NASA | Aqua’s AMSR-E Scans Earth’s Water Cycle


NASA satellites constantly circle the globe, using a range of ingenious instruments to monitor the weather, climate, and biosphere. But just like our eyes, there’s one thing many of them can’t do – see through clouds. Luckily there are a few instruments that are here to help. The AMSR-E instrument is a microwave radiometer That’s sort of like a radar in reverse. It has a big dish, kind of like one of those TV dishes that you see out in people’s yards. It sits up on the Aqua satellite kind of like a hood ornament and it measures all kinds of important things that we need to know to understand the water cycle. You know, where the water goes, from evaporation in the ocean to rainfall over ocean and land, and sea ice, and snow cover and all of the different things that we can measure with this instrument and they’re important to understand the Earth’s system, the climate system to see how everything interacts with everything else. One of the things that we can measure with AMSR-E is sea ice cover. In the Arctic and around the Antarctic. And one of the cool things you can do with this imagery that we have in the microwave – and we’re looking through clouds – at the sea ice – is, since we cover the Arctic and Antarctic every day, day after day after day after day, and sea ice changes kind of slowly as it melts or as it freezes and as the wind pushes it around, you can make an animation of this which ends up showing you very nicely how sea ice evolves during, let’s say, the freeze portion of the winter. Or during the summer melt season. And how the ice flows as the wind pushes it down past Greenland in between Greenland and Canada. It shows us dynamically what’s happening. And what’s really cool is that with an instrument like AMSR-E, you can see all this even if there are clouds in the way. Sunlight issue becomes big because in the wintertime, there are months without sunlight. So for all those months where a visible satellite instrument would not allow you to get information because you didn’t have sunlight, the AMSR-E microwave instrument will allow you to get the information, so with the AMSR we can get information daytime or nightime or cloudy or not cloudy about the Earth surface. One of the products from AMSR-E that’s being used more and more is sea surface temperatures that we can measure right through clouds because the hurricane centers around the world, using sea surface temperatures from AMSR-E to see how warm the water is out ahead of the hurricane, but then also as the hurricane goes by it leaves behind a cold wake of water. Which if there’s a hurricane that’s coming behind it, that will tend to kill the hurricane coming behind it. And the hurricane forecasters are excited about the information they have that they didn’t have before. AMSR-E data also help us understand our changing climate. AMSR’s contribution to the science of climate change has been, for example, a long term record of global sea surface temperatures in all weather conditions through clouds, so we have this very important long-term data set showing how much is the Earth warming? What happens with the Earth cools during a La Niña event? We can ask the question, what caused the cooling, how did the cooling affect cloudiness? These are things that we can do with this long period of data that we’re now getting from AMSR-E. [music]

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