NSF : Press Release 16-032 .- Ocean temperatures predict U.S. heat waves 50 days out .- Las temperaturas del océano predijeron olas de calor de Estados Unidos 50 días fuera..............

Hola amigos: A VUELO DE UN QUINDE EL BLOG., La formación de un patrón distinto de las temperaturas superficiales del mar en el medio del Océano Pacífico Norte puede predecir un mayor riesgo de olas de calor del verano en la mitad oriental de los EE.UU. hasta 50 días de antelación.
El patrón es un contraste de más cálido que el promedio de agua procedentes de mares fríos en contra de lo normal. Cuando aparece, las probabilidades de que el calor extremo se huelga durante una semana en particular - o incluso en un día en particular - puede más que el triple, dependiendo de lo bien formado es el patrón.
Los hallazgos fueron publicados en la revista Nature Geoscience. El autor principal es el científico Karen McKinnon, del Centro Nacional de Investigación Atmosférica (NCAR) en Boulder, Colorado.
"Olas de calor del verano se encuentran entre los fenómenos meteorológicos más mortales, y pueden tener grandes efectos sobre la agricultura, el uso de energía y otros aspectos críticos de la sociedad", dijo McKinnon. "Si podemos dar a los planificadores urbanos y los agricultores un mano a mano que el calor extremo se encuentra en el camino, que podría ser capaz de evitar algunas de las peores consecuencias."

More information.........

http://www.nsf.gov/news/news_summ.jsp?cntn_id=138086&WT.mc_id=USNSF_51&WT.mc_ev=click

Pacific pattern forms in advance of hot days in eastern U.S.

Scientists have found a way of predicting an increased chance of a summer heat wave. Credit and Larger Version

March 28, 2016

This is part 14 in a series on NSF's geosciences risk and resilience interest area. Please see parts one, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13 and 15.

The formation of a distinct pattern of sea surface temperatures in the middle of the North Pacific Ocean can predict an increased chance of summer heat waves in the eastern half of the U.S. up to 50 days in advance.

The pattern is a contrast of warmer-than-average water coming up against cooler-than-average seas. When it appears, the odds that extreme heat will strike during a particular week -- or even on a particular day -- can more than triple, depending on how well-formed the pattern is.

The findings were published today in the journal Nature Geoscience. The lead author is scientist Karen McKinnon of the National Center for Atmospheric Research (NCAR) in Boulder, Colorado.

"Summertime heat waves are among the deadliest weather events, and can have big effects on farming, energy use and other critical aspects of society," said McKinnon. "If we can give city planners and farmers a heads-up that extreme heat is on the way, we might be able to avoid some of the worst consequences."

In addition to McKinnon, the research team includes Andrew Rhines of the University of Washington, Martin Tingley of Pennsylvania State University and Peter Huybers of Harvard University.

"This intriguing result has enormous practical implications," said Candace Major, program director in the National Science Foundation (NSF) Division of Ocean Sciences, which funded the research along with NSF's Division of Atmospheric and Geospace Sciences. "The potential for predicting the risk of dangerous heat waves more than a month in advance is very exciting. With more time to prepare, communities have a greater chance of avoiding the serious economic and health consequences of weather extremes."

 

A fingerprint on the ocean

 

For the study, the scientists divided the country into regions that tend to experience extreme heat at the same time. They then focused on the largest of the resulting blocks: a swath that stretches across much of the Midwest and up the East Coast, encompassing important agricultural areas and heavily populated cities.

The researchers looked for a relationship between global sea surface temperature anomalies -- waters warmer or cooler than average -- and extreme heat in the eastern half of the U.S.

A pattern popped out in the middle of the Pacific, above a point roughly 20 degrees north latitude. The scientists could find the particular configuration of ocean water temperatures, which they named the Pacific Extreme Pattern, not only when the eastern U.S. was already hot, but also in advance of that heat.

"Whatever mechanisms ultimately lead to the heat wave also leave a fingerprint of sea surface temperature anomalies behind," McKinnon said.

 

Improving seasonal forecasts

 

To test how well that activity could predict future heat, the scientists used data collected from 1,613 weather stations across the eastern U.S. between 1982 and 2015, as well as daily sea surface temperatures from the same time period.

The researchers defined extreme heat in the eastern U.S. as a summer day when the temperature readings from the warmest 5 percent of weather stations in the region were at least 6.5 degrees Celsius (11.7 degrees Fahrenheit) hotter than average. They only examined extreme heat during that region's 60 hottest days of the year: June 24 through Aug. 22.

The scientists "hindcasted" each year in the data set to see if they could retrospectively predict extreme heat events -- or the lack of those events -- during that year's summer.

At 50 days out, they were able to predict an increase in the odds -- from about one-in-six to about one-in-four -- that a heat wave would strike somewhere in the eastern U.S. during a given week.

For a particularly well-formed pattern, at 30 days out or closer the scientists were able to predict that a heat wave would strike on a particular day at odds of better than one-in-two.

This new technique could improve existing seasonal forecasts, which do not focus on predicting daily extremes. Seasonal forecasts typically predict whether an entire summer is expected to be warmer than normal, normal, or cooler than normal.

For example, the seasonal forecast issued for the summer of 2012 predicted normal heat for the Northeast and Midwest. But the summer ended up being especially hot, thanks to three major heat waves that struck in late June, mid-July and late July.

When the research team used the Pacific Extreme Pattern to hindcast 2012, they were able to determine as early as mid-May increased odds of extremely hot days occurring in late June.

The hottest day of the summer of 2012, as measured by the technique used for this study, was June 29, when the warmest 5 percent of weather stations recorded temperatures that were 10.4 degrees Celsius (18.7 degrees Fahrenheit) above average.

"We found that we could go back as far as seven weeks and still predict an increase in the odds of future heat waves," McKinnon said. "What's exciting about this is the potential for long-range predictions of individual heat waves that give society far more notice than current forecasts."

 

Looking ahead

 

Scientists don't yet know why the fingerprint of sea surface temperatures in the Pacific predicts heat on the East Coast.

It could be that the sea surface temperatures themselves kick off weather patterns that cause the heat. Or it could be that they are both different results of the same phenomenon, but one does not cause the other.

To learn more about how the two are connected, McKinnon is working with colleagues at NCAR to use sophisticated computer models to try to tease apart what's happening.

The study's findings also point to the possibility that the Pacific Extreme Pattern, or a different oceanic fingerprint, could be used to forecast other weather events far in advance, including cooler-than-average days and extreme rainfall events.

"The results suggest that the state of the mid-latitude ocean may be a previously overlooked source of predictability for summer weather," McKinnon said.

-NSF-

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

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) 2016, its budget is $7.5 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives more than 48,000 competitive proposals for funding and makes about 12,000 new funding awards. NSF also awards about $626 million in professional and service contracts yearly.

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June 29, 2012, was the hottest day of the year in the eastern U.S.
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Sea surface temperature anomalies in the mid-latitude Pacific 50 days out from June 29, 2012.
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The summer of 2012 was a scorcher. Three heat waves struck the U.S.
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Heat waves affect energy use, farming and other aspects of society.
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Grasses become sere and brown in the baking summer sun.
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The National Science Foundation (NSF)
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@hotmail.com
ayabaca@yahoo.com
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nsf.gov - National Science Foundation - Ten things to know about the flowers of fall: Sunflowers.- Diez cosas que debe saber sobre las flores en Otoño: Girasoles

Hola amigos: A VUELO DE UN QUINDE EL BLOG., la Fundación Nacional de Ciencia de los Estados Unidos se hacen una serie de interrogantes sobre la floración del girasol..como..." Como campos de otoño se convierten brillante con color, ¿qué podemos aprender de filas en carretera de los girasoles - y las semillas de girasol ampliamente utilizado para alimentar a las aves en un clima más frío?....

Por ejemplo, con qué frecuencia y bajo qué condiciones la evolución toman el mismo camino? Cuando las poblaciones independientes evolucionan las mismas características, son los cambios genéticos subyacentes similares o diferentes?...

Para asomarse al mundo de la especiación - cómo uno ramas especie en otra - la Fundación Nacional de Ciencia de los Estados (NSF) hablaron con George Gilchrist, un de los  directores del programa en la División de Biología Ambiental de la agencia y con Ken Whitney, un biólogo de plantas en la Universidad de Nuevo México quien estudia poblaciones de girasoles experimentales en Texas.......

Con el financiamiento de la NSF, Whitney y botánico Loren Rieseberg de Indiana University Bloomington y la Universidad de Columbia Británica están aprendiendo si girasoles son convergentes o divergentes en sus rasgos.........

Flowers of fall: Sunflowers cover roadside farm fields in autumn. Credit and Larger Versión

October 14, 2014

As fall fields turn bright with color, what might we learn from roadside rows of sunflowers--and the sunflower seeds widely used to feed birds in colder weather?

Scientists are finding that answers to biological and environmental questions large and small may be hidden in the petals of common sunflowers.

For example, how frequently and under what conditions does evolution take the same path? When independent populations evolve the same characteristics, are the underlying genetic changes similar or different?

To peer into the world of speciation--how one species branches into another--the National Science Foundation (NSF) spoke with George Gilchrist, a program director in the agency's Division of Environmental Biology and with Ken Whitney, a plant biologist at the University of New Mexico who studies populations of experimental sunflowers in Texas.

With funding from NSF, Whitney and botanist Loren Rieseberg of Indiana University Bloomington and the University of British Columbia are learning whether sunflowers are converging or diverging in their traits.

 

1) Why do scientists study sunflowers?

 

Whitney (KW): Sunflowers represent a "recent" success story. In the past three million years, this group has diverged (or branched into new species) in some 50 species in North America. Sunflowers live in a variety of habitats, from forests to deserts to salt marshes.

Sunflowers also contain examples of many important processes, including the evolution of both annual and perennial lifestyles, hybridization (mating between species) and the phenomena of polyploidy (the doubling of chromosome sets in a lineage). All this combines in an "evolutionary cauldron."

 

2) Where did sunflowers originate?

 

(KW): The genus Helianthus, true sunflowers, is native to North America. The common sunflower, H. annuus, and its seeds are one of only three crops that were domesticated north of Mexico. The second, sumpweed, was a favorite of Native Americans, but is no longer in use; the third, Jerusalem artichoke, is actually the root of another sunflower species, H. tuberosus.

 

3) What are the major commercial uses of sunflowers?

 

(KW): Oilseed sunflower varieties are used to produce oil used in cooking. A separate set of varieties, called confectionary varieties, has been developed to produce the large seeds we eat directly--such as those that are roasted and salted.

 

4) How do sunflowers link North America and Russia?

 

(KW): Although the crop sunflower originated in North America, it had to travel to Europe to achieve its current form. Much of the breeding for large seed size and high oil content was done in Russia in the 1800s, a legacy that is still with us in the sunflower variety called "Russian Mammoth." Many of us grow this plant in home gardens.

Sunflower varieties from Russia made it back to the U.S. in the late 1880s, but it was not until the 1930s and 1940s that crop sunflowers were grown on a large commercial scale in the United States.

5) What's the difference between wild sunflowers and those that are domesticated and grown as crops?

 

(KW): Both wild and crop sunflowers are the same species, H. annuus. Wild sunflowers have many flowering heads on each plant, and have small seeds. A major event in the domestication of the sunflower was the creation of a "monocephalic" plant with a single large flowering head and large seeds.

 

6) How much diversity is there in wild sunflowers?

 

(KW): The 50 or so species of wild sunflowers are both ecologically and genetically diverse. The U.S. Department of Agriculture maintains seed stocks of most wild sunflower species, in part because they contain genetic material that can be used to improve cultivated sunflower varieties. For example, a pest-resistant species might provide genes that could decrease pest damage in cultivated sunflowers.

 

7) What ecological factors drive sunflowers' diversity?

 

(KW): Sunflowers live in a wide range of habitats, and are widespread across the North American continent. That geographic range means that sunflowers have adapted to very different environmental conditions during the course of their radiation.

 

8) Are there medical treatments derived from sunflower products?

 

(KW): Sunflower products, especially the oil from the seeds, have long been used in folk medicine, but I'm not aware of any uses in modern medicine.

 

9) Do wild sunflowers hybridize? What role has hybridization played in speciation?

 

(KW): Sunflowers are notorious for hybridizing: mating across species boundaries and exchanging genetic material between species. Sometimes this genetic exchange leads to improved performance, for example in the Texas sunflower our team has been studying.

We have evidence that when wild H. annuus captured genes from another species, H. debilis, it was able to expand its range southward and become a new subspecies, H. annuus texanus. In other sunflowers, hybridization may lead to entirely new species. The sunflowers H. annuus and H. petiolaris have hybridized repeatedly and have produced three new sunflower species that live on the desert floor, on sand dunes, and in salt marshes.

Gilchrist (GG): This research has been critical to understanding how hybridization can lead to rapid speciation. While many hybrids are sterile, some genetic changes create hybrids with extra sets of chromosomes that are fully fertile, but reproductively isolated from their parents.

These new hybrid sunflowers often are uniquely adapted to new habitats that neither of the parent species occupies. Speciation by hybridization is very common in plants and may play a major role in plant diversification.

 

10) Do insects and pathogens attack sunflowers?

 

(KW): Sunflowers are indeed attacked by insects, especially grasshoppers, caterpillars, aphids and their relatives, as well as by fungal and bacterial pathogens.

A sunflower's life, scientists say, is no bed of roses.

--	Cheryl Dybas, NSF (703) 292-7734 cdybas@nsf.gov

Related WebsitesNSF Grant: Repeatability and genetic architecture of adaptive introgression: a long-term experimental evolution study in sunflowers:

 http://www.nsf.gov/awardsearch/showAward?AWD_ID=1257965&HistoricalAwards=false

Scientists are studying a sunflower known as the East Coast dune sunflower or beach sunflower.
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The Russian Mammoth sunflower variety was bred in Russia and later came to the U.S.
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The large head of a sunflower; it will soon produce countless seeds.
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Sunflower seeds like these are widely used to feed birds in colder weather.
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The National Science Foundation (NSF)

Guillermo Gonzalo Sánchez Achutegui

ayabaca@gmail.com

ayabaca@Hotmail.com

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NASA - NASA, Newseum Present Media Preview Of PBS' Earth From Space

Global Weather Machine

• By Mark Hoover
• Posted 10.13.98
• NOVA

We live in an ocean of air, seething and flowing around us, changing-sometimes violently-every day. In the heart of this swirling machinery of rain clouds and jetstreams, hot desert winds and frozen arctic storms, there is one constant: change. A trillion and a half days have passed since the Earth was born in a spinning disk of stardust, and no two of those days have ever had the same weather.

This NASA image of wind patterns over the Pacific Ocean gives a sense of the dynamism of global weather. Enlarge Photo credit: NASA

what is weather?

Driven by the heat of the sun, weather is an interlocking system of cycles. Water evaporates, rises, cools, and falls as rain, only to evaporate once again. The sun rises and sets every day, with the air warming and cooling in response, and the cycle endlessly repeating. Low pressure systems suck high pressure systems into their vacuum, creating spinning masses of wind and clouds bigger than Texas; these cyclones are swept across the skies by persistent high-speed winds miles up in the atmosphere, rivers of air in a relentless race around the globe. Weather, in all its cycles and clashes, arises from a simple fact: the sun heats some parts of the Earth more than others.

Because the Earth is a globe, and not a flat board, the sun shines almost straight down on the tropics, baking them every day of the year. But at the poles, the angle is small and the sun's rays are weak, and the poles are therefore cold. Nature "abhors" this imbalance, and tries to fix it. As quickly as solar heat flows in to the tropics, it begins flowing out toward the poles, seeking to equalize the difference. The unrelenting march of this energy-on-the-move, from high concentration to low concentration, is the piston in the engine that propels weather.

When warm air leaves the tropics and heads toward the poles, cold air from near the poles is sucked back toward the tropics. This exchange sets up two-lane highways for air rushing to and from the tropics. These highways of air are called convection cells, and they are the reason wind blows.

The major surface wind bands of Earth. Each hemisphere is divided into three belts. The path of a storm greatly depends upon the wind belt in which it is located. The easterly (west-blowing) trade winds of both hemispheres collide near the equator, in a region called the Intertropical Convergence Zone (ICTZ). Enlarge Photo credit: University of Illinois WW2010 Project

Air flowing back and forth in these great cells is pushed sideways by the Earth's rotation, dragged by friction with the land and the sea, and squeezed by gravity. All of these distortions cause turbulent mixing of the winds, and soon lead to the organization of storm centers due to unevenness between warm and cold. In particular, the sideways push given the winds by the spinning of the planet-called the Coriolis Effect-causes the constant convective flows to organize in bands, where the flow direction varies according to latitude. These bands are responsible for prevailing winds on the surface, and jetstreams high in the atmosphere.

The ITCZ on this satellite image is the band of bright clouds located just north of the equator. This zone is a prolific contributor of storms and clouds to the world's weather. Enlarge Photo credit: NASA

We can see these bands of wind clearly in Jupiter's atmosphere, because Jupiter rotates at a furious pace, once every ten hours. We can also see them clearly on Earth when we take a picture from far out in space.

As on Earth, Jupiter shows distinct wind bands generated by convection and rotation forces. Scientists have measured wind speeds in Jupiter's "Little Red Spot" reaching up to about 384 miles per hour—twice as fast as the winds of a Category 5 hurricane. Enlarge Photo credit: NASA

El Niño'S POWER

El Niño exploits this organization of winds into bands when it causes major weather changes around the world. Specifically, El Niño can affect the path of flow in these bands, and the cyclones that are ushered across the surface by them are now delivered to different areas than normal. Think of the wind bands—both at the surface and high in the sky—as a tram, a streetcar on which storm systems hitch a ride as they travel around the Earth. El Niño moves the tracks—the stormtracks—of this tram. The answer to the puzzle of how this happens is literally blowing in the wind.

How does El Niño take over such a huge system? It begins with an effect due to the vastness of the Pacific Ocean itself, an effect intimately related to the birth of an El Niño. In the Pacific near the equator, the prevailing winds blow from east to west, as cool air sinking from higher latitudes toward the equator gets whipped sideways by the Coriolis force. We know these as the tradewinds, which sailors of old could always depend upon to blow steadily in the same direction.

In the tropical Pacific, these west-blowing tradewinds push steadily against the sea for thousands of miles. The warm water on the surface is literally blown sideways, and the water piles up in the west, creating a pool thousands of miles across. This leads to a heat imbalance: as more and more warm water is stripped from the east and moved west, cold waters from deep in the ocean near South America are drawn up to take its place. This cool water inhibits evaporation and the creation of rain clouds in east, which is why the Galapagos Islands and the coast of Peru are usually deserts.

The El Niño temperature anomaly of 1997-98 (appearing here as a red band in the Pacific Ocean) affected weather worldwide. Enlarge Photo credit: NASA / Image by R.B. Husar, Washington University; the land layer from the SeaWiFS Project; fire maps from the European Space Agency; the sea surface temperature from the Naval Oceanographic Office's

Just the opposite effect happens in the west, near Australia: intense rain cloud formation occurs as warm moist air, heated by the warm sea, rises and condenses into clouds. These clouds carry the drenching rains of the monsoons upon which the entire region of Indonesia and Southeast Asia depends. The huge volumes of rising warm air create a vacuum as they move upward, which draws cooler air from the east to replace it, strengthening the tradewinds and reinforcing the entire cycle. Another two-lane convection highway is created, but instead of between the equator and the poles, this one is between coastal South America and the region of Australia.

Here's where it gets interesting, the crux of the mystery of El Niño. This cycle should be self-perpetuating. But it's not. For unknown reasons, every few years, something hidden in the machinery causes the west-blowing tradewinds to slacken in the Pacific. The warm waters, which have been held by the winds in a pile 5 feet above sea level in the west, begin to flow back across the sea, drawn down by gravity, like a river breaching a levee. This massive surge of heated water shoots across the ocean and repositions itself near South America. East becomes west. Because of the heated water, all of the rainmaking that normally would happen in the west now happens in the east, and the convection cell reverses flow, which means rising warm air in the east sucks in the air from the west, and the tradewinds actually reverse their direction. Because the water in the west is now comparatively cool, rainmaking stops. The monsoons fail in Indonesia, but unending rains begin in Peru. The Child has arrived.

In its new, temporary headquarters off South America, the warm pool's heat again creates a huge mass of warm moist air, which bulges into the zones of prevailing winds at the surface as well as high in the air. Like a car dumped in a stream, this foreign obstruction creates ripples and waves "downstream" in the vast air rivers that circulate the Earth. These ripples cascade outward, pushing and disturbing the midlatitude jetstreams which sweep weather across the temperate zones. Off the west coast of North America, the bulging effect is pronounced. Pacific storms which normally would remain in the tropics now have an open door to the west coast, as the jet stream lurches north. California, Mexico, and even British Columbia brace for an onslaught of winter rain.

When a very strong El Niño strikes surface waters in the equatorial Pacific Ocean, warm water anomalies (red) develop in the Central Pacific. Winds that normally blow in a westerly direction weaken, allowing the easterly winds to push the warm water up against the South American coast. Enlarge Photo credit: NASA

After lurching north, the jet stream (like everything else in the system) tries to compensate for its too-far north motion by diving south, usually over the Rocky Mountains. It then snakes north again, creating the classic El Niño pattern. Because the jet stream represents a boundary between cold northern air and warm moist southern air, meteorologists are able to make general predictions for weather in an El Niño winter.

For starters, Pacific storms form farther east than usual. The northward bulge of the jet stream then conducts these abnormal storms into California and Mexico. Meanwhile, normal winter storms that would otherwise be steered through Washington and Oregon now veer northward toward the coast of Alaska, eventually being guided east into Canada. The west coast gets drenched; the Canadian Rockies get record snowfalls.

By strengthening east-blowing winds in the Caribbean, El Niño also creates a favorable environment for storms to develop in the Gulf of Mexico, and the displaced jetstream lets these storms pass up into the southeast of the United States. Florida and the southeastern states have a cool, abnormally rainy winter. A similar strengthening of the east-blowing winds in the Southern Hemisphere during its winter season brings massive storms to southern Brazil, Chile and Argentina.

In the midwest and northeast, the jetstream's strange dip and rise keeps colder Canadian air stuck in Canada, far north of its usual winter position. Acting as a boundary between this cold northern air and mild southern air, the displaced jetstream lets Chicago and New York enjoy a relatively warm, if somewhat wet, winter.

Because the rain machine in the west stops working, southeast Asia and Australia suffer devastating droughts. Meanwhile, North and South America get drenched, because the rain machine in the east is working overtime. Farther downstream in the great wind bands that circle the globe, El Niño continues to create havoc. By using the bands of prevailing winds as avenues along which to transmit its disruptive waves, El Niño eventually influences weather in Africa, the North Atlantic, even the Middle East. Teleconnected to distant regions by the Earth's rivers of air, El Niño invades the global weather machine.

This feature originally appeared on the site for the NOVA program Tracking El Nino.

NASA, Newseum Present Media Preview Of PBS' Earth From Space

 

 

WASHINGTON -- NASA and the Newseum will host a preview for news media of the upcoming NOVA special, "Earth from Space," at noon EST Monday, Feb. 4, at the Newseum, 555 Pennsylvania Ave. NW in Washington.

"Earth from Space" is scheduled to air nationwide at 9 p.m. EST Feb. 13 on Public Broadcasting Service television stations. The two-hour special explores how satellites are transforming our view of Earth and features interviews with scientists and new visualizations of our complex planet. The centerpiece of the program is an animation of the globe composed of 23 layers of satellite-based data and more than 125,000 images from space.

A question-and-answer session with scientists appearing in "Earth from Space" will follow the screening of the 20-minute preview. The panelists are:

-- Paula Apsell, senior executive producer, NOVA, and director of the WBGH science unit, Boston
-- Piers Sellers, deputy director, Sciences and Exploration Directorate, Goddard Space Flight Center, Greenbelt, Md.
-- Waleed Abdalati, director, Earth Science and Observation Center, University of Colorado, Boulder
-- Jeff Halverson, associate professor, University of Maryland, Baltimore County

To attend, news media representatives must register in advance no later than Friday, Feb. 1, with Steve Cole by telephone at 202-358-0918 or by email at stephen.e.cole@nasa.gov.

NOVA is produced by WGBH. For more information on "Earth from Space," visit:

http://www.pbs.org/wgbh/nova/space/earth-from-space.html

 NASA

Guillermo Gonzalo Sánchez Achutegui

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NASA - NASA Rover Providing New Weather and Radiation Data About Mars

 

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Five Bites Into Mars

NASA's Mars rover Curiosity used a mechanism on its robotic arm to dig up five scoopfuls of material from a patch of dusty sand called "Rocknest," producing the five bite-mark pits visible in this image from the rover's left Navigation Camera (Navcam). Each of the pits is about 2 inches (5 centimeters) wide.

The fifth scoopful at Rocknest -- leaving the upper middle bite mark -- was collected during the mission's 93rd Martian day, or sol (Nov. 9, 2012). This image was taken later that same sol. A sample from that fifth scoop was analyzed over the next two sols by Curiosity's Sample Analysis at Mars (SAM) suite of instruments inside the rover. A second sample from the same scoopful of material was delivered to SAM for analysis on Sol 96 (Nov. 12). No further scooping of soil samples is planned at Rocknest.

The first Rocknest scoop was collected during Sol 61 (Oct. 7). Fine sand and dust from that scoopful and two subsequent ones were used for scrubbing the inside surfaces of chambers in the sample-handling mechanism on the arm. Samples from scoops three, four and five were analyzed by the Chemistry and Mineralogy instrument inside the rover.

Image credit: NASA/JPL-Caltech

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Thermal Tides at Mars

This diagram illustrates Mars' "thermal tides," a weather phenomenon responsible for large, daily variations in pressure at the Martian surface. Sunlight heats the surface and atmosphere on the day side of the planet, causing air to expand upwards. At higher levels in the atmosphere, this bulge of air then expands outward, to the sides, in order to equalize the pressure around it, as shown by the red arrows. Air flows out of the bulge, lowering the pressure of air felt at the surface below the bulge. The result is a deeper atmosphere, but one that is less dense and has a lower pressure at the surface, than that on the night side of the planet. As Mars rotates beneath the sun, this bulge moves across the planet each day, from east to west. A fixed observer, such as NASA's Curiosity rover, measures a decrease in pressure during the day, followed by an increase in pressure at night. The precise timing of the increase and decrease are affected by the time it takes the atmosphere to respond to the sunlight, as well as a number of other factors including the shape of the planet's surface and the amount of dust in the atmosphere.

Image credit: NASA/JPL-Caltech/Ashima Research/SWRI

PASADENA, Calif. -- Observations of wind patterns and natural radiation patterns on Mars by NASA's Curiosity rover are helping scientists better understand the environment on the Red Planet's surface.

Researchers using the car-sized mobile laboratory have identified transient whirlwinds, mapped winds in relation to slopes, tracked daily and seasonal changes in air pressure, and linked rhythmic changes in radiation to daily atmospheric changes. The knowledge being gained about these processes helps scientists interpret evidence about environmental changes on Mars that might have led to conditions favorable for life.

During the first 12 weeks after Curiosity landed in an area named Gale Crater, an international team of researchers analyzed data from more than 20 atmospheric events with at least one characteristic of a whirlwind recorded by the Rover Environmental Monitoring Station (REMS) instrument. Those characteristics can include a brief dip in air pressure, a change in wind direction, a change in wind speed, a rise in air temperature or a dip in ultraviolet light reaching the rover. Two of the events included all five characteristics.

In many regions of Mars, dust-devil tracks and shadows have been seen from orbit, but those visual clues have not been seen in Gale Crater. One possibility is that vortex whirlwinds arise at Gale without lifting as much dust as they do elsewhere.

"Dust in the atmosphere has a major role in shaping the climate on Mars," said Manuel de la Torre Juarez of NASA's Jet Propulsion Laboratory in Pasadena, Calif. He is the investigation scientist for REMS, which Spain provided for the mission. "The dust lifted by dust devils and dust storms warms the atmosphere."

Dominant wind direction identified by REMS has surprised some researchers who expected slope effects to produce north-south winds. The rover is just north of a mountain called Mount Sharp. If air movement up and down the mountain's slope governed wind direction, dominant winds generally would be north-south. However, east-west winds appear to predominate. The rim of Gale Crater may be a factor.

"With the crater rim slope to the north and Mount Sharp to the south, we may be seeing more of the wind blowing along the depression in between the two slopes, rather than up and down the slope of Mount Sharp," said Claire Newman, a REMS investigator at Ashima Research in Pasadena. "If we don't see a change in wind patterns as Curiosity heads up the slope of Mount Sharp -- that would be a surprise."

REMS monitoring of air pressure has tracked both a seasonal increase and a daily rhythm. Neither was unexpected, but the details improve understanding of atmospheric cycles on present-day Mars, which helps with estimating how the cycles may have operated in the past.

The seasonal increase results from tons of carbon dioxide, which had been frozen into a southern winter ice cap, returning into the atmosphere as southern spring turns to summer. The daily cycle of higher pressure in the morning and lower pressure in the evening results from daytime heating of the atmosphere by the sun. As morning works its way westward around the planet, so does a wave of heat-expanded atmosphere, known as a thermal tide.

Effects of that atmospheric tide show up in data from Curiosity's Radiation Assessment Detector (RAD). This instrument monitors high-energy radiation considered to be a health risk to astronauts and a factor in whether microbes could survive on Mars' surface.

"We see a definite pattern related to the daily thermal tides of the atmosphere," said RAD Principal Investigator Don Hassler of the Southwest Research Institute's Boulder, Colo., branch. "The atmosphere provides a level of shielding, and so charged-particle radiation is less when the atmosphere is thicker. Overall, Mars' atmosphere reduces the radiation dose compared to what we saw during the flight to Mars."

The overall goal of NASA's Mars Science Laboratory mission is to use 10 instruments on Curiosity to assess whether areas inside Gale Crater ever offered a habitable environment for microbes.

JPL, a division of the California Institute of Technology in Pasadena, manages the project for NASA's Science Mission Directorate, Washington, and built Curiosity.

For more information about Curiosity and its mission, 

visit: http://www.nasa.gov/msl 

and http://mars.jpl.nasa.gov/msl .

You can follow the mission on Facebook and Twitter at: http://www.facebook.com/marscuriosity 

and http://www.twitter.com/marscuriosity .

 

 

Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster@jpl.nasa.gov

Dwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown@nasa.gov
NASA

Guillermo Gonzalo Sánchez Achuteguui

ayabaca@hotmail.com

ayabaca@gmail.com

ayabaca@yahoo.com

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