1

The Advanced Microwave Scanning Radiometer for the Earth Observing System (EOS) program,

abbreviated AMSR-E, is a part of the EOS Aqua mission, scheduled for launch in 2001. AMSR-E will monitor

various water processes that exert a strong influence on climate and weather. The variables to be measured

include precipitation, oceanic water vapor, cloud water, near-surface wind speed, sea surface temperature, soil

moisture, snow cover, and sea ice parameters (Table 1). 

From Meteorology Today (with InfoTrac) An Introduction to Weather, Climate, and the Environment, 6th edition, by C.D. Ahrens © 2000.

Reprinted with permission of Brooks/Cole, a division of Thomson Learning. Fax 800 730-2215.

AMSR-E: Monitoring the Global Water Cycle

. . . Almost all of the water that is

evap

o

ra

ted ev ne

ut

ut er yll a

nr

s to

th

e

Earth’s surface as

pr

ec pi

ti

. noit a

HYDROLOGIC CYCLE
Table 1. Standard Products from AMSR-E

All of these measurements are critical to understanding the Earth’s climate. Water vapor is the

Earth’s primary greenhouse gas, helping to keep the Earth habitable. The evaporation of water from the

surface carries away excess heat, preventing unbearably hot temperatures in most regions. Almost all of

the water that is evaporated eventually returns to the Earth’s surface as precipitation. In the process of precipitation formation, heat that was absorbed during evaporation is released to the atmosphere. This

2

PARAMETER ACCURACY SPATIAL RESOLUTION INVESTIGATORS

Brightness Temperature (Tb) 0.2° - 0.7°C 5-56 km NASDA (Level 1B);

F. Wentz (RSS, Level 2A)

Oceanic Surface Wind Speed 1.0 m/s 24 & 38 km F. Wentz (RSS)

Oceanic Integrated Water Vapor 1.0 mm 24 km F. Wentz (RSS)

Oceanic Cloud Liquid Water 0.02 mm 12 km F. Wentz (RSS)

Sea Surface Temperature (SST) 0.5°C & 0.7°C 38 & 56 km F. Wentz (RSS)

Global Rainfall Over ocean: 5 km C. Kummerow (CSU)

1 mm/hr or 20%, R. Ferraro (NOAA/NESDIS)

whichever is greater T. Wilheit (TAMU)

Over land:

2 mm/hr or 40%, 

whichever is greater

Rain Type (convection fraction) N/A 5 km C. Kummerow (CSU)

Surface Soil Moisture 0.06 g/cm3 where 25 km (equal area Earth grid) E. Njoku (JPL)

vegetation is less

than 1.5 kg/m2

Snow Water Equivalent 10 mm or 20% 25 km (equal area Earth grid) A. Chang (NASA/GSFC)

Sea Ice Concentration <5% 12.5, 25 km (equal area Earth D. Cavalieri (NASA/GSFC)

 grid) J. Comiso (NASA/GSFC)

Snow Depth Over Sea Ice <5 cm 12.5 km (equal area Earth D. Cavalieri (NASA/GSFC)

 grid) J. Comiso (NASA/GSFC)

Sea Ice Temperature <4°C 25 km (equal area Earth grid) D. Cavalieri (NASA/GSFC)

J. Comiso (NASA/GSFC)

NASDA National Space Development Agency of Japan TAMU Texas A&M University

RSS Remote Sensing System NASA/GSFC NASA Goddard Space Flight Center

CSU Colorado State University JPL Jet Propulsion Laboratory

NOAA/NESDIS National Oceanic and Atmospheric Administration/National Environmental Satellite, Data, and Information Service

Advanced Microwave

Sounding Unit-A 89

GHz image for

August 11, 2000 from

the NOAA-15 satellite. The 89 GHz

channel will also be

included in the

AMSR-E instrument,

and provides information on atmospheric

water vapor, clouds,

precipitation, sea ice,

and land surface temperature.
process provides over half of the energy needed for

the global atmospheric circulation and is the prime

mechanism for transferring the effects of local climate anomalies such as El Niño to a global scale.

Wind speed at the ocean surface has a large influence on evaporation and the organization of sea surface temperature patterns. Sea surface temperature

changes, in turn, greatly influence the atmospheric

circulation, such as during El Niño. Cloud water

reflects sunlight back out to space, cooling the Earth. 

Soil moisture is a key state variable in land

surface hydrology. It controls the proportion of rainfall that percolates, runs off, or evaporates from land. 

Soil moisture also enables photosynthesis in

plants that use solar energy to convert carbon dioxide and water into the oxygen and food necessary

for animal life on Earth. 

Sea ice reflects sunlight away from the

Earth, but it also helps the ocean to retain thermal

energy by restricting evaporation and other heat

transfers from the ocean surface. Snow cover over

sea ice further restricts heat loss from the ocean.

Similarly, snow cover over land reduces the amount

of sunlight absorbed by the Earth, while also limiting the flow of heat from the ground to the atmosphere. Snow cover is also an important part of the

land hydrology and provides a yearly replenishment

of water resources in many regions. 

3

0

ENSO Global Precipitation

(Based on observations from multiple satellites)

April 97 to March 98 Rainfall

El Niño minus La Niña composites of

Global Normalized Precipitation Anomalies

-1.2 -0.9 -0.6 -0.3 0.0 0.3 0.6 0.9 1.2

Rainfall (top panel) and anomalies from the 1979-98 climatology (bottom panel) during the El Niño year: April 1997 to

March 1998. The El Niño phenomenon is characterized by

increased rainfall over the central Pacific and a drying of the

East Indies, as well as climate changes on a global scale.

Differences of precipitation anomalies (normalized by

monthly standard deviations to show variability in low rain

areas) during the period January 1979 to June 1999. This

analysis shows rainfall differences between El Niño months

and La Niña months and emphasizes the global pattern of

wet and dry areas.

-5 0 +5

Rainfall Anomalies

369 12

(mm day-1)

(mm day-1)

Global Precipitation Climatology Project (GPCP)
Climate Change Research

How clouds, water vapor, precipitation, sea ice, soil moisture, and snow cover respond to increasing atmospheric levels of greenhouse gases is still unclear, and they all have the potential to either enhance

or suppress global warming. The same can be said for their influence on natural climate fluctuations. The

data that AMSR-E provides will be utilized by climate researchers to develop a better understanding of

climate change. The AMSR-E data will also be utilized with data from other sensors on the Aqua spacecraft to gain a more complete picture of these processes. In order to sustain a long-term dataset for climate

monitoring, the AMSR-E products will be intercalibrated with similar products from previous spacecraft

missions, where they exist, to allow long-term monitoring of climate. Currently, the Special Sensor

Microwave/Imager (SSM/I)

flying on Department of

Defense weather satellites is

the primary heritage instrument of AMSR-E. AMSR-E

will extend and enhance the

SSM/I data record, begun in

1987, and the earlier

Nimbus 7 Scanning

Multichannel Microwave

Radiometer (SMMR) data

record, begun in 1978, to

allow studies of decadalscale climate change.

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Northern and Southern Hemisphere Winter Sea Ice Coverages

Derived From Satellite Passive–Microwave Data

The values mapped are sea ice concentrations (percent areal coverages of ice)

(NASA/GSFC)

NASDA/EORC

Tokyo, Japan AMSR-E Processing and Data Flow

AMSR-E SIPS

Remote Sensing Systems

Santa Rosa, California

AMSR-E Science Team

AMSR-E Level 2A

AMSR-E Level 1A

Algorithm Updates Science QA

AMSR-E

SIPS & SCF

AMSR-E Level 1A

Users

AMSR-E SIPS

Product Delivery

Record Server

AMSR-E Science Computing Facility

Global Hydrology & Climate Center

NASA/Marshall Space Flight Center

Huntsville, Alabama

Non-ECS 

NSIDC

NCS NSIDC 

DAAC

Boulder, Colorado

AMSR-E SIPS Global Hydrology

& Climate Center

NASA/Marshall Space Flight Center

Huntsville, Alabama

Data & metadata

PDRDs

PANs

DAP

Physical Oceanography DAAC

Jet Propulsion Labratory

Pasadena, California

AMSR-E Level 1A

Internal

Algorithm Updates

Level

2 & 3

DAAC Distributed Active Archive Center

DAP Data Algorithm Package

ECS EOSDIS Core System

PDRDs Product Delivery Record Discrepancy

SIPS Science Investigator-led Processing System

SCF Scientific Computing Facility

EORC Earth Observations Resource Center

NSIDC National Snow and Ice Data Center

PANs Product Acceptance Notifications

100%

80%

60%

40%

20%

≤12%
Predictions of Climate and Weather

A better understanding of climate processes resulting from analysis of AMSR-E data will be utilized by researchers to develop and improve computer models of the climate system. These models are the

mechanism ultimately used for predictions of climate change, whether it be El Niño, La Niña, or global

warming. Climate models have shown increasing skill at the prediction of the onset of El Niño from one

year to the next. Improvements in the water-related processes in models will increase our confidence in

their predictions of global warming and the regional weather changes expected to accompany warming.

Some weather forecast models will likely ingest the AMSR-E data in near-real time to help improve daily

weather predictions. For example, wintertime tropical moisture surges into the United States, which have

a controlling influence on rainfall and snowfall, can be monitored through the AMSR-E data.

Science Teams

There are two science teams involved in the production of products from AMSR-E. The U.S.

AMSR-E Science Team works to develop methods (algorithms) to convert the raw satellite measurements

into the products listed in Table 1. The U.S. Team has a Japanese counterpart, the NASDA (National Space

Development Agency of Japan) AMSR Science Team, that has similar goals. Members from each team constitute a Joint AMSR Team that works together to share findings and unify procedures for analysis of the

AMSR-E data. Both teams are also involved in field campaigns to help validate the products after launch

of the Aqua spacecraft. The science teams are responsible for the routine processing and archival of those

products for use by the science community.

5

Lake ice sampling in Saskatchewan, Canada. Courtesy of

Dorothy Hall, NASA/GSFC

Sea ice in the Bering Sea. Courtesy of Claire Parkinson,

NASA/GSFC
6

AMSR-E Instrument 

The AMSR-E is a conically scanning

passive microwave radiometer sensing

microwave radiation at 12 channels and 6

frequencies ranging from 6.9 to 89 GHz

(gigahertz). It is built by Mitsubishi Electric

Company with NASDA funding. Horizontally

and vertically polarized radiation are measured separately

at each frequency. The AMSR-E utilizes an offset parabolic reflector

1.6 meters in diameter to focus the radiation into an array of feedhorns that

feed the radiation to detectors. During scanning, the instrument spins at 40 revolutions

per minute (rpm), covering a swath 1445 km wide on the Earth from an altitude of 705 km.

Instrument specifications are contained in Table 2.

Center Frequencies (GHz) 6.925 10.65 18.7 23.8 36.5 89.0

Bandwidth (MHz) 350 100 200 400 1000 3000

Sensitivity (K) 0.3 0.6 0.6 0.6 0.6 1.1

IFOV (km x km) 74 x 43 51 x 30 27 x 16 31 x 18 14 x 8 6 x 4

Sampling Interval (km x km) 10 x 10 10 x 10 10 x 10 10 x 10 10 x 10 5 x 5

Integration Time (msec) 2.6 2.6 2.6 2.6 2.6 1.3

Main Beam Efficiency (%) 95.3 95.0 96.3 96.4 95.3 96.0

Beamwidth (half-power, degrees) 2.2 1.4 0.8 0.9 0.4 0.18

Table 2. AMSR-E Characteristics from the 705 km Orbital Altitude of the EOS Aqua Platform.
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Education and Outreach

The AMSR-E Science team will tap into the existing international GLOBE program. Students’ observations will be compared with the satellite-derived atmospheric parameters, as part of

the AMSR-E validation program. Feedback will be provided to the

students on how their observations compare to the Aqua AMSR-E

retrieved data. As part of our educational outreach, our scientists

will participate with the GLOBE students and teachers in Web

chats and respond to questions that students FAX or mail. It is our

goal to reach and educate as many students as possible and,

through them, reach the general public.
For further information o

and data products see 

www.ghcc.msfc.nasa.gov/

Roy W. Spencer

SD 60

320 Sparkman Drive

Hunstville, AL 35805

Acknowledgemen

Text by Roy Spencer, AMSR-E 

Editing by Elena Lobl and Cla

Brochure design by Winnie Hu

AMSR-E logo (back cover) de

Image contributions: Matt Sm

Scott Curtis (page 3), GLOBE 

8
NP-2000-10-126-GSFC