27 August 2011


Hurricane Felix over the coast of eastern Honduras. Credit: NASA via Universe Today.
1. Tropical cyclones are important rainmakers, providing 25 percent or more of available rainfall to places like Japan, India, and Southeast Asia—not to mention Texas, which desperately needs a dousing ASAP.
In the course of a year, low latitudes gain more heat and high latitudes loose more heat. Tropical cyclones help transport heat from the equator towards the poles. Credit: NASA.
2. Tropical cyclones help maintain the global heat balance by moving warm tropical air away from the equator and towards the poles. Without them, the tropics would get a lot hotter and the poles a lot colder... A typical tropical cyclone releases heat energy of about 50 to 200 exajoules a day. That's equivalent to 70 times our worldwide energy consumption.

Long Island, New York, with multiple barrier islands. Credit: NASA.
3. Paradoxically, fragile barrier islands need hurricanes for their survival—especially now, when sea levels are rising. Although hurricanes erode beaches on the ocean side of barrier islands, they build up the back sides of the same islands by depositing new sediments via winds and waves. This dynamical process keeps barrier islands alive.

Global thermohaline circulation, aka the ocean conveyor belt. Credit: Avsa via Wikimedia Commons.
4. Tropical cyclones stir up the ocean and drive the process of upwelling, thus playing a part in the thermohaline circulation—another important transport mechanism distributing heat between the equator and the poles and keeping the earth's temperature in better balance.

Mangroves, fish nurseries, can benefit from a hurricane's stirring of the waters. Credit: MIT-WHOI.
5. By stirring the ocean, tropical cyclones also cycle nutrients from the seafloor to the surface, boosting ocean productivity and setting the stage for blooms of marine life.


Image links:

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15

25 August 2011


Water vapor, showing massive footprint of Hurricane Irene at 1945 UTC on 25 Aug 2011. Credit: NOAA.

No matter where Hurricane Irene makes landfall it will likely impact a huge area of the East Coast. That's because the storm is so huge—and it's still growing—and because it's so slow moving.

These two factors amplify storm surge by inundating a lot of territory for a very long time.

Crescent moon. Credit: NASA.

Worse, Irene may well end up walloping the densely populated Northeast during the highest tides of the month—on Sunday's new moon.

If all the variables line up just wrong, this could lead to a catastrophic storm tide.

Storm surge versus storm tide. Credit: NOAA.

Meteorologist Jeff Masters, writing at his Wunderblog, warns:

I am most concerned about the storm surge danger to North Carolina, Virginia, Maryland, Delaware, New Jersey, New York, and the rest of the New England coast. Irene is capable of inundating portions of the coast under 10-15 feet of water, to the highest storm surge depths ever recorded.

Historical SLOSH (Sea, Lake, and Overland Surge from Hurricanes) animation from the 1938 New England hurricane. Credit: NOAA.

The 1938 New England hurricane (back in the days before naming), the only Cat 3 storm to hit the Northeast since the 1800s, drove a 15-foot storm surge onto Long Island.  

Above, you can see the extent of that surge from New York to Cape Cod. Here's an animated simulation of that.

Hand-drawn weather map of the 1938 Hurricane. Credit: NOAA.

Masters estimates a 20 percent chance that Irene will deliver a storm surge higher than 8 feet to New York City. If so, this is what it might look like, in his words:

SLOSH model predicts that a mid-strength Category 2 hurricane with 100-mph winds could drive a 15-20 foot storm surge to Manhattan, Queens, Kings, and up the Hudson River. JFK airport could be swamped, southern Manhattan would flood north to Canal Street, and a surge traveling westwards down Long Island Sound might breach the sea walls that protect La Guardia Airport. Many of the power plants that supply the city with electricity might be knocked out, or their docks to supply them with fuel destroyed. The more likely case of a Category 1 hurricane hitting at high tide would still be plenty dangerous, with waters reaching 8 - 12 feet above ground level in Lower Manhattan.

Storm surge for a Category 3 hurricane. Credit: NOAA's Storm Surge Interactive Risk Maps.

Here's a storm surge map for a Category 3 hurricane that I generated with NOAA's Interactive Risk Maps tool.

It's a good idea to use that tool to take a look at your own risks if you're anywhere along Irene's flight path.

Credit: Rhode Island National Guard.

Here you can see the storm surge damage from 1954's Hurricane Carol in Westerly, Rhode Island. Buildings in the center of the photo were floated off their foundations. Buildings in the lower portion were swept completely away and only slabs and driveways remained. 

Sea surface temperatures on 23 Aug 2011. Credit: NASA Earth Observatory.
To make matters worse, sea surface temperatures are running 1 to 3 degrees F above average between North Carolina and New York.

Since warmer waters make for a wetter storm, Irene will likely manifest as a superwet double whammy: wet from intense rainfall, and wet from intense storm surge.

Predicted rainfall from 25-31 August 2011. Credit: NOAA/NWS HPC.

This 5-day precipitation forecast forewarns Irene's real fury. Monster rainfall totals will likely lead to flooding of streams and rivers along much of the East Coast.

Hurricane Irene forecast path as of 2200 UTC 25 Aug 2011. Credit: NOAA.

Here's Irene's projected path as of 5pm EDT today.

Hurricane Irene at 2245 UTC 25 Aug 2011. Credit: NOAA/GOES Project Science.

And here's what the storm's looking like at 4:30pm EDT.

24 August 2011


Hurricane Irene has become a huge storm as of 2040 UTC, 24 Aug 2011, with hurricane-force winds extending 50 miles from the center, and tropical storm-force winds extending up to 205 miles from the center. Credit: NASA/GOES Project Science.
A stitched hemispherical view on 24 Aug 2011. You can see the low pressure systems to the north in Canada steering Irene. Credit: NASA/GOES Project Science.
Low and high pressure systems across North America influencing Irene's path and, ultimately, her landfall. Credit: GOES/SFSU.
Infrared image showing cloud tops at 20:45 UTC, 24 Aug 2011. The highest clouds are powerful bearers/drivers of wind and rain. Credit: NASA.
Sea surface tempertaures (Celsius) are a vital part of Hurricane Irene's fuel on the run north up the Gulf Stream. Water temperatures are 1-3°F warmer than average this year between North Carolina and New York, making Irene a wetter than average hurricane. Credit: NOAA.
A top-down view of rain intensities within Irene on 23 Aug 2011. Though Irene does not appear to have an eye in visible satellite imagery (the solid white center shows that it is still completely covered over with cloud), TRMM reveals an eye surrounded by a complete eyewall of varying rain intensities deep down under the cloud tops. The eyewall forms a complete circle in the rain field at the center of the image. The northeast corner of the eyewall contains an area of intense rain (darker red area), while the southern portion contains only light rain (shown in blue). Moderate rain (green areas) makes up the rest of the eyewall. The storm is still fairly asymmetrical, however, with most of the surrounding rain northeast of the center. Credit: NASA Earth Observatory. Images produced by Hal Pierce and caption by Steve Lang and Hal Pierce.
Taken at the same time as image above, shows a three dimensional view of Irene. Areas in red mark the tops of deep convection towers where precipitation-sized particles are being carried higher into the atmosphere by strong thunderstorms. These storms within a storm can intensify tropical cyclones and hurricanes by releasing large amounts of heat, known as latent heat, via condensation. This heat can intensify the hurricane’s circulation especially when released near its core. Credit: NASA Earth Observatory. Images produced by Hal Pierce and caption by Steve Lang and Hal Pierce.
Irene at 22:15 UTC, 24 Aug 2011. The low angle of the day's last visible light illuminates the highest cloud tops in spiral bands to the southeast, north, and far to the northeast of the storm's center. Credit: NOAA.


Icarus. 2008. Gail Potocki.
I know of no other artist who wields insight, emotion, and intellectual heft—not to mention gorgeous technique—to examine the environmental ills besetting us today.

Gail Potocki's landscapes are catastrophes unfolding before our eyes—in the sea, in the air, and on the land. Yet her human subjects, shattered and vulnerable, are creatures of exquisite hope... precisely because of their melancholic awareness of their plight.

(As always, click on the images to see larger versions.)

I asked Gail to tell me about each of these paintings. Of Icarus (above), she wrote:

"Influenced by Icarus ignoring his father's warning and flying too close to the sun; I saw similarities in this myth with nature's warnings of our own possible self-destructiveness. In the case of Icarus here, his wings have been stolen from the dead bird that he has slung over his shoulder."

Thaw. 2008. Gail Potocki.

About Thaw, Gail said:

"Both the bees and the woman are out of place in this landscape. The bee brings a fleck of light to the woman representing our dependence on them as life givers/pollinators."

Overflow. 2008. Gail Potocki.

"My concern about human population growth is represented by the two people interlaced in the human paper cutouts. The background is a solid mass of buildings where only a small square of sky shows through as all of the landscape becomes consumed."

Shipwrecked. 2005. Gail Potocki.

"I've played with another idea of the disappearing bees, battered and shipwrecked against the rocky shore."

Plastic Vortex. 2008. Gail Potocki.



Plastic Vortex:

"With animals trapped in the plasticized water, the figure in this painting recoils from the Grim Reaper-like seabird as she bears witness to an omen of the future of our oceans."

Tiara. 2005. Gail Potocki.


"This is symbolic of deforestation's effect on the landscape. The woman/tree hybrid catching fire represents all of humanity's attachment to nature and how our fates are intertwined."

Gail paints in Michigan. I picture her world as a snowy canvas.

Here's what she told me about her relationship between her natural neighborhood, her work, and her audience:

"I am definitely more productive overall in the winter. I spend most of the year at my studio in Michigan (right in the middle of the snow-belt) so I love to be in my warm studio listening to music and painting when there's a blizzard outside. I try to transfer some of the drama from the weather into the work.
"Also, the view of the open field behind my studio ignites my creativity. Although I am not really a painter of landscapes, being surrounded by all this natural beauty inspires me to create narratives about it and how our actions affect the environment.
"I am not naïve enough to believe that 'art can change the world,' but I do feel that my goal as an artist is to try to bring things to peoples' attention that they might not normally think about."

For more on Gail Potocki, check out her website, plus this stunningly beautiful book, The Union of Hope and Sadness, written by Thomas Negovan, director of Century Guild, the Chicago gallery representing her.

23 August 2011


NASA's Earth Observatory posted these gorgeous views of Hurricane Irene today. Both were captured by the Tropical Rainfall Measuring Mission (TRMM) satellite, which passed directly over the storm at 15:57 UTC on 22 August 2011.

At the time, Irene was a Category 1 hurricane with maximum sustained winds of 70 knots/130 kilometers/80 miles per hour.

From the Earth Observatory caption:

The top image shows a top-down view of the rain intensity within the storm. TRMM reveals that although a hurricane, Irene has not yet developed an eye and is not yet fully organized... Rainbands, containing light to moderate rain (shown in blue and green, respectively) curve around the storm mainly to the north and east of the center, revealing the presence of the storm’s low pressure circulation, but one that is not yet intense.
The lower image, taken at the same time, provides a three dimensional perspective of the storm. It reveals an area of deep convection (shown in red) near the storm’s center where precipitation-sized particles are being carried aloft. These tall towers are associated with strong thunderstorms responsible for the area of intense rain near the center of Irene seen in the previous image. They can be a precursor to strengthening as they indicate areas within a storm where vast amounts of heat are being released. This heating, known as latent heating, is what is drives a storm’s circulation and intensification.

Hurricane Irene, lower right, at 2332 UTC 23 Aug 2011. Credit: GOES Project Science.
Irene originated from a tropical wave that propagated off the west coast of Africa to become the 8th named storm of the season. Her formation date of August 20 ties this year with 1936 as the second earliest date for formation of the season's 9th storm. Furthermore, Jeff Masters writes at his Wunderblog:

Hurricane season is only one-third over, and we've already had almost a full years' activity already. Tropical Storm Irene is the 9th named storm this year, and an average season has just 10-11 named storms... Only 2005 was more active this early. However, the first eight storms of the year have done far less damage than is typical. All eight storms stayed below hurricane strength, making 2011 the first hurricane season since record keeping began in 1851 to have more than six consecutive tropical storms that did not reach hurricane strength. As I discussed in Friday's post, a major reason for this is the lack of vertical instability over the tropical Atlantic so far this year. We've had a large amount of dry, sinking air over the tropical Atlantic, and the usual amount of dry, dusty air from the Sahara, both helping to keep the atmosphere stable and stop this year's storms from intensifying into hurricanes.

Irene however is growing fast and big—you can see her enormous diameter in the image above—and is threatening to become this year's 10th billion-dollar disaster.


Sea surface temperatures as of 24 Aug 2011 along Hurricane Irene's projected path. Credit: NOAA/Rutgers University Coastal Ocean Observation Lab.

In the image above you can see some of what is likely to fuel Irene on her northward path in the next few days—extremely warm waters, up to or above 30°C/86°F, through the Turks and Caicos and the Bahamas, all the way up the Gulf Stream to Cape Hatteras.

Top two images produced by Hal Pierce.