The Collapse of TS "Don"

Don "won" come ashore with rain!

I am not sure I have ever seen a storm like TS "Don" 2011. The complete collapse, and lack of rain ashore, reminded me of storms I have seen disappear in hours after going ashore in Oman or Yemen, or Western Australia.

The drought continues in Texas, unfortunately.

HLG

Super Typhoon "Muifa"

Typhoon "Muifa" rapidly gained Cat 5 status yesterday, and shows a narly, pin-pint eye in this visible floater image. The typhoon, which was forecast to go east of Japan earlier this week, is now going to be bad news for millions as it turned to China, and possible the Korean peninsula. - HLG

Typhoon "Muifa" Turning to Flood-Ravaged Korea?

The FWSAAB has already dispatched an observer to the Korean peninsula, in anticipation of yet another wave of flooding rains this weekend, followed by a typhoon next week? - HLG

Google Earth Tool for NHC Hurricane Tracking

July 28, 2011
Tracking hurricanes in Google Earth
The 2011 hurricane season is in full swing, and Google has recently added a nice set of hurricane-related data to Google Earth. Simply make sure that your "Places" layer is enabled, and you'll see icons appear in the water wherever hurricanes and/or tropical storms exist.

This new feature in Google Earth is quite solid, as it provides quite a bit of data about each storm, along with historical tracks and future track predictions. However, it's a bit odd that this appears in the "Places" layer; why not somewhere in the "Weather" folder? As they explain in a recent blog entry, Google is trying to make the hurricane data easier to find by leaving it in the main "Places" layer, which is likely turned on for a lot of people. Still, if people dig around trying to find it, I'd expect most will go to the "Weather" layer first.

In past seasons we've seen other great hurricane trackers, such as the one from 'Glooton' that we've used for the past five years or so. However, that tracker is no longer working, and we're having a difficult time finding any decent tools beyond the one now built-in to Google Earth.

If you know of any other great hurricane tracking files for Google Earth, let us know about it and we'll be sure to add it to our weather tools KMZ file.

People AND Explosives Missing from Flood

You just don't see that every day! - HLG in the Far East Offices of FWSAAB

People and Explosives Missing After South Korea Deluge
By CHOE SANG-HUN
Published: July 28, 2011
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SEOUL, South Korea — Thousands of soldiers and police officers searched muddy wreckage and rain-swollen streams on Thursday for victims, survivors and explosives after floods and mudslides set off by torrential rain killed at least 48 people. Three others were reported missing.

The Defense Ministry said soldiers were looking for several active land mines buried decades ago near an air defense unit on Mount Wumyeon in southern Seoul. Landslides tore away parts of the mountain, slamming through homes and killing 16 people.

In Yangju, a border town north of Seoul, soldiers have recovered most of the land mines and other ammunition lost in a landslide that damaged an army depot. But they were still looking for an undisclosed number of explosives. Several North Korean land mines, apparently swept away by floodwaters, have been found in streams near the border in recent weeks.

At a mountainside resort village in Chuncheon, 60 miles east of Seoul, university students running a volunteer summer camp for local children were asleep when a landslide engulfed their lodgings around midnight Tuesday.

Ten of the 13 people found dead in the mud were university students, the police said. Police officers rescued 20 others from the rubble that covered several homes and businesses.

In a scene captured by a resident with a home video camera and broadcast nationwide, a mudslide pushed down Mount Wumyeon, which is popular among hikers, engulfing a road and tossing cars like toys in a furious wave of mud, water and gravel.

Rain has soaked much of the country for the past month. The most recent deluge was heaviest in Seoul and towns in northern South Korea. In several towns around Seoul, people died in flash floods. In Dongducheon, a city near the border with North Korea, four people were killed in flooding set off by 26 inches of rain since Tuesday afternoon.

On Wednesday morning, commuters found roads blocked by mudslides. Large stretches of Seoul’s boulevards were turned into brown pools, with only the roofs of abandoned cars exposed.

“I heard this terrible rumble,” a 57-year-old survivor of the Chuncheon mudslide told the national Yonhap news agency. “I woke up others, and we rushed out. In a split second, our motel was under the mud

TOTAL PRECIPITABLE WATER

I don't know what it means (from the CIMSS website - http://cimss.ssec.wisc.edu) but it sure is purty.

(you can see TS Don forming in the Gulf)

BB

Hyper East Asia Monsoons for the Foreseeable Future?

EGU 2011: Effects of aerosols on the East Asia summer monsoon

By Physics Today on April 6, 2011 10:53 AM | No TrackBacks

As East Asia's economy grows, so do its emissions of carbon and sulfur. The associated aerosols scatter and absorb solar radiation and modify the radiative properties of clouds. Those modifications, in turn, cause shifts in the monsoon patterns that affect the agriculture of one of the world's leading producers of rice and wheat.

Whether aerosols by themselves are responsible for the change in EASM behavior was one of the topics discussed at this year’s general assembly of the European Geosciences Union, which was held this week in Vienna, Austria.

The EASM is a seasonal change in atmospheric circulation and precipitation associated with asymmetric heating of the land and the sea. As the air over East Asia warms, it rises and creates a low-pressure area, which draws cool moist ocean air toward it. This inward movement generally leads to a predictable precipitation increase in July and August.

For the last three decades, however, the summer rain belt has shifted toward the south. Northern China has seen a drought in recent years while southern China has seen floods. Speaking at the EGU meeting, Jianping Li of the Institute of Atmospheric Physics, Chinese Academy of Sciences, pointed out that “the primary response of the EASM to global warming may be a southward shift of the rain belt, instead of an intensity change.”



“The maximum surface warming [increase up to 0.7°C over the past 30 years] occurs over high- to mid-latitudes [45°N–60°N],” explained Li. In the past, the highest temperatures occurred at lower latitudes. The warming rate that Li refers to is a change in temperature with time experienced in the north but not in the south. Because temperatures in the north are increasing while those in the south have remained relatively constant, there is a reduction in the pressure gradient, with the result that the moisture-laden sea air does not appear to be getting as far north as has been observed in the past. So rain now falls farther south although the average precipitation over the entire monsoon region remains the same.

Li uses models developed by the Intergovernmental Panel on Climate Change to investigate how surface temperature and the resulting monsoon patterns respond to anthropogenic and natural forcing. He tests model robustness by matching mean values, signal variations, and natural oscillations with data sets from the National Center for Atmospheric Research (NCAR) and the European Centre for Medium-Range Weather Forecasts.

“The largest uncertainty [of radiative forcing components] is aerosols,” Li said. While a main cause of planetary warming is carbon dioxide gas trapping long-wave radiation from Earth, aerosol particle effects are much more complex. Li added that “we should consider natural forcing too,” which includes varying solar input, volcanic emissions, and the Arctic oscillation.

Aerosol size and composition

Xiahong Liu, climate scientist from Pacific Northwest National Laboratory in Richland, Washington, also spoke at the EGU meeting. He pointed out that China's sulfur emissions have increased nearly fivefold between 1950 and 2011. At the same time, surface energy flux over East Asia has decreased by 5 W/m2 a decade. Sulfur emissions are converted to sulfate aerosols by oxidation in the atmosphere.



Liu takes the NCAR Community Atmosphere Model (CAM5) and applies it in a novel way to investigate the role of specific aerosol properties in the weakening of the EASM. Rather than looking at collective aerosol mass as has been done before, he examines how the size distribution and composition of different aerosols can bring about changes and be used to predict future effects. Sulfate and organic carbon (OC) generally have a cooling effect because they scatter incoming solar radiation back to space. Black carbon (BC)—also emitted by diesel combustion and biomass burning but with different chemical structure to organic carbon—traps radiation, which causes a warming effect.

In their particulate form, the combination of sulfate, OC, and BC can also modify cloud properties: A larger number of particles corresponds to a larger number of nuclei on which a fixed amount of water can condense in a lifted parcel of air. The increase in nuclei leads to a larger number of smaller cloud droplets and a more uniform cloud droplet size distribution than would occur without the extra particles. The resulting clouds produce less rain because rain drops form only when cloud droplets coalesce, which requires a broad particle size distribution.

Liu's experiments with CAM5 examine the effects of combinations of BC, OC, and sulfate emissions on atmospheric structure. Although the model is benchmarked against satellite measurements of aerosol absorption for 200 sites worldwide, including 10 in East Asia, there is still no satisfactory method of checking the composition of the absorbing aerosols. “We're trying to use Chinese data sets to get more information about composition, but sulfate emission is not reported to the government by very small factories,” added Liu. Actual aerosol effects may be stronger than those predicted by the model.

Weaker monsoons

Overall, the influence of aerosols on radiation and on clouds generates a net surface cooling over China of 1 to 2 kelvin. Aerosols also reduce the solar flux reaching the land. Since 1950, the total reduction in surface flux in China is thought to total 30 W/m2, with the biggest contribution occurring after 1980. Lower land temperatures flatten the land–sea temperature gradient, thus weakening the monsoon effect.

According to Li, because aerosols promote surface cooling, they cannot be responsible for the warming that causes the southerly precipitation shift. But according to Liu, aerosols do indeed shift the precipitation pattern. “Precipitation is loss of water vapor, and the latent heat capacity of the ocean balances this,” he explained. The latent heat of the ocean has a greater effect than that of the land, which drives the ocean–land temperature gradient and also the monsoon.

Liu agreed with Li, however, that the average amount of precipitation over the entire monsoon region remains the same. When water vapor is trapped in the aerosol-laden atmosphere, the amount of rain that falls in light showers decreases, but short periods of heavy preciptation intensify.

It might not be folks just in the southern part of East Asia that should be getting out their umbrellas, though. Long-range transport of pollution from East Asia to North America is a new cause for concern. As East Asia's economy continues to grow, so will its aerosol emissions. The effect of pollutant outflow as well as monsoon effects on agriculture might not be confined to East Asia alone.

Rachel Berkowitz

DON?

HWRF model shows "Don" forming today and heading straight to the central Gulf in a few days.  Curious that the GFS doesn't even show a low in the Gulf.

Curious indeed...

BB

Over 70 mm per Hour of Rain All Night; oh my!

South Korea Landslides Leaves 17 Dead, 3 Missing
Published July 27, 2011
| Associated Press
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AP
South Korean rescue workers carry a survivor who was rescued from a collapsed house as a midnight landslide caused by torrential rains swept away several houses in Chuncheon, South Korea, Wednesday, July 27, 2011.
Heavy rain sent landslides barreling through the South Korean capital and a northern town Wednesday, killing 17 and leaving at least three missing, officials said.
Eight of those killed in the early morning landslide were college students who had been doing volunteer work. They were staying in a resort cabin in Chuncheon, about two hours northeast of Seoul, when the mud and debris engulfed them, Byun In-soo of the town's fire station said.
South Korea has been pummeled with strong rain this week, and more than 10 inches have fallen on Chuncheon in the last two days. The Korea Meteorological Administration said another 10 inches could fall through Friday in northern South Korea, including Seoul, parts of which were flooded from the rains.
In Chuncheon, about 500 rescuers searched for two students who were missing after the landslide. Twenty-four people were injured and several buildings destroyed.
Among the other dead were a married couple and a man who wasn't yet identified, said Lee Ju-hee of the Chuncheon fire station.
Fast-moving muddy water filled streets in Seoul on Wednesday, with people scrambling to the roofs of their partially submerged cars. Water filled some subway stations and spewed from sewers. About 800 houses flooded, according to a city disaster official who declined to be named because of office policy. There were no casualties or deaths reported. The official said 23 roads were closed in the city.
Local TV showed officials rescuing hikers stranded on mountainsides.
The Seoul Metropolitan Police Agency issued a traffic emergency, mobilizing more police to deal with the problems caused by the heavy rain.
Weather officials say another 10 inches could fall through Friday in northern South Korea, including Seoul, parts of which were flooded from the rains.

Weather Data Mining Making Money

EarthRisk crunches data to predict extreme weather
by Martin LaMonica

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EarthRisk Technologies is mining years of weather data for profit.
The San Diego-based start-up today launched HeatRisk, a Web-based application designed to predict extreme heat events 30 to 40 days out. The target audience is meteorologists who work for energy companies or other organizations which need a long-range forecast to hedge their risk from extreme temperatures.
Over time, EarthRisk Technologies intends to design a product aimed at less technical users and investigate whether its research method can be applied to predicting extreme storms, according to President and Chief Science Officer Stephen Bennett. Its first product, released last year, is for analyzing the factors that lead to extreme cold events.
More researchers are tapping powerful computers and software able to present big sets of data to address environmental problems, such as air and water quality or extreme weather. EarthRisk Technologies originally began as a research project at the Scripps Institute of Oceanography in San Diego, but company founders saw there was a business opportunity buried in its research.
"We realized if we could write a software application around our research, it would increase the value of the underlying research tremendously," said Bennett. "The (corporate sponsors) said if you can put together a good application and continue to do cutting-edge research, we will be the first to sign up."
Three years ago, Scripps was approached by energy companies and hedge funds which deal in energy futures to see if there was a way to identify major weather events beyond the National Weather Service forecast. In addition to causing safety hazards, extreme weather throws energy markets out of whack by creating an imbalance between supply and demand.
A power generator, for example, could use HeatRisk to prepare for a coming heat wave by purchasing fuel for auxiliary generators to meet higher demand. Having a longer lead time than traditional forecasts gives energy buyers and traders an advantage, explained Bennett.
Right now, the people who use the software need to be skilled in meteorology and be comfortable analyzing atmospheric conditions directly. Eventually, the company hopes its software could be used by retailers, farmers, or municipalities which can use long-range forecasts to prepare for extreme temperatures, Bennett said.
Dominoes lining up
The accuracy of weather forecasting has improved over the past decade from supercomputers and simulation software, but the focus tends to be on shorter-term windows than what EarthRisk is doing, Bennett said. And rather than trying to forecast average temperatures, EarthRisk is seeking the factors that lead to specific extreme temperature events.

To build the application, researchers analyzed weather data going back to 1948 to identify the patterns that led up to extreme cold or heat. Each pattern is sort of like a domino and when enough of them line up, the software can help identify the probability of an extreme weather event, Bennett explained.
In a recent example, a combination of a large high-pressure system over Scandinavia and a low-pressure system in the Atlantic, followed by another system over the Solomon Islands pointed to a heat spike in the U.S.
People can use the analytical application through a Web browser and pay a fee for using it during a season and specific regions. A forecasting application could be ready in about six months, Bennett said.
Using software to dodge weather risk is new so it's still not clear there is a strong demand for it. But EarthRisk isn't the only company to use cloud computing and large amounts of data to hedge against extreme weather. Earlier this year, WeatherBill launched a service that gives farmers insurance against the effects of extreme weather by continuously analyzing weather data.


Read more: http://news.cnet.com/8301-11128_3-20080739-54/earthrisk-crunches-data-to-predict-extreme-weather/#ixzz1SdYl5xoI

Put this in Your Global-Warming Pipe and Smoke it!

Climate change studies vexed by Vesta
by Kate Melville

Paleoclimate studies, where scientists look into the past to try and understand changes in Earth's climate, may be a waste of time if astronomers are correct in their theory that relatively minor bodies like the asteroid Vesta can cause chaotic fluctuations in Earth's orbit. NASA's Dawn space-probe flew by Vesta last Saturday.

The journal Astronomy & Astrophysics has published numerical simulations of the long-term evolution of the orbits of Ceres and Vesta, which are the largest bodies in the asteroid belt. Although Ceres and Vesta are relatively small (Ceres is only 1/80th the mass of the Moon and Vesta is around 1/300th the mass of the moon), the calculations show that they can exert a disproportionate effect on their large neighbors and, in particular, the Earth. The computations were compiled by French astronomer Jacques Laskar, from the Observatoire de Paris, and his co-researchers.

The new calculations show that Ceres and Vesta gravitationally interact with themselves and with the other planets of the solar system. Because of these interactions, they are continuously pulled or pushed slightly out of their initial orbit. The calculations show that, over time, these effects do not average out. Consequently, their orbits are chaotic, meaning that we cannot predict their positions over long periods.

According to the figures, Ceres and Vesta's interactions with the Earth cause our planet's orbit to become unpredictable after only 60 million years. This means that the Earth's eccentricity, which can cause major climatic variations, cannot be traced back more than 60 million years. This calls into question all Paleoclimate studies that seek to look back further than this point.

Updated Typhoon Positions from JTWC

Not sure if this is new, but the JTWC is posting updated positions based on composite data for Typhoon "Ma On". - HLG

Typhoon "Ma On" Closest Approach to Seoul

It appears that the experimental one-month-long-range typhoon model that is in development at FWSAAB was a bust on Typhoon Ma On. Precious FWSAAB travel funds were used to pre-deploy our observer on the Korean peninsula, but instead of a typhoon land-fall, Korea is having the nicest weather in a month. Our crack researchers will continue to pursue the goal of a one-month typhoon forecast, but progress is slow. - HLG

Joplin Tornado Damage GIS Viewer

This application was an award winner at the ESRI International GIS Users Conference. The swipe tool is pretty cool to view the before/after imagery. - HLG

http://gis.wustl.edu/joplin.html

Japan Mete Service Forecast on Typhoon "Ma On"

The jangma (monsoon) in Korea continues. Four straight days of Forrest Gump type rain (remember the scene in Viet Nam, when it started to rain, and didn't stop for 6 months!). Following the Koran and Japanese forecasts for Typhoon Ma-On and there seems to be significant dispute in the track past 72 hours. Also, the Japanese use an intensity system goes from Very Strong to Very Intense. Not sure what comes after that other than Run for the Hills!

Scale Large
Intensity Strong
Center position N20°00'(20.0°)
E147°25'(147.4°)
Direction and speed of movement W 20km/h(10kt)
Central pressure 960hPa
Maximum wind speed near the center 40m/s(75kt)
Maximum wind gust speed 55m/s(105kt)
Area of 50kt winds or more Wide 170km(90NM)
Area of 30kt winds or more E650km(350NM)
W460km(250NM)


Intensity Very Strong
Center position of probability circle N20°55'(20.9°)
E142°50'(142.8°)
Direction and speed of movement W 20km/h(11kt)
Central pressure 935hPa
Maximum wind speed near the center 45m/s(85kt)
Maximum wind gust speed 60m/s(120kt)
Radius of probability circle 140km(75NM)
Storm warning area Wide 410km(220NM)


Intensity Very Strong
Center position of probability circle N21°50'(21.8°)
E137°40'(137.7°)
Direction and speed of movement W 20km/h(12kt)
Central pressure 915hPa
Maximum wind speed near the center 50m/s(100kt)
Maximum wind gust speed 70m/s(140kt)
Radius of probability circle 260km(140NM)
Storm warning area Wide 600km(325NM)


Intensity Very Intense
Center position of probability circle N23°00'(23.0°)
E133°30'(133.5°)
Direction and speed of movement WNW 20km/h(10kt)
Central pressure 910hPa
Maximum wind speed near the center 55m/s(105kt)
Maximum wind gust speed 75m/s(150kt)
Radius of probability circle 300km(160NM)
Storm warning area Wide

Typhoon "Ma On"

In the never ending quest to bring you weather reports from the ends of the Earth, and all points in between, this FWSAAB reporter has been deployed to Korea, in anticipation of Typhoon "Ma On". Now, it is possible this storm may never head towards Korea, but just in case I have been pre-deployed to witness the storm.

Meanwhile the rainy-season, or "jangma" in Korean, has started off with a bang. Rainfall since the official start of jangma, on June 22nd, is 400 percent of normal. Oh my!

Stay tuned weather fans, yes, both of you!

HLG

Lightning Mitigation and GIS in Columbia

Colombian Oil and Gas Companies Outrun Lightning with Better Electric Network Design
Highlights

Visualizing lightning data with GIS helps grow understanding of pole design features.
Managing the grid with GIS allows maintenance prioritization.
At the La Circa Infantas petrol field in El Centro, Santander, Colombia, lightning is a major problem. Colombia ranks second to the Democratic Republic of the Congo in annual lightning strikes, according to NASA's Global Hydrology and Climate Center. In the past two years, La Circa Infantas alone attracted 30,000 lightning strikes.

"Lightning affects our electrical distribution network, which feeds the engines that operate the wells, causing the terrible effects of production loss, equipment damage, and uncertainty in the network design," says Luis Alejandro Zorrilla, an electrical engineer with Occidental Oil & Gas.

Critical lightning area with distribution lines and poles georeferenced.
Occidental operates La Circa Infantas through a joint venture contract with Ecopetrol S.A. La Circa Infantas was the first petrol field in Colombia, with its first well, Infantas 2, completed in April 1918.

"This historic field has all the great challenges of a field built by many companies," Zorrilla adds.

The oil field's electric distribution network is made up of 3,000 poles, about 300 miles of electric line, and 1,000 engines. After more than 90 years in operation and many changes in management, the electric network was suffering huge inefficiencies. Data was duplicated, incomplete, old, or inaccurate.

Complicating matters was the fact that the electric infrastructure undergoes daily changes, with new lines and poles and new electric and communication equipment due to new wells. The whole process demands planning, design, connection, and reporting—a set of tasks highly dependent on accurate data.

By contrast, the information about the wells—their geographic location, maintenance history, construction date, and more—was concentrated in a GIS.

"The well GIS helps our team develop all our engineering activities. We saw a need to build a GIS for the electric network as well," Zorrilla says. "Our first step in developing an electric network GIS was to spatially enable the information related to the load on our electric network."

Next, the team created a data model that reflected the entire workflow, from workforce to energy management. The data required in the workflow was described in the data model.

Once the data model was constructed, the distribution network inspection project began. The goal was to update and unify all geodata available. With a geodataset in hand, workers modeled the electrical GIS geodatabase and developed the system in ArcGIS.

Improving the Design
Electric network pole designs were fashioned based on average annual lightning density and current amplitude data. The designs were researched and studied. Nevertheless, every lightning storm managed to identify faults in the design. Zorrilla reported approximately 600 faults in the distribution network circuits that feed the field in one year.

"The questions were obvious," Zorrilla says. "Why are the designs failing? How can we improve the designs?"

When the engineers took a closer look at the annual fault data, a clue emerged. About 90 percent of the failures were caused by lightning discharges and flashovers. The shielding angle did not protect the lines. They would need a more specific and accurate measurement of the lightning density and current amplitude.

Colombia's national lightning data system has 50 sensors to determine the location and electric characteristics of lightning. La Circa Infantas' energy management department requested this data. The electrical studies department developed a grid within the GIS to record the lightning's extent, count, and average amplitude per square mile.

"When we overlapped the electrical GIS with the lightning density and current amplitude grid, we saw an amazing relationship between the failures and the critical areas," Zorrilla explains. "The lightning data visualized as a grid, with the correlation of the two variables—density and current amplitude per square mile—helps locally understand why the pole designs failed."

With the help of the grid and the electrical GIS that was built on ArcGIS, engineers can approach every pole design according to the pole's location and its consistency with the geodataset. The grid is colored on a blue-to-red scale, with red signifying critical. An additional benefit is that engineers can prioritize the correction of the designs and plan maintenance based on the critical areas.

"A deep understanding of the lightning situation is now available," Zorrilla says. "Better decisions are being made. Design can now be standardized, depending on pole location and similar features, in lieu of a unique design for each pole."

Now that the electrical GIS is established and integrated with other corporate systems, La Circa Infantas is enjoying the benefits. New geoapplications, such as the grid, are under way. And, there is a boost in overall performance of the energy management department's daily work.

For more information, contact Luis Zorrilla, electrical engineer, Occidental Oil & Gas (e-mail: Alejandro_zorrilla@oxy.com

Tropical Formation Alert in W-Pac

Someone wake up Dr BB, the former Director of the OOC's Pacific Analysis Team!

Another Rainy Monday in Korea

Up to 250mm of Rain In The Forecast For Central Korea + 12 Killed, 4 Missing From Downpours Over The Weekend

It is a rainy Monday morning here in Seoul and up to 250 millimeters of more downpours is in the forecast on this Monday as the monsoon current moves up towards the central parts of Korea.
There are currently rain advisories and warnings issued across the nation.
The Korea Meteorological Administration said the rain will continue in Seoul and the surrounding areas until Thursday.
Please do take extra caution when you head out to work this morning and try to stay indoors and avoid driving as much as possible for your safety.
Meanwhile, torrential downpours that hit Korea's southern regions over the weekend have caused mudslides and flash floods leaving at least 12 people dead and four missing. 0--- Korea Global TV

Strange Saturnian Storm

LOS ANGELES – It began as a bright white dot in Saturn's northern hemisphere. Within days, the dot grew larger and stormier.

Soon the tempest enveloped the ringed planet, triggering lightning flashes thousands of times more intense than on Earth.

The international Cassini spacecraft and ground telescopes have been tracking the turbulence since last December, visible from Earth as a type of storm known as a "Great White Spot."


"It's still going like crazy," said Cassini project scientist Linda Spilker of the NASA Jet Propulsion Laboratory.

Such planet-wide weather disturbances are rare on Saturn, where the atmosphere is typically hazy and calm. Since 1876, astronomers have observed only five other megastorms on Saturn.

"This is a one-of-a-kind storm," said Andrew Ingersoll, a self-described planetary weatherman at the California Institute of Technology, who was part of the discovery team.

Scientists have long studied weather on other planets. One of the solar system's most famous landmarks is Jupiter's Great Red Spot, a hurricane-like storm that has been raging for centuries. Landers and rovers to Mars' surface often carried weather stations, dodged dust storms and sought favorable places to park during the winter.

An instrument aboard Cassini, which is orbiting Saturn, first picked up radio outbursts on Dec. 5, 2010 from a lightning storm. Around the same time, amateur astronomers peering through telescopes saw a bright point in Saturn's northern half. Further observations confirmed it was a brewing storm.

The storm system, which occurred during the start of Saturn spring, grew in size and intensity, eventually stretching around the planet. Scientists don't exactly know what stirs up the storms, but they think it could be linked to the change of seasons.

At the height of the storm, Cassini detected 10 lightning strikes per second. Scientists said the electrical activity emitted by the bursts were 10,000 times stronger than lightning on Earth.

The findings were described in two papers published in Thursday's issue of the journal Nature.

The new work represents "some of the most detailed observations so far of such a dramatic event," Peter Read of the University of Oxford wrote in an accompanying editorial.

Saturn's violent weather differs from Earth and Jupiter in significant ways. Lightning storms on Earth tend to be localized and short-lived, lasting only a few hours. Jupiter storms can last for days and lightning is far more common there than on Saturn.

Since entering orbit around Saturn in 2004, Cassini has witnessed 10 storms in a region of the southern hemisphere known as "storm alley" because of the high level of storm activity.

The previous storms were much weaker compared with the latest one, the first to be detected in the northern hemisphere.

AP

Ice Island Peterman

Very large iceberg, Ice Island Peterman II-A, which calved in NW Greenland, now off Labrador and heading south. Watch out Titanic! - HLG