The result -- 285 billion metric tons, or 285 cubic kilometers of water by volume -- sounds like a lot. That amount is over half the volume of Lake Erie, which is the world’s 15th largest lake.
Until now, researchers could only estimate the amount of water in the Amazon floodplain using a few sporadic field studies and crude assumptions about water flow. In fact, water volumes on any floodplain are poorly known, if at all. Yet this information is critical to predicting the floods and droughts that could accompany global climate change, explained Alsdorf.
Much of Earth’s available fresh water resides in remote rivers, lakes and wetlands, and also underground.
“Nobody knows exactly how much water there is on the planet,” he said. “We need to understand how our water supply will change as the climate changes, and the first step is getting a handle on how much water we actually have.”
Alsdorf and his team have made it their mission to find ways to measure water from space.
Alsdorf and his team used four satellites -- three NASA satellites and one from the Japan Aerospace Exploration Agency -- to get the first direct measure of water in the floodplain.
They combined data from the Gravity Recovery and Climate Experiment, the Global Precipitation Climatology Project, the Shuttle Radar Topography Mission, and the Japanese Earth Resources Satellite. They focused on measuring water level changes during the wet and dry seasons between 2003 and 2006.
Taken together, these satellites gave a picture of how the Amazon landscape changed as highland rains surged through the river’s many tributaries and the resulting overflow spilled into the lowland jungle. After the water receded, they calculated the change in volume along the floodplain.
These calculations haven’t been made before, in part due to the immense difficulty of combining different kinds of data in a reliable way. The researchers had to meld gravity readings -- a measure of the flood water’s mass -- with radar and optical measurements of the water level and extent of the floodplain.
The measurements added up to an average of 285 cubic kilometers (285 billion metric tons) of water stored and emptied from the floodplain in a year.
At the height of the rainy season, water flowed into various locations on the Amazon floodplain at a rate of 5,500 cubic meters (5,500 metric tons) per second, and during the dry season, it drained away into the Amazon River -- and, ultimately, into the Atlantic Ocean – at a rate of 7,500 cubic meters (7,500 metric tons) per second.
The floodplain total, however large, represents only 5 percent of the amount that scientists believe is emptying from the Amazon River into the ocean every year.
To Alsdorf, the finding begs the question of exactly how much water is flowing through the Amazon system, and it underscores the many unknowns that scientists must confront as they work to understand climate change.
The Amazon, however grand in size, is just one river basin among countless basins around the planet -- each vital to the soil quality and water quality of its surroundings, he said.
Future measurements should be easier with the Surface Water and Ocean Topography (SWOT) mission, which aims to take stock of all the world’s water. Alsdorf co-leads the science team for the SWOT satellite, which NASA has set to launch in 2020.Contact: Doug Alsdorf, (614) 247-6908; Alsdorf.email@example.com
Pam Frost Gorder | EurekAlert!
How much biomass grows in the savannah?
16.02.2017 | Friedrich-Schiller-Universität Jena
Canadian glaciers now major contributor to sea level change, UCI study shows
15.02.2017 | University of California - Irvine
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
20.02.2017 | Materials Sciences
20.02.2017 | Health and Medicine
20.02.2017 | Health and Medicine