nsf.gov - National Science Foundation - Scientists tackle mystery of thunderstorms that strike at night .- Los científicos abordan misterio de tormentas que golpean en la noche................

Hola amigos: A VUELO DE UN QUINDE EL BLOG., hemos recibido información cientifica de la Fundación Nacional de Ciencias de Los Estados Unidos, quienes nos mencionan que los científicos han abordado el misterio de las tormentas que se presentan y golpean mucho por las  noches. Algo misterioso que tormentas que se forman en la noche, sin una chispa de calor del sol, son un fenómeno misterioso. Este verano, los científicos se quedarán hasta tarde en busca de algunas respuestas.

 A partir del 1 de junio al 15 de julio;  estarán los  investigadores de toda América del Norte como un abanico cada noche, desperdigados  a través de las Grandes Llanuras, donde las tormentas son más comunes en la noche que durante el día.

 El esfuerzo, co-organizado por numerosas instituciones colaboradoras, utilizará aviones con  laboratorio equipado, instrumentos terrestres y globos meteorológicos para entender mejor las condiciones atmosféricas que conducen a asaltar la formación y la evolución después de la puesta del sol.

More information...............

 http://www.nsf.gov/news/news_summ.jsp?cntn_id=135046&WT.mc_id=USNSF_51&WT.mc_ev=click

Researchers will spend six weeks this summer probing nighttime thunderstorms on the Great Plains

Plains Elevated Convection at Night (PECAN) scientists are studying nighttime thunderstorms. Credit and Larger Version

May 20, 2015

Note: PECAN scientists will hold an open house for the media and the public in Hays, Kansas, on Saturday, May 30, 2015.

Thunderstorms that form at night, without a spark from the sun's heat, are a mysterious phenomenon. This summer, scientists will be staying up late in search of some answers.

From June 1 through July 15, researchers from across North America will fan out each evening across the Great Plains, where storms are more common at night than during the day.

The effort, co-organized by numerous collaborating institutions, will use lab-equipped aircraft, ground-based instruments, and weather balloons to better understand the atmospheric conditions that lead to storm formation and evolution after sunset.

What the scientists find may ultimately help improve forecasts of these sometimes damaging storms.

The Plains Elevated Convection at Night (PECAN) field campaign will involve scientists, students and support staff from eight research laboratories and 14 universities.

The $13.5 million project is largely funded by the National Science Foundation (NSF), which contributed $10.6 million. Additional support is provided by NASA, the National Oceanic and Atmospheric Administration (NOAA), and the U.S. Department of Energy.

Aloft in the night

Thunderstorms that form during the day are less puzzling than nighttime storms.

The sun heats the surface of Earth, which in turn warms the air directly above the ground. When that warm air is forced to rise, it causes convection--a circulation of warm updrafts and cool downdrafts--and sometimes creates a storm.

But the formation of thunderstorms at night, when the sun is not baking the land, is less well understood.

"At night, the entire storm circulation is elevated higher off the ground," said National Center for Atmospheric Research (NCAR) scientist Tammy Weckwerth, a PECAN principal investigator.

"This makes observations of the conditions leading to nighttime thunderstorms much more challenging because that part of the atmosphere is not well covered by the network of instruments we normally rely on."

The vast array of instruments available to PECAN researchers will allow them to collect data higher in the atmosphere.

The data will help scientists characterize the conditions that lead to individual storm formation as well as to the clustering and organizing of these storms into large-scale systems, which can result in significant precipitation.

"Nighttime thunderstorms are an essential source of summer rain for crops, but are also a potential hazard through excessive rainfall, flash flooding and dangerous cloud-to-ground lightning," said Ed Bensman, program director in NSF’s Division of Atmospheric and Geospace Sciences, which funded the research.

"Weather forecast models often struggle to accurately account for this critical element of summer rainfall on the Great Plains," said Bensman. "The PECAN field campaign will provide researchers and operational forecasters with valuable insights into thunderstorms at night and improve our ability to model them more accurately."

Deploying in the dark

The campaign, based in Hays, Kan., will begin each day at 8 a.m. when a crew of forecasters starts developing a nightly forecast.

At 3 p.m., the scientists will use the forecast to determine where across northern Oklahoma, central Kansas or south-central Nebraska to deploy their mobile resources.

Moving dozens of people around the Great Plains each night will be a challenge for PECAN, but it's also what distinguishes it from past field projects.

"Previous severe weather campaigns focused mostly on daytime storms, for largely practical reasons, as it's more difficult to set up instruments in the dark," said Bart Geerts, an atmospheric scientist at the University of Wyoming and a PECAN principal investigator.

"But the large thunderstorm complexes traveling across the Great Plains at night really are a different beast. "

Scientists believe that several factors may interact to contribute to nocturnal storm formation and maintenance: a stable layer of air at the surface; a strong wind current above that layer, known as a low-level jet; and atmospheric waves, some of which are called "bores," that ripple out from the storms themselves.

"But we don't really know how they interact," Geerts said. "That's what PECAN is about."

A better understanding of these storms will have relevance for areas beyond the Great Plains. Clustered nighttime thunderstorms are common in regions scattered across the globe.

Adds Howie Bluestein, an atmospheric scientist at the University of Oklahoma who is participating in PECAN, “Thunderstorms that occur during the middle of the night over the central Plains in the late spring and early summer have been enigmatic. Data collected during PECAN will help us better understand and predict these rain systems.”

A fleet of instruments

PECAN will use three research aircraft, two of which--a University of Wyoming King Air and NASA DC-8--will fly in clear air away from storms.

Only the third, a NOAA P-3, which is widely used in hurricane research and reconnaissance, will be able to fly into the trailing regions of storms.

The researchers also will rely on a number of ground-based instruments, known as PECAN Integrated Sounding Arrays, or PISAs.

Six PISAs will operate from fixed locations around the study area and four will be mobile, allowing them to be repositioned each night depending on where storms are expected to form.

The instruments within each PISA vary, but collectively they will give each array the ability to measure temperature, moisture and wind profiles, as well as launch weather balloons.

Among the instruments are several that were developed at NCAR's Earth Observing Laboratory, including one that uses an innovative laser-based technique to remotely measure water vapor, and an advanced wind profiler.

Finally, the scientists will have a fleet of mobile and fixed radars.

In all, PECAN researchers will have access to more than 100 instruments brought to the effort by partner institutions.

"PECAN will be using mobile radars, traveling weather stations on vans and trucks, and other systems to probe inside severe nighttime storms," said scientist Karen Kosiba of the Center for Severe Weather Research, a PECAN participant.

"We want to understand more about when, where and why winds, hail and flooding rains occur," Kosiba said. "That will allow us to better forecast these damaging events."

-NSF-

Media Contacts Cheryl Dybas, NSF, (703) 292-7734, cdybas@nsf.gov
David Hosansky, NCAR, (303) 497-8611, hosansky@ucar.edu

Related WebsitesPlains Elevated Convection at Night (PECAN):

 http://pecan15.org
NSF Science Nation Episode: "Doppler on Wheels--the biggest 'dish' on the road":

 http://www.nsf.gov/news/special_reports/science_nation/doppleronwheels.jsp

The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2015, its budget is $7.3 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives about 48,000 competitive proposals for funding, and makes about 11,000 new funding awards. NSF also awards about $626 million in professional and service contracts yearly.

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As part of PECAN, researchers will fan across the U.S. Great Plains at night.
Credit and Larger Version

PECAN involves atmospheric scientists from eight research laboratories and 14 universities.
Credit and Larger Version

During PECAN, the University of Wyoming's King Air research aircraft will fly in clear air.
Credit and Larger Version

A National Science Foundation Doppler-on-Wheels (DOW) will take part in PECAN.
Credit and Larger Version

Through PECAN, scientists hope to make discoveries that will help forecast severe storms.
Credit and Larger Version

 The National Science Foundation (NSF)
 Guillermo Gonzalo Sánchez Achutegui
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