Featured Research

from universities, journals, and other organizations

Land Cover Changes Affect U.S. Summer Climate

Date:
March 25, 2004
Source:
NASA/Goddard Space Flight Center
Summary:
While climate may be impacted by carbon dioxide emissions, aerosols and other factors, a new study offers further evidence land surface changes may also play a significant role.

Impact of Changing Vegetation Pattern on July Temperatures
Credit: Image courtesy NASA/Goddard Space Flight Center

While climate may be impacted by carbon dioxide emissions, aerosols and other factors, a new study offers further evidence land surface changes may also play a significant role.

The study of summer climate in the United States reported changes in land cover, particularly vegetation, have impacted regional temperatures and precipitation. The study used data and computer models from NASA and other organizations such as the National Oceanic and Atmospheric Administration (NOAA).

"The largest human impacts on nature have occurred since the Industrial Revolution," said Somnath Baidya Roy, a research scientist at Princeton University, N.J. Roy is lead author of the study published in a recent issue of the Journal of Geophysical Research-Atmospheres. Co-authors included George Hurtt, University of New Hampshire; Christopher Weaver, Rutgers University; and Stephen Pacala also from of Princeton.

Previous studies simulated and compared past and present climates with current and potential vegetation. This research used the NASA-funded Ecosystem Demography computer model to trace the evolution of vegetation distribution patterns over the U.S. for nearly 300 years. "The model is truly a technological breakthrough and enables scientists to study the potential impact of land use and climate change across a wide range of scales, from individual plants to continental regions," Hurtt said.

The researchers found land cover changes produced a significant cooling effect of more than one degree Fahrenheit in parts of the Great Plains and Midwest as agriculture expanded and replaced grasslands. Farmlands tend to create lower temperatures through increased evaporation. A warming effect was found along the Atlantic coast where croplands replaced forests.

Compared to forests, croplands are less efficient in transpiration; a daytime process where water evaporates from leaves during photosynthesis and cools the air. A slight warming effect was also observed across the Southwest, where woodlands replaced some deserts.

The study found land cover changes could impact local precipitation, but not as significantly as they affect temperature. The relatively strong cooling over the central U.S. has probably weakened the temperature difference between land and the Gulf of Mexico, slowing the northern movement of weather systems and resulting in enhanced rainfall across Texas. Consequently, the air masses reaching the Central Lowlands region, including Illinois and Indiana, are drier, causing rainfall reductions.

"Land cover change is not uniform. Most people associate land cover change with deforestation, but the changes in the U.S. are more complex, creating a temperature signal that is more difficult to study," Roy said. The forest cover in the U.S. has actually increased in the last 100 years mainly due to farm abandonment in the East, fire suppression in the West, and large parts of the Great Plains have been converted into irrigated croplands, which tends to produce cooling.

The research also carries additional implications. "It is important to understand the effects of changing land cover, because it can mitigate or exacerbate greenhouse warming," Roy said. "In the U.S. over the past 100 years, it seems to be offsetting greenhouse warming. The opposite is probably true in most other parts of the world. This finding has also been supported in previous research," Roy said.

Researchers relied on several computer models. These included the Ecosystem Demography model, which incorporates data from NASA's International Satellite Land Surface Climatology Project. The model contains data from the Global Energy and Water Cycle Experiment. The experiment was conceived to take advantage of environmental monitoring satellites including NASA's Terra, Aqua, Tropical Rainfall Measuring Mission, and ADEOS I and II. The study also used the Regional Atmospheric Modeling System for regional climate simulations.

NASA's Earth Science 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. NASA, Princeton, and NOAA funded this research. For information and images about this research, visit: http://www.gsfc.nasa.gov/topstory/2004/0223landsummer.html

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


Story Source:

The above story is based on materials provided by NASA/Goddard Space Flight Center. Note: Materials may be edited for content and length.


Cite This Page:

NASA/Goddard Space Flight Center. "Land Cover Changes Affect U.S. Summer Climate." ScienceDaily. ScienceDaily, 25 March 2004. <www.sciencedaily.com/releases/2004/03/040325072251.htm>.
NASA/Goddard Space Flight Center. (2004, March 25). Land Cover Changes Affect U.S. Summer Climate. ScienceDaily. Retrieved September 16, 2014 from www.sciencedaily.com/releases/2004/03/040325072251.htm
NASA/Goddard Space Flight Center. "Land Cover Changes Affect U.S. Summer Climate." ScienceDaily. www.sciencedaily.com/releases/2004/03/040325072251.htm (accessed September 16, 2014).

Share This



More Earth & Climate News

Tuesday, September 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Researchers Explore Shipwrecks Off Calif. Coast

Researchers Explore Shipwrecks Off Calif. Coast

AP (Sep. 16, 2014) Federal researchers are exploring more than a dozen underwater sites where they believe ships sank in the treacherous waters west of San Francisco in the decades following the Gold Rush. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Conservationists Face Uphill PR Battle With New Shark Rules

Conservationists Face Uphill PR Battle With New Shark Rules

Newsy (Sep. 14, 2014) New conservation measures for shark fishing face an uphill PR battle in the fight to slow shark extinction. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

      Technology News



      Save/Print:
      Share:

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile: iPhone Android Web
      Follow: Facebook Twitter Google+
      Subscribe: RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins