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The data gathered by GPM and its international

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constellation of satellites has generated an unprecedented global

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view of rain and snow. We can see

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daily patterns, seasonal movements, the rain in our own backyard,

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and weather sweeping the continent. We can analyze regional hazards,

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and precipitation that connects the globe.

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We can build up months of data, to years,

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and decades to look at how precipitation will change in a changing climate.

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And we can explore precipitation, from pole to pole,

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in a snapshot of a single week.

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Daily rainstorms are a constant near the Equator.

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George: The interesting thing you see when you look at this is the daily pulse in convection,

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what you might call the "popcorn." So for example over Africa,

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you see this regular pulsation of convection and

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then there are the longer lived events, which are squall lines. Because this happens to be during

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August, what we can see is the squall lines, which move across the continent

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starting in Ethiopia, and when they come off the coast, they're known as easterly waves.

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These are the precursors for some of the hurricanes that we see in the United States.

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As you follow them across, the same kind of "popcorn" is taking place in

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South America. And if you watch carefully you can see that

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line of convection starts along the coast in the afternoon and starts

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propogating in. And if you watch the pulsing, what you see is it takes about two days

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for those squall lines in South America over the Amazon to reach

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the Andes Mountains, at which point they sort of die out because they interact

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with this very steep topography.
The Atlantic hurricane season was relatively

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quiet in 2014, but GPM was able to track storms into

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higher latitudes that nevertheless had unexpected impacts.

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Dalia: One of the things we can observe with the 2014 hurricane season is actually Hurricane

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Bertha, which you see here. Now it was kind of an unimpressive storm, but as you track it across

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the Atlantic, what you can see is that it caused massive flooding and wind damage

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in the UK. And so be being able to observe tropical cyclones in their

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infancy in the tropics and see how they move all the way to the high latitudes

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it gives us really important clues into how storms develop and intensify,

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all the way into the higher latitudes as extratropical systems.

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Gail: And it's really important to know what is happening in those high latitudes because

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that's where the majority of people live; it's where the populations are. And so being able

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to measure everything from the very light rain, which tends to occur at these

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high latitudes, and the falling snow, as well as the very heavy precipitation

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that occurs throughout the world, we have this data from the Global Precipitation

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Measurement mission.
Meanwhile the Pacific Ocean saw a steady

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barrage of tropical cyclones, slamming into Hawaii, the Philippines, and

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Japan.
Gail: Here you can see the different cyclones and

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typhoons as they move in the Pacific Ocean, one after another.

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What's also important about these is knowing where they are over the vast

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ocean so that once they get closer to land, operational users can make

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decisions about whether to evacuate people or not.

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George: For example we see Supertyphoon Halong, which recurved

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and then crossed Japan and started to interact with a mid-latitude cold front.

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Once it did that it went, as we say, extratropical

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and we can trace it all the way into the Northern Pacific Ocean.

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As we head south through Asia, seasonal

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rains drench India and its surrounding areas.

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Dalia: One of the things we can observe about this dataset is where and when rain is happening.

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And by being able to see, for example, this huge cluster of storms from the

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monsoons, we can understand where we might get heavy rainfall that leads to

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landslides and flooding. In fact what we observed during this time is actually a landslide

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that caused 150 fatalities. You can actually see

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what's happening just four hours after it occurred. And that near real time

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capability is critical for different disaster

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managers, understanding where we're getting floods and landslides around the world,

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and when we look at the longer term, where we're getting the absence of rain, where we have

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droughts, and understanding how those drought conditions are continuing or,

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you know, maybe, improved because of rainfall that's coming.

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With GPM we can look at how precipitation impacts very large populations,

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and shed new light on the area where almost no one lives.

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George: From South America, if we look to the south, we see the ocean that runs nearly around

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the entire globe, which we call the Southern Ocean. This is really sort of

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the terra incognita of precipitation, as far as I'm

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concerned. The Southern Ocean has almost no land and very few ships.

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It's a really challenging place; you don't go there unless you have to. As a result,

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we know very little about the meteorology and the precipitation. When you look at that zone

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what you see is the blue and darker purpley colors

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which represent snow. Because this is the Southern Hemisphere winter,

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there's some snow that we see. We've known about these storms for a long time,

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in terms of the cloud patterns but this is the first time we have a really great

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visualization of the rain, which is underneath. This is one of the features of these 

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datasets is that it's like an X-ray that looks through the clouds and actually sees the rain.

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Gail: When you take a step back and look at this dataset

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from a global perspective, you can see the precipitation at the tropics, that looks like these

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"popcorn" convective events. As well as these long-lasting

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frontal systems in the high latitudes. And it's with this data

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that we can start to understand precipitation globally

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and see how it interacts with humans and with the science in understanding it better.

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