Can You Detect a Flood Through Satellite Imagery?

In 2016, NASA introduced the Cyclone Global Navigation Satellite System (CYGNSS). Instead of one big satellite in the sky that passes over an area twice a day, the CYGNSS are eight little satellites that work together as a constellation. These eight small satellites are low to Earth’s surface and orbit on a single launch vehicle, recording the ocean surface winds. This project, fully introduced in 2016, was created to gather more information about hurricanes since there is no other type of instrument to gather information on the ocean so close to the eye of a tropical cyclone, hurricanes or typhoon. Since there are multiple satellites measuring just the tropics, it allows these regions to get a better picture. Each satellite passes over a region every 12 minutes, which produces a new image every few hours, compared to every few days. This fast imaginary allows scientists to get a better understanding of these rapidly changing storms.

The information that is being measured and recorded from the CYGNSS not only allows scientists to get a better understanding of these storms but allows them to see things that they have never been able to see before. Along with the microwave signal that the CYGNSS uses to detect wind speeds, the CYGNSS also has a built-in Global Positioning Satellite, GPS (the same one used in cars), which reduces the choppiness of the ocean to help determine the wind speeds over the ocean surface. The GPS can also pick up reflections of standing water and the amount of moisture in the soil. Putting all of this information together, scientists can detect floods, a common occurrence during hurricanes.

Since hurricanes can have very rapid intensification, the old instruments used to observe them would only produce new information every two to three days, which meant that scientists were missing a lot of information. The CYGNSS allows scientists to receive data every 12 hours. This information can show how quickly an area floods during a hurricane. Since the GPS in the CYGNSS is able to pick up reflections of standing water, scientists can discover flooded areas caused by hurricanes.

This new information that is produced from the CYGNSS is groundbreaking. Since it is still new, more and more information is being discovered daily about how powerful this new satellite system really is. Scientists can spot flooding in areas that are hit by hurricanes or by overflow from rivers. Just recently scientists have been able to spot rivers off the Amazon River. Without the CYGNSS, satellites were not capable of capturing these rivers; this is due to the distance between ground and satellite. Being so close to Earth’s surface, they are able to find standing water through clouds and vegetation. The rivers they are able to see coming off the basin of the Amazon river are only hundreds of meters wide. CYGNSS principal investigator, Chris Ruf said: “When I saw the first land images of inland water bodies, I was amazed at their quality.” He continues by saying that the thought of being able to see these types of things in the past just seemed too impossible, but the high-resolution images that the CYGNSS produces are outstanding.
While all of this is still really new information, it’s something that will be useful going forward to help predict and assesses storms.

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© 2018 Weather Forecaster Allison Finch