Advanced Earth Observation Satellite (ADEOS)

The Japanese polar orbiting ADEOS program began with the launch of ADEOS-1 (also known as MIDORI), on 17 August 1996. The satellite acquired global earth-observation data for 7 months until it suddenly went out of control on 30 June 1997, due to structural damage in its solar array. The program will continue with the expected launch of ADEOS-2 in 2000.

The ADEOS-1 satellite included the following instruments:

Advanced Visible and Near-Infrared Radiometer (AVNIR): AVNIR, provided by the National Space Development Agency of Japan (NASDA), is an optical sensor for measuring surface reflectance in 3 visible bands and 1 near-infrared band. The 3 visible bands are indicated by blue, green, and red, while the near-infrared band is suitable to observe vegetation. AVNIR has 4 multispectral bands of 16-m resolution and 1 panchromatic band of 8-m resolution. AVNIR scans about an 80-km swath width along the cross track. The AVNIR data is used to describe vegetation and soil conditions in order to contribute to solving such phenomena as desertification and deforestation of tropical forests.

Infrared Limb Atmospheric Spectrometer (ILAS): ILAS is an infrared occultation device, developed by Japan’s Environmental Agency. This sensor is used to monitor the polar stratospheric ozone. ILAS covers the infrared region and the near visible region.

Interferometric Monitor for Greenhouse Gases (IMG): IMG is a nadir-looking Fourier transform infrared spectrometer, provided by the Ministry of International Trade and Industry (MITI). This sensor is used to monitor the Earth’s radiation balance, the temperature profile of the atmosphere, the temperature of the Earth’s surface, and physical properties of clouds. IMG will obtain detailed spectra of thermal-infrared radiation from the Earth’s surface and atmosphere.

NASA Scatterometer (NSCAT): NSCAT is an active Ku-band scatterometer, provided by the National Aeronautics Space Administration (NASA). It is an active microwave radar used to measure winds over the oceans.

Ocean Color Temperature Scanner (OCTS): OCTS, provided by NASDA, is an optical radiometer used to achieve highly sensitive spectral measurements with 12 bands covering visible and thermal-infrared regions. With the swath width of OCTS being about 1,400 km, with a spatial resolution of 700 m, and with a mirror that scans west-to-east as well as north-to-south, the system can observe the entire earth’s surface in 3 days. OCTS mainly serves as an observation sensor of ocean conditions, including chlorophyll and dissolved substances in the water, temperature profile, and cloud formation processes.

Polarization and Directionality of the Earth’s Reflectances (POLDER): POLDER, provided by the French Centre National de Etudes Spatiales (CNES), is an optical sensor for observing the surface reflectance in visible and near-infrared bands. POLDER can observe the reflectance of a given Earth target under different spectral, polarization, and angular conditions. As a result, atmospheric characteristics will be further understood. POLDER will help in understanding the dynamics of the aerosols in the troposphere and the potential effects of clouds on the radiative balance of the Earth.

Retroreflector In-Space (RIS): RIS, provided by Japan’s environmental agency, is a retroreflector for an earth-satellite-earth laser used in long-path absorption experiments. Measurements of ozone, CFC12, CO2, CH4, etc., are carried out using infrared pulsed lasers.

Total Ozone Mapping Spectrometer (TOMS): TOMS, provided by NASA, is an optical sensor to measure the albedo of the earth’s atmosphere at 6 narrow spectral bands. The data can be used for the quantitative analysis of factors related to ozone issues and the potential effects of volcanic eruptions on climatic changes.

ADEOS-1/MIDORI Characteristics:

· Orbit: 797 km, sun synchronous

· Altitude: approximately 800 km

· Inclination: approximately 98.6 degrees

· Design life: 3 years (failed after 7 months)

· Launched: 17 August 1996

The ADEOS-2 satellite will include the following instruments, either new or improved since ADEOS-1:

Advanced Microwave Scanning Radiometer (AMSR): AMSR, provided by NASDA, is a 14-channel, 8 frequency passive microwave radiometer with a swath width of 1600 km that will observe various physical parameters about water by receiving weak microwave signals naturally radiated from the Earth’s surface and atmosphere (for example, water vapor content, precipitation, soil moisture, sea surface temperature, sea surface wind, and sea ice) both day and night, and with or without clouds. The data set obtained by AMSR will support studies to understand the water and energy cycle on a global scale.

Global Imager (GLI): GLI, provided by NASDA, is an optical sensor that will observe globally and frequently the reflected solar radiation from the Earth’s surface including land, ocean, and clouds. It also has an infrared radiation capability to measure the physical parameters such as chlorophyll, dissolved organic matter, surface temperature, vegetation distribution, vegetation biomass, distribution of snow and ice, and albedo of snow and ice. The GLI will be equipped with 36 spectral channels from visible to infrared wavelengths.

Sea Winds: The SeaWinds scatterometer, provided by NASA and the Jet Propulsion Laboratory (JPL), is a specialized microwave radar that measures near-surface wind velocity (both speed and direction) under all weather and cloud conditions over the Earth’s oceans. Sea Winds will collect data in a continuous 1,800-km wide band, making approximately 400,000 measurements per day. Studies performed with data from Sea Winds are expected to lead to improved methods of global weather forecasting and modeling.

Improved Limb Atmospheric Spectrometer-II (ILAS-II): ILAS-II, provided by Japan’s Environmental Agency, is an improved spectrometer for measuring infrared radiation at the edge of the atmosphere. ILAS-II covers the infrared region and the near visible region.

ADEOS-2 Characteristics:

· Orbit: 802.9 km, sun synchronous

· Altitude: 802.9 km

· Inclination: 98.62 degrees

· Design life: 3 years

· Revisit time: 4 days

· Expected launch: 2000

In addition to the scientific purposes, the data acquired by ADEOS-1/MIDORI and ADEOS-2 can and will be used for practical applications such as weather forecasting, vegetation distribution, land cover surveying, and elevation measurement.