Asian countries urged to team up on storm science

By Mike Ives

[HANOI] Teaming up on storm monitoring would make Asian nations more resilient to floods and landslides, a UN agency has said in an annual review of the region’s response to natural disasters.

The report was released last week (24 February) by the UN Economic and Social Commission for Asia and the Pacific (UNESCAP).

“Regional cooperation needs to be broadened beyond traditional approaches,” Francyne Harrigan, UNESCAP’s communications chief, told SciDev.Net by email. For example, she said, there could be more cooperation on seasonal weather forecasts and the development of climate models to predict the risk of river floods.

The report documents the impact of the 119 natural disasters in the region last year, which killed 6,050 and caused US$59.6 billion in damage. Tropical cyclone Hudhud alone, which hit India in October, caused US$11 billion worth of damage, it says.

Storm-warning systems and timely evacuations were instrumental in preventing further deaths across the region, the report says. But regional disaster preparedness could be improved through better scientific analysis and mass communication of impending disasters, and by establishing “regional cooperation mechanisms” to address preparation for floods and landslides.

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Tropical Cyclone 01B over Sri Lanka. Source: NASA

The report says joint monitoring should focus more on slow-onset disasters such as droughts, even if the severity of their impact has fairly predictable general impacts and can be difficult to quantify.

Harrigan said countries should establish national disaster preparedness agencies and that the cooperation mechanisms could fill national capacity gaps. She said one model for such an approach is the Thailand-based Regional Integrated Multi-Hazard Early Warning System for Africa and Asia (RIMES), which has helped Bangladesh forecast floods further in advance.

Regional cooperation on disaster preparedness has already improved over the past decade in tandem with growing national monitoring capacity in disaster-prone countries such as the Philippines and Vietnam, says Aslam Perwaiz, head of disaster risk management systems at Thai NGO the Asian Disaster Preparedness Center.

But responsibility for storm monitoring within Asian countries typically falls to just one or two ministries, and it would be better if other ministries, particularly ones that deal with finance and planning, played more active roles, he says.

Perwaiz adds that there is still a glaring lack of regional cooperation on disaster response and reconstruction, especially during political strife.

> Link to the UNESCAP report

This article was originally published on SciDev.Net. Read the original article.

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A melting Arctic and weird weather: the plot thickens

By Jennifer Francis, Rutgers University

Everyone loves to talk about the weather, and this winter Mother Nature has served up a feast to chew on. Few parts of the US have been spared her wrath.

Severe drought and abnormally warm conditions continue in the west, with the first-ever rain-free January in San Francisco; bitter cold hangs tough over the upper Midwest and Northeast; and New England is being buried by a seemingly endless string of snowy nor’easters.

Yes, droughts, cold and snowstorms have happened before, but the persistence of this pattern over North America is starting to raise eyebrows. Is climate change at work here?

Wavier jet stream

One thing we do know is that the polar jet stream – a fast river of wind up where jets fly that circumnavigates the northern hemisphere – has been doing some odd things in recent years.

Rather than circling in a relatively straight path, the jet stream has meandered more in north-south waves. In the west, it’s been bulging northward, arguably since December 2013 – a pattern dubbed the “Ridiculously Resilient Ridge” by meteorologists. In the east, we’ve seen its southern-dipping counterpart, which I call the “Terribly Tenacious Trough.” (See picture, below.)

Source: NOAA

These long-lived shifts from the polar jet stream’s typical pattern have been responsible for some wicked weather this winter, with cold Arctic winds blasting everywhere from the Windy City to the Big Apple for weeks at a time.

We know that climate change is increasing the odds of extreme weather such as heatwaves, droughts and unusually heavy precipitation events, but is it making these sticky jet-stream patterns more likely, too? Maybe.

Slowing, drunken path

The jet stream is a dastardly complex creature, and figuring out what makes it tick has challenged atmospheric scientists since it was discovered about 75 years ago. Even more elusive is figuring out how climate change will affect it.

Jet streams exist because of differences in air temperature. In the case of the polar jet stream, which is responsible for most of the weather we experience around the middle-latitudes of the northern hemisphere, it’s the cold Arctic butting against warmer areas to the south that drives it. (A more in-depth explanation can be found here.) Anything that affects that temperature difference will affect the jet stream.

This is where climate change comes in: the Arctic is warming much faster than elsewhere. That Arctic/mid-latitude temperature difference, consequently, is getting smaller. And the smaller differential in temperatures is causing the west-to-east winds in the jet to weaken.

Strong jets tend to blow straight west to east; weaker jets tend to wander more in a drunken north/south path, increasing the likelihood of wavy patterns like the one we’ve seen almost non-stop since last winter.

When the jet stream’s waves grow larger, they tend to move eastward more slowly, which means the weather they generate also moves more slowly, creating more persistent weather patterns.

NASA/Goddard Space Flight Center Scientific Visualization Studio

At least, that’s the theory. Proving it is not easy because other changes are happening in the climate system simultaneously. Some are natural fluctuations, such as El Niño, and others are related to increasing greenhouse gases.

We do know, however, that the Arctic is changing in a wholesale way and at a pace that makes even Arctic scientists queasy. Take sea ice, for example. In only 30 years, its volume has declined by about 60%, which is causing ripple effects throughout the ocean, atmosphere, and ecosystem, both within the Arctic and beyond. I’ve been studying the Arctic atmosphere and sea ice my entire career and I never imagined I’d see the region change so much and so fast.

‘Stuck’ weather patterns

To study the effects of Arctic change on weather patterns, we have good measurements of atmospheric temperatures and winds going back to the late 1970s, when satellites started providing data, and pretty good measurements back to the late 1940s.

My colleagues and I have been using this information to measure the waviness of the jet stream and whether it is behaving differently since the Arctic started its rapid warm-up about 20 years ago. Because the upper atmosphere is such a cacophony of swirling winds, however, measuring changes in the jet stream’s waviness is tricky, as it’s not a metric that scientists have traditionally used.

Our challenge, then, is to find new methods to measure waviness and determine whether any changes we find are related to rapid Arctic warming, to some other change in the climate system, or to just random chance. While the story is still in early days, the plot is thickening.

Several groups around the globe, including my colleagues and me, are trying to understand the linkages between rapid Arctic warming and changes in weather patterns.

A number of recent studies have found what appears to be a solid connection between sea-ice loss in an area north of western Russia during the fall and a rash of abnormally cold winters in central Asia. The loss of sea ice favors a northward bulge in the jet stream, which strengthens surface high pressure to the east. That shift pumps cold Arctic air southward into central Asia.

Other studies suggest that Arctic warming in summer leads to a split jet stream – or two separated rivers of wind – which tends to trap the waves. Those stationary waves cause weather conditions to remain “stuck” for long periods, increasing the likelihood of extreme heat waves, droughts and flooding events in Eurasia and North America.

Our own new work, published last month in Environmental Research Letters, uses a variety of new metrics to show that the jet stream is becoming wavier and that rapid Arctic warming is playing a role. If these results are confirmed, then we’ll see our weather patterns become more persistent.

In other words, Ridiculously Resilient Ridges and Terribly Tenacious Troughs may become the norm, along with the weather woes they cause.

This article was originally published on The Conversation.
Read the original article. Feature photo credits:  Stuart Rankin/Flickr, CC BY-NC

Powerful Low Pressure System Over the UK = Wind and Rain

A powerful low pressure system affected the UK yesterday evening and overnight bringing strong winds and heavy rain to many areas of the UK.

From the Met Office blog:

“The low pressure system will continue to affect the UK today, bringing sunny spells and blustery, heavy showers with the chance of thunderstorms and snow over high ground. Severe gales are again expected around western and northwestern coasts, with the strongest winds likely over Northern Ireland and southwest Scotland, extending to northern Scotland later. You can see detail on this on our forecast and warnings pages.”

More Information:
[1] https://metofficenews.wordpress.com/www.metoffice.gov.uk/public/weather/forecast
[2] https://metofficenews.wordpress.com/www.metoffice.gov.uk/public/weather/warnings
[3] https://metofficenews.wordpress.com/

Severe weather around the world

Official blog of the Met Office news team

While the UK is currently experiencing relatively benign weather for the time of year, extreme conditions are expected in some other parts of the world.

Morocco and Spain

Last Saturday, Agadir in Morocco saw 90mm of rain fall in just 24 hours, which is around twice the monthly November average for the region of just 50mm. The subsequent flooding resulted in more than 30 fatalities.

Unfortunately, more severe weather is expected through Friday and into the weekend across Morocco, but particularly around the southwest of the country.

A combination of a deep area of low pressure, relatively warm sea temperatures and strong winds will bring heavy rainfall. 100-150mm of rain could fall across SW Morocco on Friday with further heavy rain likely on Saturday, and totals could be enhanced over higher ground. Conditions should improve into Sunday.

Through the weekend, the same area of low pressure is expected to bring…

View original post 190 more words

Up to 80 mile an hour wind gusts possible from ex-hurricane Gonzalo

The remains of hurricane Gonzalo is due to strike the British Isles tonight resulting in widespread rainfall and wind gusts up to 80 miles an hour tomorrow morning.

Gonzalo travelled over the island of Bermuda earlier this week, but has since been decreasing in energy and is now downgraded from hurricane status to an extra-tropical storm. The video below, from the Met Office, shows ex-hurricane Gonzalo undergoing extra-tropical transition into an Atlantic low pressure system.

The Met Office has issued a severe weather warning for wind for large parts of the UK. The worst disruption is expected on Tuesday morning when high wind gusts coincide with the morning rush hour.

The Environment Agency has asked people to be flood aware and prepared, Although the strong winds might help drive low coastal flood risk on Tuesday and Wednesday. You can keep up to date with updated flood warnings on the Environment Agency’s website: http://apps.environment-agency.gov.uk/flood/142151.aspx

floodEkbal

More information:
[1] The Met Office warnings: http://www.metoffice.gov.uk/public/weather/warnings/
[2] The Environment Agency flood risk map: http://apps.environment-agency.gov.uk/flood/142151.aspx
[3] More about hurricanes, typhoons and cyclones: https://climateandgeohazards.wordpress.com/2013/10/07/cyclones-hurricanes-and-typhoons-whats-the-difference
[4] The latest BBC news report at time of writing (21:37 Mon 20th): http://www.bbc.co.uk/news/uk-29685066

Friday Fact – 10th October 2014

hurricane_katrina-NASA

Did you know, hurricanes, cyclones and typhoons are different names for the same weather phenomenon?

In general large cyclonic storms in the Atlantic and East Pacific are called hurricanes, those in the Indian Ocean are called cyclones while typhoons are the same weather events in the western Pacific.

More Information:
[1] Check out our blog post on these incredibly energetic weather events.

 

Image

Extreme El Niño Events Expected To Occur Twice As Often

 

1997_El_Nino.jpg

El Niño is a weather phenomenon that develops across the Pacific Ocean. Essentially it is a band of anomalously warm ocean water temperatures that develops off the west coast of South America.

El Niño causes climatic changes across the Pacific and can result in severe droughts on the western Pacific while the eastern Pacific experiences anomalously high rainfall and catastrophic floods.

These extreme weather events typically occur once every 20 years but a new study published in the journal Nature Climate Change suggests that extreme El Niño events could occur twice as often due to the effects of global warming.

The last such event occurred in 1997/98 in which the anomalous conditions caused widespread environmental disruption including the disappearance of much marine fauna in the Pacific. The impacts affected every continent and claimed an estimated 23,000 lives worldwide causing USD 35-45 billion in damage.

Ekbal

More Information:
[1] http://www.ncdc.noaa.gov/teleconnections/enso/enso-tech.php