Spectrometer (ILAS), Seawinds (scatterometer), and Polarization and Directionality of Earth's Reflectances (POLDER).
Another planned mission is Envisat, a European research satellite scheduled for launch in 2001; its instrument payload will include a SAR, an ozone spectrometer, an infrared sounder, a multiwavelength imaging radiometer, a microwave imager, an infrared spectrometer, and a lightning sensor.
A European technology-experiment satellite, called Project for On-Board Autonomy (PROBA), carries a high-resolution imaging spectrometer (visible and near-infrared wavelengths).
The Aqua satellite, to be launched in 2001, will provide information on several key variables discussed in this report. For example, Aqua will carry an Advanced Microwave Sounding Unit (AMSU) for atmospheric temperature profiles as well as cloud and aerosol properties; an Advanced Microwave Scanning Radiometer for EOS (AMSR-E) for precipitation, columnar water vapor and cloud water, aerosol properties, sea surface wind speed, snow depth on sea ice, and snow water equivalent; a Moderate-Resolution Imaging Spectroradiometer (MODIS) for atmospheric profiles, land surface characteristics, ocean primary productivity, and snow and ice albedo; and a Clouds and the Earth Radiant Energy System (CERES) for radiative fluxes and cloud-radiative interactions.
Although only in the early stages of its product assessment and utilization, the recently (December 1999) launched Terra satellite carries MODIS and CERES instruments as well as an Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), a Multi-angle Imaging Spectral Radiometer (MISR), and an instrument for Measurements of Pollution in the Troposphere (MOPITT). Applications of the Terra are directed toward aerosols characterization, changes in global cloudiness, changes in the global land surface, and the roles of the ocean in global change.