United States General Accounting Office

GAO Report to the Chairman, Committee on

Science, House of Representatives

July 1996 EARTH OBSERVING

SYSTEM

Concerns Over NASA’s

Basic Research

Funding Strategy

G O A

years

1921 - 1996

GAO/NSIAD-96-97

GAO United States

General Accounting Office

Washington, D.C. 20548

National Security and

International Affairs Division

B-271690 

July 11, 1996

The Honorable Robert S. Walker

Chairman, Committee on Science

House of Representatives

Dear Mr. Chairman:

The National Aeronautics and Space Administration’s (NASA) goal is to

launch the first spacecraft of the Earth Observing System (EOS) in 1998.1

You requested that we assess NASA’s plans for funding this program and for

developing its EOS-related basic research community.2

 This report

(1) discusses NASA’s strategy for developing such a community with

specific focus on the number of currently funded EOS science

investigations and (2) summarizes researchers’ views on whether changes

to EOS over the last few years have adversely affected their ability to carry

out their interdisciplinary Earth sciences investigations. We also address

issues related to the new Earth System Science Pathfinder program and its

potential impact on the funding availability for future EOS investigations.3

Background EOS is the centerpiece of NASA’s Mission to Planet Earth, whose overall goal

is to understand the total earth system (air, water, land, life, and their

interactions) and the effects of natural and human-induced changes on the

global environment. EOS has three major components: (1) a constellation

of satellites designed to collect at least 15 years of key climate-related

data; (2) a data and information system designed to operate the satellites

and process, archive, and distribute the data; and (3) teams of scientists

who develop algorithms for converting sensor data into useful information

and conduct basic research using the information. The satellites, and data

and information system, which will absorb most of the program’s funding,

provide the researchers with measurements that will enable them to

address established research priorities.

EOS is designed to make 24 types of long-term measurements of solar

irradiance and the earth’s atmosphere, land cover, ice sheets, and oceans

1

Refers to the AM-1 spacecraft. A pre-EOS-era spacecraft, the U.S.-Japan Tropical Rainfall Measuring

Mission is scheduled to be launched in 1997.

2

We addressed NASA’s funding plans in NASA’s Earth Observing System: Estimated Funding

Requirements (GAO/NSIAD-95-175, June 9, 1995).

3

Pathfinder is a program of low-cost space missions to do high priority Earth sciences research that is

not being addressed by current programs, including EOS.

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from orbiting spacecraft.4 By 2002, when the full constellation will be in

orbit, EOS will be generating data from 25 instruments on at least 

10 spacecraft. Over the 20-year EOS data-collection phase, about 

80 instruments will be launched on more than 30 satellites. As currently

planned, the last EOS satellite will cease operations in 2020.

EOS measurements will support researchers’ efforts to address Mission to

Planet Earth’s research priorities: (1) determine the causes and

consequences of changes in atmospheric ozone; (2) improve

seasonal-to-interannual climate prediction; (3) determine the mechanisms

of long-term climate variability; (4) document changes in land cover,

biodiversity, and global productivity; and (5) understand earth processes

that can lead to natural disasters and develop risk assessment capabilities

for vulnerable regions.

Mission to Planet Earth is NASA’s contribution to the governmentwide U.S.

Global Change Research Program.5

 An important goal of these

interconnected efforts is to improve the predictive capability of numerical

earth system models, especially global climate models that investigate and

predict the general circulation of the atmosphere and ocean.6 NASA has

identified a potentially large and diverse “user community” for EOS-related

information. Members of this community could be, for example,

educators, businessmen, and public policymakers. The focus of our

analysis, however, is the EOS basic research community, by which we

mean NASA’s currently funded EOS interdisciplinary science and instrument

investigations.

In our June 1995 report, we estimated that funding requirements of the EOS

baseline program would total about $33 billion for fiscal years 1991 to

2022. This estimate was developed for the program described in NASA’s

1995 EOS reference handbook and included costs for satellites, launch

services, data systems, science, construction of facilities, and civil service

personnel. However, NASA later recognized that this program was not

affordable in an environment of declining budgets and began studying

ways to cut costs by using advanced technology and increasing

4

See app. I for types of measurements; app. II for satellite missions, instruments, and measurements;

and app. III for the instruments’ flight schedules.

5

Research activities of the U.S. Global Change Research Program are (1) observing the global system,

(2) managing and archiving information, (3) understanding global change processes, (4) predicting

global change, (5) evaluating the consequences of global change, and (6) developing tools for assessing

policies and options.

6

Global Warming: Limitations of General Circulation Models and Costs of Modeling Efforts

(GAO/RCED-95-164, July 13, 1995).

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collaboration with other agencies, international partners, and the

commercial sector. NASA intended to use these future savings to fund more

science under EOS and to reduce the program’s total cost. Over the past

several years, the Congress has progressively reduced NASA’s planned

spending on EOS for fiscal years 1990 to 2000 from $17 billion to

$7.25 billion. In response, NASA changed EOS in 1991 and 1992 from a

complete earth system measuring program that would have supported a

wide array of global change investigations to a measurement program that

will primarily support investigations of global changes to the earth’s

climate. For example, NASA dropped the measurement of upper

atmospheric chemistry and solid earth processes. Other changes followed

in order to further adjust EOS to its progressively lower budget profile

through 2000. NASA officials stated the current planned spending for EOS

through 2000 is about $6.8 billion.

The administration’s fiscal year 1997 request for Mission to Planet Earth is

$1.402 billion, of which $846.8 million is for development of EOS’ data and

information system, spacecraft, instruments, and algorithms. NASA’s

request includes $47.5 million for EOS interdisciplinary science. According

to NASA’s 5-year plan based on its fiscal year 1996 budget submission, NASA

intends to increase spending on EOS interdisciplinary science to

$73.2 million per year in fiscal year 2000.

Results in Brief The number of currently funded EOS investigations is relatively small in

comparison with two pre-EOS-era missions and the potential research

opportunities afforded by EOS. NASA plans to use some of the anticipated

savings resulting from improved technology and increased collaboration

with others to fund more investigations. The viability of this plan is

uncertain because the anticipated savings may not materialize or may be

absorbed by budget reductions. If NASA’s strategy for increasing funding is

not successful, there may be a growing imbalance between the number of

investigations NASA would like to fund and the number it can afford.

At the same time NASA wants to fund more EOS investigations, it is also

planning to solicit proposals for new Pathfinder satellites. Although these

satellites would focus on earth system science, they are not part of the EOS

program. NASA estimates the life-cycle cost of each Pathfinder mission

would not exceed $120 million over 5 years.7

 In setting the pace of the

Pathfinder program, the Congress needs to assure itself that NASA has

adequately demonstrated that the potential value of Pathfinder

7

The cost estimate is for the total mission, including satellite development and launch.

Page 3 GAO/NSIAD-96-97 Earth Observing System
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investigations will exceed the potential value of additional EOS

investigations that could be obtained with the same resources.

NASA’s principal investigators for interdisciplinary earth system science

affirmed in a 1992-93 program review that changes to EOS following the

1992 budgetary reductions would not seriously weaken their ability to

conduct interdisciplinary research. They reaffirmed their view in 1995,

despite further budgetary reductions and other changes in the program.

NASA’s Strategy for

Developing EOS’

Basic Research

Community

Like EOS-related space systems and information systems, the development

of the EOS basic research community that will conduct interdisciplinary

global climate change research requires planning. The current number of

EOS investigations funded by NASA is relatively small, and NASA recognizes

that it needs to increase their number, broaden the membership of EOS

science teams, and take other steps to develop and sustain an EOS-era

research community. NASA’s strategy for developing the EOS research

community is partly based on increased funding.8

 In 1995, it began efforts

to fund additional investigations and to reevaluate the current

investigations. NASA’s ability to add more investigations is uncertain within

its expected future budgets, especially if it must depend on savings from

improved technology and increased collaboration with others.

Current Number of EOS

Investigations Is Relatively

Small

The EOS program is currently funding 29 interdisciplinary science

investigations that were selected in 1989 and 1990 to use data from EOS

instruments in more than one earth science discipline, such as geology,

oceanography, meteorology, and climatology. Scientists associated with

these investigations serve as members of the Investigator Working Group,

developing detailed science plans and assisting NASA in optimizing the

scientific return of the EOS mission.9

 Currently, these 29 investigations are

led by 31 interdisciplinary principal investigators (2 of the interdisciplinary

science investigations have coprincipal investigators). There are 354

coinvestigators associated with the 29 interdisciplinary science

investigations, as well as 20 instrument principal investigators/team

leaders and 197 other instrument team members.

8

Another element of this strategy relates to the effectiveness and cost-efficiency of the EOS data and

information system. See Earth Observing System: Concentration on Near-Term EOSDIS Development

May Jeopardize Long-Term Success (GAO/T-AIMD-95-103, Mar. 16, 1995).

9

NASA is wholly or partly funding 22 of these investigations, and its international partners are 

funding 7.

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The number of EOS investigations is relatively small when compared with

(1) the number of currently funded investigations associated with two

pre-EOS missions—the Upper Atmosphere Research Satellite (UARS) and

the U.S.-French Oceanography Satellite Ocean Topography Experiment

(TOPEX/Poseidon)—to their EOS-era counterparts and (2) the ratio of the

number of investigations to the raw data acquisition rate expected from

instruments on EOS spacecraft to the number of investigations and raw

data acquisition rates of UARS and TOPEX.

The comparison is based on the following EOS spacecraft and instruments:

AM; PM; Chemistry mission (CHEM); Landsat-7; Radar ALT; Laser ALT;

Stratospheric Aerosol and Gas Experiment (SAGE) III on space station; and

Solar Stellar Irradiance Comparison Experiment (SOLSTICE), Active Cavity

Radiometer Irradiance Monitor (ACRIM), and Clouds and Earth’s Radiant

Energy System (CERES) on flights of opportunity. The data rates of the EOS

spacecraft and UARS/TOPEX are not strictly comparable because the

instruments on the latter satellites do not directly observe the Earth.

Imaging instruments are more data intensive than nonimaging

instruments. However, data rate comparisons can serve as a rough

indicator of the magnitude of potential research opportunities afforded by

EOS and two pre-EOS-era missions. The National Aeronautics and Space

Administration (NASA) used similar comparisons in its 1993 and 1995

editions of the EOS reference handbook. In the 1995 edition, NASA

graphically compared the combined data rates of EOS-era satellites with

the combined data rates of numerous pre-EOS-era (including UARS and

TOPEX) and foreign satellites to demonstrate that the magnitude of

potential research opportunities for EOS is much greater than for other

combinations of Earth-sensing satellites. In its handbooks, NASA depicted

the data streams flowing from the two groups of satellites to “10,000 users”

in the 1993 edition and a more vaguely defined “user community” in the

1995 edition. In place of the broadly defined “users” and user community,

we used the actual number of currently funded EOS, UARS, and TOPEX

investigations to illustrate (1) that the magnitude of potential EOS basic

research opportunities is much greater than those afforded by UARS and

TOPEX (as indicated by their respective data rates) and (2) that the number

of currently funded EOS investigations is small compared to the number of

currently funded UARS and TOPEX investigations.

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UARS, launched in September 1991, consists of 10 instruments that are

measuring the composition and temperature of the upper atmosphere,

atmospheric winds, and energy from the sun.10 The UARS science

investigations are led by 22 teams. NASA broadened the UARS science

investigations in 1994 by selecting 40 additional teams led by “guest”

investigators. It is also funding correlative measurement investigations led

by 38 teams to develop an independent database to validate and

complement measurements made by UARS’ instruments.11 In the EOS era,

solar energy and atmospheric chemistry measurements will be made

principally by the ACRIM, SAGE, and SOLSTICE instruments and the CHEM

spacecraft.12 Currently, only 12 instrument and interdisciplinary science

investigations are associated with these instruments and the CHEM

spacecraft. In contrast, UARS supports research conducted by 

62 instrument and science teams.13

TOPEX was launched in August 1992 to study the circulation of the world’s

oceans. The primary instrument is an altimeter that measures the height of

the satellite above the ocean, wind speed, and wave height. NASA and its

French partner, Centre National d’Etudes Spatiales, selected 38 science

investigations. The 38 TOPEX-related science teams have about 200

members, and NASA plans to solicit additional investigations.14 In the EOS

era, the follow-on mission to TOPEX is Radar-ALT. An instrument team has

not yet been selected, but only 7 of the 29 interdisciplinary science

investigations currently plan to use Radar-ALT data.

There is a large difference between the number of (1) currently funded EOS

investigations and the expected volume of data from EOS and (2) the

currently funded UARS and TOPEX investigations and volume of data of these

10The atmosphere is divided into layers based on temperature. In the bottom layer, or troposphere,

temperatures decrease with height to about 10 km. The upper atmosphere consists of the stratosphere

(about 10 km to 45 km), where temperatures are constant and then slowly rise with height; the

mesosphere (about 50 to 80 km), where temperatures again decrease with height; and the

thermosphere (no well-defined upper limit), where temperatures again increase with height.

11According to the administration’s fiscal year 1996 budget submission, funding for UARS’ operations

and data analysis will cease in fiscal year 1998.

12ACRIM (1998) monitors the variability of total solar irradiance; SAGE (1998) provides profiles of

aerosols, ozone, and trace gases in the atmosphere; SOLSTICE (2002) measures full disk solar

ultraviolet irradiance; and instruments on the CHEM spacecraft (2002) measure, in part, tropospheric

ozone. Dates are for the first flight of each instrument in the EOS era.

13For this comparison, the number of UARS science investigations includes 22 instrument and

theoretical science investigations, and 40 guest science investigations. It does not include the

correlative measurement investigations because the 38 teams associated with them were required to

develop an independent database and did not have access to UARS-related data.

14According to the administration’s fiscal year 1996 budget submission, funding for TOPEX’ operations

and data analysis will cease in fiscal year 1999.

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two pre-EOS missions.15 The combined number of the UARS and TOPEX

science investigations is a little larger than the current number of EOS

investigations, even though EOS’ data rate (our indicator of the magnitude

of potential research opportunities) is close to 1,000 times greater than the

combined data rate of UARS and TOPEX. EOS will provide up to 42 million bits

of data per second to 49 interdisciplinary science and instrument

investigations.16 The corresponding ratio for UARS and TOPEX is a total of

48 thousand bits of data per second to 60 investigations.17

NASA’s Strategy to Expand

EOS Research Community

The National Research Council’s Board on Sustainable Development

reviewed the U.S. Global Change Research Program, Mission to Planet

Earth, and EOS in 1995 and stated that one of the “fundamental guiding

principles” of the U.S. Global Change Research Program is an “open and

accessible program” that will “encourage broad participation” by the

government, academic, and private sectors.18 Some NASA officials and EOS

investigators are concerned that the Earth sciences research community

perceives EOS’ science teams as a “closed shop,” whereby membership on

a current team is a precondition for conducting future EOS-related

research.

To counter this perception, NASA’s current strategy to expand the EOS

research community involves (1) an open data access policy and

(2) efforts to broaden and change the current community by adding

investigations, reevaluating the current science investigations, and

recruiting new investigators.

EOS Data Policy A vital part of the EOS data policy is that EOS data will be available to

everyone: there will be no period of exclusive access for funded

investigators. This has not always been NASA’s policy. On some past Earth

15In commenting on a draft of this report, NASA provided information on data rates and data analysis

and on its ongoing and planned efforts to prepare EOS investigators for handling large amounts of data

and providing them with the tools for doing so. (See app. V.)

16“Bit,” contracted from the term “binary digit,” is a unit of information represented by either a zero or

a one. A byte is a group of eight adjacent bits operated on as a unit and is equivalent to one character

in a text file, such as the letter “a.”

17We did not include 40 UARS guest investigations for this comparison because they were selected

after UARS was launched and thus are not comparable to the current number of EOS interdisciplinary

science and instrument investigations.

18A Review of the U.S. Global Change Research Program and NASA’s Mission to Planet Earth/Earth

Observing System National Academy Press (Washington, D.C., 1995), p. 8.

Page 7 GAO/NSIAD-96-97 Earth Observing System
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observing missions, funded investigators had exclusive use of the data for

an extended period of time. For example, the original investigators

associated with the Upper Atmosphere Research Satellite had exclusive

access to the first year’s data for up to 2 years. EOS data users as a rule will

not be charged more than the cost of distributing data to them. The data

policy contemplates a variety of potential user groups, not all of whom will

be engaged in basic research. In 1995, NASA sponsored a conference to

better define the user groups. The conferees identified 12 potential user

groups, of which only 3 were primarily composed of scientists. The others

included commercial users, resource planners, and educational groups.

NASA officials stated that about 10,000 Earth scientists might use

EOS-related data.19 Even with the large size of this potential research

community and the open-access data policy, the sufficiency of EOS

investigations might appear to be the least of NASA’s problems. Even

though 10,000 Earth scientists may be potential users of EOS data, they still

need to be funded to conduct basic research. According to NASA officials,

as a general rule, for this type of work, scientists analyze data when they

are paid to do so.

We sought to confirm this observation by reviewing the authorship of 

172 journal articles about 2 pre-EOS-era satellites—UARS and

TOPEX/Poseidon. Our review showed that publicly funded investigators

wrote all but 10 of the articles. We reviewed the authorship of UARS and

TOPEX articles published in scientific journals from the approximate dates

of launch through May 1995; these articles were selected from a database

consisting of about 4,500 periodicals.20 The principal investigators wrote

123 (72 percent) of the 172 articles. In addition, we identified two other

kinds of investigators probably associated with the principal investigators

and/or government funded—that is, investigators associated with the

principal investigator’s institution (most often a university or government

agency) or another government agency. These “associate” investigators

wrote 39 (23 percent) of the journal articles.

Not all people who get Earth sciences data use it to do basic research. For

example, from January through May 1995, NASA’s Jet Propulsion

Laboratory sent 55,521 TOPEX-related data files to 28,495 requesters

through the Internet. This figure does not necessarily represent separate

requesters. The laboratory does not know how these requesters use TOPEX

19In 1994, a NASA contractor estimated the relevant U.S. science community to be between 6,100 and

11,600. See app. V for NASA’s comments on the potential total EOS user community.

20For example, see the Journal of Atmospheric Sciences (Oct. 15, 1994) and the Journal of Geophysical

Research (Dec. 15, 1994) for papers on UARS and TOPEX-related science, respectively.

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data, but according to a laboratory official, data accessed through the

Internet is generally not sufficient for doing basic research. Investigators

want less processed data for this type of research.

Adding Investigations NASA originally solicited proposals for EOS interdisciplinary science and

instrument investigations in January 1988. The solicitation noted that NASA

planned to fund 10 to 20 science investigations, with other selections

possible before the launch of the first EOS platform, then scheduled for late

1995. NASA received 458 proposals in response to its solicitation, including

about 250 for interdisciplinary science investigations. As previously noted,

29 interdisciplinary science and 20 instrument investigations are being

funded by NASA and its international partners.21 The lifetime of the science

investigations was to extend for 4 years beyond the launch of the first

satellite, or until 1999. In other words, NASA intended to add to this first

group of investigations over a 10-year period (1989 to 1999). However, at a

minimum, the lifetime of this first group of investigations has been

extended to 13 years (1989 to 2002, including 4 years beyond AM-1’s 1998

launch date).

NASA’s plan to supplement the first group of science investigations with a

second group within 6 years was not too optimistic given its funding

expectations at that time. NASA’s EOS mission planning (1982-87) took place

during a time of expanding resources. During the 1980s, NASA’s funding

increased each year, essentially doubling from about $5 billion to

$10 billion between fiscal years 1981 and 1989.22

NASA has recognized that more EOS investigations are needed, and last year

it took a first step to add more. NASA solicited proposals in September 1995

to address, among other things, specific interdisciplinary science issues

that are not well covered by existing NASA-funded investigations.23 It

received 134 interdisciplinary science proposals and hopes to add 20 to

25 investigations with grants of about $250,000 to $400,000 per year for a

period of up to 3 years.

21See app. IV for information on the interdisciplinary science investigations.

22Taking the effects of inflation into account, NASA’s funding increased by about 48 percent during this

period. Both current and constant dollar amounts are from our report on Space Funding: NASA and

DOD Activities for Fiscal Years 1981 Through 1989 (GAO/NSIAD-89-102FS, Mar. 23, 1989).

23The solicitation asked for 5 types of proposals: Landsat investigations, EOS instrument

investigations, interdisciplinary Earth system science investigations, new investigators’ investigations,

and science education grant supplements. NASA received 336 proposals in response to the solicitation

of which at least 12 were not considered responsive to the announcement. NASA stated in the

solicitation that it intended to select from 57 to 74 investigations in the 5 areas of consideration.

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NASA is funding the interdisciplinary science part of the September 1995

solicitation with a $9-million “funding wedge” created, in part, from

reductions in the previously planned funding levels for some existing EOS

investigations. According to a NASA official, no new money will be used to

fund these investigators. It remains to be seen if NASA’s ability to generate

future savings in the program will become a major factor in increasing the

number of EOS investigations.

Although potentially useful over the longer term, these grants will not

immediately increase the number of EOS investigations in the near term

because the announcement largely precludes investigators from analyzing

data from the first EOS mission, AM-1, which is now scheduled for launch

in 1998. Instead, NASA is asking for proposals on interdisciplinary research

that primarily uses existing data sets from past satellite missions and field

experiments.24

Reevaluating Investigations The nature and membership of the EOS science teams has largely remained

unchanged for 6 years. According to NASA officials, this longevity has

created a perception among some Earth scientists that currently funded

investigators constitute a “closed shop.” NASA attempted to correct this

perception by conducting an internal program review in 1992 and 1993 and

an external peer review in 1995 and 1996. The review by EOS investigators’

peers in the Earth sciences research community is not yet finished, but it

could lead to the possible deselection and recompetition of some EOS

interdisciplinary science teams. NASA opted for the peer review, rather than

have all the current investigations reevaluated as part of a new solicitation

for proposals.

NASA’s 1992-93 program review found weaknesses in many

interdisciplinary science teams. The reviewers generally found that only

30 percent of 23 investigations could be rated “successful” in terms of

science-related assessment measures. They also noted that “most teams

need work in documenting their scientific progress, plans, and the policy

relevance of their research to the Earth Science community, as well as to

NASA.”

The reviewers specifically noted that

• 67 percent (of 24 teams) had poor management plans,

• 61 percent (of 23 teams) had a less than satisfactory publication record,

and

24The solicitation described five interdisciplinary research issues, one of which is the implications of

continued global expansion of urbanization and high-input agriculture for the environment.

Page 10 GAO/NSIAD-96-97 Earth Observing System
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• 57 percent (of 23 teams) needed to improve their contacts with the EOS

instrument teams.

The review concluded that “for most teams, the biggest factor hindering

their success is their lack of a good management plan—teams that do not

have their own house in order will not benefit from increased

collaborations” with other interdisciplinary and instrument teams.

In October 1994, the Science Executive Committee of the EOS Investigator

Working Group endorsed the need for a peer review and possible turnover

of teams, if this would enhance the quality of EOS investigations. The

Committee, however, rejected the idea that the existing investigations

should be evaluated through a new competition. It noted that a new

competition could cause a loss of credibility with EOS supporters and that

many interdisciplinary science teams had committed themselves “far

beyond” just their science tasks.

In contrast, NASA struck a different balance between continuity and change

in the pre-EOS-era U.S.-Japan Tropical Rainfall Measuring Mission. The goal

of the spacecraft’s three principal instruments is to measure rainfall more

accurately than before, particularly over the tropical oceans.25 The science

of a long-term investigatory group was reevaluated after 3 years by holding

a new funding competition for this program. NASA and Japan’s National

Space Development Agency first solicited research proposals in 1990 for a

possible launch in 1994. Both agencies selected a total of 35 investigators.

The two space agencies in October 1993 again solicited research proposals

for a launch now scheduled for 1997. The space agencies selected 27 of the

original investigators and added 12 new investigators to the science team.

Recruiting New Investigators The long-term growth of the EOS research community depends, in part, on

NASA’s ability to recruit graduate students and newly graduated Earth

scientists to use remotely sensed data. NASA supports prospective

researchers in the Earth sciences through the graduate student Global

Change Fellowship program. Successful candidates can be funded for up

to 3 years, at $20,000 per year, primarily for tuition support and living

expenses. NASA supported 112 fellowships for the 1993-94 academic year.

In September 1995, NASA also established a new investigator program as

part of Mission to Planet Earth and solicited proposals for 10 to 15

25The spacecraft also carries two EOS-funded instruments: Lightning Imaging Sensor and the Clouds

and the Earth’s Radiant Energy System (CERES). CERES will measure Earth’s radiation budget and

atmospheric radiation from the top of the atmosphere to the surface. CERES is scheduled to fly on

several EOS-era spacecraft. In September 1995, NASA announced that it intends to add two new

members to the mission’s science team. NASA received eight proposals in response to this solicitation.

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interdisciplinary investigations from recent Ph.D. recipients. The proposed

investigations must be based on data from existing satellite missions. NASA

received 65 proposals in response to this solicitation.

Most EOS

Interdisciplinary

Scientists Say Their

Planned Work Is Not

Severely Affected by

Budgetary Turbulence

Scientists associated with EOS stated in 1994, following the program’s

proposed reduction to $7.25 billion, that

while some of the multi-year reductions may be accomplished without serious effect on the

program, it must be stated that the achievement of several essential elements (e.g.,

continuity of observations for 15 years) of the program are now at significantly greater risk.

Despite this apprehension, most interdisciplinary science investigators

have experienced or expect little or no effect of budgetary turbulence on

their own research. In the 1992-93 program review, NASA’s investigators

were generally optimistic that they could withstand EOS’ continuing

budgetary turbulence. In 1995, investigators reaffirmed this optimism.

Investigators’ Perception

of Program Changes in

1992 and 1993

As part of the 1992-93 program review, NASA asked EOS’ interdisciplinary

science principal investigators to evaluate the effect changes to EOS would

have on their work. The reviewers classified the 23 responding

investigators’ remarks as follows:

• no effect (11 investigators, 48 percent);

• minor effect (8 investigators, 35 percent); and

• major effect (4 investigators, 17 percent).

The program review followed the cancellation of three major EOS

instruments over several years: Laser Atmospheric Wind Sounder

(observation of lower atmospheric winds); High-Resolution Imaging

Spectrometer (identification of surface composition); and Synthetic

Aperture Radar (high-resolution global measurements of the Earth’s

surface). Whether scientists planned to use a canceled instrument was a

major part of how they perceived the impact on their work.

Some investigators also cited changes to their ongoing research resulting

from little or no growth in most of their fiscal year 1994 budgets.

According to a NASA official, only seven investigations received as much as

a 10-percent increase in their 1994 budget above the amount for fiscal year

1992. One investigator, citing a flat budget for 1994, said that as a result,

coinvestigators could not give full attention to EOS-related research and

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that it was “difficult for us to contemplate an accelerated or broadened

attack on the global change problems we are addressing.” Another

investigator noted that such a budget meant that “some research tasks

have to be trimmed” and would not “allow much flexibility in terms of new

ideas and initiatives.”

Investigators’ Perception

of Program Changes in

1995

In 1995, NASA again asked the interdisciplinary science principal

investigators to assess how changes over the previous 3 years to the EOS

program had affected their future and ongoing research. The scientists

cited the same mix of concerns as they had previously—namely, the loss

of several instruments and lack of growth in their funding. One

investigator noted that a 20-percent budget reduction in 1994 “decimated

our attempts to carry out field studies in collaboration with [international]

team members.” His view, however, was unique. Most investigators

reported that the changes had so far created only relatively minor

problems that could be adequately resolved.

A NASA official told us that a reason for investigators’ optimism is that NASA

officials consciously tried to minimize the impact of budget reductions on

EOS-related science.

New Earth System

Science Pathfinder

Program: Implications

for EOS Science

Funding

Starting in 1996, NASA plans to solicit additional Earth science research

through a new Earth System Science Pathfinder program. This effort will

be based on data sets collected by new satellite missions. According to

NASA officials, the Pathfinder program is intended to develop quick

turnaround, low-cost space missions for high priority Earth sciences

research not being addressed by current programs, including EOS, thus

providing an opportunity to accommodate new science priorities and to

increase scientific participation in Mission to Planet Earth.

The administration is requesting $20 million for Pathfinder in fiscal year

1997 and plans to request $30 million, $75 million, and $75 million for fiscal

years 1998, 1999, and 2000, respectively—a total of $200 million over the

next 4 fiscal years. After then, NASA plans to offset Pathfinder’s funding

requirements with reductions generated from the introduction of lower

cost technology into future Mission to Planet Earth-related research.

Pathfinder’s goal is to launch one mission every year, starting in 1999. NASA

estimates the life-cycle cost of each mission would not exceed

$120 million and would include the cost of the launch vehicle, civil service

Page 13 GAO/NSIAD-96-97 Earth Observing System
B-271690 

labor, investigator support, and 2 years of spacecraft operations.26

However, NASA has not demonstrated that the potential value of

Pathfinder’s science would exceed the potential value of additional

EOS-related science, if savings allocated to Pathfinder were allocated to EOS

science.

Agency Comments

and Our Evaluation

NASA criticized our analysis and conclusions. NASA stated that our draft

report underestimated the size of the EOS research community and the

abilities of EOS investigators to process the large amount of data expected

from EOS. We do not agree with NASA’ s description of our report’s focus

and scope. Our objective was not to estimate the size of the EOS research

or broader user communities, or to assess the abilities of current

researchers to handle the large amount of data expected from EOS. Rather,

our objective was to assess NASA’s plans for developing its basic research

community, with specific focus on the number of currently funded EOS

investigations. This issue is the basis for the majority of NASA’s concerns.

To address NASA’s point, we revised our final report to clarify the specific

focus and scope of our work.

NASA said that our analysis of the number of EOS investigations did not

consider the broader user community. Although NASA’s statement is

correct, it was not the objective of our work to analyze the broader user

community. We focused on comparing the number of NASA’s currently

funded EOS-related investigations with the number of funded investigations

associated with two pre-EOS-era missions. This comparison constituted our

analytic framework and formed the basis of our conclusion that the

magnitude of potential basic research opportunities afforded by EOS is

much greater than those afforded by UARS and TOPEX, but the number of

currently funded EOS investigations is relatively small compared to the

number of investigations funded under the two pre-EOS-era missions. Our

conclusion is consistent with NASA’s desire, as expressed in its comments

on our draft report, “to expand the size of the direct EOS community,” and

its actions during the course of our review to increase the number of EOS

investigations in a budget-constrained environment.

NASA’s comments also addressed our concern about its ability to increase

the number of EOS investigations based on savings from EOS and other

parts of Mission to Planet Earth. NASA stated that it has already made

changes to lower EOS’ costs and that it will be able to decrease costs

26Each Pathfinder mission would have a principal investigator and a limited number of guest

investigators. Considering satellite development and launch costs, only a small portion of each

mission’s funding would be available to pay for data analysis.

Page 14 GAO/NSIAD-96-97 Earth Observing System
B-271690 

further while improving overall capability and maintaining data continuity.

We have not evaluated NASA’s claims in this regard.

In our draft report, we recommended that the NASA Administrator provide

the Congress with an assessment of Pathfinder’s potential impact on

NASA’s strategy for Earth system science research, including a

determination that the potential value of Pathfinder’s investigations is

expected to exceed the potential value of additional EOS investigations.

NASA generally agreed with this recommendation, stating that it would

provide a strategic assessment of Pathfinder. NASA also said it planned to

proceed with the Pathfinder missions on the basis of already having

analyzed the tradeoffs and having had its approach validated by outside

review groups. The concern that prompted our recommendation in the

draft report was the availability of adequate funding for EOS basic research

given NASA’s funding strategy. That continues to be our concern and, in

view of NASA’s position, we are changing our recommendation to the NASA

Administrator to a matter for congressional consideration. Our purpose in

making this change is to alert the Congress to the need to address the EOS

funding issue before substantial funding commitments are made to the

new Pathfinder program.

NASA’s comments are in appendix V.

Matter for

Congressional

Consideration

In judging the extent to which it should support the proposed Earth

System Science Pathfinder program, the Congress may wish to have NASA

demonstrate that the potential value of Pathfinder investigations will

exceed the potential value of additional EOS investigations that could be

obtained with the same resources.

Scope and

Methodology

To accomplish our objectives, we obtained documents related to EOS’

science program from and interviewed officials at NASA headquarters in

Washington, D.C.; NASA’s Goddard Space Flight Center, Greenbelt,

Maryland; and at the Jet Propulsion Laboratory, Pasadena, California. We

attended the EOS Investigators Working Group meeting in June 1995 in

Santa Fe, New Mexico, and the Payload Panel meeting in November 1995

in Annapolis, Maryland.

In analyzing the development of the EOS research community, we reviewed

information on pre-EOS Earth science ground- and space-based research,

as well as EOS’ interdisciplinary science research. In analyzing the

Page 15 GAO/NSIAD-96-97 Earth Observing System
B-271690 

authorship of articles related to UARS and TOPEX/Poseidon, we used

“Scisearch,” an international, multidisciplinary index to science literature.

Scisearch indexes articles from approximately 4,500 scientific and

technical journals. We used the scientists’ progress reports for 1992 to

1993, and 1995 to assess whether changes to EOS have adversely affected

EOS’ interdisciplinary research.

We performed our work between February 1995 and February 1996 in

accordance with generally accepted government auditing standards.

As agreed with your office, unless you publicly announce its contents

earlier, we plan no further distribution of the report until 30 days from its

issue date. At that time, we will send copies to other appropriate

congressional committees; the NASA Administrator; and the Director, Office

of Management and Budget. We will also make copies available to other

interested parties upon request.

Please contact me on (202) 512-8412 if you or your staff have any

questions concerning this report. Major contributors to this report were

Brad Hathaway, Frank Degnan, Thomas Mills, Richard Eiserman, and

Richard Irving.

Sincerely yours,

David R. Warren

Director, Defense Management Issues

Page 16 GAO/NSIAD-96-97 Earth Observing System
Page 17 GAO/NSIAD-96-97 Earth Observing System
Contents

Letter 1

Appendix I 

Twenty-Four Earth

Observing System

Measurement Sets

20

Atmosphere Measurements 20

Solar Radiation Measurements 21

Land Measurements 22

Ocean Measurements 23

Cryosphere Measurements 23

Appendix II 

EOS Satellite

Missions, Instruments,

and Measurements

25

Appendix III 

EOS Instrument Flight

Schedule Through

2009

28

Appendix IV 

EOS Science

Objectives and

Interdisciplinary

Investigations

29

Appendix V 

Comments From the

National Aeronautics

and Space

Administration

35

GAO Comments 47

Tables Table II.1: EOS Instruments and Measurements 25

Table II.2: EOS Satellite Missions 27

Page 18 GAO/NSIAD-96-97 Earth Observing System
Contents

Abbreviations

ACRIM Active Cavity Radiometer Irradiance Monitor

CERES Clouds and Earth’s Radiant Energy System

CHEM Chemistry mission

EOS Earth Observing System

NASA National Aeronautics and Space Administration

SAGE Stratospheric Aerosol and Gas Experiment

SOLSTICE Solar Stellar Irradiance Comparison Experiment

TOPEX U.S.-French Oceanography Satellite Ocean Topography

Experiment

UARS Upper Atmosphere Research Satellite

Page 19 GAO/NSIAD-96-97 Earth Observing System
Appendix I 

Twenty-Four Earth Observing System

Measurement Sets

The National Aeronautics and Space Administration (NASA) considers the

following measurement sets to be critical to preserving the Earth system

science approach of the Earth Observing System (EOS) and important to

making environmental policy decisions. The information in appendixes

I-IV was derived from NASA sources.

Atmosphere

Measurements

Cloud Properties The formation, dissipation, and radiative properties of clouds influence the

atmosphere’s response to greenhouse forcing (i.e., mechanisms that

promote the greenhouse effect). The net effect of cloud forcing and

feedback determines the energy budget of Earth and its cozy temperature,

which supports life.

Radiative Energy Fluxes Earth’s radiation budget drives the biological and physical processes of

the atmosphere, land, and ocean, which in turn affect water resources,

agriculture, and food production.

Precipitation There is a net outflow of atmospheric moisture from the tropics to the

higher latitudes. This redistribution is accomplished through evaporation

and precipitation, which determine the freshwater resources for

agricultural and industrial development.

Tropospheric Chemistry Tropospheric chemistry is linked to the circulation of Earth’s water (the

“hydrologic cycle”), the ecosystem, and transformations of greenhouse

gases in the atmosphere, thus determining the oxidizing capacity of the

atmosphere for cleansing pollutants.

Stratospheric Chemistry Stratospheric chemistry measurements involve chemical reactions,

interactions between the sun and the atmosphere, and the sources and

sinks of gases, such as ozone, that are critical to Earth’s radiation balance.

Page 20 GAO/NSIAD-96-97 Earth Observing System
Appendix I 

Twenty-Four Earth Observing System

Measurement Sets

Aerosol Properties An aerosol is a fine solid or liquid particle suspended in gas, such as the

atmosphere. Aerosols affect the climate through their radiative properties

by serving as nuclei for the condensation of clouds. Aerosols tend to cool

Earth’s atmosphere, thus offsetting some of the warming effects of

greenhouse gases.

Atmospheric Temperature Along with atmospheric humidity, atmospheric temperature is used in

short-term weather prediction and long-term climate monitoring.

Improved measurement accuracy, precision, and spatial and temporal

coverage will enhance weather prediction skills beyond current limits and

reduce weather prediction “busts,” or failures.

Atmospheric Humidity See “Atmospheric Temperature.”

Lightning Lightning measurements will include the distribution and variability of

both cloud-to-cloud and cloud-to-ground lightning. Electrical discharge

contributes to the formation and dissipation of certain trace gases in the

atmosphere.

Solar Radiation

Measurements

Total Solar Irradiance Sustained changes in the total radiation output from the sun could

contribute to significant climate changes on Earth over time. Solar

radiation is the main source of energy for biological activities on Earth.

Ultraviolet Spectral

Irradiance

Out of the entire spectrum of radiation that Earth receives from the sun,

the ultraviolet portion is the dominant energy source for the Earth’s

atmosphere. Small changes in the radiation field have an important effect

on atmospheric temperature, chemistry, structure, and dynamics. Excess

ultraviolet energy on the Earth’s surface is harmful to living organisms.

Page 21 GAO/NSIAD-96-97 Earth Observing System
Appendix I 

Twenty-Four Earth Observing System

Measurement Sets

Land Measurements

Land Cover and Land Use

Change

Land use includes monitoring crops for efficient irrigation and pest

control, public lands for good stewardship, and urban areas for

development. Some changes in land use, such as deforestation and

biomass burning, reduce the standing stock of vegetation, release carbon

dioxide into the atmosphere, and reduce the capacity for the removal of

carbon dioxide from the atmosphere.

Vegetation Dynamics Terrestrial vegetation absorbs atmospheric carbon dioxide by

photosynthesis to offset its greenhouse warming effect.

Surface Temperature Terrestrial surface temperature controls the formation and distribution of

atmospheric water vapor and also contributes to the determination of

cloud amount. In addition, surface temperatures control the biological

activity and health of agricultural fields, forests, and other natural

ecosystems.

Fire Occurrence Biomass burning releases carbon dioxide into the atmosphere and also

increases concentrations of other harmful gases, such as carbon monoxide

and nitrogen oxides. Land cover monitoring can be used to assess

potential fire hazards and monitor fire recovery in natural ecosystems.

Volcanic Effects The volcanic ejection of aerosols and particulates into the atmosphere can

increase precipitation and ozone destruction and cause the lowering of

global temperatures. Volcanic activities also contribute to the formation of

continents.

Surface Wetness Surface wetness controls the availability of fresh water resources for

agricultural and industrial activities.

Page 22 GAO/NSIAD-96-97 Earth Observing System
Appendix I 

Twenty-Four Earth Observing System

Measurement Sets

Ocean Measurements

Surface Temperature Sea surface temperature measurements are important to understanding

heat exchange between the ocean and the atmosphere. Such an

understanding will contribute to the development of accurate general

circulation models, which enhance our understanding of seasonal and

interannual climate variations that contribute to hurricanes, floods, and

other natural hazards.

Phytoplankton and

Dissolved Organic Matter

Planktonic marine organisms and dissolved organic matter play a major

role in the carbon cycle, as they incorporate, or “fix,” about as much

carbon as land plants. This contributes to removing carbon dioxide from

the atmosphere and to offsetting the greenhouse effect.

Surface Wind Fields Surface winds over the oceans contribute to ocean circulation and the

interaction between the air and sea, which affect short-term and long-term

climate variations.

Ocean Surface Topography Sea height and ocean circulation are related. Ocean circulation transports

water, heat, salt, and chemicals around the planet. Accurate information

about these circulation patterns should contribute to understanding the

oceans’ impact on weather, climate, and marine life, and thus the fisheries

industry and other maritime commerce.

Cryosphere

Measurements

Ice Sheet Topography and

Ice Volume Change

Measurements of the polar ice caps, including ice sheet elevation and ice

volume, will determine the contribution of the ice sheets to sea-level

variation. These data will also contribute to understanding the role of the

polar ice caps in Earth’s freshwater and energy budgets, as well as climate

fluctuations.

Page 23 GAO/NSIAD-96-97 Earth Observing System
Appendix I 

Twenty-Four Earth Observing System

Measurement Sets

Sea Ice Measurements of the extent and thickness of sea ice will help determine

atmospheric warming. Sea ice measurements will also be useful to

operational ice forecasting centers, thus affecting maritime commerce.

Snow Cover Snow cover, extent, and duration determine fresh water resources,

especially in Alpine regions of the world.

Page 24 GAO/NSIAD-96-97 Earth Observing System
Appendix II 

EOS Satellite Missions, Instruments, and

Measurements

Table II.1: EOS Instruments and

Measurements Instrument Measurements

ACRIM Active Cavity Radiometer Irradiance Monitor (ACRIM)

monitors the variability of total solar irradiance.

AIRS Atmospheric Infrared Sounder (AIRS) measures

atmospheric temperature and humidity.

AMSR

(Japan)

Advanced Microwave Scanning Radiometer (AMSR)

observes atmospheric and oceanic water vapor profiles

and determines precipitation, water vapor distribution,

cloud water, sea surface temperature, sea ice, and sea

surface wind speed.

AMSU Advanced Microwave Sounding Unit (AMSU) measures

atmospheric temperature.

ASTER

(Japan)

Advanced Spaceborne Thermal Emission and Reflection

Radiometer (ASTER) provides high spatial resolution

images of the land surface, water, ice, and clouds.

CERES Clouds and the Earth’s Radiant Energy System (CERES)

measures Earth’s radiation budget and atmospheric

radiation.

DFA

(France)

Dual Frequency Altimeter (DFA) maps the topography of

the sea surface and its impact on ocean circulation.

EOSP Earth Observing Scanning Polarimeter (EOSP) globally

maps radiance and linear polarization of reflected and

scattered sunlight to measure atmospheric aerosols.

ETM+ Enhanced Thematic Mapper Plus (ETM+) provides high

spatial resolution images of the land surface, water, ice,

and clouds.

GLAS Geoscience Laser Altimeter System (GLAS) measures ice

sheet topography, cloud heights, and aerosol vertical

structure.

HIRDLS

(UK-US)

High-Resolution Dynamics Limb Sounder (HIRDLS)

observes gases and aerosols in the troposphere,

stratosphere, and mesosphere to assess their role in the

global climate system.

LATI Landsat Advanced Technology Instrument (LATI)

provides high spatial resolution images of the land

surface, water, ice, and clouds beyond Landsat ETM+.

LIS Lightning Imaging Sensor (LIS) measures the distribution

and variability of lightning.

MHS Microwave Humidity Sounder (MHS) provides

atmospheric water vapor profiles.

MISR Multi-Angle Imaging Spectroradiometer (MISR) measures

the top-of-the-atmosphere, cloud, and surface angular

reflectance.

MLS Microwave Limb Sounder (MLS) measures chemistry from

the upper troposphere to the lower thermosphere.

(continued)

Page 25 GAO/NSIAD-96-97 Earth Observing System
Appendix II 

EOS Satellite Missions, Instruments, and

Measurements

Instrument Measurements

MODIS Moderate-Resolution Imaging Spectroradiometer

(MODIS) studies biological and physical processes in the

atmosphere, the oceans, and on land.

MOPITT

(Canada)

Measurements of Pollution in the Troposphere (MOPITT)

measures upwelling radiance to produce tropospheric

carbon monoxide profiles and total column methane.

MR Microwave Radiometer (MR) provides atmospheric water

vapor measurements for DFA.

ODUS

(Japan)

Ozone Dynamics Ultraviolet Spectrometer (ODUS)

measures total column ozone.

SAGE III Stratospheric Aerosol and Gas Experiment III (SAGE III)

provides profiles of aerosols, ozone, and trace gases in

the mesosphere, stratosphere, and troposphere.

SeaWinds Provides all-weather measurements of ocean surface

wind speed and direction.

SOLSTICE Solar Stellar Irradiance Comparison Experiment

(SOLSTICE) measures full-disk solar ultraviolet irradiance.

TES Tropospheric Emission Spectrometer (TES) provides

profiles of all infrared active species from Earth’s surface

to the lower stratosphere.

Page 26 GAO/NSIAD-96-97 Earth Observing System
Appendix II 

EOS Satellite Missions, Instruments, and

Measurements

Table II.2: EOS Satellite Missions

Satellite Description

Landsat-7

ETM+

Mission continues Landsat land-imaging satellite series.

Future Landsat-type instrument is planned for AM-2 and

AM-3.

AM

ASTER

CERES

EOSP

LATI

MISR

MODIS

MOPITT

Morning equator-crossing mission (AM series) will study

clouds, aerosols, and radiation balance; the terrestrial

ecosystem; land use; soils; terrestrial energy/moisture;

tropospheric chemical composition; volcanoes; and

ocean productivity. ASTER and MOPITT will be on AM-1

only. EOSP and LATI will be on AM-2 and AM-3 only.

PM

AIRS

AMSR

AMSU

CERES

MHS

MODIS

Afternoon equator-crossing mission (PM series) will study

cloud formation, precipitation, and radiative properties;

air-sea fluxes of energy and moisture; sea-ice extent; and

ocean primary productivity. The PM series will carry

prototypes of future operational weather satellite

instruments.

CHEM

HIRDLS

MLS

ODUS

TES

Chemistry mission (CHEM series) will study atmospheric

chemical composition; chemistry-climate interactions; and

air-sea exchange of chemicals and energy. ODUS will be

on CHEM-1 only. A later CHEM flight may include 

SAGE III.

LaserALT

GLAS

Laser altimeter mission (LaserALT series) will study ice

sheet mass balance.

RadarALT

DFA

MR

Radar altimeter mission (RadarALT series) will study

ocean circulation. RadarALT is a joint mission with France.

ISS, Meteor, and Flight of

Opportunity

SAGE III

SAGE III instrument carried on International Space Station

(ISS) and Russian Meteor satellite will study distribution of

aerosols, ozone profiles, and greenhouse gases in the

lower stratosphere.

TRMM

CERES

LIS

Tropical Rainfall Measuring Mission (TRMM) will study

precipitation and Earth radiation budget in the tropics and

high latitudes. TRMM is a joint mission with Japan.

ADEOS-II

SeaWinds

Japanese Advanced Earth Observing System II

(ADEOS II) satellite carrying NASA scatterometer

instrument will study ocean surface wind vectors.

ACRIM

ACRIM

Mission will monitor the variability of total solar irradiance

and is currently planned to fly on a series of small

satellites.

Flight of Opportunity

CERES

Mission will study Earth’s radiation budget and

atmospheric radiation.

Flight of Opportunity

SOLSTICE

Mission will study full-disk solar ultraviolet irradiance.

Page 27 GAO/NSIAD-96-97 Earth Observing System
Appendix III 

EOS Instrument Flight Schedule Through

2009

Timeline bars denote periods during which at least one copy of the indicated instrument is in orbit.

ACRIM

AIRS


MR

AMSU

ASTER

CERES

DFA

EOSP

ETM+

GLAS

HIRDLS

LATI

LIS

MHS

MISR

MLS

MODIS

MOPITT

ODUS


SAGE III

TES

EOS


Instrument 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

SeaWinds

SOLSTICE

AMSR

Page 28 GAO/NSIAD-96-97 Earth Observing System
Appendix IV 

EOS Science Objectives and

Interdisciplinary Investigations

EOS science objectives are listed below, along with the interdisciplinary

investigations designed to address them. These investigations are intended

to cross discipline boundaries, and therefore, address more than one

science objective.

The Water and Energy Cycles objective covers the formation,

dissipation, and radiative properties of clouds, which influence the

atmosphere’s response to greenhouse forcing. In addition, Water and

Energy Cycles include large-scale hydrology and moisture processes, such

as precipitation and evaporation.

• National Center for Atmospheric Research Project to Interface Modeling

on Global and Regional Scales With EOS Observations. This investigation is

intended to use surface and atmospheric data sources to improve climate

models and their predictions of global change. Components of climate

models to be addressed include surface-atmosphere interactions, the

hydrologic cycle, global energy balance, cloud and aerosol radiative fields,

and atmospheric chemical cycles.

• Climate Processes Over the Oceans. Climate is strongly influenced by the

amount and distribution of water vapor, liquid water, and ice suspended in

the atmosphere. This atmospheric water, and the climate over land areas,

is largely controlled by processes occurring over the oceans. This

investigation will improve modeling of both the atmosphere and its

interactions with the ocean. It will address the roles of circulation, clouds,

radiation, water vapor, and precipitation in climate change as well as the

role of ocean-atmosphere interactions in the energy and water cycles.

• Hydrologic Processes and Climate Interdisciplinary Investigation. The

global water and energy cycles link the atmosphere, land, and ocean. In

addition, water supports life and plays a crucial role in climate regulation.

This investigation is to enhance our understanding of the physical

processes that affect these cycles.

• The Processing, Evaluation, and Impact on Numerical Weather Prediction

of AIRS, AMSU, and MODIS Data in the Tropics and Southern Hemisphere.

This investigation involves the development of algorithms and techniques

to improve atmospheric science, specifically numerical weather prediction

models, using three EOS instruments.

• Investigation of the Atmosphere-Ocean-Land System Related to Climate

Processes. The atmosphere, ocean, and land interact with each other

through the exchanges of heat energy, momentum, and water substance.

These interactions influence climate. This investigation will examine the

atmosphere-ocean-land system by pursuing seven supporting studies that

will involve both observations and modeling.

Page 29 GAO/NSIAD-96-97 Earth Observing System
Appendix IV 

EOS Science Objectives and

Interdisciplinary Investigations

• The Development and Use of a Four-Dimensional

Atmospheric-Ocean-Land Data Assimilation System for EOS. This

investigation will incorporate all available data, from a variety of sources,

into a single model of the Earth system. This model can then be used to

project the Earth system beyond the range of actual observations, estimate

expected values of observations to assess instrument quality, provide

products for environmental studies, and supplement observations by

estimating quantities that are difficult or impossible to observe.

• An Interdisciplinary Investigation of Clouds and the Earth’s Radiant

Energy System: Analysis. This investigation will examine the role of clouds

and radiative energy balance in the climate system. Studies include cloud

feedback mechanisms that can greatly modify the response of the climate

system to increased greenhouse gases.

The Oceans objective covers the exchange of energy, water, and

chemicals between the ocean and atmosphere, and between the upper

layers of the ocean and the deep ocean.

• Coupled Atmosphere-Ocean Processes and Primary Production in the

Southern Oceans. The southern ocean plays an important role in both the

carbon cycle and heat exchange between the ocean and atmosphere. This

investigation will focus on developing predictive models so we can better

understand the effects of changes in the physical forcing of the ocean 

(e.g., small shifts in the location of westerly wind systems may affect

ocean processes).

• Biogeochemical Fluxes at the Ocean/Atmosphere Interface. Solar

radiation impinging on the oceans creates chemical, physical, and

biological effects. One result is the creation of gases, such as carbon

dioxide, dimethyl-sulfide, and carbon monoxide, which are then circulated

by wind and water. This investigation will develop models to better

understand these gases and the influence of oceanic processes upon them.

• Interdisciplinary Studies of the Relationships Between Climate, Ocean

Circulation, Biological Processes, and Renewable Marine Resources. This

investigation will study (1) the ocean’s role in climate change, particularly

in the Australian region; (2) the influence of the carbon cycle in Australia’s

waters on the global carbon cycle; and (3) changes in Australian

oceanography and the implications for marine ecosystems, including

commercial fisheries.

• The Role of Air-Sea Exchanges and Ocean Circulation in Climate

Variability. Exchanges of water, momentum, and heat at the interface of

the ocean and atmosphere drive the transport and change the storage of

heat, water, and greenhouse gases, thus moderating the world’s climate.

Page 30 GAO/NSIAD-96-97 Earth Observing System
Appendix IV 

EOS Science Objectives and

Interdisciplinary Investigations

This investigation will study these exchanges and ocean circulation in

order to improve our understanding of natural global changes and enable

us to discern human-induced effects.

• Polar Exchange at the Sea Surface: the Interaction of Ocean, Ice, and

Atmosphere. This is an investigation of energy exchanges in Earth’s polar

regions, both at the atmosphere-ice-ocean interface and lower latitudes. It

will study the role these processes play in global oceanic and atmospheric

circulation and help improve our understanding of whether polar regions

show any sign of climate change.

• Middle and High Latitude Oceanic Variability Study. This investigation will

examine the variability of the atmosphere’s influence on the oceans, the

effect on the oceanic response, and the resulting effect on biological

productivity in the oceans. The study will focus on the mid- to

high-latitude regions of the oceans. It will examine changes in the surface

fluxes of momentum, heat, water, and radiation, as well as the variability

of ocean circulation and biological activity.

• Earth System Dynamics: the Determination and Interpretation of the

Global Angular Momentum Budget Using EOS. Momentum and mass

transport among the atmosphere, oceans, and solid Earth produce changes

in the planet’s rotation and gravity field. Predictions of these changes

based on the mass and motion of air and water can be compared with

observations to improve models of the interactions of the oceans,

atmosphere, and solid Earth. This investigation will examine these

interactions as represented by the exchange of angular momentum, mass,

and energy among these components.

The Chemistry of the Troposphere and Lower Stratosphere objective

includes links to the hydrologic cycle and ecosystems, transformations of

greenhouse gases in the atmosphere, and interactions inducing climate

change.

• Interannual Variability of the Global Carbon, Energy, and Hydrologic

Cycles. Analysis of the carbon, energy, and water cycles may increase the

predictability of climate change. The goals of this investigation are to

(1) understand contemporary climate variability and trends and

(2) contribute to our ability to predict the impact of human activities on

the climate.

• Changes in Biogeochemical Cycles. Models of biogeochemical cycles can

be used to project the interactions of atmospheric composition, climate,

terrestrial and aquatic ecosystems, ocean circulation and sea level, and

human-induced effects. This investigation will develop models and

Page 31 GAO/NSIAD-96-97 Earth Observing System
Appendix IV 

EOS Science Objectives and

Interdisciplinary Investigations

databases to describe the dynamics of water, carbon, nitrogen, and trace

gases over seasonal-to-century time scales.

The Land Surface Hydrology and Ecosystem Processes objective

covers sources and sinks of greenhouse gases, the exchange of moisture

and energy between the land surface and atmosphere, and changes in land

cover. Investigations in this category could result in improved estimates of

runoff over the land surface and into the oceans.

• Global Water Cycle: Extension Across the Earth Sciences. The global

water cycle stimulates, regulates, and responds to the other components

of the Earth system on regional and global scales. This investigation is

aimed at developing a hierarchy of models, using EOS data, that will

contribute to our understanding of cloud cover and radiative transfer, as

well as energy and moisture changes at the interface of the atmosphere

with the oceans, cryosphere, and land surface. These models will

contribute to the prediction of changes in water balance and climate.

• Long-Term Monitoring of the Amazon Ecosystems Through EOS: From

Patterns to Processes. Natural and human-induced changes in the Amazon

are expected to disrupt regional vegetation distributions, alter the physical

and chemical characteristics of the continental river system, and change

regional hydroclimatology, possibly influencing global climate patterns.

The aim of this investigation is to understand the circulation of water,

sediment, and nutrients through the basin.

• Northern Biosphere Observation and Modeling Experiment. Natural and

human-induced climate changes in the northern latitudes will affect

terrestrial ecosystems, and feedbacks from these changing systems will

influence the climate. The goal of this study is to better understand the

relationship between the climate and northern ecosystems over a range of

spatial scales.

• Hydrology, Hydrochemical Modeling, and Remote Sensing in Seasonally

Snow-Covered Alpine Drainage Basins. Seasonally snow-covered Alpine

regions are important to the hydrologic cycle, as they are a major source

of water for runoff, ground water recharge, and agriculture. This

investigation will monitor conditions in Alpine basins and develop models

to better understand the cycling of water, chemicals, and nutrients in these

areas.

• Climate, Erosion, and Tectonics in Mountain Systems. In mountain belts,

climatic and tectonic processes produce Earth’s highest rates of

weathering and erosion. Alpine regions are important to downstream

hydrology, providing both inorganic and organic material to lowland areas.

This investigation will observe the effects of climate changes on Alpine

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Appendix IV 

EOS Science Objectives and

Interdisciplinary Investigations

land processes and develop models to improve our understanding of these

interactions.

• The Hydrologic Cycle and Climatic Processes in Arid and Semiarid Lands.

Knowledge of the hydrologic cycle will help scientists predict the effects

of natural and human-induced climate change. This investigation will

study the hydrologic cycle and climatic processes in arid and semiarid

lands, where agricultural productivity is especially sensitive to changes in

the cycle.

• Using Multi-Sensor Data to Model Factors Limiting Carbon Balance in

Global Arid and Semiarid Land. This investigation will address the role of

arid and semiarid lands in processes affecting the global environment,

such as the production and consumption of trace gases. It will also

examine the vulnerability of these lands to climate change in terms of

productivity and soil quality, and develop predictive models of ecosystem

function for dry lands.

• Biosphere-Atmosphere Interactions. This investigation is to improve our

understanding of the role of the terrestrial biosphere in global change. It

will cover short-term interactions between the land and atmosphere, such

as biophysics, as well as long-term interactions, such as ecology and

human-induced impacts. The goal of the investigation is to understand and

predict the response of the biosphere-atmosphere system to global change,

specifically to the increase in atmospheric carbon dioxide.

Glaciers and Polar Ice Sheet measurements could contribute to

predictions of sea level and global water balance.

• Use of the Cryospheric System to Monitor Global Change in Canada. The

cryosphere is an important component of the global climate system, and

better understanding of cryospheric processes may improve global climate

models. This investigation seeks to understand cryospheric variations,

develop models that will improve our knowledge of the role of the

cryosphere in the climate system, and use various cryospheric data sets to

support climate monitoring and model development.

The Chemistry of the Middle and Upper Stratosphere objective

includes chemical reactions, solar-atmosphere relations, and sources and

sinks of radiatively important gases.

• Observational and Modeling Studies of Radiative, Chemical, and

Dynamical Interactions on the Earth’s Atmosphere. Understanding the

circulation, transformations, and sources and sinks of gases, such as

carbon dioxide, water vapor, ozone, and chlorofluorocarbons, is important

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EOS Science Objectives and

Interdisciplinary Investigations

in dealing with the issues of global warming, ozone depletion, and the

coupling of atmospheric chemistry and climate. This investigation seeks to

improve our understanding of the fundamental processes influencing

these gases in the atmosphere and contribute to the development of a

predictive capability for global change studies.

• Chemical, Dynamical, and Radiative Interactions Through the Middle

Atmosphere and Thermosphere. Carbon dioxide and ozone play important

radiative roles in the middle atmosphere. Ozone absorbs ultraviolet

radiation, heating the middle atmosphere and shielding the biosphere from

dangerous ultraviolet dosages. The interactions of other gases, as well as

temperature and middle atmosphere circulation, affect ozone. This

investigation will improve our understanding of interactions in the middle

atmosphere and our ability to predict long-term atmospheric trends.

• Investigation of the Chemical and Dynamical Changes in the Stratosphere.

Chemical changes in the atmosphere are occurring largely as a result of

changes in the surface emission of trace gases. This investigation will

focus on the response of ozone to trace gas changes, isolating natural from

human-induced changes to determine their effects on ozone and to assess

radiative and dynamical feedbacks.

The Solid Earth objective deals with volcanoes and their role in climate

change.

• A Global Assessment of Active Volcanism, Volcanic Hazards, and Volcanic

Inputs to the Atmosphere from EOS. The injection of material from

volcanoes into the atmosphere can affect the local or hemispheric climate.

This investigation will improve our understanding of the processes behind

volcanic eruptions; study the injection of sulfur dioxide, water vapor,

carbon dioxide, and other gases into the atmosphere; and place eruptions

into the context of the regional tectonic setting of the volcano.

Page 34 GAO/NSIAD-96-97 Earth Observing System
Appendix V 

Comments From the National Aeronautics

and Space Administration

Note: GAO comments

supplementing those in the

report text appear at the

end of this appendix.

See comment 1.

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See comment 1.

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and Space Administration

See comment 1.

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See comment 2.

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and Space Administration

See comment 3.

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See comment 1.

See comment 4.

See comment 5.

See comment 1.

See comment 1.

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and Space Administration

See comment 6.

See comment 7.

See comment 8.

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See comment 9.

See comment 10.

See comment 11.

See comment 12.

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Appendix V 

Comments From the National Aeronautics

and Space Administration

The following are GAO’s comments on NASA’s letter dated May 17, 1996.

GAO Comments 1. Refer to the “agency comments and our evaluation” section of the

report.

2. Our analytic framework was not designed to assess the science teams’

ability to do the tasks they are currently funded to do. In its comments,

NASA points out that the breadth of scientific interest in EOS measurements

is likely to be greater than the interest in Upper Atmosphere Research

Satellite (UARS) and Ocean Topography Experiment (TOPEX)

measurements. This view is consistent with our observation that the

scientific opportunities afforded by EOS are likely to be greater than those

afforded by these pre-EOS-era missions. The difference in potential

research opportunities afforded by EOS and, for example, UARS and TOPEX is

illustrated by the differences in the number of investigations and data

rates of EOS and these two pre-EOS-era missions. NASA’s strategy is to begin

increasing the number of EOS investigations.

3. We met with NASA personnel at various times throughout our fieldwork

and considered their views in preparing our draft report. In this section of

its comments, NASA notes a number of issues related to its interpretation

that our draft report was intended to estimate the potential EOS user

community and to assess the ability of current EOS researchers to process

the large amounts of data expected from EOS. We have made changes in

the final report to clarify our objectives. As an example of NASA’s

misinterpretation, it specifically criticizes our data rate comparison,

presents a comparison of its own, and expresses its confidence that this

difference (EOS CHEM mission investigators must handle 100 times more

data than UARS investigators) is not significant. Again, we did not assess

the ability of investigators to handle data. Also, we did not discuss the

“average data rate per investigator,” as stated by NASA. Further, our use of

data rates is consistent with the way NASA used them in its 1993 and 1995

editions of the EOS Reference Handbook—namely, to help illustrate the

magnitude of science opportunities afforded by EOS compared to

pre-EOS-era Earth observing missions.

4. Our comparisons, coupled with NASA’s efforts to begin increasing the

number of EOS investigations, support the need to assess what is necessary

and sufficient EOS basic research. As NASA stated, this question merits

“further, more detailed, and more comprehensive analysis.” The

recommendation to NASA in our draft report was intended to ensure that

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Comments From the National Aeronautics

and Space Administration

this question is at least addressed in the context of Pathfinder. In our

judgment, the matter for congressional consideration has the same

intention.

5. The observation that “scientists analyze data when they are paid to do

so” was made by several senior NASA officials. Our analysis of the

authorship of UARS and TOPEX journal articles was to verify these officials’

observation.

6. Our use of the term “limited” was not referring to the number of

investigations NASA hopes to add. Rather, it refers to the fact that newly

selected interdisciplinary science investigators will be largely precluded

from analyzing data from the first EOS mission. We have clarified the

report.

7. We did not say the near-term community of researchers is “too small.”

We said the number of currently funded EOS science investigations is small

compared with two pre-EOS-era missions and the potential research

opportunities afforded by EOS. Senior NASA officials told us that budget

constraints slowed their efforts to increase the number of EOS

investigations. In September 1995, NASA began its formal efforts to add

more investigations because it had created sufficient “savings” to fund

them. We did not say, as NASA contends, that it is limiting the “focus” of

newly selected investigations to pre-EOS-era missions. Rather, we said that

the new investigators would be largely precluded from analyzing data from

the first EOS mission, based on the following language from the

September 1995 announcement:

Investigations to begin in 1996 cannot depend solely on data from EOS instruments because

the earliest launch dates are planned for 1997 (for [Tropical Rainfall Measuring Mission])

and 1998 (for EOS-AM-1). Instead, research plans should be based on use of existing data

sets . . . or expected data from relevant near-term (1996-1997) satellite missions and field

experiments.

8. Our draft report discussed the 1995-96 peer review, noting that the

review could lead to possible deselection and recompetition of some EOS

science teams.

9. We incorporated the amount of funds involved in the program into the

report’s text.

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and Space Administration

10. We included NASA’s current estimate of planned EOS spending through

fiscal year 2000 in the report’s text.

11. We revised our report to include NASA’s comments about lower

program baseline costs and its confidence that it will decrease costs

further.

12. We deleted the material NASA is referring to.

(709154) Page 49 GAO/NSIAD-96-97 Earth Observing System
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