Aqua, Latin for water, is a NASA Earth Science satellite mission named for the large amount of information that the mission is collecting about the Earth's water cycle, including evaporation from the oceans, water vapor in the atmosphere, clouds, precipitation (rain and snowfall), soil moisture, sea ice, land ice, and snow cover on the land and ice. Aqua carries a slew of instruments, including AIRS, AMSU, CERES, MODIS, and AMSR-E.
Each instrument on Aqua performs a specific function. These include:
- The Atmospheric Infrared Sounder (AIRS) is an advanced sounder containing 2378 infrared channels and four visible/near-infrared channels, aimed at obtaining highly accurate temperature profiles within the atmosphere plus a variety of additional Earth/atmosphere products.
- The Advanced Microwave Sounding Unit (AMSU-A), a 15-channel microwave sounder designed primarily to obtain temperature profiles in the upper atmosphere (especially the stratosphere) and to provide a cloud-filtering capability for tropospheric temperature observations.
- The Humidity Sounder for Brazil (HSB), a 4-channel microwave sounder provided by Brazil aimed at obtaining humidity profiles throughout the atmosphere.
- The Advanced Microwave Scanning Radiometer for EOS (AMSR-E) is a twelve-channel, six-frequency, total power passive-microwave radiometer system. It measures brightness temperatures at 6.925, 10.65, 18.7, 23.8, 36.5, and 89.0 GHz.
- The Moderate Resolution Imaging Spectroradiometer (MODIS), is a 36-band spectroradiometer measuring visible and infrared radiation and obtaining data that are being used to derive products ranging from vegetation, land surface cover, and ocean chlorophyll fluorescence to cloud and aerosol properties, fire occurrence, snow cover on the land, and sea ice cover on the oceans.
- The Cloud's and the Earth's Radiant Energy System (CERES) is a 3-channel radiometer measuring reflected solar radiation in the 0.3-5 µm wavelength band, emitted terrestrial radiation in the 8-12 µm band, and total radiation from 0.3 µm to beyond 100 µm. These data are being used to measure the Earth's total thermal radiation budget, and, in combination with MODIS data, detailed information about clouds.
The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite provides new insight into the role that clouds and atmospheric aerosols (airborne particles) play in regulating Earth's weather, climate, and air quality. CALIPSO probes the vertical structure and properties of thin clouds and aerosols over the globe. CALIPSO was launched on April 28, 2006 with the cloud profiling radar system on the CloudSat satellite. CALIPSO and CloudSat are highly complementary and together provide new, never-before-seen 3-D perspectives of how clouds and aerosols form, evolve, and affect weather and climate. CALIPSO and CloudSat fly in formation with three other satellites in the A-train constellation to enable an even greater understanding of our climate system from the broad array of sensors on these other spacecraft.
NASA launched the CloudSat and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) spacecraft to study the role that clouds and aerosols play in regulating Earth's weather, climate and air quality. The satellites fly in orbital formation as part of the "A-Train" constellation of three other Earth Observing satellites including Aqua, and Aura. Together, the A-Train satellites are increasing our understanding of the climate system and the potential for climate change. Scientists are improving their understanding of Earth's climate system, but many questions remain. CloudSat and CALIPSO are collecting information about the vertical structure of clouds and aerosols unavailable from other Earth observing satellites. The data they gather continuously improve our models and provide a better understanding of the human impact on the atmosphere.
Aura's instruments measure trace gases in the atmosphere by detecting their unique spectral signatures. MLS observes the faint microwave emissions from rotating and vibrating molecules. HIRDLS and TES observe the infrared thermal emissions also due to molecular vibrations and rotations. OMI detects the molecular absorption of backscattered sunlight in the visible and ultraviolet wavelengths. Aura flies in formation about 15 minutes behind Aqua in the "A-Train" satellite constellation which consists of several satellites flying in close proximity. Each individual mission has its own science objectives; all will improve our understanding of aspects of the Earth's climate. The synergism that is expected to be gained by flying in close proximity to each other should enable the overall science results of the Afternoon Constellation to be greater than the sum of the science of each individual mission.
The Suomi National Polar-orbiting Partnership (NPP) represents a critical first step in building this next-generation Earth-orbiting satellite system. Suomi NPP orbits the Earth about 14 times each day and observe nearly the entire surface. The NPP satellite continues key data records that are critical for climate change science.
The five instruments manifested for flight on the Suomi NPP spacecraft trace their heritage to instruments on NASA's Terra, Aqua and Aura missions, on NOAA's Polar Operational Environmental Satellite (POES) spacecraft, and on DOD's Defense Meteorological Satellite Program (DMSP).
The five instruments are:
- The Advanced Technology Microwave Sounder (ATMS): a cross-track scanner with 22 channels, provides sounding observations needed to retrieve profiles of atmospheric temperature and moisture for civilian operational weather forecasting as well as continuity of these measurements for climate monitoring purposes.
- The Visible Infrared Imaging Radiometer Suite (VIIRS): a scanning radiometer, collects visible and infrared imagery and radiometric measurements of the land, atmosphere, cryosphere, and oceans. VIIRS data is used to measure cloud and aerosol properties, ocean color, sea and land surface temperature, ice motion and temperature, fires, and Earth's albedo. Climatologists use VIIRS data to improve our understanding of global climate change.
- The Cross-track Infrared Sounder (CrIS): a Fourier transform spectrometer with 1305 spectral channels, produces high-resolution, three-dimensional temperature, pressure, and moisture profiles. These profiles are used to enhance weather forecasting models, and they facilitate both short- and long-term weather forecasting.
- The Ozone Mapping Profiler Suite (OMPS): an advanced suite of two hyper spectral instruments, extends the 25-plus year total-ozone and ozone-profile records. These records are used by ozone-assessment researchers and policy makers to track the health of the ozone layer. The improved vertical resolution of OMPS data products allows for better testing and monitoring of the complex chemistry involved in ozone destruction near the troposphere.
- Clouds and the Earth's Radiant Energy System (CERES), a three-channel radiometer, measures both solar-reflected and Earth-emitted radiation from the top of the atmosphere to the surface. It also determines cloud properties including the amount, height, thickness, particle size, and phase of clouds using simultaneous measurements by other instruments.
How is Earth changing and what are the consequences for life on Earth? In December 1999, NASA launched the Terra satellite as the flagship mission of the Earth Observing System to answer these questions.
Terra carries five instruments that observe Earth’s atmosphere, ocean, land, snow and ice, and energy budget. Taken together, these observations provide unique insight into how the Earth system works and how it is changing. Terra observations reveal humanity’s impact on the planet and provide crucial data about natural hazards like fire and volcanoes. See Terra science.
Terra is an international mission carrying instruments from the United States, Japan, and Canada. These five instruments are:
- The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) 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.
- There are two identical Clouds and Earth’s Radiant Energy System (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.
- The Multi-Angle Imaging SpectroRadiometer (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).
- With its sweeping 2,330-km-wide viewing swath, the Moderate Resolution Imaging Spectroradiometer (MODIS) sees every point on our world every 1-2 days in 36 discrete spectral bands. Consequently, MODIS tracks a wider array of the earth’s vital signs than any other Terra sensor. For instance, the sensor measures the percent of the planet’s surface that is covered by clouds almost every day. This wide spatial coverage enables MODIS, together with MISR and CERES, to help scientists determine the impact of clouds and aerosols on the Earth’s energy budget.
- 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.
Did you Know?
Side View of Cumulonimbus Anvil
This striking photograph was taken from an airplane window - good thing they decided to go around! It shows the classic ""anvil"" shape that a thunderstorm takes. This shape arises from the lifting of air in the cloud right up to the tropopause, at which point it cannot rise any more and spreads into the anvil.
Photo by Terry O'Leary, Virginia Beach, VA, USA.