Results for: 2003

Weighing Earth's Water from Space

Weighing Earth's Water from Space

Launched in 2002, a pair of identical satellites that make up NASA's Gravity Recovery And Climate Experiment (GRACE) are tackling the problem in an unexpected way: they are weighing Earth's fresh water from space. Serving as a sort of "divining rod" in space that moves in response to a powerful, fundamental force of nature--gravity--the satellites respond to changes in Earth's gravitation field that signal shifts in the movement of water a cross and under Earth's surface. Read more

Savanna Smog

Savanna Smog

Each August in southern Africa, literally thousands of people equipped with lighters or torches go out into the African savanna, a region dotted with villages and teaming with animals, and intentionally set the dry grasslands ablaze. Read more

Drought Lowers Lake Mead

Drought Lowers Lake Mead

In the space of just three years, water levels in Lake Mead have fallen more than sixty feet due to sustained drought. Landsat images show the extent of the change to the lake's shoreline. Read more

Denali's Fault

Denali's Fault

During the afternoon of November 3, 2002, the water in Seattle’s Lake Union suddenly began sloshing hard enough to knock houseboats off their moorings. Water in pools, ponds, and bayous as far away as Texas and Louisiana splashed for nearly half an hour. The cause? Alaska’s Denali Fault was on the move, jostling the state with a magnitude 7.9 earthquake. Read more

Dwindling Arctic Ice

Dwindling Arctic Ice

Since the 1970s, Arctic sea ice has been melting at the rate of 9 percent per decade. NASA researcher Josefino Comiso points to an accelerating warming trend as a primary cause and discusses how global climate change may be influencing the shrinking Arctic ice cap. Read more

Little Islands, Big Wake

Little Islands, Big Wake

The Hawaiian Islands interrupt the trade winds that blow across the Pacific Ocean, with far-reaching effects on ocean currents and atmospheric circulation. Read more

Watching the World Go By

Watching the World Go By

Space Station Science Officer Ed Lu describes what it is like to look at the Earth over the course of an orbit. His descriptions are accompanied by digital photographs of Earth he has taken and transmitted to the ground during his mission. Read more

Just Add Water: a Modern Agricultural Revolution in the Fertile Crescent

Just Add Water: a Modern Agricultural Revolution in the Fertile Crescent

Satellite observations in the Middle East's Fertile Crescent have documented a modern agricultural revolution. The dramatic changes in crop production in southern Turkey over the last decade are the result of new irrigation schemes that tap the historic Tigris and Euphrates Rivers. Read more

Land Matters

Land Matters

Storm-related losses from the 1982-83 El Nino cost the state of California an estimated $2.2 billion. Fifteen years later, damages from the 1997-98 El Nino cost California only half that amount. Differences in storm intensity and duration accounted for some of the reduced costs, but other factors were also at work. Read more

Double Vision

Double Vision

For the first time, scientists can rely on not one, but two satellites to monitor ocean surface topography, or sea level. TOPEX/Poseidon and Jason-1, launched nearly 10 years apart, are now engaged in a tandem mission, creating a spaceborne ocean observatory that provides scientists, climate modelers, and forecasters with nearly global coverage of the world's ocean surface at an unprecedented level of precision. Read more

Watching our Ozone Weather

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

The Incredible Glowing Algae

The Incredible Glowing Algae

The latest development in oceanographic remote sensing enables researchers to detect the glow, or phytoplankton fluorescence, from chlorophyll. Read more

Under a Variable Sun

Under a Variable Sun

In their continued effort to understand the Sun, solar physicists of the 21st century have used satellite data to study how much energy reaches the outskirts of the Earth’s atmosphere and whether or how much that amount varies over time. Recently published research claims that the amount of solar energy reaching the Earth has increased over the past two solar cycles, while other scientists doubt that any such change has occurred. This story describes how gaps in the set of observations and uncertainty about the accuracy of different satellite sensors have made splicing together a complete data set so controversial. Read more

Searching for Atlantic Rhythms?

Searching for Atlantic Rhythms?

All over the globe there are relationships between the conditions of the atmosphere and oceans that affect weather and climate at great distances. The North Atlantic Oscillation is one of these teleconnections, linking the temperature of the North Atlantic Ocean with winter weather in North America and Europe. Read more

The Great Bend of the Nile, Day and Night

The Great Bend of the Nile, Day and Night

Photographs from the Space Shuttle reveal the densley populated communities along the banks fo the Nile River. Read more

Squeezing Water from Rock

Squeezing Water from Rock

Survivors of the New Madrid earthquakes reported not only intense ground shaking and land movement, as would be expected during an earthquake, but also an unfamiliar phenomenon: water and sand spouting up through fissures, or cracks, in the Earth's surface Read more

A Delicate Balance: Signs of Change in the Tropics

A Delicate Balance: Signs of Change in the Tropics

While NASA climate scientists were reviewing radiation data emanating from the tropics simply to test existing notions, they uncovered a phenomenon no one expected. They found that progressively more thermal radiation has been escaping the atmosphere above the tropics and progressively less sunlight has been reflecting off of the clouds. Read more

Global Garden Gets Greener

Global Garden Gets Greener

Between 1982-1999, the climate grew warmer, wetter, and sunnier in many parts of the global greenhouse. For the most part, these changes were favorable for Earth's vegetation. Satellite observations of vegetation combined with nearly 20 years of climate data reveal that productivity of Earth's land-based vegetation increased by 6 percent during the time period. The greatest increase occurred in the tropics, where decreasing cloudiness made more sunlight available. Compared to the increase in human population, however, the small increase in productivity has not changed the Earth's habitability in any significant way. Read more

Lightning Spies

Lightning Spies

In 1997, NASA launched the Lightning Imaging Sensor (LIS) aboard the Tropical Rainfall Measuring Mission (TRMM) satellite. The LIS detects and maps the distribution and variability of cloud-to-cloud, intracloud, and cloud-to-ground lightning. Read more

Vanishing Ice

Vanishing Ice

Konrad Steffen arrived on the Greenland Ice Sheet for the 2002 fieldwork season and immediately observed that something significant was happening in the Arctic. Pools of water already spotted the ice sur face, and melting was occurring where it never had before. Read more

Escape from the Amazon

Escape from the Amazon

In this era of heightened concern about the relationship between the build up of atmospheric carbon dioxide and climate change, scientists are working to itemize all the ways carbon moves into and out of forest ecosystems. Perhaps nowhere on Earth do questions about the role of forests in the carbon cycle need answers more than in the Amazon Rainforest. Using satellite mapping and ground-based observations, scientists have discovered that carbon dioxide gas escaping from wetlands and flooded areas is a significant source of carbon emissions in the Amazon. Read more

Measuring Ozone from Space Shuttle Columbia

Measuring Ozone from Space Shuttle Columbia

New remote-sensing technology called limb viewing allows observation of the atmosphere from the side rather than straight down. From that side view the layers of the atmosphere appear like layers in a cake, allowing instruments to see the lower layers of the stratosphere where most of the recently observed ozone change, like the ozone hole, occurs. Read more

How on Earth was this Image Made?

How on Earth was this Image Made?

Remotely sensed Earth observations can include everything from sonar measurements used to map the topography of the ocean floor to satellite-based observations of city lights. Combining observations collected by a variety of instruments at different times and places allow scientists to create an otherwise impossible view of the Earth, showing underwater mountain ranges, cloud-free skies, and city lights that are brighter than daylight. Such visualizations are invaluable for interpreting complex data and communicating scientific concepts. Read more

From Space to the Outback

From Space to the Outback

The 2002-03 fire season in Australia echoes the devastating 2001-02 season that climaxed in the bush on the outskirts of Sydney and drew international attention once again to the city that had hosted the 2000 Summer Olympics. In the aftermath of that season, Australian scientists and government agencies developed a new fire monitoring system that uses observations from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on the Terra and Aqua satellites to identify fires in remote locations in Australia. The system provides a big-picture perspective of fires across the country and helps fire emergency agencies allocate resources to the areas where they are needed most. Read more

Flame & Flood

Flame & Flood

In the desert, fires can move fast; constant winds funnel through shallow dry creek beds to keep parched vegetation burning. A hot fire can make soil "hydrophobic," meaning that water runs off instead of soaking into the ground. Read more

The Human Footprint

The Human Footprint

In North America, the black-tailed prairie dog occupies as little as 5 percent of its former habitat. In Madagascar, more than 20 lemur species are threatened with extinction, and at least 15 species are already extinct. And on the island of Mauritius in the Indian Ocean, fewer than 50 mature mandrinette hibiscus plants remain in the wild. Read more

Chemistry in the Sunlight

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

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

The Road to Recovery

The Road to Recovery

A recent study in the Amazon rain forest shows that some types of logging may not negatively impact the carbon cycle as originally thought. Read more

ICESat Factsheet

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

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World of Change

Satellite images showing how our world— forests, oceans, cities, even the Sun— has changed in recent decades.
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The night side of Earth twinkles with light in these composite global and regional views.
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A catalog of NASA images and animations of our home planet.
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