The measurements made by SWOT will show how the oceans affect climate change and how global warming affects lakes, rivers and reservoirs. (Credit: CNES)
With the launch of a new NASA satellite on December 16, we’ll be able to see water on Earth in a whole new way. The satellite called Surface Water and Ocean Topography (SWOT), made jointly with the French space agency Center National d’Études Spatiales (CNES), will examine the water on more than 90% of the planet’s surface and measure the water height in both. oceans and bodies of fresh water.
The measurements made by SWOT will show how global warming affects oceans, lakes, rivers and reservoirs. In addition, this satellite data can help communities better prepare for floods and other water-related disasters, which are becoming more frequent as a result of the climate crisis.
Water is essential for life on Earth, but it also affects our weather and climate by storing and moving carbon and heat absorbed from the atmosphere. Scientists can learn more about the global water budget by looking at this resource and then find out about the main sources of water, how those sources are changing, and what effects it will have on different environments.
“It’s going to help us understand where the water is, where it’s coming from and where it’s going,” said Katherine Calvin, NASA’s chief scientist and senior climate advisor.
Scientists have many questions about how heat moves between the Earth’s atmosphere and the ocean, and how this could accelerate global warming. SWOT will answer some of these.
SWOT’s Ka-band radar interferometer, or KaRIn, will be able to find details 10 times finer than the information sensors can retrieve at sea level. KaRIn sends out radar pulses from one of the antennas that are reflected off the Earth’s surface, and the return signal is picked up by the two antennas working together. The combined efforts of the antennas allow scientists to map surface water in two dimensions. Current ground and satellite monitoring collects data from only a few thousand of the world’s largest lakes, but SWOT will increase that number to more than a million.
Currently, to study water bodies, researchers use instruments such as river or ocean gauges that measure specific locations. One thing that makes it difficult to get accurate readings is the banks of rivers – it’s hard to control the size of rivers with steep banks. Pre-space satellites could not determine the depth of Earth’s water bodies.
But the KaRIn radar can take measurements even when there are clouds in the sky or when it is dark at night. On the satellite, each antenna is at the end of a 33-foot-long (10-meter-long) boom. These antennas send radar pulses to the surface of the water and collect the signals that come back. The spacecraft will take 3D photographs of nearly all rivers more than 330 feet (100 meters) wide and measure ocean features less than 60 miles (100 kilometers) in diameter.
(Credit: NASA)
SWOT also includes an X-band radio communication system to transmit data to scientists, a radiometer to compensate for delays in receiving signals from moving water, an altimeter, and a thermal management system to maintain the satellite stable bed while in extreme heat and space. cold
“If we really want to understand [the water cycle] in ways that are important to us, we need to be able to think about it not just conceptually, but in terms of volumes,” explained Tamlin Pavelsky, head of hydrology science during a Dec. 13 briefing. How much water is there and how does it flow from one place to another? SWOT will allow us to do that.”