A screenshot from a timelapse of Landsat images showing the growth of Shanghai since 1984. Click for the timelapse animation.

I launched the ImaGeo blog here at Discover back in February, and ever since I’ve been focusing on spectacular visuals related to the science of our planet. Starting Thursday, May 16, I’ll be slowing down a bit on my posts as I head off to China and Cambodia for a few weeks.

I plan on continuing to blog here at ImaGeo while I’m gone. Just not every day. I’m particularly interested in the phenomenon of megacities. Along those lines, check out the image above. It’s a screenshot of a timelapse animation consisting of Landsat images showing the growth of Shanghai since 1984. Click on it to see the animation on Google’s Earth Engine.

The growth of Shanghai’s urbanized area is simply astonishing. It has been driven by rapid industrialization and a rise in population from about 12 million people in 1984 to 23 million today.

I’m bringing two cameras on my trip, and I hope to share photographs and other imagery while I’m away.

I’ll also be visiting the famed Angkor Wat complex in Cambodia. Recent archeological evidence suggests that in the 15th century, it became the world’s first pre-industrial megacity — and it covered something on the order of 700 square miles. That’s about the size of greater London.

For now, I’m intrigued by the tale of two cities theme. But who knows what else I’ll find?

So stay tuned for updates from Asia. And thank you for reading ImaGeo!

A fourth solar flare has erupted on the sun. It’s the bright spot to the left of this image, which was captured by NASA’s Solar Dynamics Observatory. (Image: NASA/SDO/jhelioviewer)

The sun really seems to be ramping up its activity. At 9:45 EDT on Tuesday night, it unleashed its fourth flare in as many days. You can see it toward the left side of the sun in the image above from the Earth-orbiting Solar Dynamics Observatory spacecraft.

The false coloring in this picture is due to the wavelengths of light that the instrument on SDO viewed the sun with. These wavelengths are particularly good at revealing flaring activity.

Characterized as an X1.2 flare, it was not nearly as powerful as the one late Monday night. Nonetheless, X-class flares are the strongest, unleashing the energy of millions of hydrogen bombs almost all at once.

For more details about solar flares, including information about Monday’s big one, see my previous post here.

This flare, like the previous ones, was associated with a coronal mass ejection, or CME — a huge blow-out into space of billions of tons of matter. NASA’s SOHO spacecraft captured these images showing the evolution of the CME over the course of about 25 minutes:

A coronal mass ejection associated with Tuesday’s solar flare is seen at three separate times in its evolution in these images captured by the SOHO spacecraft. (Image: NASA/SOHO)

The sun is surely not done yet. It is heading toward the peak of its 11 year cycle.

Four images from NASA’s Solar Dynamics Observatory of an X3.2-class flare from late at night on May 13, 2013. Starting in the upper left and going clockwise, the images show the flare in four different wavelengths. (Image: NASA/SDO)

Last night the sun unleashed its latest tirade: the third flare in as many days, and the most powerful one in 2013 so far.

Exploding from the Sun’s surface with energy equivalent to millions of 100-megaton hydrogen bombs, the flare spewed intense radiation into space. It peaked last night at 9:11 p.m. EDT.

It was not directed toward Earth, but NASA says solar material from all three of the recent flares will pass by the Spitzer Space Telescope  and could give a “glancing blow” to the STEREO-B and Epoxi spacecraft. All these spacecraft can be put into a protective safe mode.

The latest eruption was characterized as an X3.2-class flare. The X-class category is the most powerful, and each step up in number indicates a doubling of energy. So this flare was more than twice as powerful as Sunday’s X1.7-class flare.

The panel of images above, from NASA’s Earth-orbiting Solar Dynamics Observatory spacecraft, shows the massive eruption of energy in four different wavelengths. Each panel shows what was happening at a different temperature. According to NASA, this provides scientists with insights into the causes of solar flares.

Here’s a screenshot from a movie showing the two previous flares, which occurred over the course of May 12 and 13 — click on it to watch it (and check out the cool accompanying music):

A movie consisting of images from NASA’s SDO spacecraft shows an X1.7-class and X2.8-class flare, as well as two coronal mass ejections, or CMEs, off the upper left side of the sun. Solar material also blew off the lower right side of the sun in a prominence eruption. (Movie: NASA/SDO/ESA/SOHO)

A solar flare occurs when magnetic energy builds up in the sun’s atmosphere and is then suddenly released with an accompanying burst of radiation across the electromagnetic spectrum. As the sun builds toward the peak of the 11-year solar cycle this year, all of this activity is completely normal.

So stay tuned for more.

Korea’s Kompsat-2 satellite captured this image over the sand seas of the Namib Desert on January 7 2012. (Image: KARI/ESA)

You have to wonder after looking at this image whether nature has an imagination. I know it doesn’t, but still…

You’re looking at sand dunes in the Namib desert, as seen from space by Korea’s Kompsat-2 satellite, along with an ephemeral, braided stream called the Tsauchab, which rises in the Kauklift Mountains.

The waterway carries water only when rain falls in the mountains. In the bone dry Namib desert, those flows are pretty few and far in between. But over he course of 2 million years, the river has done quite a bit of handiwork:

Sesriem Canyon, Nambia. (Image: Harald Süpfle)

Tsauchab has carved this 6 kilometer long gash through the sedimentary rock of the region. It’s alled Sesriem canyon, and it’s one of the prime tourist attractions of southern Namibia.

A composite image made up of multiple swaths of the Earth’s surface taken by the VIRRS instrument on the Suomi NPP satellite on January 4, 2012. (Image: NASA)

Best wishes to all the mothers out there (including this one).

What darkened the South Pacific northeast of Australia on May 10, as seen by NASA’s Terra satellite? (Image: NASA)

What’s up with that brown splotch sprawling across a broad swath of the South Pacific in the upper right corner of this satellite image?

Nope, it’s not some black hole that has just materialized in the middle of the ocean, threatening to suck New Guinea and Australia into its depths. Neither is a gargantuan oil spill, or a massive bubble of air pollution that’s drifted in from China.

What happened on May 10 northeast of Australia was completely natural and unthreatening: an annular eclipse of the sun. When this kind of eclipse happens, the moon passes in front of the sun, but it doesn’t black it out completely. That’s why the shadow cast onto the ocean in this image captured by NASA Terra satellite is not completely black and opaque. Some sunlight is getting through, producing more of a brown-out. (The black stripes are areas not imaged by Terra.)

Here’s what the X-Ray Telescope on the Hinode spacecraft saw when the moon passed between it and the sun:

The annular eclipse of the Sun as seen on May 10 by the Hinode spacecraft. Click for a detailed explanation. (Animation: XRT Picture of the Week — SAO, NASA, JAXA, NAOJ)

In an annular eclipse, the moon lines up in just the right way to allow only a fiery ring to be seen around its dark disk. That wasn’t the case here because Hinode was seeing the sun from a perspective in which the moon wasn’t perfectly aligned.

Lastly, here’s an image from closer to home:

A close-up from the Terra satellite of the South Pacific as the annular eclipse occurred. (Image: NASA)

The outlined areas in the image are the Solomon Islands.

The average concentration of CO2 for May 9 as measured on Hawaii’s Mauna Loa exceeded 400 parts per million. (Graphic: NOAA Earth Systems Research Laboratory)

It seems that in recent weeks people were waiting with great anticipation for something everyone knew would come some day. And now it has happened: The concentration of carbon dioxide in the atmosphere, as measured from near the summit of Mauna Loa on Hawaii, averaged more than 400 parts per million yesterday. (See here and here.)

It is the first time in 55 years of measurement that this has happened. And the Earth probably has not seen CO2 levels this high for millions of years.

Robert Kunzig has an excellent story at National Geographic about the science of CO2 monitoring. He also describes what research on ancient climates tells us about the significance of CO2 levels this high. So rather than address those issues, I thought I’d bring up something else: Just what kind of “milestone,” as Kunzig called it, is this? What is the significance of surpassing the 400 ppm “threshold”? 

Actually, I’m not entirely sure of the nature of that supposed milestone. Yes, for one day carbon dioxide in the Northern Hemisphere during spring surpassed 400 ppm. But will the weekly mean show that high a reading? Maybe. Maybe not. And it is unlikely that May will show an average higher than 400 ppm. Moreover, as plant growth kicks into high gear with warming temperatures, thereby removing CO2 from the atmosphere, the concentration will drop. And unless something remarkable happens, the average for 2013 won’t exceed the magic number either.

Don’t get me wrong. I’m not at all questioning the inexorable rise in CO2, or the impacts it has been having on the globe’s average temperature, and climate system. Far from it. But I am asking myself this question: What milestone have we passed? What threshold have we stepped over? A purely symbolic one, for sure. And a rather indistinct one at that. Not until the entire globe averages 400 parts per million for a year will the fuzziness disappear. That will take awhile.

And even when it does, except for a number, nothing tangible will have changed — most especially not the endless, seemingly dead-end debate we’ve been having about climate change.

It didn’t have to be that way.

I wrote my first feature article about climate change in 1984. I recently re-read it, and I was amazed at two things: How much the science of climate change has advanced since then, but also how little the overall parameters of the issue have changed.

In the story, I wrote about a report from the National Academy of Sciences, which said that clear signs of the climate change might appear as soon as the 1990s. And I also noted news accounts of the report focusing on the possible dire impacts: “…of cities like Charelston, South Carolina, submerged, of the nation’s breadbasket transformed into a desert and of New York City enjoying the same average temperature that Daytona Beach, Florida, does today.”

I also noted that these were worst-case scenarios that might develop if we failed to take action. But that we had time to begin grappling with the problem:

In short, said the NAS, the greenhouse effect is a reason for ‘caution, not panic.’ It will unquestionably pose serious, costly dilemmas for society. Building seawalls, altering agricultural techniques, moving farms, making provision for those who lose their livelihood from a change in climate and adapting to extremes of weather are all truly daunting prospects.

But the impact won’t come all at once. We have the luxury of knowing in a scientific way what may happen 100 years from now — a luxury not available to societies that survived catastrophes more horrifying than global warming. So there is reason to hope that we will not only cool the calamity of greenhouse Earth but also take advantage of whatever benefits it provides us.”

Now it’s almost three decades later, and yesterday we passed by some sort of fuzzy milestone. Whatever that means, we have a lot less time to grapple with the problem than we did in 1984 — when CO2 as measured on Mauna Loa stood at 340 parts per million.

This false color view over New Zealand was captured by NASA’s Terra satellite in April. (Image: NASA)

This beautiful squadron of clouds formed over New Zealand’s South Island on April 27 — and I’ve been meaning to showcase it ever since. I spotted it using NASA’s Worldview web site.

The false-color image, captured by NASA’s Terra Satellite, emphasizes wavelengths of light that are particularly good at revealing snow and ice, including ice crystals in clouds that register in peach colors. The bright red tones toward the top of the image reveal snowpack in New Zealand’s Southern Alps mountain range.

I’m no meteorologist, so I could be wrong, but these look to me like lee-wave lenticular clouds. These can form when wind blows across a mountain range, becoming disturbed in such a way as to create standing waves in the atmosphere. Depending on conditions, clouds can form at the top of the wave crests. For a technical explanation (very…), see this paper.

Some of the clouds in the image above have materialized downwind of The Remarkables mountain range, which form a dramatic backdrop for Lake Wakatipu on the South Island. The wind seems to be torquing one of the clouds into what appears like a weird corkscrew shape. Look in the lower right quadrant for it.

A screenshot of a timelapse video showing a lenticular cloud over New Zealand’s North Island. Click on the image to watch the video. (Video: Primal Earth Images)

New Zealand seems to produce its share of spectacular cloud formations. And not just on the South Island. The image above is a screenshot of a timelapse video showing a saucer-like lenticular cloud hovering over the Rangipo Desert on the North Island. Make sure to click on it to watch the mind-blowing video. And definitely check out Primal Earth Images for more. After looking at their amazing stuff, I am really tempted to drop everything and just move to New Zealand.

An animation of infrared images from the GOES-13 satellite shows a massive system of convective clouds approaching and then enveloping the New York area on the morning of May 8. (Source: Cooperative Institute for Meteorological Satellite Studies.)

Lately, I get the impression that New York City’s weather is more akin to the tropics than the Northeastern United States. And Wednesday’s torrential rain, accompanied by flooding, didn’t disabuse me of that idea.

Much of the United States has felt the effects of a storm that lumbered slowly eastward the past week, and on Wednesday morning it reached New York. Feeding on water vapor streaming from the tropical Atlantic, the storm caused lots of flooding in the city. In an echo of Hurricane Sandy, water poured into the subway system in places.

The animation above, from the Cooperative Institute for Meteorological Satellite Studies (where would ImaGeo be without these awesome folks?), consists of infrared images from the GOES-13 satellite. It shows what happened when the storm moving in from the west entrained the moisture from the Atlantic. Massive convective clouds formed and moved ashore, temporarily turning New York into something resembling the Amazon rain forest.

Technically speaking, images in the infrared show the temperature of cloud tops, as well as of the land and surface of the ocean. As clouds blossom in the atmosphere, the rising mass of moisture cools. In infrared images and animations like the one above, these colder temperatures are shown in the redder tones. The angrier and darker the red, the colder the temperature, and therefore the taller — and more massive — the cloud.

The VIIRS instrument on the Suomi-NPP satellite acquired these animated images of the Springs Fire blazing at night near Los Angeles. (Image: William Straka III, University of Wisconsin, CIMSS)

Some striking new remote sensing images of California’s Springs Fire came out today. I’ve followed the event with multiple posts (here, here and here), so I thought I’d share the new ones with you.

The blaze, which erupted on May 2, is expected to be fully contained by tomorrow. It was at first thought to have consumed 28,000 acres (about twice the size of Manhattan), but officials have now lowered their estimate to 24,251 acres.

The animated gif above consists of two images taken of the fire at night by the Suomi-NPP satellite on May 3 and 4. The sprawling night lights of Los Angeles can be seen on the right side of the picture. The fire, near Point Mugu State Park, appears as the bright white circular area on May 3. It pretty much disappears on May 4 as firefighters gain increasing control. For more information, as well as a still image taken by Suomi-NPP, check out NASA’s post here.

Meanwhile, the Landsat Data Continuity Mission, or LDCM, captured a pair of highly defined before-and-after images of the burn area. Heres the “after” image:

The Landsat Data Continuity Mission captured this the false-color image of the burn scar from the Springs Fire on May 4. (Image: NASA Earth Observatory)

For the pair together, check out the Earth Observatory post here. The images were taken by the Landsat Data Continuity Mission, the newest Landsat satellite, on May 2 and 4 respectively. In the false-color after image above, the burn scar shows up in reddish tones. (I’m not sure why NASA did it, but north is to the right.)

The LDCM spacecraft is currently undergoing engineering checks. When it becomes fully operational, control will pass to the U.S. Geological Survey, and the satellite will officially be re-named Landsat 8.