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 New plate adds plot twist to ancient tectonic tale
15.08.2017 | Rice University

nachricht Global warming will leave different fingerprints on global subtropical anticyclones
14.08.2017 | Institute of Atmospheric Physics, Chinese Academy of Sciences

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

Im Focus: Scientists improve forecast of increasing hazard on Ecuadorian volcano

Researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science, the Italian Space Agency (ASI), and the Instituto Geofisico--Escuela Politecnica Nacional (IGEPN) of Ecuador, showed an increasing volcanic danger on Cotopaxi in Ecuador using a powerful technique known as Interferometric Synthetic Aperture Radar (InSAR).

The Andes region in which Cotopaxi volcano is located is known to contain some of the world's most serious volcanic hazard. A mid- to large-size eruption has...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

New thruster design increases efficiency for future spaceflight

16.08.2017 | Physics and Astronomy

Transporting spin: A graphene and boron nitride heterostructure creates large spin signals

16.08.2017 | Materials Sciences

A new method for the 3-D printing of living tissues

16.08.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>