AGU期刊一周Research Spotlight (March 3~ March 9, 2017)

发布时间:2017-3-10 8:49:28 点击次数:367

I. Atmospheric Sciences

1. A Two-Way Relationship Between the Atlantic and Pacific Oceans

Researchers have uncovered a new connection between sea surface temperatures in the Atlantic and tropical cyclones in the eastern Pacific that could improve accuracies of future cyclone forecasts.

II. Science Policy

1. Activists Set Out to Save Data, One Byte at a Time

Leaders of the DataRefuge movement hope that volunteer efforts across the country can stop government data from disappearing.

2. Critics Assail White House Proposal for Steep Cuts to EPA

Even EPA administrator Scott Pruitt, a longtime critic of the agency, said that he disagrees with the White House about some of the planned cuts.

3. Getting Down to Business: Committee Seats Set in 115th Congress

Appointments of a new chairman and two new ranking members may affect how key panels handle federal funding and oversight of the Earth and space sciences in the next 2 years.

4. Cities Smarten Up and Go Green

CIENS Urban Conference 2016: Smart and Green Cities – For Whom?; Oslo, Norway, 13 October 2016

III. Hydrology, Cryosphere & Earth Surface

1. Kilimanjaro's Iconic Snows Mapped in Three Dimensions

New ground-penetrating radar measurements reveal the thickness and total ice volume of the mountain's Northern Ice Field.

IV. Hazards & Disasters

1. Alteration Along the Alpine Fault Helps Build Seismic Strain

Detailed analysis of cores drilled through New Zealand's most dangerous on-land fault indicates that its permeability and strength are altered by mineral precipitation between seismic events.

V. Ocean Sciences

1. Scientists Develop New Tool to Monitor Reef Health

A first-of-its-kind system could reveal short-term changes in threatened reefs worldwide.

VI. Geophysical Research Letters

1. East Antarctic ice sheet most vulnerable to Weddell Sea warming

Models predict considerable spatial variability in the magnitude of future climate change around Antarctica, suggesting that some sectors of the continent may be more affected by these changes than others. Furthermore, the geometry of the bedrock topography underlying the East and West Antarctic ice sheets, together with regional differences in ice thickness, mean that certain ice drainage basins may respond more or less sensitively to environmental forcings. Here we use an ensemble of idealized climates to drive ice-sheet simulations that explore regional and continental-scale thresholds, allowing us to identify a hierarchy of catchment vulnerabilities based on differences in long-term catchment-averaged ice loss. Considering this hierarchy in the context of recent observations and climate scenarios forecast for 2100 CE, we conclude that the majority of future ice loss from East Antarctica, both this century and over subsequent millennia, will likely come from the Recovery subglacial basin in the eastern Weddell Sea.

2. Allochthonous sources and dynamic cycling of ocean dissolved organic carbon revealed by carbon isotopes

We present concentration and isotopic profiles of total, size, and polarity fractionated dissolved organic carbon (DOC) from Station ALOHA (A Long-term Oligotrophic Habitat Assessment), an oligotrophic site in the North Pacific Ocean. The data show that, between the surface and 3500 m, low molecular weight (LMW) hydrophilic DOC, LMW hydrophobic DOC, and high molecular weight (HMW) DOC constitute 22–33%, 45–52%, and 23–35% of DOC, respectively. LMW hydrophilic DOC is more isotopically depleted (δ13C of −23.9‰ to −31.5‰ and Δ14C of −304‰ to −795‰; mean age of 2850 to 15000 years) than the LMW hydrophobic DOC (δ13C of −22‰ to −23‰ and Δ14C of −270‰ to −568‰; 2470 to 6680 years) and HMW DOC (δ13C of ~−21‰ and Δ14C of −24‰ to −294‰; 135–2700 years). Our analyses suggest that a large fraction of DOC may be derived from allochthonous sources such as terrestrial and hydrothermal DOC and cycle on much longer time scales of >10000 years or enter the ocean as preaged carbon.

3. The influence of the Calbuco eruption on the 2015 Antarctic ozone hole in a fully coupled chemistry-climate model

Recent research has demonstrated that the concentrations of anthropogenic halocarbons have decreased in response to the worldwide phaseout of ozone depleting substances. Yet in 2015 the Antarctic ozone hole reached a historical record daily average size in October. Model simulations with specified dynamics and temperatures based on a reanalysis suggested that the record size was likely due to the eruption of Calbuco but did not allow for fully coupled dynamical or thermal feedbacks. We present simulations of the impact of the 2015 Calbuco eruption on the stratosphere using the Whole Atmosphere Community Climate Model with interactive dynamics and temperatures. Comparisons of the interactive and specified dynamics simulations indicate that chemical ozone depletion due to volcanic aerosols played a key role in establishing the record-sized ozone hole of October 2015. The analysis of an ensemble of interactive simulations with and without volcanic aerosols suggests that the forced response to the eruption of Calbuco was an increase in the size of the ozone hole by 4.5 × 106 km2.

4. Abiotic processes are insufficient for fertile island development: A 10-year artificial shrub experiment in a desert grassland

The relative importance of biotic and abiotic processes in the development of “fertile islands” in dryland systems has rarely been investigated. Here we approached this question by using artificial shrubs, which exclude plant litter production and soil nutrient uptake, but retain the functions of trapping windblown material, funneling of stemflow, and differential rain splash. We conducted a vegetation manipulation study more than a decade ago in the desert grassland of southern New Mexico and subsequently revisited the site in 2012 and 2015. The results show that no notable soil mounds were observed under the artificial shrubs; however, soil texture under the artificial shrubs has gradually changed to resemble the patterns of soil particle-size distribution under natural shrubs. Our results highlight that with the exclusion of direct biotic additions, soils captured by shrub canopies are not necessarily fertile and thus do not themselves contribute to the development of fertile islands.

5. Temperature- and pressure-dependent structural transformation of methane hydrates in salt environments

Understanding the stability of volatile species and their compounds under various surface and subsurface conditions is of great importance in gaining insights into the formation and evolution of planetary and satellite bodies. We report the experimental results of the temperature- and pressure-dependent structural transformation of methane hydrates in salt environments using in situ synchrotron X-ray powder diffraction, solid-state nuclear magnetic resonance, and Raman spectroscopy. We find that under pressurized and concentrated brine solutions methane hydrate forms a mixture of type I clathrate hydrate, ice, and hydrated salts. Under a low-pressure condition, however, the methane hydrates are decomposed through a rapid sublimation of water molecules from the surface of hydrate crystals, while NaCl • 2H2O undergoes a phase transition into a crystal growth of NaCl via the migration of salt ions. In ambient pressure conditions, the methane hydrate is fully decomposed in brine solutions at temperatures above 252 K, the eutectic point of NaCl • 2H2O.

6. Air-sea gas transfer in high Arctic fjords

In Arctic fjords and high-latitude seas, strong surface cooling dominates during a large part of the year, generating water-side convection (w* w) and enhanced turbulence in the water. These regions are key areas for the global carbon cycle; thus, a correct description of their air-sea gas exchange is crucial. CO2 data were measured via the eddy covariance technique in marine Arctic conditions and reveal that water-side convection has a major impact on the gas transfer velocity. This is observed even at wind speeds as high as 9 m s−1, where convective motions are generally thought to be suppressed by wind-driven turbulence. The enhanced air-sea transfer of CO2 caused by water-side convection nearly doubled the CO2 uptake; after scaled to open-sea conditions the contribution from w* w to the CO2 flux remained as high as 34%. This phenomenon is expected to be highly important for the total carbon uptake in marine Arctic areas.

7. Radiocarbon in dissolved organic and inorganic carbon of the Arctic Ocean

Dissolved organic carbon (DOC) in the ocean is thousands of 14C years old, yet a portion of the DOC cycles on much shorter time scales (days to decades). We present 14C measurements of DOC in the Arctic Ocean and estimate that ≥8% of the DOC in the deep Eurasian Basin contains bomb 14C. While this is a limited data set, there appears to be selective loss of modern DOC in the surface and halocline waters of the open Beaufort Sea versus the Beaufort slope. At one of the Beaufort Sea stations, there is a linear relationship between DOC Δ14C values and previously measured total hydrolysable amino acid concentrations as reported by Shen et al. (2012), indicating that deep DOC contains small amounts of bioavailable DOC. The 14C data show that not all of the deep DOC is recalcitrant.


1. New technique can improve particle warnings that protect astronauts

In a new study, scientists from NASA and the National Center for Atmospheric Research find the warning signs of one type of space weather event can be detected tens of minutes earlier than with current forecasting techniques – critical extra time that could help protect astronauts in space.

2. Study improves forecasts of summer Arctic sea ice

Each year, as sea ice starts to melt in the spring following its maximum wintertime extent, scientists still struggle to estimate exactly how much ice they expect will disappear through the melt season. Now, a new NASA forecasting model based on satellite measurements is allowing researchers to make better estimates.

3. Historic earthquakes discovered along San Andreas Fault

A new U.S. Geological Survey study offers a view into the past behavior of large earthquakes along the southern San Andreas Fault. In the study, USGS geologist Kate Scharer and her team excavated trenches across the fault near Frazier Mountain in northeastern Ventura County. This section of the San Andreas previously had no long paleoearthquake record. The researchers found evidence of 10 ground-rupturing earthquakes on this section of the fault between 800 A.D. and the last rupture in 1857.

4. What NOAA means to me, and how to “make it matter” to others

As the only Federal agency charged with water prediction and warning responsibilities, NOAA is uniquely positioned to address water challenges facing the nation – what does this mean, especially with a proposed reduced budget? And how/why should non-scientists care?

5. NOAA Turns Off GOES-16 Data For Broadcast Meteorologists

Many broadcast meteorologists have been looking at the non-operational GOES-16 (Formerly GOES-R) data that was posted by CIMMS at the University of Wisconsin. The data was amazing and it was handy to have, especially while doing training modules on using the imagery once it becomes operational.

6. Color Imagery from GOES-16 Today

More images from GOES-16 today. This is a geo-color image at 5-minute intervals. The new satellite has sensors that allow images in almost true color and it sends an image every 5 minutes vs 4 times per hour. Images every 3- seconds are possible as well. This is still non-operational test imagery. See my previous post with the first images from lighting mapper.

IX. AGU News


WASHINGTON, DC — A fault system that runs from San Diego to Los Angeles is capable of producing up to magnitude 7.3 earthquakes if the offshore segments rupture and a 7.4 if the southern onshore segment also ruptures, according to a new study led by Scripps Institution of Oceanography at the University of California San Diego.


Washington, DC— The American Geophysical Union (AGU) and Wiley today announced that GeoHealth, AGU’s newest open access journal, has published its first set of articles. The journal was created to support and foster collaboration between geoscientists, ecologists, and environmental and health professionals. GeoHealthfeatures original research, reviews, policy discussions, and commentaries that cover the growing intersection of Earth, atmospheric, oceans and environmental sciences, ecology, and the agricultural and health sciences. Researchers and contributors will discuss the impacts to, risks, and opportunities associated with human, agricultural, and ecological health and disease.