Results for: Fact Sheets

Sea Ice

Polar sea ice grows and shrinks dramatically each year, driven by seasonal cycles. Habitat for wildlife and harbinger of changing climate, sea ice offers scientists important clues about the state of our planet. Read more

Methane Matters

The concentration of methane in the atmosphere has been fluctuating, mostly rising. The question is why. Scientists wonder if they have the right monitoring systems in place to answer that question adequately. Read more

How to Interpret a Satellite Image: Five Tips and Strategies

What do you do when presented with a new satellite image? Here's what the Earth Observatory team does to understand the view. Read more

The Carbon Cycle

Carbon flows between the atmosphere, land, and ocean in a cycle that encompasses nearly all life and sets the thermostat for Earth's climate. By burning fossil fuels, people are changing the carbon cycle with far-reaching consequences. Read more

Aerosols: Tiny Particles, Big Impact

Tiny aerosol particles can be found over oceans, deserts, mountains, forests, ice sheets, and every ecosystem in between. They drift in the air from the stratosphere to the surface. Despite their small size, they have major impacts on our climate and our health. Read more

The Water Cycle

Landscape sculptor. Climate driver. Life supporter. Water is the most important molecule on our planet. Read more

What are Phytoplankton?

Microscopic plant-like organisms called phytoplankton are the base of the marine food web, and they play a key role in removing carbon dioxide from the air. Read more

Global Warming

Global warming is happening now, and scientists are confident that greenhouse gases are responsible. To understand what this means for humanity, it is necessary to understand what global warming is, how scientists know it's happening, and how they predict future climate. Read more

Climate and Earth’s Energy Budget

Earth’s temperature depends on how much sunlight the land, oceans, and atmosphere absorb, and how much heat the planet radiates back to space. This fact sheet describes the net flow of energy through different parts of the Earth system, and explains how the planetary energy budget stays in balance. Read more

Tropical Deforestation

Tropical forests are home to half the Earth's species, and their trees are an immense standing reservoir of carbon. Deforestation will have increasingly serious consequences for biodiversity, humans, and climate. Read more

Hurricanes: The Greatest Storms on Earth

Few things in nature can compare to the destructive force of a hurricane. Called the greatest storm on Earth, a hurricane is capable of annihilating coastal areas with sustained winds of 155 mph or higher and intense areas of rainfall and a storm surge. In fact, during its life cycle a hurricane can expend as much energy as 10,000 nuclear bombs! Read more


Questions from visitors to the Earth Observatory and answers from scientists. Read more

Aura: A Mission Dedicated to the Health of Earth’s Atmosphere

On July 15, 2004 at 3:02 a.m., NASA launched the Aura satellite, the third flagship in a series of Earth-observing satellites designed to view Earth as a whole system, observe the net results of complex interactions within the climate system, and understand how the planet is changing in response to natural and human influences. Read more

GRACE Fact Sheet

Launched in March 2002, the Gravity Recovery and Climate Experiment is a five-year mission intended to produce maps of the Earth’s gravity field with unprecedented precision and resolution. Read more

Watching our Ozone Weather

Until about 30 years ago, atmospheric scientists believed that all of the ozone in the lower atmosphere (troposphere) intruded from the upper atmosphere (stratosphere), where it formed by the action of sunlight on oxygen molecules. Read more

Chemistry in the Sunlight

Ozone has proven to be among the most difficult air pollutants to control. To control ozone requires understanding its complex chemistry and how the chemical travels from one locality to another. Chemistry in the Sunlight explains basic aspects of ozone formation and provides a sample set of chemical reactions involved in ozone production. Read more

Solar Radiation and Climate Experiment (SORCE) Fact Sheet

Earth scientists will move a step closer to a full understanding of the Sun's energy output with the launch of the Solar Radiation and Climate Experiment (SORCE) satellite. SORCE will be equipped with four instruments now being built at the University of Colorado that will measure variations in solar radiation much more accurately than anything now in use and observe some of the spectral properties of solar radiation for the first time. With data from NASA's SORCE mission, researchers should be able to follow how the Sun affects our climate now and in the future. (Original 2001-11-30; updated 2003-01-21) Read more

ICESat Factsheet

The ICESat mission will provide multi-year elevation data needed to determine ice sheet mass balance as well as cloud property information, especially for stratospheric clouds common over polar areas. It will also provide topography and vegetation data around the globe, in addition to the polar-specific coverage over the Greenland and Antarctic ice sheets. Read more

CALIPSO: A Global Perspective of Clouds and Aerosols from Space

The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite mission helps scientists answer significant questions about climatic processes by providing new information on clouds and aerosols. Read more

Human Spaceflight Factsheet

Astronaut photography of Earth from the first space flights in the 1960s formed the foundation for the remote sensing technologies that followed. Read more


Aqua carries six state-of-the-art instruments to observe the Earth's oceans, atmosphere, land, ice and snow covers, and vegetation, providing high measurement accuracy, spatial detail, and temporal frequency. This comprehensive approach enables scientists to study interactions among the many elements of the Earth system. Read more

NOAA-M Continues Polar-Orbiting Satellite Series

Since the 1960s, NASA has developed polar-orbiting operational environmental satellites for the National Oceanic and Atmospheric Administration (NOAA). NOAA-M, the latest NOAA spacecraft, was launched on June 24, 2002. Read more

The Ozone We Breathe

Ozone in the lower atmosphere (troposphere) is toxic to human beings and many species of plants, causing harm without visible symptoms. The Ozone We Breathe focuses chiefly on the ozone's effects on human respiratory health and and the productivity of agricultural crops. Read more

Highways of a Global Traveler - Tracking Tropospheric Ozone

Ozone in the lower atmosphere (troposphere) is toxic to human beings and to many other living things that breathe it. After combining satellite observations with data-rich models that simulate the atmosphere’s chemistry and dynamics, scientists are finding tropospheric ozone in some unexpected places. Tropospheric ozone turns out to be an intercontinental traveler, crossing geographic and political boundaries. Read more

Stratospheric Aerosol and Gas Experiment III

The Stratospheric Aerosol and Gas Experiment (SAGE III) is a fourth-generation satellite instrument for observing the long-term health of the upper atmosphere, including the amounts of ozone, aerosols (suspended particles), and water vapor. Read more

Weather Forecasting Through the Ages

Only fifty years ago, weather forecasting was an art, derived from the inspired interpretation of data from a loose array of land-based observing stations, balloons, and aircraft. Since then it has evolved substantially, based on an array of satellite and other observations and sophisticated computer models simulating the atmosphere and sometimes additional elements of the Earth's climate system. The AIRS/AMSU/HSB combination on board the [soon to be launched] EOS Aqua satellite should further these advances, enabling more accurate predictions over longer periods. Read more

Research Satellites for Atmospheric Science, 1978-Present

NASA and its affiliated agencies and research institutions developed a series of research satellites that have enabled scientists to test new remote sensing technologies that have advanced scientific understanding of both chemical and physical changes in the atmosphere. Read more

Ultraviolet Radiation: How It Affects Life on Earth

Stratospheric ozone depletion due to human activities has resulted in an increase of ultraviolet radiation on the Earth's surface. The article describes some effects on human health, aquatic ecosystems, agricultural plants and other living things, and explains how much ultraviolet radiation we are currently getting and how we measure it. Read more

Biomass Burning

Biomass burning is the burning of living and dead vegetation, including both human-initiated burning for land clearing, and burning induced by lightning and other natural sources. Researchers with the Biomass Burning Project at NASA Langley Research Center are seeking to understand the impact that biomass burning has on the Earth's atmosphere and climate. Read more

Earth Observing 1 (EO-1)

In 2000, NASA launched Earth Observing-1 (EO-1). While flying at an altitude of 705-kilometers, EO-1's primary focus is to test advanced instruments, spacecraft systems, and mission concepts in flight. EO-1 will also return scientific data which is used in comparison with other satellite data to ensure the continuity of land-imaging data. Read more

Measuring Vegetation (NDVI & EVI)

In an effort to monitor major fluctuations in vegetation and understand how they affect the environment scientist use satellite remote sensors to measure and map the density of green vegetation over the Earth. By carefully measuring the wavelengths and intensity of visible and near-infrared light reflected by the land surface back up into space, scientists use an algorithm called a “Vegetation Index” to quantify the concentrations of green leaf vegetation around the globe. Read more

Drought: The Creeping Disaster

Though it is a gradual disaster, drought can have devastating effects on agriculture and water supplies, but monitoring and forecasts can allow people to take early actions that prevent harsh impacts later. Read more

Watching the Sun

The Active Cavity Radiometer Irradiance Monitor III will monitor the sun's total radiation output so scientists can better predict the sun's effect on global climate change. Read more

Space-based Observations of the Earth

With increasingly sophisticated satellite remote sensors, we can measure a wide range of geophysical parameters (such as surface temperature, distribution of clouds and aerosol particles, the abundance of trace gases in the atmosphere, or the distribution and types of life on land and in the ocean) with unprecedented accuracy and resolution. Read more

Sunspots and the Solar Max

This fact sheet describes solar phenomenon such as sunspots and the solar wind. Read more


By measuring the total amount of energy that the sun delivers to the Earth with ACRIMSAT, scientists will be able to build better scientific models of the Earth’s climate system, providing a vital piece of the global climate change puzzle. Read more

Global Fire Monitoring

Forest fires, brush fires, and slash and burn agriculture—types of biomass burning—are a significant force for environmental change. Fires may play an important role in climate change, emitting both greenhouse gases and smoke particles into the atmosphere. Read more

Remote Sensing

Remote sensing is the science and art of identifying, observing, and measuring an object without coming into direct contact with it. This involves the detection and measurement of radiation of different wavelengths reflected or emitted from distant objects or materials, by which they may be identified and categorized. Read more


A relatively unstable molecule that represents a tiny fraction of the atmosphere, ozone is crucial for life on Earth. Depending on where ozone resides, it can protect or harm life. Read more


QuikSCAT provides climatologists, meteorologists and oceanographers with daily, detailed snapshots of the winds swirling above the world’s oceans. Read more

Land Cover Classification

For years scientists across the world have been mapping changes in the landscape (forest to field, grassland to desert, ice to rock) to prevent future disasters, monitor natural resources, and collect information on the environment. While land cover can be observed on the ground or by airplane, the most efficient way to map it is from space. Read more

Landsat 7 Fact Sheet

The latest mission in the Landsat series—Landsat 7—continues the flow of global change information to users worldwide. Scientists use Landsat satellites to gather remotely sensed images of the land surface and surrounding coastal regions for global change research, regional environmental change studies and other civil and commercial purposes. Read more

Tropical Rainfall Measuring Mission

The Tropical Rainfall Measuring Mission (TRMM), is the first mission dedicated to measuring tropical and subtropical rainfall through microwave and visible infrared sensors, and includes the first spaceborne rain radar. Read more

Changing Global Cloudiness

Clouds are one of the most obvious and influential features of Earth’s climate system. They are also one of its most variable components. The natural diversity and variability of clouds has intrigued and challenged researchers for centuries. Read more

Changing Global Land Surface

Satellite remote sensing enables researchers to consistently monitor distribution and seasonal changes of the world’s vegetation and the exchanges of water and carbon between land vegetation and the atmosphere. These observations will help us understand the rate of change of atmospheric carbon dioxide and its effect on climate. Read more

La Niña Fact Sheet

The phenomenon known as El Niño is sometimes reverses, leading to strong trade winds, colder than normal water off the coast of Peru, and warmer than normal water near Australia. This cold counterpart to El NiƱo is known as La Niña. Read more

Ocean and Climate Fact Sheet

The Earth’s ocean and atmosphere are locked in an embrace. As one changes, so does the other. Read more

What is a Coccolithophore? Fact Sheet

Coccolithophores are one-celled marine plants that surround themselves with a microscopic plating made of limestone (calcite). Read more

Clouds & Radiation Fact Sheet

The study of clouds, where they occur, and their characteristics, plays a key role in the understanding of climate change. Low, thick clouds reflect solar radiation and cool the Earth's surface. High, thin clouds transmit incoming solar radiation and also trap some of the outgoing infrared radiation emitted by the Earth, warming the surface. Read more

Terra Spacecraft Fact Sheet

On December 18, 1999, NASA launched a new flagship, the Terra satellite, to begin collecting a new 18-year global data set on which to base future scientific investigations about our complex home planet. Read more