TERRA

The Advanced Spaceborne Thermal Emission and Reflection Radiometer obtains high-resolution (15 to 90 square meters per pixel) images of the Earth in 14 different wavelengths of the electromagnetic spectrum, ranging from visible to thermal infrared light. Scientists use ASTER data to create detailed maps of land surface temperature, emissivity, reflectance, and elevation.

ASTER is the only high spatial resolution instrument on the Terra platform. ASTER's ability to serve as a 'zoom' lens for the other Terra instruments is particularly important for change detection, calibration/validation and land surface studies. Unlike the other instruments aboard Terra, ASTER will not collect data continuously; rather, it collects an average of 8 minutes of data per orbit. All three ASTER telescopes (VNIR, SWIR, and TIR) are pointable in the crosstrack direction. Given its high resolution and its ability to change viewing angles, ASTER produces stereoscopic images and detailed terrain height models

There are two identical CERES instruments aboard Terra that measure the Earth's total radiation budget and provide cloud property estimates that enable scientists to assess clouds' roles in radiative fluxes from the surface to the top of the atmosphere. One CERES instrument operates in a cross-track scan mode and the other in a biaxial scan mode. The cross-track mode essentially continues the measurements of the Earth Radiation Budget Experiment (ERBE) and the Tropical Rainfall Measuring Mission (TRMM), while the biaxial scan mode provides new angular flux information that has improved the accuracy of angular models used to derive the Earth's radiation balance.

Measurement of Pollution in the Troposphere (MOPITT) is an instrument designed to enhance our knowledge of the lower atmosphere and to observe how it interacts with the land and ocean biospheres. MOPITT’s specific focus is on the distribution, transport, sources, and sinks of carbon monoxide in the troposphere. Carbon monoxide, which is expelled from factories, cars, and forest fires, hinders the atmosphere's natural ability to rid itself of harmful pollutants.

MOPITT is the first satellite sensor to use gas correlation spectroscopy. The sensor measures emitted and reflected radiance from the Earth in three spectral bands. As this light enters the sensor, it passes along two different paths through onboard containers of carbon monoxide. The different paths absorb different amounts of energy, leading to small differences in the resulting signals that correlate with the presence of these gases in the atmosphere.

MOPITT's spatial resolution is 22 km at nadir and it 'sees' the Earth in swaths that are 640 km wide. Moreover, it can measure the concentrations of carbon monoxide in 5-km layers down a vertical column of atmosphere, to help scientists track the gas back to its sources.

MODIS measures the properties of clouds such as the distribution and size of cloud droplets in both liquid water and ice clouds. MODIS also measures the properties of aerosols—tiny liquid or solid particles in the atmosphere. Aerosols enter the atmosphere from manmade sources like pollution and biomass burning and natural sources like dust storms, volcanic eruptions, and forest fires. MODIS helps scientists determine the amount of water vapor in a column of the atmosphere and the vertical distribution of temperature and water vapor—measurements crucial to understanding Earth’s climate system.

MODIS is ideal for monitoring large-scale changes in the biosphere that are yielding new insights into the workings of the global carbon cycle. MODIS measures the photosynthetic activity of land and marine plants (phytoplankton) to yield better estimates of how much of the greenhouse gas is being absorbed and used in plant productivity. Coupled with the sensor's surface temperature measurements, MODIS' measurements of the biosphere are helping scientists track the sources and sinks of carbon dioxide in response to climate changes.

Most satellite instruments look only straight down, or toward the edge of the planet. To fully understand Earth's climate, and to determine how it may be changing, we need to know the amount of sunlight that is scattered in different directions under natural conditions. MISR is a new type of instrument designed to address this need — it views the Earth with cameras pointed at nine different angles. One camera points toward nadir, and the others provide forward and aftward view angles, at the Earth's surface, of 26.1°, 45.6°, 60.0°, and 70.5°. As the instrument flies overhead, each region of the Earth's surface is successively imaged by all nine cameras in each of four wavelengths (blue, green, red, and near-infrared).


Referred by NASA(http://aqua.nasa.gov) website