Data from satellite sensors show that during the Northern Hemisphere’s growing season, the Midwest region of the United States boasts more photosynthetic activity than any other spot on Earth, according to NASA and university scientists.
Healthy plants convert light to energy via photosynthesis, but chlorophyll also emits a fraction of absorbed light as a fluorescent glow that is invisible to the naked eye. The magnitude of the glow is an excellent indicator of the amount of photosynthesis, or gross productivity, of plants in a given region. (more…)
A solar tsunami observed by NASA’s Solar Dynamics Observatory (SDO) and the Japanese Hinode spacecraft has been used to provide the first accurate estimates of the Sun’s magnetic field.
Solar tsunamis are produced by enormous explosions in the Sun’s atmosphere called coronal mass ejections (CMEs). As the CME travels out into space, the tsunami travels across the Sun at speeds of up to 1000 kilometres per second.
Similar to tsunamis on Earth, the shape of solar tsunamis is changed by the environment through which they move. Just as sound travels faster in water than in air, solar tsunamis have a higher speed in regions of stronger magnetic field. This unique feature allowed the team, led by researchers from UCL’s Mullard Space Science Laboratory, to measure the Sun’s magnetic field. The results are outlined in a paper soon to be published in the journal Solar Physics. (more…)
Researchers working with data from NASA’s Cassini spacecraft have discovered one way the bubble of charged particles around Saturn — known as the magnetosphere — changes with the planet’s seasons. The finding provides an important clue for solving a riddle about the planet’s naturally occurring radio signal. The results might also help scientists better understand variations in Earth’s magnetosphere and Van Allen radiation belts, which affect a variety of activities at Earth, ranging from space flight safety to satellite and cell phone communications.
The paper, just published in the Journal of Geophysical Research, is led by Tim Kennelly, an undergraduate physics and astronomy major at the University of Iowa, Iowa City, who is working with Cassini’s radio and plasma wave science team. (more…)
PASADENA, Calif. – An area of the Amazon rainforest twice the size of California continues to suffer from the effects of a megadrought that began in 2005, finds a new NASA-led study. These results, together with observed recurrences of droughts every few years and associated damage to the forests in southern and western Amazonia in the past decade, suggest these rainforests may be showing the first signs of potential large-scale degradation due to climate change.
An international research team led by Sassan Saatchi of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., analyzed more than a decade of satellite microwave radar data collected between 2000 and 2009 over Amazonia. The observations included measurements of rainfall from NASA’s Tropical Rainfall Measuring Mission and measurements of the moisture content and structure of the forest canopy (top layer) from the Seawinds scatterometer on NASA’s QuikScat spacecraft. (more…)
AMHERST, Mass. – Though it seems like an oxymoron, Arctic hurricanes happen, complete with a central “eye,” extreme low barometric pressure and towering 30-foot waves that can sink small ships and coat metal platforms with thick ice, threatening oil and gas exploration. Now climate scientists at the University of Massachusetts Amherst and in England report the first conclusive evidence that Arctic hurricanes, also known as polar lows, play a significant role in driving ocean water circulation and climate.
Results point to potentially cooler conditions in Europe and North America in the 21st century than other models predict. (more…)
A device designed by engineers at the Georgia Tech Research Institute (GTRI) is part of the Hurricane Imaging Radiometer (HIRAD), an experimental airborne system developed by the Earth Science Office at the NASA Marshall Space Flight Center in Alabama.
Known as an analog beam-former, the GTRI device is part of the radiometer, which is being tested by NASA on a Global Hawk unmanned aerial vehicle. The radiometer measures microwave radiation emitted by the sea foam that is produced when high winds blow across ocean waves. By measuring the electromagnetic radiation, scientists can remotely assess surface wind speeds at multiple locations within the hurricanes. (more…)
Light pollution is often associated with negative effects on wildlife. Now, ecologists have found that by mimicking a perpetual full moon, the gas flares and electrical lighting along Scotland’s Forth estuary are helping shorebirds stock up on more food during the winter to fuel their spring migration.
The research is the first to use night-time light data from US military satellites to study animal behaviour.
Coasts and estuaries are among the most rapidly developing areas on Earth. Night-time satellite images of the planet show that except Antarctica, continents are ringed with halos of brightly-lit human development. But coasts are also key wildlife sites. Every year, millions of waterbirds arrive from the Arctic to overwinter on UK coasts, yet scientists remain largely in the dark about how these birds respond to the bright lights of coastal cities and industry. (more…)
PASADENA, Calif. – A new analysis led by NASA’s Jet Propulsion Laboratory, Pasadena, Calif., has estimated how much the growth of plants worldwide is limited by the amount of nutrients available in their soil. The maps produced from the research will be particularly useful in evaluating how much carbon dioxide Earth’s ecosystems may be able to soak up as greenhouse gas levels increase.
A research team led by JPL research scientist Josh Fisher used 19 years of data from NASA, National Oceanic and Atmospheric Administration and international satellites to assess the maximum possible growth of vegetation all over the world based upon available water and light conditions. The scientists then cross-compared that potential maximum with observed vegetation productivity as measured by satellites. This is the first time such an analysis has been conducted.(more…)
