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Terra · Aqua · Aura
Aqua: Studying Our Ocean Planet
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Giving us unprecedented insight into our planet's global water cycle, Aqua is one of the siblings in a family of Earth Observing System satellites dedicated to studying the Earth and our knowledge of global climate change.
Aqua uses six state-of-the-art science instruments to gather information about water in Earth's land, sea and atmosphere. Specifically, it collects data on global precipitation, evaporation, and the cycling of water.
During its six-year mission in space, Aqua watches for changes in ocean circulation and looks for clues to how clouds and surface water processes affect our climate. As it observes our Earth's oceans, atmosphere, land, ice, snow cover and vegetation, Aqua makes possible more accurate weather forecasts.
The information it produces helps scientists understand how global ecosystems are changing, and how they respond to and affect global environmental change. It helps scientists study the interactions among key elements of the Earth system so as to better understand our planet.
What Is It About Water?
All of the water in Earth's atmosphere is recycled completely about 33 times per year.
Because water has a larger effect on global weather patterns than even carbon dioxide, it has been called "the most active greenhouse gas" by an atmospheric scientist at NASA's Jet Propulsion Laboratory in Pasadena, California.
Scientists want to know how water in Earth's atmosphere responds to the rising concentrations of carbon dioxide. And how water could enhance global warming or even counteract it. They ask if rising atmospheric temperatures increase the number of catastrophic storms? Aqua is helping them find answers.
Aqua and the A Train:
Satellite Launch Aura 2004 July 15 Aqua 2002 May 4 Terra 1999 December 18
Aqua is a Latin word for water. As its name implies, Aqua is all about water, mapping Earth's water system continuously to help scientists fathom the causes of changing climate and figure out if global warming is causing a unusual deluge of weather in the form of hurricanes, tornadoes, and snowstorms-of-the-century.
One of NASA's central missions is to understand and protect our home planet. During its six-year mission in space, Aqua is increasing our understanding of Earth's water cycle and climate change.
Aqua was the second satellite to be launched in NASA's Earth Observing System (EOS) and a sister spacecraft to Terra launched earlier and Aura launched later.
Aqua is destined to be part of a flotilla of satellites flying in formation in space, including Terra, Aura, CloudSat, Parasol and Calipso. CloudSat, Calipso and Parasol are scheduled for launch in 2005.
The formation of orbiting satellites is referred to as the A-Train. Together, their overlapping radars will give a more comprehensive picture of weather and climate down on Earth.
The A Train satellites fly in low polar orbits 438 miles above Earth. They circle Earth 14 times a day. Aqua crosses the equator at approximately 1:30 AM and 1:30 PM, local time, about 3 hours behind Terra. Due to the instrument's narrow field of view, it takes about 16 days for Aqua to map the entire surface of the planet.
Aqua's afternoon observations and Terra's morning observations help scientists understand the daily cycle of key science parameters such as precipitation and ocean circulation.
NASA describes Aqua as focusing on the multi-disciplinary study of Earth's interrelated processes – atmosphere, oceans, and land surface – and their relationship to changes in the Earth system.
The global change research emphasized in Aqua's science instruments include:
The A Train satellites explore how Earth lives and breathes, and how people care for the planet. The satellites observe climate change, global plant productivity, snow cover, and the health of the oceans.
- atmospheric temperature and humidity profiles, clouds, precipitation and radiative balance
- terrestrial snow and sea ice
- sea surface temperature and ocean productivity
- soil moisture
- improvement of numerical weather prediction
- monitoring of terrestrial and marine ecosystem dynamics.
Aqua Science Instruments:
Each of the school-bus-sized satellite's six science instruments is designed to monitor a different part of our global plumbing system. The six instruments are:
- Atmospheric Infrared Sounder (AIRS)
- Advanced Microwave Sounding Unit (AMSU-A)
- Humidity Sounder for Brazil (HSB)
- Advanced Microwave Scanning Radiometer for EOS (AMSR-E)
- Moderate-Resolution Imaging Spectroradiometer (MODIS)
- Clouds and the Earth's Radiant Energy System (CERES)
Each has unique characteristics and capabilities for collecting data on global precipitation, evaporation and the cycling of water. Together, the six form a powerful package for Earth observations.
The first benefit to the general public from Aqua has been an improvement in daily weather forecasts. With the science data from Aqua, weather forecasters are able to offer predictions two or three times better than past forecasts.
- AIRS, AMSU-A and HSB track water as it cycles from Earth's surface and through the atmosphere.
- AMSR-E, MODIS and CERES measure cloud cover and surface vegetation, temperatures across Earth's surface and in the atmosphere, humidity, and the flow of energy though the system.
Aqua is an International Project
Aqua is a joint project between the United States, Japan and Brazil:
- The United States provided the spacecraft and four of Aqua's six scientific instruments.
- NASA's Goddard Space Flight Center provided the Moderate Resolution Imaging Spectroradiometer and the Advanced Microwave Sounding Unit
- NASA's Jet Propulsion Laboratory provided the Atmospheric Infrared Sounder
- NASA's Langley Research Center provided the Clouds and the Earth's Radiant Energy System instrument
- Japan's National Space Development Agency provided the Advanced Microwave Scanning Radiometer
- The Brazilian Institute for Space Research (Instituto Nacional de Pesquisas Espaciais) provided the Humidity Sounder for Brazil
Earth Observing System:
Scientists need to take measurements all over the world, over a long period of time, to be able to assemble the information needed to construct accurate computer models that will enable them to forecast the causes and effects of climate change.
At this time, the only feasible way to collect such widespread information is through the use of so-called remote sensors in space. That is, satellites orbiting Earth and carrying instruments that can measure things like temperature from a distance. Aqua, Aura and Terra are such satellites.
NASA built its Earth Observing System (EOS) as an international study of planet Earth. EOS has three main parts:
EOS Direct Broadcast:
- a series of satellites designed to study the complexities of global change
- an advanced computer network called EOSDIS for processing, storing and distributing data
- teams of scientists around the globe studying the data
The EOS satellites broadcasts data for reception by anyone around the world.
Aqua broadcasts data from its science instruments AIRS/AMSU-A/HSB, AMSR-E, CERES, and MODIS on X-Band radio. The satellite broadcasts continuously except for five-minute interruptions once per obit when it contacts its ground stations at Poker Flat, Alaska, and Svalbard, Norway.
Terra broadcasts portions of the data from its MODIS science instrument on X-Band. The broadcast is continuous except when the satellite is dumping its play-back data to ground stations for 15 minutes each orbit, and when Terra is within line-of-sight of NASA Deep Space Network (DSN) stations at Goldstone, California, Canberra, Australia, and Madrid, Spain.
Anyone interested in obtaining direct broadcast data or establishing a downlink site should navigate to the EOS Direct Broadcast Web site.
[ EOS Direct Broadcast Web site »» ]
Earth Science Enterprise:
NASA has positioned EOS as the centerpiece of what it calls an Earth Science Enterprise (ESE). In the U.S. space agency's words, EOS is a scientific information gathering system and a data storage and retrieval system supporting a coordinated series of polar-orbiting and low inclination satellites for long-term global observations of the land surface, biosphere, solid Earth, atmosphere and oceans.
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