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Wind topples California’s famous Tunnel Tree

January 9, 2017 Leave a comment
pioneers-cabin-tree-circa-1966
This photo of California’s Pioneer’s Cabin Tree, dated 1866, is from the Library of Congress.

The Pioneer Cabin Tree, a California landmark loved by tourists for decades, has been toppled by wind.

A giant sequoia, the huge tree was 150 feet tall. The cutout in its trunk was wide enough to drive cars through and, over the years, many cars did pass under the tree.

Eventually California authorities closed access to cars, but in recent years there has been a hiking trail that leads to it and visitors could still stand in the cutout.

tunnel-tree-photo-by-claudia-beymer
This photo of the base of California’s Tunnel Tree was posted on the Facebook page of the Calaveras Big Trees Association. Image by Claudia Beymer.

Located in Calaveras Big Trees State Park, the Pioneer Cabin Tree – also known as the Tunnel Tree – was estimated to be over 1,000 years old. The large hole in its trunk was carved by owners of the land on which it grew in 1880.

A report in the San Francisco Chronicle explained that there is no way to be sure of the reason why the Tunnel Tree could not withstand the storm that has hit the Golden State in recent days. That storm, the worst in at least a decade, flooded Calaveras Big Trees State Park. The Chronicle explained that the Tunnel Tree’s shallow root system, typical for a sequoia, was likely a factor.

fallen-tunnel-tree
This photo shows the splintered remains of California’s Tunnel Tree on Jan. 8, 2017. Image courtesy Calaveras Big Trees Association, photo by Jim Allday.

Giant sequoias (Sequoiadendron giganteum), also known as redwoods, are the world’s largest organisms by volume. They can grow to a height of 85 meters and have been known to live for more than 3,500 years.

Now that the Pioneer Cabin Tree has fallen, there are no longer any known living sequoia trees with tunnels through their trunks.

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New book by paleontologists Naish and Barrett is a treat for dinosaur fans

December 19, 2016 Leave a comment

naish-and-barrett-dinosaurs-how-they-lived-and-evolved-oct-2016

Those of us who love dinosaurs know that there is something poetic about these animals – the spectacular size of some,  their amazing variety, the mysteries of their long life on this planet . We still feel a thrill when we envision the fantastic beasts and we sometimes find ourselves drifting into a reverie in which we imagine the world under their 140 million-year domination. We can almost see, in our mind’s eye, the graceful long-necked sauropods nibbling the trees and shrubs, the stalking bipedal, sharp-toothed theropods tall and small, and the horned, crested, and armored herbivores wandering the landscape.

Our endless willingness to imagine the great beasts, and our persistent desire to learn more about them, is catered to by a growing variety of mass market books that aim to help us understand their biology and the ecosystems in which they lived. One of the best recent additions to this library, by the British paleontologists Darren Naish (author of the popular Tetrapod Zoology blog) and Paul Barrett (of London’s Natural History Museum), stands out for its depth and its wide-ranging look at dinosaurs’ anatomy, behavior, diversity, and evolution.

The book, Dinosaurs: How They Lived and Evolved, starts with a look at some basic biological principles and the history of dinosaur discoveries. Readers are provided a cogent overview of Earth’s geology and climate during the Mesozoic era, the value of cladistics as a tool to make sense of dinosaur variety, and the place of dinosaurs in the larger group of animals known as archosaurs.

Naish and Barrett then move on to a helpful explanation of the relationships among dinosaur species and a detailed look at dinosaur skeletal systems.

This discussion shines for its skillful and picturesque descriptions of the major dinosaur groups. The authors focus not just on the famous Saurischians and Ornithiscians; they take the reader into a just-deep-enough examination of the clades into which these groups are divided.

In the third section of the book Naish and Barrett shift to an examination of scientists’ current understanding of the deeper aspects of dinosaur biology: their diets, their mating habits, the intricacies of their movement, and their social behaviors. This part of the book is a smorgasbord of insights into how fossils, both trace and body, teach us about the structure of an animal’s life.

Next we are presented with a thorough discussion of modern dinosaurs. Here Naish and Barrett not only delve into the ways in which avian anatomy resembles that of their coelurosaur cousins, but also explain the current understanding of feather origins and the genesis of flight.

In the book’s final section Naish and Barrett, after a review of the impact by an asteroid or comet and its consequences for dinosaurs and their world, highlight another possible contributor to the Mesozoic terminus: active volcanoes around the planet.

The authors explain that, notwithstanding the ecological catastrophe that essentially ended their long reign over the planet’s biosphere (an incident known as the K-Pg event), dinosaurs may have been experiencing both climate change and a loss of diversity at the time it occurred. They take pains to emphasize that, contrary to popular myth, some dinosaurs did survive the end of the Cretaceous period. We know them, of course, as the birds.

Gracing the text are numerous photographs, graphs, and computer-generated reconstructions. Naish and Barrett did not, though, include citations to scientific papers or a bibliography.

Dinosaurs: How They Lived and Evolved is ideal for readers that have some basic familiarity with the biological sciences, though detailed knowledge is not required to enjoy the book.

Published by Smithsonian Books and carrying a cover price of $29.95, the book is a worthy and entertaining read for all of us who continue to be fascinated by the dinosaurs.

NOTE: This reviewer obtained a copy of Dinosaurs: How They Lived and Evolved on loan from the Arapahoe Library District. He was not asked by any publisher or author to prepare this review and has not been compensated for it.

NOAA’s new weather satellite reaches geostationary orbit; promises improvement in weather forecasting

December 2, 2016 Leave a comment

goes-r-satellite-logoThe nation’s most advanced weather satellite has reached geostationary orbit and will soon begin helping the National Oceanic & Atmospheric Administration improve weather forecasting.

Capable of imaging the entire western hemisphere of Earth every 15 minutes and the continental United States every five minutes, GOES-16 is expected to improve NOAA’s ability to predict and track thunderstorms, tornadoes, and hurricanes and anticipate solar activity that can impact human activities on Earth.

“The next generation of weather satellites is finally here,” NOAA administrator Kathryn Sullivan said in a statement released after the satellite was launched Nov. 19. “GOES-R is one of the most sophisticated Earth-observing platforms ever devised.”

Sullivan was referring to the generic name for the series of satellites to be launched in the next several years, of which GOES-16 is the first.

The key to GOES-16’s likely impact on meteorology is the satellite’s Advanced Baseline Imager (ABI).

Basically a sophisticated photography instrument, ABI will observe Earth across 16 bands of the electromagnetic spectrum. That is an improvement from weather satellites currently in orbit, which can only make use of five spectral bands.

ABI will also provide a four-fold increase in image resolution and transmit data back to Earth five times faster than is possible with current satellites.

GOES-16 is also equipped with a device that permits the mapping of lightning. The Geostationary Lightning Mapper detects short duration changes in near-infrared radiation, which indicates the presence of atmospheric electrical activity. GLM will operate over North America and South America and the marine areas immediately adjacent to those continents.

A device on the satellite known as Extreme Ultraviolet and X-Ray Irradiance Sensors will detect solar flares, which will in turn assist ground-based agencies in preserving communication and navigation capability when the flares occur.

Another instrument, the Solar Ultraviolet Imager, will allow for observation of other solar activity such as coronal holes and coronal mass ejections. These events can subject satellites and even the International Space Station to risks of increased radiation and disrupt Earth-based communications, navigation, and transmission of electricity.

The GOES-16 satellite is powered by a solar array.

Clifford F. Mass, a professor of atmospheric sciences at the University of Washington in Seattle, said that the potential of the GOES-16 satellite to improve accuracy of forecasts is significant. He explained that the challenge will be to make the most optimal use of the data it provides.

“How do you use the sensor information to create a physically consistent three-dimensional simulation of the atmosphere? That’s something that can be worked on.”

Weather satellites have been crucial to meteorology since the first, TIROS-1, was launched by NASA on April 1, 1960. Since then countries including China, India, Japan, and Russia have joined the United States in building an extensive network of weather satellites in orbit.

tiros-1-image-of-earth-courtesy-nasa
TIROS-1 transmitted the first televised image of Earth on April 1, 1960.
Image courtesy NASA.

Geostationary weather satellites, which permit constant observation of large areas on Earth’s surface, premiered in December 1966 when ATS-1 was sent skyward. In the 1970s NOAA began deployment of the GOES series of satellites, which work in pairs to observe atmospheric conditions from the west coast of Africa to the western Pacific Ocean.

Altogether the U.S. has sent at least 58 weather satellites into orbit.

The first in NOAA’s new Geostationary Operational Environmental Satellite-R series, the 2,800 kilogram-sized GOES-16 is now 35,800 kilometers away from Earth.

GOES-16, which earned its name when it reached stationary orbit above the equator on Nov. 29, is designed for ten years of operation. It will commence observations and data transmission next year, after testing of its instruments is completed.

The launch of GOES-16 does not address an ongoing concern among meteorologists that a gap in weather satellite coverage at the planet’s poles might occur. A 2016 report by the U.S. Government Accountability Office said that the risk that an existing satellite in polar orbit might fail could leave a lapse of coverage before the launch of a new spacecraft, JPSS-1, in March 2017.

 

Arctic sea ice reaches lowest extent of year

September 16, 2016 Leave a comment

The amount of summer sea ice in the Arctic fell this year to the second-lowest ever recorded by satellite.

NASA and the National Snow and Ice Data Center in Boulder, Colo. announced Thursday that the Arctic has reached its summer season low extent.

The 4.14 million square kilometers of ice measured on Sept. 10 is statistically tied with the minimum ice extent during the summer of 2007 for second place on the historic minimum list. This year’s minimum ice cover is more than two million square kilometers below the 1981-2010 mean.

Arctic Summer Minimum Sea Ice Extent Record, 2007-2016

YEAR EXTENT (millions of km2) DATE MEASURED
2012 3.39 Sept. 17
2016 4.14 Sept. 10
2007 4.15 Sept. 18
2011 4.34 Sept. 11
2015 4.43 Sept. 9
2008 4.59 Sept. 20
2010 4.62 Sept. 21
2014 5.03 Sept. 17
2013 5.06 Sept. 13
2009 5.12 Sept. 13
1979-2000 mean 6.70 Sept. 13
1981-2010 mean 6.22 Sept. 15
sea-ice-graph-sept-12-2016-graphic-courtesy-national-snow-and-ice-data-center
This graphic shows the minimum Arctic sea ice extent (according to a preliminary assessment) with the seasonal minimum in prior years. Graphic courtesy National Snow and Ice Data Center.

A statement released by NSIDC starkly described the conditions in the Arctic this summer:

“This year’s minimum extent is 750,000 square kilometers (290,000 square miles) above the record low set in 2012 and is well below the two standard deviation range for the 37-year satellite record.”

Cloudy skies and atmospheric pressure conditions slowed ice melt in June and July, which may have prevented this season from becoming the most ice-free summer ever observed from space.

“June and July are usually key months for melt because that’s when you have 24 hours a day of sunlight – and this year we lost melt momentum during those two months,” Walt Meier, a scientist at NASA’s Goddard Space Flight Center, said in a statement.

2016-arctic-sea-ice-minimum-sept-10-graphic-courtesy-nasa-goddard-space-center-visualization-studio-graphic-by-c-starr
This graphic shows the 2016 seasonal minimum, reached on Sept. 10, in comparison with the 1981-2010 average (shown by the gold-colored line). Graphic courtesy NASA Goddard Space Flight Center Scientific Visualization Studio; graphic by C. Starr.

The pace of melting accelerated in August when two cyclones crossed the Arctic Ocean.

Meier explained that these may have especially impacted the speed with which ice in the Chukchi and Beaufort seas melted.

The three-and-one-half decade long satellite record shows a marked decline in the mean extent of Arctic sea ice during each month of the year.

In fact, a paper published on Sept. 15 in the journal Remote Sensing of Environment concluded that no record for maximum Arctic sea ice extent has been set since 1986, while during the 37 years of satellite monitoring there have been 75 new minimum ice extent records set.

“The record makes it clear that the ice is not rebounding to where it used to be, even in the midst of winter,” Claire Parkinson, the lead author of that study and a senior climate scientist at GSFC, said.

Arctic sea ice ordinarily reaches its maximum reach for the year in March, late in the winter. The sun is not visible in the region during the winter and does not contribute much to warming of land and sea surfaces during that season.

NSIDC’s statement cautioned that the estimate released Thursday could be revised if late-summer winds or other factors causing ice melt impact the sea ice cover during the remaining days of summer.

The monitoring record dates to 1978.

Earth’s poles are the two regions of the planet that are most sensitive to warming of the atmosphere. As sea ice melts, more solar energy is absorbed by the Arctic Ocean. The deep and dark waters absorb about 90 percent of the sun’s energy that reaches them.

By contrast, expansion of sea ice during the colder autumn and winter months causes about 80 percent of the solar energy that hits the frozen surface of the region’s marine environment to be reflected to space.

 

Look up tonight to see first summer solstice strawberry moon since 1967

June 20, 2016 Leave a comment
June full moon

A June full moon is also called a “honey moon” because it appears amber-colored through Earth’s atmosphere.

Today’s summer solstice in the northern hemisphere does not bring only the longest day of the year. Night sky watchers also have the opportunity to see, for the first time in 49 years, a full moon on the first day of summer.

The full moon occurs about once each month. The lunar year – the amount of time it takes for the moon to cycle through 12 lunar cycles – is 354 days; the lunar cycle averages 29.53 days.

A full moon occurs when the sun, Earth, and the moon are nearly aligned. During most  full moons we see nearly all of one of the Moon’s hemispheres from our planet. We do not see all of that hemisphere during a typical full moon because, if we did, the sun, Earth, and moon would be so aligned as to result in a lunar eclipse.

The other hemisphere of the moon is never visible from Earth because the moon’s rate of  rotation is equal to the amount of time it takes to orbit our planet.

Because tonight’s full moon occurs in June, it is colloquially known as a “strawberry moon.” According to the 1918 book The American Boy’s Book of Signs, Signals and Symbols, the nickname originated with native Americans of the northeastern United States because June is the month in which strawberries were harvested.

According to a 2012 National Geographic article, “Europeans have dubbed [a June full moon] the rose moon, while other cultures named it the hot moon for the beginning of the summer heat.”

The summer solstice in the northern hemisphere is the one day of the year on which the sun will be directly overhead at noon at the Tropic of Cancer. The sun is never directly overhead at a latitude north of the Tropic of Cancer or south of the Tropic of Capricorn.

In Colorado and the rest of the Mountain Time Zone of North America, the sun will get to its annual highest point in the sky at 4:34 pm.

Earth at summer solstice

This graphic shows Earth’s northern hemisphere at the summer solstice. Graphic courtesy Space.com.

The sun is directly overhead at high noon above the Tropic of Capricorn on the winter solstice in the northern hemisphere.

The southern hemisphere experiences its summer solstice on that day and its winter solstice when the sun is directly overhead at the Tropic of Cancer.

CORRECTION, June 20, 2016, 5:24 pm MDT: This article originally stated that the last summer solstice full moon occurred in 1949, 67 years ago. That is not an accurate statement and the article has been edited to correct the error.

Asian fossil discovery may help explain how tyrannosaurs became dominant predators

June 17, 2016 Leave a comment
Timurlengia euotica - March 2016 - courtesy

This artist’s conception shows the tyrannosaur Timurlengia euotica in its environment 90 million years ago, accompanied by two flying reptiles (Azhdarcho longicollis). The fossilized remains of a the horse-sized dinosaur help explain how Tyrannosaurus rex and its close relatives became top predators. The paper describing the discovery was published in March in the Proceedings of the National Academy of Sciences. Illustration by Todd Marshall.

Researchers have discovered 90 million-year old fossils of an early tyrannosaur that may help improve scientists’ understanding of how that group of dinosaurs evolved into the predatory giants that later roamed North America.

The horse-sized animal, which would have likely weighed about 250 kilograms, apparently had impressive hearing ability. Its capacity to hear low frequency sounds can be deduced from an elongated cochlear duct.

Named Timurlengia euotica, the newly-identified tyrannosaur helps fill a gap in knowledge about how the relatively small theropods, which had to compete with larger allosaurs, evolved into some of the largest land predators ever known.

The discovery indicates that the tyrannosaur clade probably gained the sensory tools needed to become apex predators before late Cretaceous enormity took hold.

“Tyrannosaurs had to get smart before they got big,” Dr. Stephen L. Brusatte, a paleontologist at the University of Edinburgh in the United Kingdom and lead author of the paper describing the discovery, said.

Enormity on the scale so obviously presented by later tyrannosaurs like Tyrannosaurus rex, which stood about five meters tall and about 12 meters long and weighed about 3,600 kilograms, evolved during the last 20 million years of the dinosaurs’ dominance of Earth.

Researchers found a brain case, which they then subjected to a computed microtomography (CT) scan. That scan revealed not only the animal’s inner ear structure, but also likely similarities between T. euotica‘s brain and the brain of Tyrannosaurus rex.

Brusatte wrote in The Conversation that these features likely helped T. euotica become a very skilled tracker of prey.

“Their intelligence and sharp senses made tyrannosaurs perfectly equipped to swoop into the top-predator role,” he wrote.

As the tyrannosaur head became larger, it became more useful for hunting.

“Their heads became giant killing machines and their arms, now unnecessary, shrunk down to nubbins,” Brusatte wrote in The Conversation feature.

The fossilized braincase, along with a variety of other bones, had been stored in a museum for about ten years. Brusatte and his colleagues examined them in 2014.

Reconstructed T. euotica skeleton

This is a reconstructed skeleton of Timurlengia euotica with discovered fossilized bones, highlighted in red, and other bones remaining to be discovered inferred from other related species of tyrannosaurs in white. Individual scale bars for the pictured fossilized bones each equal 2 centimeters. The fossilized remains of T. euotica may reveal how Tyrannosaurus rex and its close relatives became top predators. Graphic (c) National Academy of Sciences.

“Working on Timurlengia has been one of the highlights of my career,” Brusatte said. “It gives us a glimpse of what the ancestor of T. rex was – a tyrannosaur right on the cusp of becoming huge.”

The fossils were found in the remote Kyzylkum Desert of Uzbekistan. Their significance was described in a paper published in March in Proceedings of the National Academy of Sciences.

Southwest U.S. readies for possible record-breaking heat

June 15, 2016 Leave a comment

The southwestern United States may be facing near record-breaking summer heat during the next few days.

According to the National Weather Service, major cities in Arizona, Nevada, and even southern California will experience temperatures of at least 100 degrees Fahrenheit at the beginning of next week.

The forecast officially calls for Phoenix to hit 117 degrees on Sunday and 118 degrees on Monday. Las Vegas may hit 110 degrees on Monday and Tuesday, while Tucson’s temperature could reach 114 degrees on Sunday and 112 degrees on Monday.

Meteorologist Bob Henson, writing at the Weather Underground blog, thinks it could be warmer.

WU forecast SW June 2016

Graphic courtesy Weather Underground.

So does Ryan Maue, a meteorologist affiliated with Weatherbell Analytics. Maue predicts that the temperature in Phoenix will reach 120 degrees on Monday.

The all-time hottest temperature in Phoenix is 122 degrees, which was reached in 1990. At least one forecast map shows that the metropolis in central Arizona’s Salt River Valley might reach 120 degrees on Monday.

The Valley of the Sun has experienced four straight record-breaking warm days this month (June 3-7), as well as its earliest 115 degree day in recorded history. If Phoenix reaches 116 degrees on Sunday, it would be the hottest day ever recorded in the city prior to the summer solstice.

The heat record in Las Vegas (most recently on June 30, 2013) and Tucson (June 26, 1990) is 117 degrees, while Yuma’s all-time mark is 124 degrees (July 28, 1995).

Los Angeles could reach 101 degrees on Monday, June 20. That is not close to the city’s all-time record high temperature of 113 degrees.

Southwest temperatures

This graphic shows the forecasted high temperatures on June 20, 2016. Graphic courtesy Weatherbell Analytics, National Weather Service.

Records maintained by the National Centers for Environmental Information, an agency of the National Oceanic & Atmospheric Administration, show that record high temperatures are much more common in the U.S. this year than are record low temperatures.

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