This is one day’s observations from Himawari-8, a Japanese weather satellite, animated in a loop. It shows the western Pacific, Australia, and parts of Asia, Antarctica, and Alaska as they looked on one day in mid-2015. It covers 24 hours in 12 seconds – a time lapse factor of 7,200×.
Thanks to NICT, JMA, and CEReS for producing and distributing the data.
Update: I talked (somewhat babblingly) with Rob Meyer at The Atlantic about this. For media requests, you can get in touch by e-mail. (But note that I can’t grant license clearance for the underlying data; you would need to talk to NICT for that.)
This is by Charlie Loyd, January 2016. The processing is based on this code. Feel free to get in touch with questions if you don’t see an answer here:
No. It’s one day in early August, 2015. (On the front page. For subpages, look in the URL.) It’s just that day in a loop. Covering more days would mean a bigger video file, and it’s already huge.
Short answer: Yes, other than speeding it up.
Long answer: Yes, basically, but it’s complicated. Big images of Earth always seem to get questions about why they don’t look exactly like others, and it’s a super interesting topic. I’ve tried to make the colors in the video look like Earth would look if you were an astronaut next to Himawari-8 after your eyes adjusted. I work in satellite imagery, and I’m sensitive to people feeling that they’re seeing something “doctored”, but the adjustment is what ordinary cameras do automatically: white balance and so on. It’s slightly different from what you’ll see in other representations, like DSCOVR EPIC, NASA’s Blue Marble, the Space Station’s stream, different film frames from the Apollo missions, DSLR photos – and even NICT’s versus CIRA RAMMB’s displays of Himawari-8’s data.
These are all ways of representing the huge contrast range and complex color palette of Earth for different purposes – meteorological, oceanological, general interest, etc. – on ordinary monitors.
The satellite’s camera system is designed for daylight, at least in the visible spectrum. A street in direct sunlight is about 10,000× brighter than when it’s lit by street lights. Our eyes adjust, but Himawari-8’s sensor doesn’t. If you’ve done manual photography, think of it like this: the camera is hardwired at the equivalent of 1/500 second at f/8 and ISO 100. Daylight is perfectly exposed, but night cityscapes just won’t show up.
If you’re looking for visible night imagery, your choices are: astronauts taking long exposures with DSLRs, EROS B (barely, in monochrome, for really well-lit places), and Suomi-NPP VIIRS’s day-night band (also in monochrome, and low-res, but sensitive enough to image by moonlight – and it’s the source of the Black Marble data, which is overlaid in the night hemisphere of CIRA RAMMB’s Himawari-8 images). Other than those, all the night imagery I know of is infrared.
I think you might be able to make out city lights with the naked eye from Himawari-8’s orbit if the sun isn’t in view at all, which only happens during the eclipses around midnight near the equinoxes. Otherwise it would be like trying to see dim orange specks on a black paper while holding it up next to the sun.
Yes, it’s Typhoon Soudelor (Hanna) near its peak intensity, gusting at about 285 kph (180 mph). It was unusual for its strength – a supertyphoon, equivalent to category 5 – and its small eye. It had just caused severe damage in the Marianas.
Several things. The turquoise in the tropics (especially along southern New Guinea and northern Australia) is shallow water – we’re seeing bright sand under a relatively thin layer of ocean. Around China, it’s air pollution from coal power, plus the naturally muddy water of big rivers. Around Japan there are some minor plankton blooms as well.
Himawari-8 is in geostationary orbit, meaning it circles around Earth exactly as fast as Earth is spinning – once a day – and so it’s always over one spot. (On the equator, near Jayapura.) This perspective is like being swung around by a dancer: we always see their face, but we see the light moving over it.
Himawari-8 is much farther than the orbits of the International Space Station and high-resolution imaging satellites, which are just outside the atmosphere. If the video is about 30 cm (1 ft) wide, then if Earth were that size, Himawari-8 would be 85 cm (2′ 9″) away – so the way it looks on your screen is roughly to scale from Himawari-8’s point of view. Maybe scooch back a bit. The video also shows roughly the amount of detail that you could see with the naked eye. (Himawari-8’s resolution is higher, but I didn’t want to make the video any enormouser.)
Himawari-8 is careful never to collect images of the sun, because they could blow out its sensor. (There are other satellites just for observing the sun.) Stars are too dim to show up in the same image as the sunlit Earth with current-generation sensors, just like city lights at night. Other planets are only about as bright as the stars – at the scale of the Solar System, Himawari-8 is still much closer to Earth than to anything else. That said, some back-of-the-envelope math suggests the sensor might pick up a recognizable Venus with some luck.
The moon does appear occasionally, dimly – it’s made of rock about as dark as asphalt.
The video has a ground resolution of about 8 km, and even the Space Station is only about 100 m across, which is 1/6,400 of a pixel. You can’t see satellite-sized things in low Earth orbit for the same reason you can’t see them only slightly further away on Earth’s surface: they’re hella itty-bitty. (GPS satellites, for example, are considerably closer, but they’re still crazy wee.)
There are no fires noticeable in this video (although later in the year you could see smoke from the Indonesian fires). We’re seeing the daily cloud cycle of the tropics: in the morning, the sun heats the forests, and the warm, moist air rises in convective cells to form cumulus clouds, some of which become thunderheads.
Sunglint – the reflection of the sun. It’s brightest where the water is smoothest.
Short answer: The same reason they are from Earth’s surface.
Long answer: Air scatters short wavelengths of light (blues and greens) much more than longer ones (yellows and reds). This is different from a blue pane of glass, which absorbs most reds. If you look at a white light through blue glass, it’s blue. But if you look at a white light through air over very long distances, it’s slightly orange-red – like the sun. The physical mechanism is Rayleigh scattering, and you can also see it in certain opalescent household plastics, smoke, and diluted milk.
The upshot is that direct sunlight is redder the more air it’s gone through, because its shorter frequencies have scattered off and become indirect light. If the sun is to your south on a clear day and you look up, you’re likely to see some blue photons that would have landed somewhere to the north except that they scattered off air molecules. That’s the blue sky. The slight blue haze in the video, especially at the edges (where we’re looking through more air) is the sky from above. It’s where the short frequencies that we don’t see at dawn and dusk ended up.
I doubt you can. They could always say that this is fake, as a huge amount of even harder to forge evidence would have to be as well. It’s hard to argue people out of conspiracy theories. If you’re worried about people not understanding the wonders of science and so forth, your effort might be better spent on helping someone who wants help than on fighting someone who doesn’t.
No, at least not nearly as cool. Himawari-8 has the best sensor of its kind in space today. Europe’s weather authorities are extremely stingy with their nearest equivalent data – their attitude is that the observations are for science or for money, not for silly websites.
And in America, our federal science budget is controlled by climate denialists who dishonestly impede Earth observation because environmental science embarrasses them and their funders. They have hidden their deliberate neglect of Earth observation behind cynical enthusiasm for headline-friendly pure science missions beyond Earth. (I strongly support solar system exploration. But to use it as a weapon against terrestrial research is appalling.)
In 2015 we launched DSCOVR, a satellite that had sat on a shelf going obsolete since 2001 for political reasons: because it was proposed by Al Gore and is useful for climate science. Its images are important for research, but the 15 years of development between it and Himawari-8 are painfully obvious in data volume and in data quality. That’s how seriously we’re taking climate change: we left a scientific instrument in mothballs for more than a decade because it might have told us something inconvenient about our homeworld.
We’ll have the GOES-R series of geostationary weather satellites coming online over the Americas probably starting in 2017, long after we should have had them. Its sensor is similar to the one in the Himawari-8/9 series, though without true color – the same US company built both. If we’d funded it and managed it like it mattered, you’d have just seen its data instead of Himawari-8’s. But instead we dragged our heels as if $11 billion is a problem for four hemisphere-wide, high-res, realtime weather satellites in service to 2036. (We’re not incapable of spending money on high-end aerospace projects: $11 billion is 7% of the amount by which the Joint Strike Fighter program is overbudget.)
The United States is a spacefaring society – not a nation of 318 million astronauts, but a nation of physical and environmental science, GPS, satellite and street maps, weather forecasts, DirecTV, safe aviation, high-yield agriculture, marine and wilderness rescue services, and $87 billion per year in satellite industry revenue. Strange, then, that it isn’t yet a nation of high-res realtime satellite weather. Running a modern weather satellite system is difficult and expensive, but we know how to do it, and we know it’s worth it. What’s always slowing us down is the fear that we’ll find something that makes political buyers mad. These Himawari-8 animations delight me, but it hurts that they aren’t yet possible in my hemisphere because someone’s selling out the future’s climate. If I sound angry it’s because I’m angry.
