Cristobal Whirls Toward Iceland

By Tom Yulsman | September 1, 2014 12:25 am

Formerly a hurricane, Cristobal takes aim on Iceland in this image captured by NASA’s Aqua satellite on Sunday, Aug. 31, 2014. (Source: NASA)

As I’m writing this on Sunday night (Aug. 31), the cyclone formerly known as Hurricane Cristobal is taking dead aim on Iceland.

You can see it whirling off Iceland’s coast in the image above, captured by NASA’s Aqua satellite on Saturday. No longer a hurricane, it is, in the parlance of meteorology, an “extra-tropical cyclone” — a whirling dervish of a storm that has moved far north from its origins in the tropics.

To get even more technical, Cristobal may be what’s known as a “warm seclusion cyclone,” meaning a core of unusually warm and moist air at its center is encircled by colder air, causing that core to be “secluded.”

The remnants of Cristobal will likely bring high winds and lots of rain to Iceland on Sunday.

Getting Droned On Greenland’s Ice Sheet

By Tom Yulsman | August 30, 2014 12:54 pm

If you’re as fascinated by the science of our planet as I am, you’ve probably seen all sorts of imagery of the world’s frozen places, including dramatic photos of summer meltwater coursing across the surface of the Greenland Ice Sheet.

And now, for a new and thoroughly spectacular perspective, check out the video above. Shot from an unmanned aerial vehicle (UAV) — more commonly known these days as a drone — it shows ephemeral rivers of meltwater pouring into shafts, called moulins, in the ice sheet.

It’s part of a project, called the Dark Snow Project, managed by Jason Box of the Geologic Survey of Denmark and Greenland. Box and his colleagues are studying the impact of soot from wildfires and industry, and snow microbes as well, on the reflectivity of snow and ice in Greenland.

If that sounds esoteric, consider that darkening of snow and ice can lead to increased melting. This happens because dark snow and ice are less reflective, which means they absorb more solar energy.

And make no mistake about it: As the climate has warmed, large portions of Greenland have been experiencing accelerated melt: Read More

Come Fly With Me, Let’s Fly Let’s Fly Away…

By Tom Yulsman | August 22, 2014 12:36 pm

My friend and colleague Andrew Revkin found this wonderful video on the National Weather Service New York Facebook page and posted it to DotEarth, his N.Y. Times blog, this morning. It’s so impossibly cool I just had to share it with you too.

As rain showers disperse, there is an outward explosion visible in the radar loop  — apparently the signature of many thousands of insect-eating tree swallows taking off from their roosts along the Connecticut River at dawn today. As they fly away, they create a massive, expanding, flapping cloud that looks like rain showers on the radar. Andy has posted links to additional information about the birds at DotEarth, so check that out if you’re interested.

These birds aren’t the only winged creatures to have shown up on radar. Read More

Time-lapse Satellite Animations Show Birth of Giant Thunderstorms in Glorious Detail

By Tom Yulsman | August 19, 2014 8:03 am

I often find myself transfixed when big, towering thunderheads boil up along Colorado’s Front Range, where I live. Hail-spitting, tornado-spawning supercells are not required. Even a lone cell can have that effect on me.

So when the folks at the Satellite Blog of the Cooperative Institute for Meteorological Satellite Studies began posting animations of thunderstorms taking shape — as seen from space by  the GOES-14 weather satellite — I thought I would share them with you, along with imagery shot from the ground.

Typically, GOES satellite animations consist of images taken every 30 minutes. But for the two animations I’m posting here, the satellite was put into a ‘rapid scan’ mode, with images captured every minute. They are, in a sense, timelapse animations that dramatize the incredibly dynamic nature of the atmosphere from a vantage point and at a scale that we don’t experience very often. When I look at them, I get a sense of an atmosphere boiling and seething with energy — solar energy, of course.

The animation at the top of the post shows the development of thunderstorms near Las Vegas on Aug. 14, 2014. These storms caused some flash flooding.

FYI: Some of the fine detail in the clouds has been lost in the Youtube video. It also goes by kind of fast. So for a higher resolution version that is also a bit slower, check out the CIMSS post here. The animated gif may take awhile to load. Be patient. It’s really cool once it’s running.

The birth of a thunderstorm on Aug. 14, 2014 over Boulder City, Nevada on the shore of Lake Mead and just east of Las Vegas was captured by NASA's Terra satellite.  (Source: NASA)

The birth of thunderstorms on Aug. 14, 2014 near Lake Mead and Las Vegas was captured by NASA’s Terra satellite. (Source: NASA)

Read More

Tropical Cyclones Parade Across the Pacific

By Tom Yulsman | August 8, 2014 5:54 pm

Screenshot of an animation showing patterns of water vapor in the atmosphere. Magenta color indicates areas where clear, dry air penetrates lower in the atmosphere. White areas show areas of high water vapor — including in three storms swirling in the Pacific Ocean between Aug. 3rd and 8th, 2014. (Source: NOAA)

Tropical Storm Iselle made landfall on the Big Island of Hawaii today, Aug. 8th — only the second tropical storm in recorded history ever to do so, and one of four cyclones that have been swirling in the Pacific Ocean.

Iselle struck with winds of 60 miles per hour, and it brought torrential rains of 4 inches per hour or more. Here’s what all that rain has wrought:

Following on Iselle’s heels is Hurricane Julio, which luckily is forecast to skirt just north of the Hawaiian Islands. And out to the west are Hurricane Genevieve, which does not pose a threat to land, and Typhoon Halong, which most definitely does.

Halong is a big and dangerous typhoon that’s already lashing Japan with rainfall. It is moving slowly and is poised to lumber ashore at Shikoku Island Saturday evening, bringing maximum sustained winds of between 75 to 90 miles per hour.

The image at the top of the post is a screenshot of an animation based on GOES weather satellite data showing a parade of three of the four storms swirling just north of the equator in the Pacific Ocean between Aug. 3rd and 8th. Click on it to watch the animation. Read More

Iselle Now a Hurricane Threat to Hawaii; Julio is Following — and a New Disturbance Has Just Formed

By Tom Yulsman | August 6, 2014 7:45 pm

Hurricanes Iselle and Julio, as well as a disturbance that has just formed off Central America, are visible in this image captured by NASA’s Terra Satellite on Aug. 6, 2014. (Source: NASA)

Yesterday, I posted a satellite image showing double cyclonic trouble headed for Hawaii. Today the threat became even more troubling.

Source: Central Pacific Hurricane Center

Source: Central Pacific Hurricane Center

At 5:15 p.m. EDT today, the National Weather Service issued a hurricane warning for the Big Island of Hawaii, as Iselle is now expected to lash the island with hurricane-strength winds on Thursday. Maui and Oahu may experience tropical storm conditions. Click on the thumbnail at right to see the forecast track for Iselle.

As I’m writing this, Iselle’s winds are pegged at about 90 miles per hour. As it approaches Hawaii, drier air is expected to cause weakening. But it’s not yet clear how strong the storm will be. It could wind up as tropical storm. But consider this warning from the Central Pacific Hurricane Center:


Those impacts include torrential rains of 4 to 8 inches, and possibly double that in places, leading to flash flooding and mudslides.

Following Iselle is Hurricane Julio, now with 75 mile per hour winds. That storm is not as much of a threat to Hawaii, because it’s current forecast track would take the heart of the storm a little north of the islands at midday on Sunday. But if the models are just a bit wrong, and Julio passes closer to the islands, the storm could bring additional rain — which could be quite damaging in the aftermath of Iselle.

At Mashable, my friend and colleague Andrew Freedman is calling this scenario — two hurricanes approaching Hawaii from the east — “unprecedented.” Read More

Rosetta Has Arrived, and the View is Astounding

By Tom Yulsman | August 6, 2014 5:46 pm

This animation comprises 101 images acquired by the Navigation Camera on the European Space Agency’s Rosetta spacecraft as it approached comet 67P/C-G. The first image was taken on August 1, 2014, and the last on August 6 at a distance of 110 kilometers, or 68 miles. (Source: ESA/Rosetta/Navcam)

It took five loops around the Sun, three gravity-assist fly-bys of Earth and one of Mars, and a journey of 3.97 billion miles lasting 10 years, five months and four days. After all that, the Rosetta spacecraft finally reached it destination today — and made history.

Rosetta is the first spacecraft ever to rendezvous with a comet. It is now in quasi-orbit (more about that in a minute) around comet 67P/Churyumov-Gerasimenko. For more than a year, it will take pictures and gather data, and it will also send a lander down to the surface, all in a quest to help us understand the origin and evolution of the solar system. In so doing, it will tell us something of our own origins.

The animation above records the final leg of that long and lonesome journey. It consists of 101 images taken by the probe’s navigation camera as it approached the comet, the first from Aug. 1 and the last from today. Read More

Giant Fire Clouds Over California

By Tom Yulsman | August 6, 2014 1:21 am
A developing pyrocumulus cloud above the Oregon Gulch fire, part of the Beaver Complex fire. Photographed from an Oregon Air National Guard F-15C fighter jet by James Haseltine on July 31, 2014, at 8:20 PM Pacific Daylight Time. (Source: Nasa Earth Observatory)

A developing pyrocumulus cloud above the Oregon Gulch fire, part of the Beaver Complex fire. Photographed from an Oregon Air National Guard F-15C fighter jet by James Haseltine on July 31, 2014, at 8:20 PM Pacific Daylight Time. (Photo: James Haseltine via NASA Earth Observatory)

On Sunday, I posted satellite images of massive fire clouds billowing from wildfires raging along the California-Oregon border.

On Tuesday, NASA’s Earth Observatory weighed in with more details, as well as spectacular photographs taken on the evening of July 31 by James Haseltine from an Oregon Air National Guard F-15C fighter jet — including the one above.

And this one too: Read More

After a 4-Billion-Mile Journey, the Rosetta Probe is Less than a Day Away from Historic Rendezvous With a Comet

By Tom Yulsman | August 5, 2014 11:16 am

The Rosetta space probe captured this image of comet 67P/Churyumov-Gerasimenko on August 4, 2014 from a distance of about 234 kilometers (145 miles). The spacecraft is less than a day away from its final rendezvous. (Please click the image for a spectacular closeup view of the comet’s surface. Source: ESA/Rosetta/NAVCAM)

The Rosetta spacecraft is poised to make history.

If all continues to go well, it will complete its rendezvous with comet 67P/Churyumov-Gerasimenko at 8 GMT tomorrow, Aug. 6 (4 a.m. Eastern Daylight Time), and settle into orbit.

This would be a first: No spacecraft has ever orbited a comet before.

Rosetta is now closer to the comet than the International Space Station is to the surface of Earth — and the image above shows that the view is already quite spectacular. The spacecraft’s NAVCAM camera acquired the image yesterday.

Read More

Double Trouble for Hawaii: Iselle and Julio

By Tom Yulsman | August 5, 2014 12:26 am
double trouble

NASA’s Aqua satellite captured this image of Hurricane Iselle, to the left, and Tropical Storm Julio, to the right, on Monday, Aug. 4, 2014. Both are headed toward Hawaii. (Source: NASA)

Heads up Hawaii: Double trouble is headed your way in the form of two tropical cyclones.

The image above, acquired Monday (Aug. 4) by NASA’s Terra satellite, shows the situation: Hurricane Iselle to the left, and Tropical Storm Julio to the right. Both are expected to affect the Hawaiian Islands in the coming week.

As I write this late on Monday night, Iselle is a strong storm with winds over 130 miles per hour, qualifying her as a Category 4 cyclone. Iselle also has the distinction of being a very rare “annular” cyclone, according to Jeff Masters, chief meteorologist for Weather Underground. This means it features a thick eye wall and a dearth of spiral bands. Read More


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ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

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