New NASA Van Allen Probes observations helping to improve space weather models

Using data from NASA's Van Allen Probes, researchers have tested and improved a model to help forecast what's happening in the radiation environment of near-Earth space -- a place seething with fast-moving particles and a space weather system that varies in response to incoming energy and particles from the sun.

NASA's Van Allen Probes orbit through two giant radiation belts that surround Earth. Their observations help improve computer simulations of events in the belts that can affect technology in space.

When events in the two giant doughnuts of radiation around Earth -- called the Van Allen radiation belts -- cause the belts to swell and electrons to accelerate to 99 percent the speed of light, nearby satellites can feel the effects. Scientists ultimately want to be able to predict these changes, which requires understanding of what causes them.

Now, two sets of related research published in the Geophysical Research Letters improve on these goals. By combining new data from the Van Allen Probes with a high-powered computer model, the new research provides a robust way to simulate events in the Van Allen belts.

"The Van Allen Probes are gathering great measurements, but they can't tell you what is happening everywhere at the same time," said Geoff Reeves, a space scientist at Los Alamos National Laboratory, or LANL, in Los Alamos, N.M., a co-author on both of the recent papers. "We need models to provide a context, to describe the whole system, based on the Van Allen Probe observations."

Prior to the launch of the Van Allen Probes in August 2012, there were no operating spacecraft designed to collect real-time information in the radiation belts. Understanding of what might be happening in any locale was forced to rely mainly on interpreting historical data, particularly those from the early 1990s gathered by the Combined Release and Radiation Effects Satellite, or CRRES.

Imagine if meteorologists wanted to predict the temperature on March 5, 2014, in Washington, D.C. but the only information available was from a handful of measurements made in March over the last seven years up and down the East Coast. That's not exactly enough information to decide whether or not you need to wear your hat and gloves on any given day in the nation's capital.

Thankfully, we have much more historical information, models that help us predict the weather and, of course, innumerable thermometers in any given city to measure temperature in real time. The Van Allen Probes are one step toward gathering more information about space weather in the radiation belts, but they do not have the ability to observe events everywhere at once. So scientists use the data they now have available to build computer simulations that fill in the gaps.

The recent work centers around using Van Allen Probes data to improve a three-dimensional model created by scientists at LANL, called DREAM3D, which stands for Dynamic Radiation Environment Assimilation Model in 3 Dimensions. Until now the model relied heavily on the averaged data from the CRRES mission.

One of the recent papers, published Feb. 7, 2014, provides a technique for gathering real-time global measurements of chorus waves, which are crucial in providing energy to electrons in the radiation belts. The team compared Van Allen Probes data of chorus wave behavior in the belts to data from the National Oceanic and Atmospheric Administration's Polar-orbiting Operational Environmental Satellites, or POES, flying below the belts at low altitude. Using this data and some other historical examples, they correlated the low-energy electrons falling out of the belts to what was happening directly in the belts.

"Once we established the relationship between the chorus waves and the precipitating electrons, we can use the POES satellite constellation -- which has quite a few satellites orbiting Earth and get really good coverage of the electrons coming out of the belts," said Los Alamos scientist Yue Chen, first author of the chorus waves paper. "Combining that data with a few wave measurements from a single satellite, we can remotely sense what's happening with the chorus waves throughout the whole belt."

The relationship between the precipitating electrons and the chorus waves does not have a one-to-one precision, but it does provide a much narrower range of possibilities for what's happening in the belts. In the metaphor of trying to find the temperature for Washington on March 5, it's as if you still didn't have a thermometer in the city itself, but can make a better estimate of the temperature because you have measurements of the dewpoint and humidity in a nearby suburb.

The second paper describes a process of augmenting the DREAM3D model with data from the chorus wave technique, from the Van Allen Probes, and from NASA's Advanced Composition Explorer, or ACE, which measures particles from the solar wind. Los Alamos researchers compared simulations from their model -- which now was able to incorporate real-time information for the first time -- to a solar storm from October 2012.

"This was a remarkable and dynamic storm," said lead author Weichao Tu at Los Alamos. "Activity peaked twice over the course of the storm. The first time the fast electrons were completely wiped out -- it was a fast drop out. The second time many electrons were accelerated substantially. There were a thousand times more high-energy electrons within a few hours."

Tu and her team ran the DREAM3D model using the chorus wave information and by including observations from the Van Allen Probes and ACE. The scientists found that their computer simulation made by their model recreated an event very similar to the October 2012 storm.

What's more the model helped explain the different effects of the different peaks. During the first peak, there simply were fewer electrons around to be accelerated.

However, during the early parts of the storm the solar wind funneled electrons into the belts. So, during the second peak, there were more electrons to accelerate.

"That gives us some confidence in our model," said Reeves. "And, more importantly, it gives us confidence that we are starting to understand what's going on in the radiation belts."

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Climate change will improve survival rates of British bird -- the long-tailed tit

Climate change may be bad news for billions, but scientists at the University of Sheffield have discovered one unlikely winner -- a tiny British bird, the long-tailed tit.

Like other small animals that live for only two or three years, these birds had until now been thought to die in large numbers during cold winters. But new research suggests that warm weather during spring instead holds the key to their survival.

The findings come from a 20-year study of long-tailed tits run by Professor Ben Hatchwell at the Department of Animal and Plant Sciences. The recent work is led by PhD student Philippa Gullett and Dr Karl Evans from Sheffield, in collaboration with Rob Robinson from the British Trust for Ornithology.

"During spring, birds must work their socks off to raise their chicks," said Philippa Gullett.

"For most small birds that live for only two or three years, not raising any chicks one year is a disaster. They might only get one more chance, so they can't afford to fail."

No surprise then that these birds are willing to invest everything and risk death if it means their young survive. The surprise is that weather makes all the difference. The research discovered that birds trying to breed in warm and dry springs have much better chances of surviving to the next year -- a novel result that counters common assumptions about the cause of death for small birds.

"What seems to be going on is that the tits try to raise their chicks at any cost," added Ms Gullett.

"If it's cold and wet in spring, that makes their job much tougher. Food is harder to find; eggs and chicks are at risk of getting cold. The result is that by the end of the breeding season, the adult birds are exhausted."

The study found no real effect of winter weather in recent years on adult survival, however cold and wet autumns were associated with a higher death rate.

"We're not saying that birds never die in winter -- in harsh years there are bound to be some fatalities," explained Dr Karl Evans.

"However, it seems that in most years autumn weather plays a bigger role, perhaps acting as a filter that weeds out weaker birds before the real winter hits."

Although autumns may get wetter in the coming years, any increase in mortality is likely to be offset by the benefits of warmer breeding seasons, when more benign conditions reduce the costs of breeding.

Dr Evans added: "Looking ahead to the future, our data suggests that every single plausible climate change scenario will lead to a further increase in long-tailed survival rates. While many species struggle to adjust to climate change, these delightful birds seem likely to be winners."

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Partners deploy underwater robots to improve hurricane science

September 9, 2013

A fleet of underwater robots is descending into waters off the east coast to collect data that could help improve storm intensity forecasts during future hurricane seasons. Several regions of the NOAA-led U.S. Integrated Ocean Observing System (IOOS®) are partnering to deploy 12 to 16 autonomous underwater robotic vehicles, also known as gliders, from Nova Scotia to Georgia.  

The gliders will be available through the peak fall Atlantic storm season to collect data on ocean conditions, which will help improve scientists’ understanding of hurricanes and pave the way for future improvements in hurricane intensity forecasts.  

“When storms are moving along our coasts, lives depend on accurate forecasts,” said Zdenka Willis, U.S. IOOS program director. “The unmanned gliders will allow us to collect data even in the middle of the storm and eventually provide this information to NOAA’s National Weather Service to help improve forecast precision so decision makers can keep people safe.”

Scientists will deploy the first gliders in the fleet in early September and continue deploying from different locations throughout the next two to three weeks. Each glider will be deployed for three to eight weeks, collecting data into October.

The underwater gliders can travel thousands of miles and continuously collect and send back ocean data. They can operate for several months at a time and can dive repeatedly to collect three-dimensional ocean observations.

Rutgers University is leading this combined science mission involving all three of the east coast IOOS regions: Northeast, Mid-Atlantic and Southeast. In addition to glider data, the mission will use satellite, moored buoy and coastal radar data. During the mission, the gliders will also collect acoustic data about fish and mammal migrations to improve the understanding of their behaviors.  

Collected glider data will go through NOAA’s National Data Buoy Center to NOAA’s National Weather Service, the U.S. Navy and other data users for modeling. Data from the glider missions will also be public and available on the IOOS Glider Asset Map and at http://www.ndbc.noaa.gov/gliders.php

In addition to NOAA funding, provided through the IOOS regions, other funding sources for the project include the Office of Naval Research, the Environmental Protection Agency, NASA, a private donor from the University of Delaware, and Canada’s Ocean Technology Network.

IOOS is a federal, regional and private sector partnership working to enhance the ability to collect, deliver and use ocean information. IOOS delivers the data and information needed to increase understanding of our ocean and coasts so that decision makers can act to improve safety, enhance the economy, and protect the environment.

NOAA’s mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources. Join us on Facebook, Twitter, Instagram and our other social media channels.

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