JPL
Careers
Education
Science & Technology
JPL Logo
JPL Logo
Earth
.

NASA Scientists Discover Spring Thaw Makes a Difference

Dec. 10, 2003
Alaska's freeze and thaw by satellite.

Using a suite of microwave remote sensing instruments aboard satellites, scientists at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the University of Montana, Missoula, have observed a recent trend of earlier thawing across the northern high latitudes.

Using a suite of microwave remote sensing instruments aboard satellites, scientists at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the University of Montana, Missoula, have observed a recent trend of earlier thawing across the northern high latitudes.

This regional thawing trend, advancing almost one day a year since 1988, has the potential to alter the cycle of atmospheric carbon dioxide intake and release by vegetation and soils across the region, potentially resulting in changes in Earth's climate. The lengthening growing season appears to be promoting more carbon uptake by the vegetation than is being released into the atmosphere for the region. How long this trend will occur depends on whether soils continue to remain cold and wet.

Research scientists have been studying the freeze/thaw dynamics in North America and Eurasia's boreal forests and tundra to decipher effects on the timing and length of the growing season. These regions encompass almost 30 percent of global land area. They store a major portion of Earth's carbon in vegetation,, in seasonally frozen and permafrost soils. Large expanses of boreal forest and tundra are underlain by permafrost, a layer of permanently frozen soil found underneath the active, seasonally thawed soil.

"Frozen soil can store carbon for hundreds to thousands of years," said lead author Dr. Kyle McDonald of JPL, "but when the permafrost thaws and begins to dry out, it releases the carbon back into the atmosphere." The concern is that eventually carbon released from the soil will prevail over the amount being taken in by growing plants. Carbon dioxide levels in the atmosphere would increase at an accelerated rate, fostering even greater warming of the region and affecting global climate.

With help from NASA radars and other orbiting satellite microwave remote sensing instruments, including the National Oceanic and Atmospheric Administration's Special Scanning Microwave/Imager, scientists can monitor growing season dynamics of the global boreal forest and tundra daily. These instruments sense the electrical properties of water in the landscape, allowing scientists to determine exactly when and where the springtime thaw occurs.

Because of the large extent and location of boreal forest and tundra, and the global reservoir of carbon stored in their vegetation and soils, this region is extremely sensitive to environmental change. It has the capacity to dramatically impact Earth's climate.

"If global climate change is happening, here's where you would expect to see it first," McDonald said.

As the research team observed, the earlier the spring thaw occurs, the longer the growing season. These changes appear to be promoting plant growth for the region. The longer growing season allows plants to remove more carbon dioxide from the atmosphere over a longer period of time.

Carbon dioxide is an important greenhouse gas that, if left in the atmosphere, would promote additional warming. The plants release oxygen and store the carbon as biomass that eventually decomposes and transfers the carbon into the soil. Soil microbes decompose dead plant material, returning a portion of the soil carbon back into the atmosphere. The rate at which soil microbes decompose plant material and release carbon to the atmosphere is also very sensitive to temperature. It could potentially increase with warming temperatures and longer growing seasons.

From this general study, McDonald, Dr. John Kimball of the University of Montana, and JPL's Erika Podest have lead three different investigations, each focusing on different noticeable changes in the boreal region. Results of three related papers on this research will be presented to the American Geophysical Union's Fall Meeting this week in San Francisco.

The research is funded by NASA's Earth Science Enterprise. The Enterprise is dedicated to understanding the Earth as an integrated system and applying Earth System Science to improve prediction of climate, weather, and natural hazards using the unique vantage point of space.

For information about NASA's Earth Science Enterprise on the Internet, visit: http://www.earth.nasa.gov .

The California Institute of Technology in Pasadena manages JPL for NASA.

For information about NASA, visit: http://www.nasa.gov.

News Media Contact

Alan Buis

818-354-0474

alan.buis@jpl.nasa.gov

Elvia Thompson

(202) 358-1696

2003-166

Related News

Earth .

NASA’s ECOSTRESS Sees Las Vegas Streets Turn Up the Heat

Technology .

5 Things to Know About NASA’s New Mineral Dust Detector

Earth .

Soil, Sutures, and Climate Modeling Among Investigations Riding SpaceX CRS-25 Dragon to International Space Station

Earth .

NASA’s ECOSTRESS Detects ‘Heat Islands’ in Extreme Indian Heat Wave

Climate Change .

International Satellite to Track Impacts of Small Ocean Currents

Earth .

From Weather Forecasting to Climate Change, NASA’s AIRS Builds a Legacy

Climate Change .

NASA’s EMIT Will Map Tiny Dust Particles to Study Big Climate Impacts

Weather .

Clusters of Weather Extremes Will Increase Risks to Corn Crops, Society

Earth .

California Field Campaign Helping Scientists Protect Diverse Ecosystems

Earth .

NASA Finds New Way to Monitor Underground Water Loss

Explore More

Image .

Sheep Fire

Image .

Colorado Fire

Image .

High Temperatures in the San Francisco Bay Area

Image .

Lake Shuwarang Chhat, Pakistan

Image .

Earth Day Poster

Mission .

ISS-RapidScat

Image .

NASA's ECOSTRESS Shows Surface Heat in Houston

Image .

NASA's ECOSTRESS Shows Heat in Dallas and Fort Worth

Image .

NASA's ECOSTRESS Sees Las Vegas Streets Turn Up the Heat

Image .

EMIT Put to the Test at JPL

About JPL
Who We Are
Executive Council
Directors
Careers
Internships
The JPL Story
JPL Achievements
Documentary Series
Annual Reports
Missions
Current
Past
Future
All
News
All
Earth
Solar System
Stars and Galaxies
Subscribe to JPL News
Galleries
Images
Videos
Audio
Podcasts
Apps
Visions of the Future
Slice of History
Robotics at JPL
Events
Lecture Series
Team Competitions
Speakers Bureau
Calendar
Visit
Public Tours
Virtual Tour
Topics
JPL Life
Solar System
Mars
Earth
Climate Change
Exoplanets
Stars and Galaxies
Robotics
More
Asteroid Watch
NASA's Eyes Visualizations
Universe - Internal Newsletter
Social Media
Get the Latest from JPL
Follow Us

JPL is a federally funded research and development center managed for NASA by Caltech.

More from JPL
Careers Education Science & Technology Acquisitions JPL Store
Careers
Education
Science & Technology
Acquisitions
JPL Store
Related NASA Sites
Basics of Spaceflight
Climate Kids
Earth / Global Climate Change
Exoplanet Exploration
Mars Exploration
Solar System Exploration
Space Place
NASA's Eyes Visualization Project
Voyager Interstellar Mission
NASA
Caltech
Privacy
Image Policy
FAQ
Feedback
Site Managers: Veronica McGregor, Randal Jackson
Site Editors: Tony Greicius, Naomi Hartono