Remote Islands IV: Where’s Waldo (Pitcairn)? Edition

Take a look at this VIIRS “Natural Color” image and see if you can find Pitcairn Island. It’s in there somewhere:

VIIRS Natural Color RGB composite of channels I-1, I-2 and I-3, taken 22:25 UTC 10 April 2014

VIIRS Natural Color RGB composite of channels I-1, I-2 and I-3, taken 22:25 UTC 10 April 2014

You’re definitely going to want to click through to the full resolution version. (Click on the image, then click again.) You won’t be able to see it otherwise. Take your time. Note: this is actually pretty similar to searching for fires.

Did you see it?

If you answered “no”: Good! That’s just what the early settlers of Pitcairn Island wanted: an island that no one could find! If you answered “yes”: I think you’re mistaken. You probably saw Henderson Island, which is bigger and easier to see.

Pitcairn is only 3.6 km across. That’s just 7 pixels in this composite of high-resolution (375 m at nadir; I-band) channels. It’s total land area is 4.6 km2. Henderson Island is 37.3 km2. There’s even a third island visible in this picture, but you need the eyes of an eagle to see it – Oeno at 0.65 km2. Look again and see if you see any green pixels.

If you give up, here’s the answer:

VIIRS Natural Color RGB composite of channels I-1, I-2 and I-3, taken at 22:25 UTC 10 April 2014

VIIRS Natural Color RGB composite of channels I-1, I-2 and I-3, taken at 22:25 UTC 10 April 2014. The visible islands are labelled.

Now, you may have just clicked to the full-resolution version and are now wondering if I’m right about Oeno Island. Is there really anything there? Yes. Just look at that part of the image zoomed in by 800%:

VIIRS Natural Color image (10 April 2014) zoomed in on Oeno Island

VIIRS Natural Color image (10 April 2014) zoomed in on Oeno Island

See those three green pixels (not counting the latitude line drawn on there) that are surrounded by lighter blue pixels? That’s Oeno. It is one of the smallest islands you can say that VIIRS “saw”. Here’s what it looks like from a really high-resolution satellite. The light blue pixels surrounding it are the surrounding reef and lagoon of the atoll.

So, why all the interest in a couple of tiny islands in a remote part of the Pacific Ocean? First of all, there are winter storms battering both coasts of the United States, so it’s nice to enjoy a little bit of escapism. Now you can fantasize about being on a tropical island instead of facing the reality of shoveling another 2 feet of snow. Second, it’s fun to look for little islands that can’t be seen with current geostationary satellites (although it will be interesting to see if the high-resolution [0.5 km] visible channel on Himawari will be able to see it; it might be too far east, though). Plus, it’s been over two years since I last looked at remote islands – there may a whole new generation of viewers interested in this stuff who never knew this was part of the blog. Third, I don’t have to write as much and you don’t have to read as much as I fill my blog post quota for the month.

However, to barely keep things on the topic of atmospheric science and satellite meteorology, I will note that, in the images above, you can see a string of clouds streaming to the northwest from both Pitcairn and Henderson Islands. This is the visible manifestation of fluid dynamics which we have discussed before.

If you’ve heard of Pitcairn Island prior to this, it’s probably because you heard of the Mutiny on the Bounty. A group of mutineers who didn’t want to be hanged for their crime settled on Pitcairn Island and burned their ships so they could never leave and, hopefully, never be found. That is the very definition of “getting away from it all”. (Pitcairn is also known to stamp collectors who seek the very rare stamps from the far corners of the world. Selling stamps to tourists is actually a significant part of their economy.)

Today, the island is home to ~50 people – all but two of which are direct descendents of the mutineers. Oeno and Henderson Islands are uninhabited. Henderson Island is a UNESCO World Heritage Site that has been largely untouched by mankind. Oeno Island is a favorite “get-away” spot for Pitcairn Islanders for whom an island of 50 people is just too crowded!

If you want to know more about Pitcairn or you have an hour of free time to use up, check out this documentary on the island, its history, and the people who make it their mission to visit one of the world’s most remote islands:

Investigating Mysteries of the Deep, Dark Night

Conspiracy theorists will tell you that conspiracies exist everywhere; that they’re part of daily life; and that most people are ignorant of all the attempts by various governments around the world to covertly control every facet of your life. Only they know the truth. But, that’s just what they want you to believe! Conspiracy theorists are simply manipulating you in order to control you and create a New World Order! Wake up!

Full disclosure: I am subsidized by the U.S. government to inform people of the capabilities and uses of the satellite instrument called VIIRS and today I’ll show you how that satellite instrument can help separate fact from fiction when it comes to the latest conspiracy theory. (Of course, working for the government means I could be part of the conspiracy!  Mwa ha ha!)

During the last week of August 2014, I was sent this link to a story from a pilot/photographer who captured “the creepiest thing so far” in his long flying career. I’ll quote his initial post again in its entirety here (for those of you too lazy to click on the links):

Last night [24 August 2014] over the Pacific Ocean, somewhere South of the Russian peninsula Kamchatka I experienced the creepiest thing so far in my flying career. After about 5 hours in flight we left Japan long time behind us and were cruising at a comfortable 34.000ft with about 4,5 hours to go towards Alaska.
We heard via the radio about earthquakes in Iceland, Chile and San Francisco, and since there were a few volcanos on our route that might or might not be going off during our flight, we double checked with dispatch if there was any new activity on our route after we departed from Hongkong.

Then, very far in the distance ahead of us, just over the horizon an intense lightflash shot up from the ground. It looked like a lightning bolt, but way more intense and directed vertically up in the air. I have never seen anything like this, and there were no flashes before or after this single explosion of light.

Since there were no thunderstorms on our route or weather-radar, we kept a close lookout for possible storms that might be hiding from our radar and might cause some problems later on.

I decided to try and take some pictures of the night sky and the strange green glow that was all over the Northern Hemisphere. I think it was sort of a Northern Lights but it was much more dispersed, never seen anything like this before either. About 20 minutes later in flight I noticed a deep red/orange glow appearing ahead of us, and this was a bit strange since there was supposed to be nothing but endless ocean below us for hundreds of miles around us. A distant city or group of typical Asian squid-fishing-boats would not make sense in this area, apart from the fact that the lights we saw were much larger in size and glowed red/orange, instead of the normal yellow and white that cities or ships would produce.

The closer we got, the more intense the glow became, illuminating the clouds and sky below us in a scary orange glow. In a part of the world where there was supposed to be nothing but water.

The only cause of this red glow that we could think of, was the explosion of a huge volcano just underneath the surface of the ocean, about 30 minutes before we overflew that exact position.

Since the nearest possible airport was at least 2 hours flying away, and the idea of flying into a highly dangerous and invisible ash-plume in the middle of the night over the vast Pacific Ocean we felt not exactly happy. Fortunately we did not encounter anything like this, but together with the very creepy unexplainable deep red/orange glow from the ocean’s surface, we felt everything but comfortable. There was also no other traffic near our position or on the same routing to confirm anything of what we saw or confirm any type of ash clouds encountered.

We reported our observations to Air Traffic Control and an investigation into what happened in this remote region of the ocean is now started.

If you go back and click on the link, you’ll see he posted several pictures of the mysterious red lights along with more detailed information about where and when this occurred. To save you some time, here is a representative picture (taken at 11:21 UTC 24 August 2014). And here is the location of the aircraft when they saw the lights.

There are three parts to this story: 1) the bright flash of light that looked like lightning coming up from the surface; 2) the aurora-like features in the sky; and 3) the red and orange lights from the clouds below that appeared to be larger than ordinary ship lights.

Since the story was first posted, people from all over commented on what they thought the lights were and the pilot has been updating his webpage to cover the most common and/or most likely explanations. The media picked up the story and used it to claim the world was coming to an end. Existing theories range from UFOs (unidentified flying objects) and UUSOs (unidentified under-surface objects) operated by space aliens to covert military operations to spontaneously-combusting methane bubbling out of the ocean to “earthquake lights“. The pilot himself initially thought it was an underwater volcanic eruption.

So, can VIIRS shed light on what was going on? Yes – at least, on #2 and #3. VIIRS passed over the area in question at 15:35 UTC on 24 August, which is about 4 hours after the pilot took his pictures. This means VIIRS can’t say anything about the lightning-like flash that was observed. So #1 is unexplained.

As for #2 – the aurora-like features in the sky – those are simply airglow waves. We’ve discussed airglow and airglow waves before here and here.

Now, onto #3 where VIIRS is most informative: the mysterious surface lights. I mentioned the VIIRS overpass at 15:35 UTC on 24 August. Here’s what the Day/Night Band (DNB) saw:

VIIRS Day/Night Band image from 15:35 UTC 24 August 2014.

VIIRS Day/Night Band image from 15:35 UTC 24 August 2014.

Look at 47.5°N latitude and 159°E longitude. (You can click on the image, then on the “4329 x 2342” link below the banner to see the full resolution image.) Those are the lights the pilot saw! (Note also that this night was near new moon, so any illumination of the clouds in that area comes from airglow. Light in the northeast corner of the image is twilight from the approaching sunrise.)

Now, VIIRS also has bands in the short-, mid- and long-wave infrared (IR). Surely, they must have seen the heat signature put out by a volcanic eruption, right? Not necessarily. The pilot’s photographs clearly show the lights shining through a layer of clouds, and it doesn’t take much cloud cover to obscure heat signatures at these wavelengths. But, for completeness, here are the observed brightness temperatures at 3.7 µm (channel M-12) and 10.7 µm (channel M-15):

VIIRS M-12 image from 15:35 UTC 24 August 2014

VIIRS M-12 image from 15:35 UTC 24 August 2014

VIIRS M-15 image from 15:35 UTC 24 August 2014

VIIRS M-15 image from 15:35 UTC 24 August 2014

I don’t see any hotspots in either of those images near the location of the lights. But, as I said, this doesn’t disprove the presence of flaming methane or volcanic activity because of possible obscuration by clouds. (Note that the clouds are easier to see in the DNB image than either of the IR images because there is no thermal contrast between the clouds and the open ocean for the IR images to take advantage of. There is, however, reflection of airglow light available to provide contrast in the DNB.)

What about the night before? The night after? Were the lights still there?

Here’s the DNB image from 15:54 UTC 23 August 2014 (aka the night before):

VIIRS DNB image from 15:54 UTC 23 August 2014

VIIRS DNB image from 15:54 UTC 23 August 2014

The light is there in pretty much the same place, although it looks like one big circle instead of a number of smaller lights. What is going on? Once again, it’s clouds. This time, the longwave IR shows we have optically thicker and/or an additional layer of high clouds over the lights:

VIIRS M-15 image from 15:54 UTC 23 August 2014

VIIRS M-15 image from 15:54 UTC 23 August 2014

Optically thicker clouds scatter and diffuse the light more, and what you are seeing in the DNB image is the area of clouds surrounding the light source that scatter the light to the satellite. See how clouds scatter the city lights of the U.S. Midwest in this comparison between the DNB and M-15 from 07:42 UTC 2 September 2014:

(You may have to refresh the page if this before/after image trick doesn’t work.)

It’s not that Chicago, Illinois and Gary, Indiana extend that far out into Lake Michigan or that the map is not plotting correctly. It’s that the optically thicker clouds over the southern end of the lake scatter more of the light back to the satellite (and over a larger area than the lights themselves), making it appear that the light is coming from over the lake.

Similarly, scattering in the clouds makes the individual “mystery lights” over the Pacific Ocean appear to be one large area of light, instead of a number of smaller lights.

How do the lights look on 25 August 2014 (aka the night after)? Here’s the DNB image:

VIIRS DNB image from 15:18 UTC 25 August 2014

VIIRS DNB image from 15:18 UTC 25 August 2014

Did you notice that? The lights aren’t in the same place as before. They moved. In fact, I tracked these lights in the DNB for two weeks. And I got this result:

Do volcanoes move around from day to day? I think we can safely say the pilot was not observing a volcanic eruption.

Now, I don’t know much about spontaneously combusting methane bubbles in the ocean, but I doubt they are this frequent. The pilot found another pilot’s report of methane burning over the ocean from 9 April 1984 (which also occurred during a flight from Japan to Alaska) but, that was during the day and it was the resulting cloud that was spotted, not the actual flames. There is no evidence of clouds being produced by these lights over this two week period. There also isn’t much evidence from seismic activity over this period to justify earthquake lights.

Another theory put forth was meteorites but, again, it seems highly improbable that VIIRS would be capturing this many meteorites hitting this localized area of the Pacific Ocean every night for two weeks. Plus, they would have to be pretty large meteors to appear as large as these lights.

Unless you believe in UFOs (or UUSOs), that leaves only one question: why were the pilots of this flight so quick to dismiss ships? The DNB has seen ships on the ocean before, and they look a lot like this. (You can find examples of individual boats observed by the DNB here and an example of larger squid boat operations here.)

It is true that most squid boats use white or greenish light and the pictures clearly show red and orange lights coming up through the clouds. But military ships are known to use red lights at night, at least, according to Yahoo! Answers.

If it looks like a fleet of ships and moves like a fleet of ships, I’m guessing it’s a fleet of ships. Unless, of course, it’s a gam of sharks with freakin’ laser beams attached to their heads.

 

Daniel, Emilia and Fabio, oh my!

It’s been a while since we last looked at some tropical cyclones with VIIRS. If you don’t keep up to date on tropical activity, you might not know there that have been a few. Granted, since Debby dumped a bunch of rain on Florida three weeks ago, the Atlantic basin has been pretty quiet. The East Pacific basin, however, has had one storm after another. The national media has largely ignored them since they have posed no threat to any landmasses. See this article from the L.A. times. Boring! Unless you can capture video of Jim Cantore struggling to stand upright, it isn’t a hurricane, right?

Wrong! First of all, eastern Pacific hurricanes affect some major shipping lanes. Second, and this is true of all hurricanes: they transport energy and moisture and help moderate the temperature imbalance between the tropics and mid-latitudes. They are important components of global energy transport.

In this post, we are going to compare the view of hurricanes provided by VIIRS against the view provided by GOES (specifically GOES-15). On 9 July 2012, there were two storms in the East Pacific: Daniel and Emilia.

Here is the GOES-15 view of Daniel followed by the VIIRS view of Daniel in their respective visible channels:

GOES-15 visible image (channel 1) of Hurricane Daniel, taken 22:45 UTC 9 July 2012

GOES-15 visible image (channel 1) of Hurricane Daniel, taken 22:45 UTC 9 July 2012. Image courtesy John Knaff.

VIIRS visible image (channel I-01) of Hurricane Daniel, taken 22:29 UTC 9 July 2012

VIIRS visible image (channel I-01) of Hurricane Daniel, taken 22:29 UTC 9 July 2012

Both images have the same latitude and longitude lines printed on them for reference and they both use the same color scales. If you zoom in, you’ll notice that the VIIRS image, with ~375 m resolution at nadir shows a bit more detail than the 1 km (1000 m) resolution GOES image. The additional detail provided by VIIRS really stands out in the infrared (IR) window channels, where GOES has 4 km resolution and VIIRS still has ~375 m resolution:

GOES-15 IR image (channel 4) of Hurricane Daniel, taken 22:30 UTC 9 July 2012

GOES-15 IR image (channel 4) of Hurricane Daniel, taken 22:30 UTC 9 July 2012

VIIRS IR image (channel I-05) of Hurricane Daniel, taken 22:29 UTC 9 July 2012

VIIRS IR image (channel I-05) of Hurricane Daniel, taken 22:29 UTC 9 July 2012

Now, it is worth noting that the high resolution IR image of VIIRS shown above comes from channel I-05, which is centered at 11.45 µm. The GOES image was produced from Imager channel 4, which is centered at 10.7 µm, so the two channels don’t exactly have the same spectral properties. VIIRS has a 10.7 µm IR channel as one of its moderate resolution bands (M-15). Here’s what that image looks like:

VIIRS IR image (channel M-15) of Hurricane Daniel, taken 22:29 UTC 9 July 2012

VIIRS IR image (channel M-15) of Hurricane Daniel, taken 22:29 UTC 9 July 2012

There isn’t a big difference between the two VIIRS channels, although you can see a bit more detail in the higher resolution (I-05) image.

On the previous orbit, VIIRS caught images of Hurricane Emilia, which was also in the view of GOES-15. Here’s how the images compare:

GOES-15 visible image (channel 1) of Hurricane Emilia, taken 21:00 UTC 9 July 2012

GOES-15 visible image (channel 1) of Hurricane Emilia, taken 21:00 UTC 9 July 2012. Image courtesy John Knaff.

VIIRS visible image (channel I-01) of Hurricane Emilia, taken 20:48 UTC 9 July 2012

VIIRS visible image (channel I-01) of Hurricane Emilia, taken 20:48 UTC 9 July 2012

GOES-15 IR image (channel 4) of Hurricane Emilia, taken 20:48 UTC 9 July 2012

GOES-15 IR image (channel 4) of Hurricane Emilia, taken 20:48 UTC 9 July 2012

VIIRS IR image (channel I-05) of Hurricane Emilia, taken 20:48 UTC 9 July 2012

VIIRS IR image (channel I-05) of Hurricane Emilia, taken 20:48 UTC 9 July 2012

In addition to the resolution differences, there is also a time difference of ~15 minutes between the VIIRS images and the GOES images. If you were to overlap these images, you would see that Emilia rotated a bit during that time. Emilia was not willing to hold the same pose for that long when having her picture taken. Once again, the M-15 image from VIIRS looks pretty similar to the I-05 image, so there’s no pressing need to show it.

Finally, let’s compare GOES-15 with VIIRS on Hurricane Fabio, which formed about a week after Daniel and Emilia were hurricanes.

GOES visible image (channel 1) of Hurricane Fabio, taken 20:30 UTC 15 July 2012

GOES-15 visible image (channel 1) of Hurricane Fabio, taken 20:30 UTC 15 July 2012. Image courtesy John Knaff.

VIIRS visible image (channel I-01) of Hurricane Fabio, taken 20:36 UTC 15 July 2012

VIIRS visible image (channel I-01) of Hurricane Fabio, taken 20:36 UTC 15 July 2012

GOES-15 IR image (channel 4) of Hurricane Fabio, taken 20:30 UTC 15 July 2012

GOES-15 IR image (channel 4) of Hurricane Fabio, taken 20:30 UTC 15 July 2012

VIIRS IR image (channel I-05) of Hurricane Fabio, taken 20:36 UTC 15 July 2012

VIIRS IR image (channel I-05) of Hurricane Fabio, taken 20:36 UTC 15 July 2012

The GOES and VIIRS images of Fabio were taken only 6 minutes apart, so there is less movement to impede the comparison.

In all three hurricanes, you can see a lot more structure to the VIIRS images in the both the visible and IR channels. It’s as if GOES represents a standard definition TV camera, and VIIRS represents a hi-def TV camera. All those wrinkles GOES is smoothing over are showing up in VIIRS. Daniel, Emilia and Fabio are going to need more makeup. (Or, they would if they weren’t already dead.)