Climate Sense

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bserving

, P

redicting

and

rojecting

limate

onditions

bration are also under study, such as the satellite 90-degree yaw

manoeuvre.

The total system design of IRS comes from the previous GLI on

ADEOS-2, as well as the Ocean Colour and Temperature Scanner

on ADEOS. IRS is a full catroptic optical system with a compact

conical scanner to avoid any colour aberration. The detector range is

covered by PV-MCT type detectors for TIR channels, while indium

gallium arsenide detectors were selected for shortwave infrared

(SWIR) to attain higher sensitivity and lower noise than on the GLI.

For the cryo-cooler of the TIR focal plane assembly, a staring cycle

cooler system is used. The required thermal environment for infra-

red detectors is about 55 Kelvin. For SWIR calibration we will also

use solar and internal light, the same as VNR. For TIR, an ambient

black body will be used as a high level input source. A deep space

view is used for both SWIR and TIR at zero level. For TIR band the

resolution is set at 500 metres, whereas the SWIR channel is set at

1 kilometre except for one 250-metre channel.

International cooperation

GCOM-W will play a role in the global precipitation

measurement (GPM), a joint mission between NASA

and Japan. GPM consists of a core satellite carrying

a dual-frequency precipitation radar, a microwave

radiometer and contributing satellites carrying

microwave radiometers. GPM will enable frequent

global observation of precipitation and water-related

quantities.

GCOM has also started cooperating with the National

Polar-orbiting Operational Environmental Satellite

System (NPOESS). NPOESS and GCOM will support

the operational and research needs of the meteorologi-

cal, oceanographic, environmental and climatic remote

sensing programmes as well as provide global environ-

mental support. Data from these satellites will also be

made available to meteorological and environmental

organizations to support their weather forecasting and

climate prediction capabilities. The USA and Japan

will jointly operate these two major satellite systems;

sharing data and conducting joint calibration, valida-

tion and science activities.

The GCOM satellite series in overview

The GCOM-W satellite series will globally observe

water-related quantities in the atmosphere, ocean and

on land. Data measured by AMSR-2 will be used to

derive: water vapour content, cloud water content and

precipitable water in the atmosphere; surface tempera-

ture, surface wind and ice in the ocean; and soil water

content and snowfall on the land. This data will be used

for societal benefits such as describing and forecasting

phenomena such as El Niño and La Niña, monitoring

sea-ice variations, monitoring and forecasting typhoons

and providing a meteorological data service to daily

weather forecasting facilities. Close collaboration mech-

anisms for the data use have already been established

with national and international operational organiza-

tions for meteorology, maritime operations and fishery

information services.

The GCOM-C satellite series will observe vegetation

on the land, phytoplankton (ocean colour) in the coastal

region and sea-surface temperature with a horizontal

resolution of 250 metres. Highly variable aerosols in the

atmosphere and snow, as well as ice parameters will be

observed. Data can be practically applied to benefit society

in collaboration with meteorological and fishery informa-

tion services. National and international environment

research institutes will analyse the global changes in vege-

tation and sea-surface temperature.

The GCOM programme is Japan’s first attempt at 13

years of continuous satellite observation with three series

of satellites, each with a five-year lifespan, and one-year

overlap. This mission was implemented because it is

necessary to reveal the relationship between climate and

the effects of human activity, namely to exclude the influ-

ences of solar activity, which change on an 11-year cycle,

and natural variability on shorter cycles, to improve the

accuracy of predicting climate change.

Polarimetry and non-polarimetry observation

Non-polarimetry part using three telescopes (left); Polarimetry part using two

telescopes (right)

Source: JAXA

Overview of the GCOM-C1 satellite

Image: JAXA