AGU 期刊一周Research Spotlights (June 16~June 22, 2016)

发布时间:2016-6-23 23:49:09 点击次数:672

I. Atmospheric Sciences

1. When Thunderstorms Have Wings

A new study uncovers the origin of a gull wing–shaped cirrus cloud above an Argentinian thunderstorm captured in satellite images.


II. Geology & Geophysics

1. The Fate of Hydrocarbons Seeping from the Ocean Floor

Researchers investigate the properties of bubbles at deep-ocean oil seeps to improve oil spill models.


III.Hydrology, Cryosphere & Earth Surface

1. Silty Streams Muddy Freshwater Conservation Issues

Throughout the Pacific Northwest, dirt from unpaved roads can clog streams, threatening fish habitats. Scientists have only a murky understanding of how to clear up these turbid waters.


IV. Science Policy

1. Experts Look for Early Successes from Paris Climate Accord

Although many current country pledges may be "unambitious" and "vague," one expert said the Paris agreement is just the first round in reducing emissions.

2.Geoscientists Visit Their Legislators on Capitol Hill

The American Geophysical Union's Congressional Visits Day acquaints members of Congress with the breadth of geophysical research being carried out in their districts and across the nation.


V. Climate Change

1. AOMIP and FAMOS for Enhancing Understanding of Arctic Changes

This community-based approach to modeling provides a unique forum for coordination, investigation, and synthesis.

2. El Niño Will Increase Atmospheric Carbon to Historic Levels

Tropical fires and drought-stricken ecosystems that normally serve as sinks will release carbon, contributing to high atmospheric concentrations through 2016 and beyond.

3. Focusing the Human Lens on Glacial Outburst Floods

To better prepare mountain communities for possible floods, experts say that it is important to understand the communities themselves.

4. Ocean Observatories Initiative Expands Coastal Ocean Research

OOI Coastal Arrays Community Workshop; Washington, D. C., 5–7 January 2016

5. Habitat Fragmentation Prevents Migration During Climate Change

East Coast species will face the most difficulty finding routes to cooler homes as climate change forces migration.


VI. Planetary Sciences

1. NASA’s Juno Spacecraft Set to Orbit Jupiter Starting 4 July

The spacecraft's titanium vault and a polar orbiting flight plan that avoids intense radiation regions around Jupiter's equator will help reduce damage to Juno's instruments.

2. Chasing Down the Slow Solar Wind

The Sun's plasma blasts Earth's magnetosphere at more than a million miles per hour. The fastest pours from holes in the corona, but until recently the source of the "slow" solar wind was a mystery.


VII.Ocean Sciences

1. Adapting Weather Forecasting Techniques to Paleoclimate Studies

First results of the Last Millennium Climate Reanalysis Project demonstrate the potential of the method to improve historical climate estimates by linking proxy data with climate models.

2. Predicting Temperature Shifts off the U.S. East Coast

New research reveals the relative importance of oceanic and atmospheric processes in year-to-year changes in ocean temperature along the Middle Atlantic Bight.


VIII.Earth and Space Science

1. Communicating the importance of our oceans

Every day is a celebration of something. National Ice Cream Day (17 July), Winnie the Pooh Day (18 January), and Celebrate those whose last names begin with Z day (yes, a real thing, 1 January), are just a few of the countless (unconventional) holidays that have been created over the years. Some more recognizable (environmental) ones are Earth Day (22 April), Arbor Day (last Friday in April), and Bike-to-Work Day (or at least for me as a bicyclist commuter, third Friday in May). A relatively new addition to this list is World Oceans Day. It was proposed in 1992 at the Earth Summit and officially recognized in 2008. 

2. New study questions source of rare Earth metals that provide clues to life’s origins

A new study is reviving a decades-old debate about how Earth’s rarest elements came to exist on our planet – theories that have implications for the origin of life.

Most scientists agree the precious metals – gold and the six platinum group elements – were added to Earth’s surface sometime after it formed 4.5 billion years ago. In the late 1980s, scientists debated how this happened. Some thought these elements were added to the Earth’s mantle and crust by countless asteroid impacts during the Late Heavy Bombardment 4 billion years ago, while others believed they came from the collision of Earth and Theia, a planetary body the size of Mars, which spawned our moon 20 million to 100 million years after the solar system’s formation.

3. The Expected Unexpected

Unrelenting questions that press for definitive, but elusive, answers are precisely the kind of questions that fuel Chief Scientist Joseph Montoya’s love for oceanography. He often goes to bed trying to solve the oceans’ latest riddle and wakes up the next morning knowing his mind was not idle. He might feel rested but is also full of new hypotheses.

4. Scientists shed light on electrostatic dust transport in reshaping airless planetary bodies

Researchers at the University of Colorado Boulder have conducted laboratory experiments that may bring closure to a long-standing issue of electrostatic dust transport, explaining a variety of unusual phenomena on the surfaces of airless planetary bodies, including observations of the moon from the Apollo era and the recent Rosetta mission to comet 67P.

5. Saturn moon Enceladus’ ice shell likely thinner than expected

A vast ocean of water beneath the icy crust of Saturn’s moon Enceladus may be more accessible than previously thought, according to new research. A new study has revealed that near the moon’s poles, the ice covering Enceladus could be just two kilometers (one mile) thick—the thinnest known ice shell of any ocean-covered moon. The discovery not only changes scientists’ understanding of Enceladus’ structure, but also makes the moon a more appealing target for future exploration, according to the study’s authors.


IX. Geophysical Research Letters

1. Impacts of the 2015-2016 El Niño on the California Current System: Early assessment and comparison to past events

The 2015-16 El Niño is by some measures one of the strongest on record, comparable to the 1982-83 and 1997-98 events that triggered widespread ecosystem change in the northeast Pacific. Here, we describe impacts of the 2015-16 El Niño on the California Current System (CCS) and place them in historical context using a regional ocean model and underwater glider observations. Impacts on the physical state of the CCS are weaker than expected based on tropical sea surface temperature anomalies; temperature and density fields reflect persistence of multi-year anomalies more than El Niño. While we anticipate El Niño-related impacts on spring/summer 2016 productivity to be similarly weak, their combination with pre-existing anomalous conditions likely means continued low phytoplankton biomass. This study highlights the need for regional metrics of El Niño's effects and demonstrates the potential to assess these effects before the upwelling season, when altered ecosystem functioning is most apparent.

2. Benthic marine calcifiers coexist with CaCO3-undersaturated seawater worldwide3

Ocean acidification and decreasing seawater saturation state with respect to calcium carbonate (CaCO3) minerals have raised concerns about the consequences to marine organisms that build CaCO3 structures. A large proportion of benthic marine calcifiers incorporate Mg2+ into their skeletons (Mg-calcite), which in general, reduces mineral stability. The relative vulnerability of some marine calcifiers to ocean acidification appears linked to the relative solubility of their shell or skeletal mineralogy, although some organisms have sophisticated mechanisms for constructing and maintaining their CaCO3structures causing deviation from this dependence. Nevertheless, few studies consider seawater saturation state with respect to the actual Mg-calcite mineralogy (ΩMg-x) of a species when evaluating the effect of ocean acidification on that species. Here, a global dataset of skeletal mole % MgCO3 of benthic calcifiers and in situ environmental conditions spanning a depth range of 0 m (subtidal/neritic) to 5600 m (abyssal) was assembled to calculate in situ ΩMg-x

3. Evidence of rising and poleward shift of storm surge in western North Pacific in recent decades

Recently, there has been considerable interest in examining how sea-level extremes due to storm surge may be related to climate change. Evidence of how storm-surge extremes have evolved since the start of the most recent warming of mid-1970s to early 1980s has not been firmly established however. Here we use 64 years (1950-2013) of observations and model simulations, and find evidence of a significant rise in the intensity as well as poleward-shifting of location of typhoon surges in the western North Pacific after 1980s. The rising and poleward-shifting trends are caused by the weakening of the steering flow in the tropics, which is related to climate warming, resulting in slower-moving and longer-lasting typhoons which had shifted northward. This article is protected by copyright. All rights reserved.

4. Discovery of a widespread low-latitude diurnal CO2 frost cycle on Mars

While the detection of CO2 ice has only been reported outside the Martian polar regions at very high elevation (i.e. Elysium, Olympus Mons, the Tharsis Montes), nighttime surface observations by the Mars Climate Sounder (MCS) onboard the Mars Reconnaissance Orbiter document the widespread occurrence of atmospherically-corrected ground temperatures consistent with the presence of extensive carbon dioxide frost deposits in the dusty low thermal inertia units at mid/low latitudes. Thermal infrared emissivities, interpreted in conjunction with mass balance modeling, suggest micrometer size CO2 ice crystals forming optically thin layers never exceeding a few hundreds of microns in thickness (i.e., 10-2 kg m-2) locally, which is insufficient to generate a measurable diurnal pressure cycle (<<0.1% of the Martian atmosphere). Atmospheric temperatures at mid/low latitudes are not consistent with precipitation of CO2 ice, suggesting that condensation occurs on the surface. 

5. Induced earthquake magnitudes are as large as (statistically) expected

A major question for the hazard posed by injection-induced seismicity is how large induced earthquakes can be. Are their maximum magnitudes determined by injection parameters, or by tectonics? Deterministic limits on induced earthquake magnitudes have been proposed based on the size of the reservoir or the volume of fluid injected. However, if induced earthquakes occur on tectonic faults oriented favorably with respect to the tectonic stress field, then they may be limited only by the regional tectonics and connectivity of the fault network. In this study, we show that the largest magnitudes observed at fluid injection sites are consistent with the sampling statistics of the Gutenberg-Richter distribution for tectonic earthquakes, assuming no upper magnitude bound. 


X. AUG Newsroom

1. PERMAFROST THAWING BELOW SHALLOW ARCTIC LAKES

Warmer winters combined with an increase in snowfall during the last 30 years have limited the growth of seasonal lake ice. In response, lakebed temperatures of Arctic lakes less than 1 meter (3 feet) deep have warmed by 2.4 degrees Celsius (4.3 degrees Fahrenheit) during the past three decades, and during five of the last seven years, the mean annual lakebed temperature has been above freezing.

2. “ELECTRIC WIND” CAN STRIP EARTH-LIKE PLANETS OF OCEANS AND ATMOSPHERES

Venus has an “electric wind” strong enough to remove the components of water from its upper atmosphere, which may have played a significant role in stripping Earth’s twin planet of its oceans, according to new results from the European Space Agency’s Venus Express mission by NASA-funded researchers.