Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Satellites show effect of 2010 drought on Amazon forests

30.03.2011
A new study has revealed widespread reductions in the greenness of Amazon forests caused by the last year's record-breaking drought.

"The greenness levels of Amazonian vegetation -- a measure of its health -- decreased dramatically over an area more than three and one-half times the size of Texas and did not recover to normal levels, even after the drought ended in late October 2010," says Liang Xu of Boston University and the study's lead author.

The drought sensitivity of Amazon rainforests is a subject of intense study. Computer models predict that in a changing climate with warmer temperatures and altered rainfall patterns, the ensuing moisture stress could cause some of the rainforests to be replaced by grasslands or woody savannas. This would release the carbon stored in the rotting wood into the atmosphere, and could accelerate global warming. The United Nations' Intergovernmental Panel on Climate Change has warned similar droughts could be more frequent in the Amazon region in the future.

The comprehensive study was prepared by an international team of scientists using more than a decade's worth of satellite data from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) and Tropical Rainfall Measuring Mission (TRMM).

Analysis of these data produced detailed maps of vegetation greenness declines from the 2010 drought. The study has been accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.

The authors first developed maps of drought-affected areas using thresholds of below-average rainfall as a guide. Next, they identified affected vegetation using two different greenness indexes as surrogates for green leaf area and physiological functioning.

The maps show the 2010 drought reduced the greenness of approximately 2.5 million square kilometers (965,000 square miles) of vegetation in the Amazon -- more than four times the area affected by the last severe drought in 2005.

"The MODIS vegetation greenness data suggest a more widespread, severe and long-lasting impact to Amazonian vegetation than what can be inferred based solely on rainfall data," says Arindam Samanta, a co-lead author from Atmospheric and Environmental Research Inc. in Lexington, Mass.

The severity of the 2010 drought was also seen in records of water levels in rivers across the Amazon basin, including the Rio Negro which represents rainfall levels over the entire western Amazon. Water levels started to fall in August 2010, reaching record low levels in late October. Water levels only began to rise with the arrival of rains later that winter.

"Last year was the driest year on record based on 109 years of Rio Negro water level data at the Manaus harbor. For comparison, the lowest level during the so-called once-in-a-century drought in 2005, was only eighth lowest," said Marcos Costa, coauthor from the Federal University in Vicosa, Brazil.

As anecdotal reports of a severe drought began to appear in the news media during the summer of 2010, the authors started near-real time processing of massive amounts of satellite data. They used a new capability, the NASA Earth Exchange (NEX), built for the NASA Advanced Supercomputer facility at the agency's Ames Research Center in Moffett Field, Calif. NEX is a collaborative supercomputing environment that brings together data, models and computing resources.

With NEX, the study's authors quickly obtained a large-scale view of the impact of the drought on the Amazon forests and were able to complete the analysis by January 2011. Similar reports about the impact of the 2005 drought were published about two years after the fact.

"Timely monitoring of our planet's vegetation with satellites is critical, and with NEX it can be done efficiently to deliver near-real time information, as this study demonstrates," said study coauthor Ramakrishna Nemani, a research scientist at Ames. An article about the NEX project appears in today's issue of Eos, the weekly newspaper of the American Geophysical Union.

Notes for Journalists:

As of the date of this press release, the paper by Xu et al. is still "in press" (i.e. not yet published). Journalists and public information officers (PIOs) of educational and scientific institutions who have registered with AGU can download a PDF copy of this paper by clicking on this link: http://www.agu.org/journals/pip/gl/2011GL046824-pip.pdf

The Eos article by Nemani et al. is also available online at: http://www.agu.org/journals/eo/eo1113/2011EO130001.pdf#anchor

Or, you may order a copy of the paper by emailing your request to Peter Weiss at pweiss@agu.org. Please provide your name, the name of your publication, and your phone number. Neither the paper nor this press release are under embargo.

Title: "Widespread Decline in Greenness of Amazonian Vegetation Due to the 2010 Drought"

Authors: Liang Xu and Ranga B. Myneni: Department of Geography and Environment, Boston University, Boston, Massachusetts, USA;

Arindam Samanta: Atmospheric and Environmental Research Inc., Lexington, Massachusetts, USA;

Marcos H. Costa: Federal University of Viçosa (UFV), Viçosa, , Brazil;

Sangram Ganguly: Bay Area Environmental Research Institute, NASA Ames Research Center, Moffett Field, California, USA;

Ramakrishna R. Nemani: Biospheric Science Branch, NASA Ames Research Center, Moffett Field, California, USA.

Contact information for the authors: Liang Xu: bireme@gmail.com, (617) 510-6583 Arindam Samanta: arindam.sam@gmail.com, (617) 852-5256 Marcos Costa: mhcosta@ufv.br, +55-31-3899-1899 Rama Nemani: ramakrishna.r.nemani@nasa.gov, (650) 919-4270 Ranga Myneni: ranga.myneni@gmail.com, (617) 470-7065

Eos Article on the NASA Earth Exchange (NEX)

Title: "Collaborative Supercomputing for Global Change Science"

Authors: R. Nemani: NASA Ames Research Center, Moffett Field, California, USA;

P. Votava, A. Michaelis, F. Melton, and C. Milesi: California State University, Monterey Bay, Seaside, California, USA.

Contact information for the authors: Rama Nemani: ramakrishna.r.nemani@nasa.gov, (650) 919-4270

Additional information available online about:

This study and the NEX project: https://c3.ndc.nasa.gov/nex/projects/1209/

The MODIS sensor and data products: http://modis.gsfc.nasa.gov The Tropical Rainfall Measuring Mission: http://trmm.gsfc.nasa.gov

Peter Weiss | EurekAlert!
Further information:
http://www.agu.org

More articles from Earth Sciences:

nachricht Ice cave in Transylvania yields window into region's past
28.04.2017 | National Science Foundation

nachricht Citizen science campaign to aid disaster response
28.04.2017 | International Institute for Applied Systems Analysis (IIASA)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>