear.
Chris Scolese, EOS AM-1 Project Manager (GSFC), along with Yoram Kaufman, AM-1 Project Scientist (GSFC) gave the status of the AM-1 science, platform, and instrumentation. The big news from Scolese was that the spacecraft is complete, all instruments are on board; and the Deep Space maneuver has been authorized. Of two instrument problems, the MOPITT data problem will be fixed by Monday of the week after this meeting, and a MISR problem is "being worked."
There is a problem with the spacecraft solid-state recorder. The simultaneous record/playback feature is not working, but a fix is available. There is also a problem with the S-band transponder.
The ATLAS 2-AS launch vehicle is on the stand at Vandenberg Air Force Base. The solar array is now at Valley Forge in its folded configuration. Its power exceeds the specification.
Kaufman said that the AM-1 mission presents a new way to look at the Earth as one living system. "AM-1 is a fantastic system!" AM-1 will give a snapshot of the Earth using, for the first time, a set of scientific instruments that are thoroughly calibrated and characterized. It will measure human-induced impacts on the Earth, and will determine the radiative and hydrological forcings of Earth's climate.
Kaufman reviewed the phenomenon of biomass burning, saying that it has both regional and global effects. The highest uncertainty lies in the aerosol climate forcing. Aerosols have more-specific regional effects than trace gases. Kaufman ended his talk by saying that we must be concerned with the impact of this mission in two years not just over the long term. We need an early demonstration of the value of our work.
Sara Graves (University of Alabama, Huntsville) discussed the EOSDIS Review Group (ERG) report. The group has met twice so far and will meet again in February. It has no recommendations that would hurt the AM-1 era instruments. The Group finds the current status of EOSDIS to be suffering from complexity, making for difficult management, and suffering from budget overruns with a shortfall still expected.
For the AM-1 era there is need for EOSDIS capabilities; EOSDIS has had successes; the V0 system is operational; and the DAACs are performing well, providing critical support to users. Relaxation of data interdependencies is required. Achieving the ECS B0' functionality milestone is critical for the launches in 1998.
Speaking of the August 28, 1997 test of EOSDIS, she said that the ERG considered that it showed a "qualified" success. They urged that the Alternative Implementation Path be dropped, but the instrument back-up plan should be kept. Significant improvements are still needed prior to the AM-1 launch. There are concerns with the Java interface, and with tiling.
ERG urges that there be no "requirements creep." The DAACs should be more involved in costs.
Looking ahead to the PM-1 era and beyond, the group said that large data volumes should be reduced to save costs; MTPE should look at different architectures and consolidation of processing.
The ERG recommends an adaptive approach which will be less centralized, giving more responsibility to the PIs.
Rick Obenschain (GSFC) reviewed the status of EOSDIS. The EOS Data and Operations System (EDOS) has been successfully tested with the AM-1 spacecraft. Also, the ECS Flight Operations Segment and ECS testbed have been successfully tested. Critical functions were successfully demonstrated at the August 28 review. Of 46 critical areas of functionality only three were not demonstrated.
Obenschain said that the system performance exceeded the ingest-archive goal. According to the incremental development plan, the Java interface will not be ready at launch, nor will automated on-demand user requests be possible. $10 M has been set aside for emergency back-up systems. There is no money in the ESDIS budget for transferring data between DAACs to support interoperability. Using tapes might be a less-expensive alternative. (The network money went to the R&A budget.)
Martha Maiden (GSFC) reported on the EOSDIS Federation Earth Science Information Partners (ESIP) program. She described the National Research Council (NRC) and NASA Response Task Force (RTF) concepts for the Federation. Three concepts were looked at, including Type 1ESIPs are like DAACs, Type 2emphasis on flexible service, and Type 3provide value-added service.
There is a Phase 1 governance approach defined in two Cooperative Agreement Notices with selection already due November 12 and start-ups to follow in January. Federation issues that have arisen have to do with product quality and peer review, and with intellectual property rights.
Thursday Morning, November 6
Session on Seasonal to Interannual Climate Variability (chaired by Michael Freilich, Oregon State University)
Tim Liu (Jet Propulsion Laboratory) gave a review of "Space-Based Monitoring and Analysis of El Niño." He defines El Niño as a change in trade winds with a related deeper thermocline in the Western Pacific. He used NSCAT, TOPEX, and AVHRR data to show effects of El Niño on near-surface ocean winds, sea level, and sea-surface temperature (SST), respectively. He used OCTS and SeaWiFS data to show the changes in pigments off the coast of South America between December 1996 and September 1997. Similarly, he used MLS data to show a complete reversal in upper-tropospheric water vapor between September 1996 and
September 1997. TOPEX data have been used to improve the SST anomaly predictions provided by the National Centers for Environmental Prediction (NCEP).
Byron Tapley (University of Texas-Austin) reviewed the "Gravity Recovery and Climate Experiment (GRACE)," which will provide the gravity measurements required to fully utilize the TOPEX/Poseidon altimeter measurements for global ocean circulation and sea-level studies in the early new millennium. The objective of GRACE is to map the global gravity field with an unparalleled accuracy at intervals of the order of one month for a period of five years. Such data will contain the signatures of a number of time-varying gravity phenomena involved in the mass exchange between the atmosphere, oceans, and solid Earth.
The various components of GRACE are conceived of as being from an off-the-shelf mode. Both the spacecraft and the accelerometer that are used will have CHAMP heritage. The technique involves using two satellites to measure the intersatellite range rate to better than 1 mm s-1. The satellites will be injected at 450-km orbital altitude and, over a period of five years, will decay to about 300 km.
William Lau (Goddard Space Flight Center) addressed "Climate Change and the Global Hydrologic System." His work has a new focus on regional climate modeling. He noted that the GISS T22 ocean model shows reduced warming. Using wavelet analysis he has found two-year and ten-year long-term components in the NCEP SST records. He said that before an equilibrium warming can be established there can be high-latitude cooling as well as low-latitude warming! In his research he will be downscaling global warming into its effects on regional rainfall.
Chuck McClain (Goddard Space Flight Center) presented some "Early SeaWiFS Results." SeaWiFS has served as NASA's trial balloon for the "data buy" approach. In this approach NASA specified the data quality but not the instrument. After a four-year delay, launch of SeaWiFS took place on August 1 of this year and the instrument became operational on September 18. SeaWiFS gives daily coverage with 14 orbits/day.
There has been much emphasis on calibration/validation of the data, starting with simulated data. Lunar calibration using a rollover maneuver is possible. Also MOBY data, off the island of Lanai, are used for vicarious calibration. The SYMBIOS program will provide cross correlation. Information from SeaWiFS is available on its web page.
Data are for both land and sea. They will soon be archiving NDVI data.
Data are to be released only to science users. There is a 2-week embargo on data release, and this will be maintained until January 1998. There is a SeaWiFS Technical Memorandum series, with 1000 subscribers currently, giving SeaWiFS plans and results.
Orbital Sciences charges independently for scenes from SeaWiFS, but it is not clear what the charges are. McClain believes that the charges will run about $100 per scene, probably less than Landsat charges.
McClain showed the distribution of Saharan dust blowing off Africa as brought out by phytoplankton blooms across the Atlantic.
Dave Schimel (National Center for Atmospheric Research) along with Berrien Moore and Rob Braswell (both of the University of New Hampshire) presented some recent findings on the "Response of Global Terrestrial Ecosystems to Interannual Temperature Variability." The question being considered is what controls the annual variability in terrestrial ecosystems. There are issues of nitrogen availability and stored soil moisture. In warm years the ecosystem releases CO2 to the atmosphere. Then some years later there is an anomalous uptake of CO2 by the biosphere. The respiration response is stronger than the photosynthesis response.
There is strong evidence of a slight asymmetry in the respiration of plants and of microbes. The release of carbon from the soil leads to the lag effects. Schimel stressed that we need to consider the diversity of ecosystem responses to temperature anomalies. He said that, just looking at two vegetation classes, we have seen two different responses.
Schimel reviewed the work of the VMAP project. In VMAP-1 just one year of climatology was reviewed; and in VMAP-2 a historical climatology record was reviewed. "Real" topography was taken into account in the modeling. There was a large impact of nitrogen availability, leading to nitrogen-related trace-gas fluxes.
Bob Dickinson suggested that a lot of the lag response may be due to phenomena in the tropics. Berrien Moore said that EOS data will offer several improvements over AVHRR data through improved station keeping and improved atmospheric corrections.
Thursday Morning/Afternoon, November 6
Session on Atmospheric Chemistry (chaired by P.K. Bhartia, Goddard Space Flight Center)
Gary Rottman (University of Colorado) reviewed the "Influence of Solar Radiation on Climate and Atmospheric Chemistry." Rottman began by showing the global average 342 Wm-2 irradiance reaching the Earth from the sun. He then compared the time variations in irradiance at the top of the atmosphere to the variation in irradiance at the surface of the Earth and commented that the term "solar constant" was an unfortunate one.
The radiation at less than 300 nm is completely absorbed in the stratosphere. There has been a 0.2% enhancement in irradiance between the solar maximum and the minimum. In the UV there is a much greater variation in the short term, as observed during a single rotation of the sun. 30% of the variation in total solar irradiance (TSI) occurs at less than 300 nm.
Rottman gave several examples of variations in Earth phenomena that seem to correlate with solar cycle variations. These include variations in atmospheric chemistry and upper stratospheric winds.
Rottman compared the characteristics of the SOLSTICE instrument he is planning for EOS with the corresponding characteristics of SOLSTICE on UARS. He said that spectral measurements with the new instrument will be good to 1 part in 104. Dickinson commented that 30% of the UV below 300 nm is taken up by ozone and the rest goes into the troposphere.
Jeffrey Kiehl (National Center for Atmospheric Research) was not able to give his scheduled presentation, and so the order of presentations was changed with Ralf Toumi (Imperial College, London) filling in with a talk on "Chemical, Dynamical, and Radiative Interactions Through the Middle Atmosphere and Thermosphere."
Toumi said that he was representing John Pyle's Interdisciplinary Investigation (IDS). The group now has two chemical transport models (CTMs): SLIMCAT is an isentropic model for stratospheric studies, and TOMCAT is a s-pressure model. Under development are a CTM for surface to mesopause and a coupled GCM.
Midlatitude ozone loss has been seen to be a multi-year process as against seasonal changes in the Arctic and Antarctic. Arctic ozone depletion is a more-complicated process than is Antarctic ozone depletion. The influx of low-value ozone from low latitudes can account for some "apparent" ozone deletion at higher latitudes, in contrast to chemical effects.
In the 1990s, the probability of low temperatures increased considerably thus leading to an increase in PSCs.
There is a possible lightning/ozone feedback process to consider. Lightning can produce NO in the upper troposphere and thus produce ozone. Then lightning might increase with global warming and thereby lead to still more ozone. Schoeberl pointed out the possibility that an increase in ozone would lead to greater atmospheric stability, thereby suppressing thunderstorms and decreasing lightning.
Toumi pointed out that HALOE data show a trend in increasing water vapor, which is not due just to the addition of methane.
Mark Schoeberl (Goddard Space Flight Center) gave the "Scientific Highlights of the UARS Mission." UARS was launched in September 1991, and eight of the ten instruments are still functioning. CLAES and ISAMS are no longer functioning. There is a yaw maneuver every month to avoid sunlight striking the instruments.
UARS instruments measured both ClO and NOx but not OH. HALOE provides a methane map. UARS was intended to look for changes in ozone in the mid stratosphere, but later it was found that it could examine ozone-hole chemistry. The extended goals of UARS include looking for trends in UV as well as studying stratospheric chemistry, the QBO cycles, and El Niños. The QBO signal has been detected in zonal winds.
UARS is showing the beginning of a flattening in the amount of CFC byproducts in the 50-km region. MLS data have shown an exciting finding of upper tropospheric water vapor, irrespective of the presence of clouds. MLS can show water vapor at four different levels. The data have also shown El Niño-related changes in water vapor below the tropopause.
Schoeberl listed seven questions that have not been answered by UARS:
Following "questions not answered," Schoeberl gave "lessons learned," including the following:
Daniel Jacob (Harvard University) followed with "Results from Tropospheric Chemistry Aircraft Missions." He said that aircraft are the best platforms for in situ studies, for the study of chemical characteristics of atmospheric layers, and for regional mapping of bio-atmosphere fluxes.
Tropospheric ozone largely comes from the stratosphere, but it is also formed as a result of reactions involving UV and water vapor leading to a one-week lifetime. In the tropics the largest source of tropospheric ozone is reactions involving peroxyl radicals with NO. Biomass burning in the South American tropics leads to the production of NOx and hydrocarbons, thereby producing elevated ozone over the Atlantic.
Jacob described the PEM Tropics campaign, which took place in September 1996. They investigated the impact of biomass burning over the South Pacific using DC-8 and P-3B aircraft. They found thick layers of biomass-burning products all over the Pacific and heavy concentrations of ozone with elevated CO and acetylene but not propane and butane. They determined that this was continental air, possibly from southern Africa or Brazil. They used measurements from Ed Browell's Differential Absorption Lidar (DIAL) instrument in their work. They concluded that the import of biomass-burning pollution accounts for the increase in ozone over the South Pacific.
Jacob said that now there should be another campaign in a region in the South Pacific where biomass burning is not a factor. He also mentioned a campaign using the P-3 aircraft and focusing on sulfur chemistry in the South Pacific. He pointed out that OH and HO2 measurements are now available and that OH is the main oxidant of DMS, leading to the production of SO2.
Michael Gunson (Jet Propulsion Laboratory) described the "Chemistry and Circulation Occultation Spectroscopy Mission." Gunson said that he is deputy to Mike Luther (University of California, Irvine), who is the PI for the mission. He said that this mission was not yet accepted as part of MTPE, but that he will be applying to have it become an ESSP mission. The focus of the mission is to determine what happens to pollution from the surface and where consequent ozone may appear.
The instrument concept is based on Fourier Transform Spectroscopy (FTS) with heritage from the ATMOS project. A technique originated by James Watt is used for linking the two moving mirrors of the FTS. A UV/VIS spectrometer is also incorporated in the instrument. The plan is to have a Pegasus launch, with 18 months lifetime, and an orbital altitude of 440 km with 48-degree inclination. Vertical resolution will depend on the sampling rate, but could be about 1-1/2-to-2 km.
A spring launch has been chosen to permit observations during two northern latitude summers. There is a hope to detect seasonal and latitudinal variations in several types of gases such as ethane. The high spectral resolution of the instrument will allow ClONO2 determination along with many other halogenated species.
In another rearrangement of the schedule Kelly Chance (Harvard University) gave "Recent Results from the ERS-2 GOME Instrument." (GOME stands for Global Ozone Monitoring Experiment.) The Smithsonian Astrophysical Observatory is the U.S. investigator on this international program.
GOME was launched in April 1995. It acquires 30,000 spectra per day. It is a nadir-looking instrument with 0.2-to-0.4 nm resolution. GOME also has polarization channels with 16 times higher spatial resolution than the spectral channels. It can measure BrO globally. Operational products include O3 and NO2 column density and clouds. Level-2 products are now available. Currently, GOME measurements of ozone are not as good as the TOMS measurements, but they expect to achieve TOMS quality. Ozone profiles compare favorably with ozonesonde profiles and have ~1 scale height vertical resolution. They use an ozone spectrum vs. temperature technique to arrive at the ozone profile.
SCIAMACHY (1999) and OMI (on ENVISAT in 2003) will follow as GOME derivatives.
Prasad Kasibhatla (Duke University) presented "A Study of Carbon Monoxide Using Trace Constituent Data Assimilation: A New Approach in Global Tropospheric Chemistry Analysis." The project wants to achieve a better understanding of CO chemistry because of its role in OH chemistry. The OH-CO reaction is the dominant sink for CO. Among sources and sinks for CO are the nonmethane hydrocarbons.
The project uses a chemistry transport model (CTM) developed by the Goddard Data Assimilation Office (DAO). The model has 20 s levels and 2°-latitude-by-2.5°-longitude resolution, spatially.
The project now has 4 tasks: (1) improve on the DAO global CTM; (2) assemble global CO measurement database; (3) analyze CO simulations for 1993/1994; and (4) assimilate CO measurements.
Kasibhatla said that they have compared the model CO with MAPS Shuttle measurements for the spring and then the fall of 1994 and found "fair" agreement. He said, in summary, that they have developed new OH chemistry, using updated kinetic information and they also updated the CO simulation. They are now doing sensitivity analyses. The assimilation procedure to be used has not yet been selected. They could start with a Kalman filter.
Charles Kolb (Aerodyne Research, Inc.) described "Tools to Characterize Urban Respiration." This is a relatively new project that started in February 1997. They analyze urban metabolism and urban respiration. In terms of metabolism, cities consume materials and energy and export/excrete materials. In terms of respiration, cities take in oxygen and emit gaseous pollutants and aerosols. The emissions have both regional and global impacts. Boundary layer emissions are hard to measure from space, so NASA needs surrogate observational variables.
This fall they have begun making testbed city measurements in Manchester, New Hampshire, a city of about 100,000 inhabitants. Following Manchester they will proceed to make measurements in Boston. In doing this they use specially-outfitted vans with various trace-gas monitors on board. They also use various meteorological instruments, mapping devices, GPS receivers, and acoustic sounders. They use releases of SF6 as tracers.
The final speaker of this IWG meeting was Georgiy Stenchikov (University of Maryland) on "Impact of Aerosols on Photochemical Ozone Production."
Stenchikov said this group did a case study on July 13-15, 1995, a particularly high ozone incidence time. All the measurements were made at GSFC. They found mostly sulfate and ammonium sulfate aerosols in the Baltimore/Washington, DC area. Values of t were as high as 2.0. Calculations and measurements of photolysis rates showed good agreement. This demonstrated the effect of aerosols on the photolysis rate of NO2 and thereby on ozone production. Pure scattering aerosols were found to produce the highest levels of ozone. It was found that absorbing dust or smoke aerosols decreased ozone levels.