November 29, 2009, 16:00 PST

Follow the yellow brick road

Wintertime drought linked to fewer tornadoes

The Dimmitt Tornado, captured on film south of Dimmitt, Texas on June 2, 1995. Credit: NOAA Photo Library, OAR/ERL/NSSL.
The Dimmitt Tornado, captured on film south of Dimmitt, Texas on June 2, 1995. Credit: NOAA Photo Library, OAR/ERL/NSSL.

From Gretchen Cook-Anderson, NASA Earth Science News Team

Perhaps Dorothy, from the famed film Wizard of Oz, should have hoped for a fall or wintertime drought. According to findings from a NASA-funded study published in Environmental Research Letters back in June, dry fall and winter seasons in the southeastern United States mean it is less likely that southern twisters will develop in springtime to sweep anyone off their feet. Using rainfall data from NASA satellites, information from rain gauges, and a tornado record dating back to 1952 (courtesy of the National Oceanic and Atmospheric Administration’s Storm Prediction Center), University of Georgia meteorologists Marshall Shepherd and Tom Mote and Purdue University climatologist Dev Niyogi discovered a statistical tendency for drought-ravaged fall and winter seasons to pave the way for “below normal tornado days” in spring seasons that follow. “This is conceptually similar to what Bill Gray been doing for more than 25 years when he predicts how active the hurricane season will be based on African rain,” said Shepherd, the study’s lead author, of the Colorado State University’s pioneer hurricane season forecaster. They culled data from Northern Georgia and other parts of the southeast, but Shepherd and his colleagues believe their findings may have relevance for other regions. The new study also adds to the body of related work Shepherd and Niyogi are ushering in, including their study earlier this year in the aftermath of Atlanta’s spring 2008 twister that linked urbanization and drought to tornado activity. For Shepherd in particular, there’s no place like home when considering the geographical focus of much of his meteorological research. “Science is my proverbial yellow brick road,” explained Shepherd. “It’s taken me down some fascinating paths, especially in learning more in recent years about tornado phenomena in my own backyard.”

Cross posted from NASA’s What on Earth blog. Gretchen is based at NASA’s Goddard Space Flight Center outside Washington, D.C.

November 24, 2009, 16:00 PST

Tour NASA’s new Climate Reel

Movies and animations for climate lovers

Some of the images taken by NASA's MODIS satellite sensor as the Larsen B ice shelf in Antarctica collapsed in early 2002. Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio.
Some of the images taken by NASA's MODIS satellite sensor as the Larsen B ice shelf in Antarctica collapsed in early 2002. Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio.

We’re less than two weeks away from the United Nations’ long-awaited Copenhagen Climate Change Conference. In anticipation of the event, we’ve compiled a climate resource reel that highlights some of NASA’s most compelling climate videos and data animations.

Take a tour of Earth’s rapidly changing frozen places, learn more about the unexpected role that honeybees can play as climate data collectors, and find out how we take the temperature of the planet. Learn why the oceans are really the Earth’s big heat bucket and check out just how carbon dioxide levels have changed over the past 400,000 years.

You can see our top ten movie picks on the Climate Reel site, as well as a whole host of additional climate-related videos and animations, which are also available through NASA’s Scientific Visualization Studio. Enjoy!

November 15, 2009, 16:00 PST

Up close and personal

Operation Ice Bridge

Operation Ice Bridge.

From Kathryn Hansen, NASA Earth Science News Team

NASA and partners are nearing the end of the 2009 Antarctic campaign of Operation Ice Bridge — a multi-year airborne survey to study Earth's polar ice sheets, ice shelves and sea ice. Data collected from the DC-8 aircraft will help scientists monitor changes in West Antarctica and bridge the gap between NASA's ICESat and ICESat-2 satellites. Also, the close-up look — not possible from satellites — will help scientists learn more about the region's ice dynamics.

The detailed look with lasers and radar, sometimes from just 1,000 feet above the ice, is now returning a wealth of scientific information about the ice surface and what's below. And to the human eye, the low-altitude view shows West Antarctica's intricacies: the vast expanse of white giving way to deep crevasses and volcanoes, and sea ice resembling pancakes and oil slicks.

The 2009 Operation Ice Bridge campaign concludes no later than November 21. Want to follow the remainder of the flights? Here's how to connect:

Webisodes - Watch this series of YouTube videos for a behind-the-scenes look at Ice Bridge mission planning and flights in Antarctica.

Image gallery - Curious what pancake ice looks like or want to take a peek inside the DC-8? Check out the image gallery for photos added throughout the mission

Blog - Read about the campaign straight from the scientists and public affairs officers on site.

Twitter - Be among the first to know if a flight took off or if it was grounded due to weather, and discover the target of most flights — glacier, ice sheet or sea ice?

Cross posted from NASA's What on Earth blog. Kathryn is based at NASA’s Goddard Space Flight Center outside Washington, D.C.

November 12, 2009, 16:00 PST

Science for a hungry world

Risky business


Some have called it "the human enterprise most vulnerable to climate change".

What they're talking about is agriculture, which is an integral part of the lives of many of the world's poorest people. Climate change is already affecting global food production, and is likely to have even more of an impact in the years to come. Studies have shown that increasing temperatures and decreasing precipitation over Asia and Africa could cause severe crop losses. Southern Africa could lose more than 30 percent of its main crop, maize, by 2030, while south Asia losses of many regional staples, such as rice, millet and maize could exceed 10 percent. And this would come at a time when there are ever-increasing numbers of mouths to feed.

A new video from NASA explores the way its satellites are helping to collect data from around the planet, in an effort to predict the challenges that farmers are facing as our climate changes, and ultimately to help come up with solutions. Check out the video below.

November 8, 2009, 16:00 PST

Keeping an eye on the storm

Tropical storm Ida comes to town

As of this morning, hurricane Ida was downgraded to a tropical storm and is approaching the U.S. Gulf Coast at a rate of about 18 mph (30 km/hr). NASA's Quikscat satellite (short for "Quick Scatterometer") snapped this shot of the storm today at 11:23 UTC, which reveals the storm's wind speeds.

Tropical storm Ida, as captured by NASA's Quikscat satellite this morning.
Tropical storm Ida, as captured by NASA's Quikscat satellite this morning.

According to the National Hurricane Center, Ida's maximum sustained winds are around 70 mph (110 km/hr), and the storm is expected to become weaker as it approaches the coast. In the next 24 hours, tropical storm conditions are expected in a region that ranges from Grand Isle Louisiana eastward to the Aucilla River in Florida, and includes New Orleans.

Ida may have been responsible for causing 124 deaths in El Salvador following days of heavy rain and subsequent flooding and landslides.

November 4, 2009, 16:00 PST

Spooky clouds

Eerie goings-on at the edge of space

Noctilucent clouds at twilight.
One of the first ground sightings of night-shining clouds in the 2007 summer season. Credit: Veres Viktor of Budapest, Hungary.

Hallowe’en has come and gone, but there are still signs of spooky things afoot. Take a look at this picture — of clouds shining at night. Yes, that’s right, at night. These are known as “noctilucent” clouds and, unlike normal clouds, they are only visible near twilight, when the sun is just below the horizon and the sky is dark. Scientists are still trying to get their heads around what causes them to form.

Noctilucent clouds (see here for a gallery) were first reported in 1885, two years after the eruption of Krakatoa, and were originally linked to the volcanic ash that had been launched high into the atmosphere. But even after the ash settled, the clouds remained. Since then, research into these mysterious objects has ramped up, but we still know relatively little about their basic physics. They can be seen from the ground, but are even more brilliant from space, as astronauts have testified.

Noctilucent clouds from space.
Night-shining clouds over the Arctic regions of Europe and North America, represented in white and blue, captured from space on June 11, 2007. Credit: Cloud Imaging and Particle Size Experiment data processing team at the University of Colorado's Laboratory for Atmospheric and Space Physics.

What we do know is that noctilucent clouds lie near the edge of space, about 50 miles (80 km) up, and are made up of ice crystals, just like some of the regular clouds you see. Typically these clouds are seen at high latitudes (around the Earth’s poles) during summer months. But, for some reason, they are now being seen at latitudes as low as 40 °N, in places like Utah and Colorado. The clouds have also been getting brighter. Many scientists suspect they are related to changes in our atmosphere spurred on by global warming.

Since the 1970s, night-shining clouds have been monitored from space as well as from the ground in an effort to solve this puzzle. Where does the water that makes up the clouds come from? Where do the particles that “seed” the clouds’ ice crystals originate? And what controls temperatures in this part of the atmosphere, so high up?

AIM (Aeronomy of Ice in the Mesosphere), launched by NASA in 2007 and slated to run until 2012, was the first satellite mission dedicated solely to studying these weird clouds and is bringing back new information every day. And in September of this year, NASA’s Wallops Flight Facility in Virginia launched a rocket into the atmosphere in a scheme to artificially create night-shining clouds. The project, known as the Charged Aerosol Release Experiment, or CARE for short, was designed to trigger cloud formation around the rocket’s exhaust particles emitted high up in the atmosphere. A plethora of cameras and radar instruments on the ground and in space will track the dust for the next few months and learn more about how noctilucent clouds form and evolve.

Our ancestors no doubt looked up at the night sky and were mesmerized by what they saw. In some ways, things are not so very different today, except that now we have the technology to send rockets up to chase those objects of fascination.